Note: Descriptions are shown in the official language in which they were submitted.
~0S~50~
~he pr~3nt invention provide3 a r~ew process
for the preparat~on of 8--alXyl-5~ 5 ~ dtbydropyr~do--
~ 2 ~ 3-d )pyri.midine-6-carbor~yl~c acids o~ the l~ormula ~ .
o
COOH
R~
in ~hich R i~ hydrogen, lower alkyl, lower alkoxy,
lo~Jer alkylmercapto, phenyl, ~ubstituted phenyl, ox a
radical o~ formula - ~ ~ wherein ~ and ~ , ta~en
separately~ each repre~ent lower alkyl or, taken
together, are bonded to one another to ~orm with the
nitro~en atom to which they are a~tached, a heterocyclic
nucleus with 5 or 6 riny atoms which i8 UnBUb8titUted
or substituted and which can contain anot~er hetero-
atom, such as pyrrolidino, piperidino, ~hydro~y-
piperid~no, morpholino, pi~erazino or N4-~ubstituted
piperazino, and R' iB lower alkyl. Fre~erred W~sub-
~tituted piperazino radicals are those o~ the formulat
: ~3-(C~ )n~~ ~
whexe n i~ 0, 1, 2, or 3~ and ~ iR l~ydrogen, hydroxyl,
vinyl~ phenyl, or phenyl substituted by halogen or
lo~er alkoxy, The term "lower alXyl" as used herein
mean~ an alkyl radical ~th 1 to 5 carbon atoms.
The compound~ of formNla I are valuable anti-
bacterial agent~, especially those in ~rhich ~ is
4-llydroxypiperidino, piperazino, or ~substituted
piperaz~no, which are new compounds.
q~ .
lOS~?S~
The proce~s o~ the invention for the production
o~ the aforesald compou~ds comprise9 ~
a) condensing a ~-chloro-5 carbethoxy-pyrLmidine
of ~ormula~
~ COO alkyl
/~ ~\ Cl
with a lower alkyl ~amino-propionate o~ formulas
R ' ~ CH2 -- CH2 -- COO allcyl
to form a 4_N~ carbalkoxyethylamino)-5-carbethoxy-
pyrimidine o~ formulat
~ ~ COO alkyl III
R I cn~cH2--coo alkyl
b) cyclising the compound of ~ormula III to ~orm
a 5-~oxo-6-carbalkoxy-5,6,7,8-tetrahydro-pyxido~2,3-d)-
pyrimidine of formula~
~b~ Co alkyl IV
R
R'
c) halogenating the ~-ket~-ester of formula IV
to yield the corresponding 6-halogeno derivat~ve~
d) treating the ~aid derivative with a base to
bring about dehydrohalogenatio~ to give a 6-carbalXoxy-
5-oxo-5~8-d$hyd~o-pyrido(2~3-d)pyrimidine o~ ~ormula~
:~ - 2 -
.
.. .
-
. ~ .
lOS9509
e) snd saponifying the compound of formula VI to
yield the desired ac~d o~ formula I.
me starting material in thi~ proce~ 18 a
4-chloro-5-carbethoxy-pyrimidine (II), conden~ation of
which with a lower alkyl (especially ethyl) ~-amino-
propionate, ~ub~tituted at the nitrogen by the radical
R~, leads to a 4-~ carbalkoxyethylamino)-5-carbethoxy-
pyrimidine (III). Cycli~ation of the latter, under the
- 10 effect of a (pxe~erably tertiary) alkali metal
alcoholate form~ a 5-o~co-6-carbalkoxy-5~6~7~8-tetrahydro-
pyrido(2,3-d)pyrimidine (IV). ~hen this ~-Xeto-ester
iB treated with a halogenatin~ agen~ such a~ bromine or
~ulphuryl chloride, it yields a derivative halogenated
in ~e 6-po~ition (V) ~Jhich i8 not i~olated and which~
~hen treated wlth an aliphatic tertiary base (for
; example triethylamine) or an aromati.c tertiary base
.; (8UCh as dimethylaniline) or a heterocyclic tertiary
base (sudh a~ pyridine and its methyl derivatives),
undergoes dehydrohalogenation leading to a 6-carbalkoxy-
5-o~-5,8-dihydro-pyrido(2~3-d)pyrimidine (VI),
~aponification of which yields the desired acid ~I).
These reactions may be represented a~ ~ollow~s
.~ .
~ _ 3 _
11)59~09
~ COOC2H5
R/~ 1~ Cl
~¦~R' N~CH2-CH2-COOC2H5
N~ COOC2H~;
~ C1~2--COOC2115 (III)
1,~
N~COOC2H5 ~IV~
.~ RJ~N~ ::
J, 2
COOC2~ (V)
.~ 1,
COOC2H5
0
, 1 :
" (VI)
;'''
1059509
In a modi~ication of thi~ proces~ useful for
preparing compounds in ~hich R iB ~ the ~tarting
material i~ 2,~-dichloro-5-carbethoxy-pyrimidine
(II, R - Cl), conden~ation o~ ~hich witll an
S N~su~b3tituted ethyl ~-aminopropionate gives 2-chloro-
~ carbethoxyethylamino-5-carbethoxy-pyrimidine (VII),
which can be used by one of two methods.
In the first methodS it i8 treated under hot
conditions ~tith a compound of formulas ~ R2, which
lead~ to a N2-substituted 2-amino~ -carbethoxyethyl-
amino-5-carb~thoxy-pyrimidine ~VIII), ~tl~ich, when
cycLised by an alkali ~lcoholate, preferably potassium
tertiary butylate, yields the N2-substi~uted 2-amino-
5-oxo-6-carbetlloxy-5~6~7~8-tetrahydr.opyrido(2~3-d)-
py~imidine (IX) which, according to the methods indicated
above~ leads, after halogenation ~ollo~Jed by dehydrc-
: halogenation, to an ester carrying an amine group in tha
2-position ~X)~ saponificati.on of which give3 the
corresponding acid.
In the second method, the 2-cl~oro-4-~-carbethoxy-
ethylamino-S-carbethoxy-pyrImidine (VII) is cyclised by
a tertiary alkali alcoholate, preferably potass~um
tertiary butylate ~o give a 2-chloro-5-o~o-6-carbethoxy-
; 5~6~7~8-tetrahydro-pyrido(2,3-d)pyrimidine (XI), the
halogenation followed by dehydrohalogenation of which
yiolds a N8-sub~tituted 2-chloro-6-carbethoxy-5-oxo-5,8-
dihydro-pyrido(2,3-d]pyrimidine (XII). The action of
- a compound of for.mula En ~ ~ (generally at ordinary
temperature) on the latter lead~ to an ester (X),
_ 5 _
.
~o59~9
saponificatlon of which yields an acid accordin~ to the
invention. The second method iR particularly valu~ble
when the radicals ~1 and ~ are sensitive to the
halogenation~ which leads to the ~ormation of by-product3
during the ~tage (IX) ~ (X).
These reaction~ may be repre~ented as followst
~COOC2H5
C~ C~OC2H5
,, ~ H2
/ (VII)
/ \ tert,C~ OK
~ O
~'q-OC2H5 ~OC~5
R2 ~ i 2 CC2~ ~ R
Rl
~VIII) (XI)
tert. 1) Br2 or
C4~ 0R ~ ~ ~ C12
. ,
~` .
. .
1 1059509 ~1,
o o
R~OOC2N
2 R'
t~X) / (xlI)
) Br2
O
Rl~ j~2il5
R2/ ~.t'
~ he condensation o the 4-chloro-5-carbethoxy-
pyrimid~ne~ (II) with the N~ubstituted ethyl ~-amlno-
propionate i8 carried out at ambiant t~mperature in aneutral solv~nt ~uch as an aromatic hydrocarbon ~benzene
or toluene) or a halogenated hydrocarbon (for example
chloro~onm or dichloroethane). Per mol of chloro-
pyrimidine~ either two mol~ of the aminc-a ter or one mol
o~ the lattex and one mol o~ a tertiary amine ~e.g.
triethylamine), used a~ an acceptor of the hydracid formed
in ~he reaction, are employed. After ~tanding for 2 to
10 hour~ the ~olution i8 f~ltered, wa3hed with water
and dried. Evaporation leaves the ester (ITI) or (VII)~
in an approximately theoretical yield, mo~t frequently
as an oil which i8 difficult ~o cry~talll~e and which
can bo u~ed directly for the following operation.
One mol of ester (III) or (VII), prefera~ly
dis~olved in an aroma~ia hydrocarbon (benzene or toluene),
, .
.
_ 7 _
.
. .................... , ~
- . . .
.
1059509
.
i8 added at ambient temp~rature to a ~olution of potas~i~m
tertiary butylate (1 mol) t prepared by dissolving 1 gram
atom of metal in anhydrous tertiary butanol The
pota~ium ~alt o the enolate of the ~-lceto-e~ter (IV)
or (Y~) precipitates ~rom the start o~ the addition.
After standing for at least two hours at am~ient
temperature, the mixture i9 taken up in ic~a water and
the agueou~ pha~e i8 ~eparat~d by decanting and acidified
with acetic acid ~1 mol) to cau~e precipitation of the
~-keto-e~ter which i9 ei~racted with a suitable solvent,
The organic solution i8 dried and then evaporated
; i~ ~35~uo~ the keto-e~ter (IV) or (XI) i5 purified by
racrystalli~ation. The yield i9 generally between 75
and 8~.
Fbr the halogenation~ the ester (IV~ IX or XI)
is di~solved (at a concentration o~, e.g., 10 to 20~)
in a suitable solvent ~uch as chloro~orm or acetic acid.
e solution i8 stirred and cooled e~ernally. On~ mol
o~ ~romlne, a~ a lZ~ solution in chloroform or acetic
acid~ i8 added dropwise, taXing care that the temperature
remains below 15C. A~ter ~tanding ~or 2 hours at
ordinary temperature~ he ~olvent is removed at a low
t~mperature (40C.) i~ vacuo. The residue i3 di~901VQd
; ~n 10 parts of chlorofonm~ the ~olution is cooled, and a
solution of 2.5 to 3 mol~ o~ a tertiary amine~ preferably
triethylamine~ i~ the same solvent, is added t~ it at a
t~nperature o~ bet~en 10 and 15C. A~ter contact (tw~
to ten hour~9 the solvent i9 evaporated ~ yacuo. m e
re~idue i8 taken up in water and the precipitate i~
.: . ~ . . . . . .
~59 509
~iltered f~ t washed until the triethylamine hydrobrom~de
ha~ been completely r~noved, and recrystallised from a
~uitablQ solvents me ~ields are generally between 75
and 8~X. When the halogena~ion i~ carried out in
chloroform~ it i8 po~sible to add the ~ertiary amine
directly, under the conditions de~cribed above, to the
solution resulting from the addition of bromine to the
~-keto-e~ter.
The halogenation can also be caxried out with
other reagents, especially sulphuryl chloride, The
reaction ls then preferably carried out in a chloroform
Rolution, The addition of sulphuryl cllloride to t~e
~olution o~ the ~-keto-ester in equimolar proportions
may be ca~ried out at 15-20C" and th~ reaction i9
lS com}iLeted at ambient temperature within a period of two
to four hours, 2.5 to 3 mol proportions of tr~ethyl-
amine or other tertiary amine are then added to the
301ution wh~ch i~ kept at 10-15C " and the dehydro-
halogenation reaction is allo~.~ed ~o continue for 4 to 12
hour~, The reaction product i9 isolated and purif~ed as
in t1te case whe~e the haloqenating ~sent i8 bramine,
The conaensation of the 2-chloro~
carbethoxyethyl_N~alkyl)amino-5_carbethoxy-pyrimldine
(VTI) with the compaund HNRl ~ in a molar ratio of lt2
iB carried out at 70-100C.~ in a neutral solvent with a
sui~a~l~ bo~ling point, e.g, benzene or toluene.
: Depending on the reactivity of the compcund HNRl ~ ~ the
heating period can be ~rom one to six hour3. Ater
cooling, the hydrochloride o~ the exce~3 compound
, g_ .:
, . .
. . .
~0595~)9
R2 which has precipitated~ i8 fil~ered off~ Evapora-
tion of the Qolv~nt gives the diestQr (VIII), either in
solid fonm (in which ca~e it i~ then purified hy
recrystallisation from a ~uitable solvent), or a~ an
S oil which cannot be cry~tallised and t~ich i~ u~ed
directly for the follo~ring ~tages. The cyclisation
with potassium tertiary butylate and the halogenation
and dehydrohalogenation o~ tha ~-keto-ester (IX) are
continued in accordance t~th the ~echniques de~cribed
above,
me conden~ation of 2-chloro-5-oxo-6-carbethoxy~
8-e~lyl-5~8-dihydro-pyrido(2~3-d)pyrimidine (XII) ~1 mol)
W~l the compound ~ ~ can be carried out either by
using an excQss of the lat~er, i.e. 2 to 2.S molar
proportions, a~ an acceptor for the hydracid formed in
the reaction~ or by ~nploying 1 molar proportion of the
compound ~ ~ and 1 ~o 1,5 molar proportion~ of a
tertiary amine, (for exam~le triethyla~ine), the latter
playing the role of acid acceptor. ~ne reaction can be
caxried out in an aror~atic hydrocarbon (e.g. benzene or
; toluene), a halogenated aliphatic hydrocaxbon (e.g.
chloroform or dichloroethane) or a lot~er alcohol ~e,g.
ethanol or isopropanol).
The compound ~ ~ ~ u3ed in excess, or its
mixture with the tertiaxy amine i~ added to the stirred
solution or suspension ~sually at 10 to 2~o concentration)
of the halogenated derivative. In the majority of cases~
the reaction i8 rapid and complete at ordinary temperature,
Where necessary~ it i9 completed by heating at 80-100C.
:'
: ;
., ,~ . . : - ~ ,
~()59 SQ 9
~or one to two hour~. After evaporating the ~olvent
Q, the residue i9 taken up in ~Jater and th~
precipitate is filtered Off and recry~talli~ed from a
suitable solvent.
However~ under these conditions~ it i~ not
practicable to obtain the ester~ (X~ wl~erein
R.
~N~ i8 a l-piperazino group ( ~ ~), by
reacting piperazine with the chlorinated derivative
(XII). In effect, in t~lis ca~e, no matter what the
exper~nental conditions may be, the two imine groups of
piperazine both react and a mixture of the mono-
substituted and disubstituted derivatives i~ obtained.
The de~ired mono-~ubstituted compound can however be
obtained by condensing a chlorinated derivative (XII)
sj 15 with 1-fonnyl-piperazine- a 2~ ormyl-piperaz~no)
derivative ~X, ~ R2N~ = ~IOCN ) i~ thus obtained,
which can then be defor~ylated, e.g. by treat~ent with a
solution of hydrogen chloride in ethanol, to give the
piperazino derivative
~ X~ E~LR2~ a }~
: The e~ters (VI) and (X) may be saponified~ most
fre~uently in an aqueous-alcoholic medium, with an alkali
metal hydroxide ~1.2-1.5 molar proportion~). At
ordinary temperature, the reaction is ~enerally complete
in one to three hour~. The excess ethanol is removed by
evaporation i~ vacuo at a low temperature, the residue is
. dissolved in water, and the solution i~ rendered slightly
:. ~
~ .os~509
acidic ~pH 3 to 6), The acid (I) usually precipitates:
it iB then filtered off? washed and recrystallised from
a suitable ~olvent. If, however9the acid (I) is soluble
in ~ater~ the solution is saturated wi1:h a ~3alt, e.g. by
S adding sodium chloride or sodium aceta~e~ and the acid
is extracted wnth a suitable solvent ~uch a~ for example~
chloroform. After evaporating the latter, the acid is
recry~tallised from a ~uitable ~olvent.
~ince certain compounds are sensitive to the
action of ~trong base~ the saponification can also be
carried out by heating the estQr~ under reflux with a
solution of an alkali metal carbonate. After cooling,
the acids are isolated as above.
The following Example3 illustrate the invention,
~XAMPLE I
5-0xo-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine-6-
car~oxylic acid
(I, R = H~ R' = C2H5)
15.2 g. of ethyl ~ethyl-~-aminopropionate are
added, with stirrin~, to a solution o~ 9.3 g. o~
~chloro-6-carbethoxy-pyrimidine in 75 cm of benzene.
After standing overnight at ambient temperature~ in the
absence of moisture (calcium chloride guard tube)~ the
precipitate o~ the amino-ester hydrochloride iQ filtered
off and the organic solu~ion is washed with water and
dried over Na2S0~ Evaporation of the solvent leave~
1~ g. of 4-~-carbethoxyethylamino-5-carbethoxy-pyrimidine
as an uncrystallisable oil.
This oil, di3so1ved in 100 cm3 of benzene, i8
- 12 -
;
.. , . . .
1(~S95~9
add~d with vigorouQ stirring to a 301ution o~ pota~ium
tertiary butylate prepared from 1,2 g. of pota~ium and
90 cm of tertiary butyl alcohol. The potas~ium derivative
of the reaction product precipitates. After ~tanding
overnight at ordinary temperature, the ma3s i~ taken up
in 300 cm3 of iced ~ater, the organic pha~e i9 isolated
by decanting and the aqueous phase is wa~hed with ether
and tl~en acidified with acetic acid t3 ~m3)! '~he
precipitate which has formed i~ filter~d off? wa~hed with
wa~er and then dissolved in chlorofo~m. After drying
over MgS04~ evaporation of the solvent leaves 10 g. of
5-o:~-6-carbethoxy-8-ethyl-5,6,7~8-tetrahydro-pyrido-
(2~3-d)pyrimidine which i9 purified by recrystallisation
~rom isopropyl ether~ melting point 12~C. (~OFL~R bench).
Analy~i8 for C12 ~5N303 (molecular weight 2~9)
Calculated % C 57.82 H 6.07 N 16.~6
Found % C 57.56 H 6.17 N 1~.95
6.25 g. of this ~-keto-ester are di~solved in
25 cm3 of chloroform. The solution i8 3tirred vigorously
and i8 cooled externally by a bath of iced water.
A golution of 4.1 g. of bromine in ~0 cm of chloroform
i8 added to it~ dropwise, over ~he course of about
30 minute3. When the addition is complete, the mixture
is left ~or one hour at ambient temperature.
The solution is concen~rated to dryness in vacuo
at ~0C. The residue is taken up in 20 cm3 of ethanol
and 5,4 am3 of triethylamine are added to the solution.
'~he mixture i~ heated under reflux for 30 minute3t the
sDlvent is removed in vacuo, the re~idue i3 taken up in
100 cm of water and ~he insoluble matter i~ extracted
- 13 -
... . . .
-. .
~059509
with chlorofonm (3 x 50 cm3). m e organic solution i8
dried (Na2S04) and decolouri~ed by means of anLmal charcoal.
Af~er evaporating the solvent, the re3idue i8 recrystallised
from a mixture of isopropyl ether and benzene. 5 g. of
5-o~o-6-carbethoxy-8-ethyl-5,8-dihydro~pyrido~2,3-d)-
pyrimidine are obtained. Melting point 136C.
Analysis for C12H13N303
Calculated % C 58.29 ~ 5.30 N 17.00
Found % C 58.26 ~I 5,21 N 17.11
0.6 g. o this ester and 10 cm3 o~ a l~h solution
o~ ~la2C03 are heated under reflux for 20 minutes. After
cooling, the solution is acidified by mean~ of acetic acid.
Ihe precipitate (0.5 g.) is filtered off and recrystallised
from water. 0.2 g. of S-oxo-8-ethyl-5,8-dihydro-pyrido-
~2~3-d)pyrimidine-6-car~oxylic acid i8 obtained, melting
point 225C, (decomposition).
Analy3iB for C10 ~ N303 (219-2)
Calculated % C 54.79 H ~.14 N 19.17
~ound % C 55.05 H 4,45 ~ 19.5
In this Example and in the EX3mples which follow the
acids were dried under vacuum (5 mn) at 150C prior to a~y
EX~MPL~ II
2-~ethylmercapto-5-oxo-8-ethyl-5,~-dihydro-pyrido(2,3-d)- -
. . --- -- - - -- -
pyrimidine-6-carboxylic acid
... . .. ..
~ ~ 7' -- Cs~
~5 `~' ~ ''3~' ~ 2 ~'
A solution of 23.2 g. of 2-methylmercapto-4-
chloro-S-carbethoxy-pyrimidine in 100 cm3 of anhydrous
benzene is stirred vigorou~ly and a solution of 29 g. of
ethyl N~ethyl-~-aminopropionate in 60 cm3 of the same
solvent i~ added ~o it. After standing overnight at
... . :.
. .
105~509
ambient temperature, the hydrochloride of the ester i~
filtered ~ff~ the solu~ion i3 washe~ with water, dried
and then concentrated to dryness and leaves 3.2 g. o~
crude 2-methylmercapto-4-~-carbethoxy-ethylamino-5-
carbethoxy-pyrimidine as a v~ SCOU8 oil which ~8 u~ed
directly for the following stage.
16.5 g~ of the crude diester, dis~olved in 80 cm3
of anhydrous benzene, are added, with stirring, to a
! solution of pota~sium tertiary butylate prepared from
10 2 g, of potassium and 150 cm3 of tertiary butyl alcohol
The potassium derivative o~ the cyclisation product
precipitates. After ~tanding overnight at ambient
temperature, the mass i~ taken up in 300 cm3 of water.
m e ~lightly cloudy aqueous phase is filtered, washed w~th
water and then acidified with 3 cm3 of acetic acid. ~he
pxecipitate is extracted with chloroform, the organic
solution is dried ovex ~a2S0~ the 301vent i8 evaporated
and the residue is recry3tallised from ethanol. 6.5 g.
of 2-methylmercapto-5-oxo-6-carbetho~y-8-ethyl-5,6,7,8-
tetrahydro-pyridot2,3-d)pyrimldine are obtainedf meltin~
point 157C.
Analysi8 ~or C13 ~ 7N303S (molecular weight 295.29)
Calculated % C 52.87 H 5.80 N 14.23
Found % C 52.84 H 5.65 ~ 1~.35
A solution of 3.7 g. o~ bromine in ~0 cm o
chloroform i8 added~ an described it~ E~ample I (duration
o~ the additions 15 minute~), to a ~olution of 6.3 g.
o~ the above ~-~eto-ester in 50 cm3 o~ chlorofonm. After
~tirring for 1 hour 30 minutes at ambient temperature~ the
. . . .
~ 15 -
;
,
~10595'3
xeaction product ~R i301ated as descriked in Example I,
It i~ di~solved in 40 cm3 of ethanol and 9 cm`3 of
triethylamine are added to it, m e mixtuxe i8 heated
under reflux ~or 30 minutes and the solvent i8 evaporated
S in vacuo. m e residu~ is taken up in 50 cm3 of water and
the insoluble matter is e~racted with 2 x 50 cm3 of
chloro~ormO The organic solution is dried over MgS04~
the ~olvent is evaporated and the reqidue i3 recry~tallised
~rom ~thanol. 4.5 g. (72%) o~ 2-methylmercapto_5-oxo-6-
carbethoxy-8-ethyl-pyrido(2,3-d)pyrir~dine are obtained~
melting point 1~8C.
ygi~ ~or C13 ~sN303S ( lecular weight 293,27)
Calculated % C 53.24 H S,16 ~ 14.33
Found % C 53.56 H 5.26 N 1~.23
1 g. of the above e~ter and 15 cm o~ a lo~ ;
strength solution of ~a2c03 are heated under reflux ~or
45 minutes. The ~olution is acidi~i~d with acetic acid.
m e precipitate is ~iltered off, ~ashed with water and
recry~tallised from dimethyl~ormamide. 0.4 g. of
2-methyl-mercapto-5-o~o-8-ethyl-5,~-dihydro-pyrido~2,3-d)-
pyr~nidine-6-carboxylic a~id i~ obtained. Mblting point
258C,
Analysi~ ~or Cll ~ lN303S (molecular weight 265,22)
Calculated % C 49.Bl H 4.18 N 15.84
Found % C 49.88 Il 4.41 N 16.42
E~L~ III
2-Pyrrolidino-5-oxo-8-ethyl~5~8-dihydro-~yrido(2~ 3-d ) -
pyrimidine-Ç-carboxylic;acid
~I, R = C4~ ~, R = C
- 16 _
:.
.. .. :
. - ~ . . . . ..
-, ., -
10595~9
A ~olution of 50 g. of 2~-dichloro-5-carbethoxy-
pyrimidine in 250 cm3 of ~enzene is stirxed and cooled
externally by mean~ of an ice bath~ A ~olution of 70 g~
of ethyl N~ethyl-~-2minopropionate disRolved in 70 cm3
S of benzene i8 added to it~ dropwi~e, and the addition iB
carried out at a rate such that the temperature of the
mixture remain~ betw~en 10 and 15C, (duration 1 hour to
1 hour 30 minutes). ~le reaction i~ continued for a
~uxther 3 hour~ at ordinary temperature.
Ethyl NLethyl~-ethylaminopropionate h~drochloride
i~ filtered off and the ~olvent is driven of~ in vacuo.
The residue is takenup in 200 cm3 of etller to remove a
small amount of hydrochloride. m e solution i9 filtered
and evaporated and 70 g. of 2-chloro-4-~-caxbethoxy-
ethylamino-5-carbethoxy-pyrimidine are obtained a3 a
viscou~ oil which i8 used directly for the ~ubsequent
opexations,
11 g. of 2-chloro-4-~-car~etho~ethylamino-5-
carbethoxy-pyrimidine, 4,7 g. of pyrrolidine and 75 cm3
of anhydrous benzene are heated under reflux for 6 hours.
After cooling, the solu~ion is filtered and concentrated
to dryne~s. m e oil obtained (11 g.)~ dis301ved in
; 75 cm3 o~ benzene, is added to a solution of potas~ium
tertiary butylate prepared ~rom 1.2 g. of potassium and
;: ~
50 om of tertiary butyl alcohol. After ~tanding over-
; night at ordinary temperature~ the mass is taken up in
200 ~m3 of iced water. m e aqueous phase is acidified
with 2.5 cm3 o~ acetic acid. The precipitate i8 extracted
,
; with chlor~form. After drying over ~a2S04~ the solvent is
- 17 -
.
.... - :: .. . .
1059509
evaporated and the residue i8 recryst~llised from i80-
propyl ether and yield~ 3 g, of 2-pyrrolidino-5-oxo-6-
car~ethoxy-8-ethyl-5,6,7,8-te~rahydro-pyrido[2,3-d)-
pyrimidine~ melting point 120C. :
AnalyBi~ for C16~ 2N~03 ~molecular w~ight 318.37)
Calculated % C 60.36 H 6.97 N 17.60
Fbund % C 60.12 H 7.26 ~ 17.68
A solution of 0.6 g. of bromine ln 5 cm3 o~ acetic
acid i~ added, with stirring and cooling, to 1.06 g. of
this ~-keto-eqter~ dis~olved in 10 cm3 of acetic acid.
After standing for 1 hour at ambient temperature~ the
~olvent i9 evaporated in vacuo at 40C. The residue is
dissolved in 10 cm3 of ethanol, 1.4 cm3 of triethylamine
: are added to the solution and the mixture i~ heated under
re~lux for 30 minutes. After evaporating the solvent~
the residue i~ taken up in 20 cm3 of w~ter and the
in~oluble matter i9 extxacted with chloroform, After
drying and evaporating the solvent~ recrystallisation of
:; the residue ~rom ethanol yields 0.76 g. (7~h) of
. .
. 20 2-pyrrolidino-5-oxo-6-car~etho~y-8-ethyl-5,8-dihydro-
; pyrido~2,3-d)pyrimidine~ melting point = 202C.
Analy8i8 for C16H20N403 (molecular ~eight 316.35)
Calculated % C 60.74 H 6.37 ~ 17.71
;. Found % C 60.39 H 6.17 N 17.53
; 0.9 g. of this ester and 20 cm of a l~h solution
of Na2C03 are heated under reflux for 3 hours. m e
reaction product iB isolated as described in Example II.
After recrystalli~ation from dimethylformamide~ 0~3? g.
jl
;i of 2-pyrrolidino-5-oxo-8-ethyl-5~8-dihydro-pyrido(2~3-d)-
: .
- 18 -
... .
.
,
~059509
'
pyrimidine-6-carboxylic acid i~ obtained~ melting point
314-316 C (Maquenne block)~
ysis for C14H16N~03 (molecular weight 288.3)
Calculated % C 58.32 H 5.59 N 19.44
Found % C 58.02 ~ 5.68 N 19.50
E~MPLE IV
2~ Hydroxy-piperidino) 5-oxo-8-ethyl-S,8 dihydro-
"
pyridot2,3-d)pyrimidine-6-carboxylic acid
(I~ R = ~ ~ , R; = C2~ )
In a 1 litre 3-necked flask equipped with a
mechanical stirrer, a dro~ping funnel and a thermometer~
a ~olu~ion of potasRium tcrtiary butylate is prepared
~rom 400 cm3 of the t~rtiary alcohol and 8 g of potassium
metal. mi8 solution is brought to 20C. and 66 g. of
2-chloro-4-~-carbethoxyethylamino-5-car~ethoxy-
pyrimidine are added to i~ and the mix~ure i8 stirred
at ordinary temperature for 2 hourss tlle pota3sium
derivative of the reaction product pr~cipitates. The
mis~.ture i5 poured into 200 cm3 of iced water and the
solution is brought to pH 3 by adding ~N hydrochloric
acid with stirring. m e precipitate i~ ~iltered off~
Wa5hed with water and recry~tallised ~rom 320 cm3 of
; isopropanol and yields 46 g. t81.2%) of 2-chloro-5-oxo-
6_carbethoxy-8-ethyl-5,6~7~8-tetrahydro-pyrido(2,3-d)-
pyrimidine; melting point 146C.
Analy8i~ for C12H14C1~33 tm~leCular weight 283-5)
Calculated % C 50.79 H 5.07 1~ 14.81 Cl 12.S0
Found % C 51.10 H 5.1~ 1~ 14.61 Cl 12.68
'~
-- 19 --
.
,
~0595U9
64 g. (0.22 mol) of the above ~ -keto-ester are
dissolved in 250 cm of chloroform. The solution is
cooled in a bath of iced water and a solution of bromine
(35.1 g., 0.44 gram atom) in 300 cm3 of chloroform is
added to it at a rate such that the temperature of the
reaction mixture remains between 10 and 15C., which
takes about 2 hours. The solution is stirred for a
further hour at ambient temperature, the solvent is
driven off in vacuo and the residue is taken up in
200 cm3 of anhydrous chloroform. The solution is
stirred in a bath of iced water and a solution of
triethylamine (50 g, 0.48 mol) in 100 cm of chloroform
is added to it, dropwise, at a rate such that the
temperature of the mixture remains between 15 and 10C.
(duration 2 hours).
!~ When the addition is complete, the solution is
i stirred for a further hour at 20C., the solvent is
, evaporated ln vacuo and the residue is taken up in 200
cm of water. The insoluble matter is extracted with
benzene and the organic solution is dried over MgS04.
Evaporation of the solvent leaves a residue
which, after recrystallisation from 450 cm3 of a mixture
of isopropyl ether (1 volume) and benzene (1 volume),
yields 50 g. (78.1%) of 2-chloro-5-oxo-6-carbethoxy-5,8-
, 25 dihydro-pyrido(2,3-d)pyrimidine; melting point 158C.
Analysis for C12H12ClN303 (molecular weight 281.5)
Calculated % C 51.15 H 4.26 N 14.91 Cl 12.61
Found % C 51.32 H 4.52 N 14.84 Cl 12.50
3.5 g. of 2-chloro-S-oxo-6-carbethoxy-8-ethyl-
.,, ~.
- 20 -
.~.. . , . ~
,:
lQS~SO9
pyrido(2,3-d)pyrimidine, dissolved in 15 cm3 of chloroform,
are cooled and stirred at -SC. 1.7 g. of sulphuryl
chloride, dissolved in 10 cm3 of anhydrous chloroform,
are added The cooling mixture is removed and the
solution is stirred at ordinary temperature for 2 hours.
It is again cooled to 5-10C., and a solution of 5 5 cm3
of triethylamine in 10 cm3 of chloroform is added to it,
dropwise, The mixture is left to stand overnight at
ambient temperature. The solvent is evaporated and the
residue is taken up in S0 cm3 of water. The precipitate
is filtered off, washed with water and dissolved in 50 cm3
of ethyl acetate. The solution is dried (MgSO4), the
solvent is evaporated and the residue is recrystallised
from a mixture of isopropyl ether and benzene. 2.2 g.
; 15 (63%) of 2-chloro-5-oxo-6-carbethoxy-8-ethyl-5,8-dihydro-
pyrido(2,3-d)pyrimidine are obtained; melting point
156C~ (identical to the product described above).
2.8 g. of 2-chloro-5-oxo-6-carbethoxy-8-ethyl-
5,8-dihydro-pyrido(2,3-d)pyrimidine and 2 g. of 4-hydroxy-
piperidine, dissolved in 35 cm3 of toluene, are heated
under reflux for 4 hours. After cooling, 20 cm3 of water
are added to the mixture; the organic phase is washed
again with water and dried over MgSO4; the solvent is
evaporated and the residue is recrystallised from ethanol
and yields 1.75 g. of 2-(4'-hydroxy-piperidino)-5-oxo-6-
carbethoxy-5,8-dihydro-pyrido(2,3-d)pyrimidine; melting
point 205C.
- 21 -
.. :.
~ ~059 5 09
Analysi8 for C17H22N~O~ (molecular weight 3~6.38)
Calculated % C 58.9~ H 6,~0 N 16.18
Found % C 59.00 H 6.30 N 16.12
1.75 g. of this e~ter are added to a ~olution of
sodium hydroxide (0 25 g.) in a mi~ure of alcohol ~30
crn ~ and water (2 cm ). The mixture is stirred for one
hour at ambient temperature~ the solvent is driven o~f
in vacuo and the residue is di~olved in 10 cm of water.
The solution i~ acidified by means of acetic acid. The
precipitate i9 filtered off, ~lashed with water and
recry~tallised from ethanol and yield~ 0.6 g. o~
2~ hydroxy-piperidino)-5-oxo-8-ethyl-5,8-dihydro-
pyrido(2,3-d)pyrimidin~-6-carbo~lic acid. Melting point
2~C
AnalyDi~ for C15H18N~0~ (molecular w~ight 318.33)
Calculated % C 56.5~ M 5.70 N 17.60
Found % C 56.37 H 5.95 ~ 17.~7
~qPLE V
2~ Methyl-piperazino)-5-oxo-5,8-diliydro-pyrido(2~3-d)-
pyrimidine-6-carboxylic acid
(I, R = H3C - ~ - ~ Rl = -C2H5)
8.~ g. (0.03 mol) of 2-chloro-5-oxo-6-carbethoxy-
8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine~ suspended ~ -
in 60 cm o~ ethanol~ are s~irred vigorously, ~ mixture
of 3.3 g. (0 03 mol) of l-methyl-piperazine and 3.3 g.
of triethylamine~ dissolved in 20 cm o~ ethanol, i~ added
rapidly. The chlorinated derivative dissolves with
evolution of heat. After stirring for 2 hours at æmbient
- 22 -
'
.
~059509
t~mperature, the solvent i9 driven off in vacuo, the
residue iQ taken up in 50 om of a saturated solution of
Na2C03 and the mixture is extracted ~ith chloroform.
A~ter drying tNa2SO~) and evaporation, the re~idue
(9.5 g.) is recryqtallised from 100 cm3 o~ a mixtuxe of
isopropyl ether (1 volume) and benzene (1 volume) and
yields 8.5 g. (85%) o~ 2~ methyl-piperazino)-5-oxo-6-
carbethoxy-8-ethyl-pyrido(2,3-d)pyrimidine which melts
in t~o stage3: 146C. and ~hen 158C.
Analy~i~ for C17H23N503 ~rnolecular weiyht 3~5,39)
Calculated % C 59.11 H 6.71 ~ 20.28
Found % C 59,23 H 6,68 N 20,42
25.3 g, of this ester (0,075 mol) are ~tirred
with 100 cm3 o~ ~ NaOH ~olution. The ~olution is heated
to 50-60C., to dissolve the ester and then the
saponification i8 completed at ambient temperature over
the course of 2 hours. rL~he solution is brought to pH 6
~nth acetic acid, After ~aturating t~e mixture with
sodium acetate, the solution is e;~racted with 4 x 50
cm3 of chloro~orm.
The combined chhoroform extracts axe dried over
MgSO~ the solvent is e~aporated and th~ residue is
recrystalli~ed from a mixture of ethano~ (500 cm3) and
dime~hylfonmamide (100 cm3)3 14,5 g. of acid are thu~
obtained. On concentrating the crystallisation mother
liquors to 1/3 of their volume, a further 1.5 g~ of
product are obtained, corresponding to a total yield of
16 g. (7~h). 2-(4~-Methyl-piperazino)-5-oxo-8-ethyl-5~8
dihydro-pyrido(2,3-d)pyrimidine~6-carbo ~lic acid melt~
- 23 -
. ., . :
1~35~g ::
227C.
Analysis for C15HlgN503 (molecular weight 317. 34)
Calculated ~ C 56.77 H 6.04 N 22.07
Found % C 56.69 H.6.23 N 22.35
S EXAMPLE VI
2-(4-~-Hydroxyethyl-p perazino)-5-oxo-8-ethyl-5,8-dihydro-
E~rido(2~3-d)p~rimidine--6-carboxylic acid
(I, R = HOCH2-CH2-N ~ , 2 5)
5.6 g. of 2-chloro-5-oxo-6-carbethoxy-8-ethyl-5,8-
dihydro-pyrido(2,3-d)pyrimidine, 5.2 g. of l-~-hydroxy-
; ethyl piperazine and 50 cm3 of toluene are heated under
reflux for 2 hours. After cooling, the solution is
; filtered to remove the hydrochloride which has precipi-
tated, and the organic solution is diluted with its own
volume of chloroform, is washed with water and dried
~MgSO4). After evapoxation, the residue is recrystallised
from 40 cm3 of a mixture of isopropanol ~1 volume) and
isopropyl ether (2 volumes). 5.14 g. (68~) of 2-(4'-~-
hydroxyethyl-piperazino)-5-oxo-6-carbethoxy-8-ethyl-
pyrido~2,3-d)pyrimidine are obtained; melting point 172C.
Analysis for C18H25N5O4 (molecular weight 375.42)
Calculated ~ C 57.58 H 6.71 N 18.60
Found % C 57.53 H 6.57 N 18.80
5.14 g. of the ester are added to an aqueous-
; 25 alcoholic solution of sodium hydroxide (N NaOH: 15 cm3,
ethanol: 10 cm3); the mixture is stirred for 2 hours
at ordinary temperature and is then brought to pH 6 by
adding acetic acid. After concentration to dryness
- 24 -
.
,, .~
~ ' .
10595~
in vacuo, the residue i~ taken up in a saturated solution
o~ 30dium acetat~ lS0 cm3) and i8 extract~d with chloro-
~orm ~3 x 50 cm3). Af~-er dryiny (MgS0~), the solvent
- i~ evaporated and th~ residue i~ recry~tal1ised from
S 80 cm of ethanol. 2.4 g, (53.3%) of 2-~ hydroxy-
ethyl-piperazino)-5-oxo-8~ethyl-5,8-dihydro-pyrido-
~2,3-d)pyrimidin~_6-carboxylic acid ar~ obtained~
melting point 222C.
y 8 for C16~ 1N50~ (mol~cular weigiht 347.37)
Calculated % C 55.32 H 6.09 N 20.16
Found % C 5~.96 ~ 6.0~ N 19.92
E~LE VII
2~ enzyl-piperazino)-5-oxo-8-ethyl-5 ~ dihydro-
pyrido~2,3-d)pyrimidine-6-carbo~lic acid
( ~ R 6Hs CH2 ~ Rl a ~2Hs )
As described in ~cample VI~ a mixturQ of 5.6 g.
of 2-chloro-5-o~o-6-car~ethoxy-~-ethyl-5~8-dihydro-
pyrido(2,3-d)pyrimidine, 7.04 g. of ,~benzylpiperazine
and 80 cm3 of toluene i~ ~eated under reflux for 2 hours.
After cooling, the mass i8 diluted wi~ll 100 cm of
chloroform and i8 taken up in 200 cm3 of water, After
a~hing the organic phase with ~tater~ the reaction product
i8 isolated as de~cribed in the Example mentioned. It i8
recrystalli~ed from isopropanol, 7,6 g. (9~h) of
,~ 25 2-~4'-benzyl-piperazino)-5-oxo-6-carbethoxy-8-ethyl-5,8-
; dihydro-pyrido(2~3-d)pyrimidine are obtained~ melting
point 152C.
-- 25 --
,, ,
lVS950~
Analysis for C23H27N503 ~molecular weight 421 49)
Calculated % C 65.54 H 6.46 N 16.62
Found % C 66.03 H 6.44 N 16.97
Saponification of 9.5 g of this ester with an
aqueous-alcoholic solution of sodium hydroxide (N NaOH,
15 cm3 + water, 30 cm3 + ethanol, 30 cm3) is complete
in one hour at ordinary temperature. After acidification,
the precipitate is filtered off and recrystallised from
160 cm3 of a mixture of dimethylformamide (1 volume) and
ethanol (1 volume). 6.8 g. of 2-(4'-benzyl-piperazino)-
5-oxo-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine-6-
car~oxylic acid are obtained; melting point 207C
Analysis for C21H23N5O3 (molecular weight 293.43)
Calculated ~ C 64.11 H 5.89 N 17.80
Found % C 64.42 H 6.03 N 17.79
EXAMPLE VIII
2-Piperazino-5-oxo-8-ethyl-5,8-dihydro-pyrido(2,3-d)-
~yrimidine-6-carboxylic acid
(I, R = H ~ - , R~ = C2H5)
A mixture of 8.4 g of 2-chloro-5-oxo-6-carb-
ethoxy-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine,
5.9 g of formylpiperazine and 160 cm3 of chloroform is
heated under reflux for one hour. After cooling, the
solution is washed with water and dried and the solvent
is evaporated. The oily residue crystallises on being
taken up in 100 cm3 of isopropyl ether. The solid is
filtered off and recrystallised from 50 cm3 of ethanol
and yields 8.9 g (82%) of 2-(4'-formylpiperazino)-5-oxo-6-
, :
- 26 -
. . .: .
lOS~3~09
carbethoxy-8-ethyl-598-dihydro-pyrido~2,3-d)pyrimidine
which melts in two stage~; melting point 195C, ~olidifi-
cation, followed by m.p. 20~C,
Analysi~ for C H N 0 (molecular weight 35~.38
17 21 5 ~
Calculated % C 56.81 H 5.89 ~ 19.49
Found ~ C 56.97 H 5.95 1~ 19.58
3.6 g of the above formyl derivative are ~uspended
in 25 cm3 of a 5% ~trength ~olution of ~ICl in alcohol,
After gentle heating (at ~0-50C) to facilitate dis-
solution ~ the mixture i~ left to stand for 8 hours at
ordinar~ temperature, The dihydrochloride of the deformy-
lated derivative precipitates. After being taken in 100 cm3
of ether~ it i~ filtered off and ~uspended in 40 cm3 of
water and the mixture~ having been rendered alkaline ky
adding Na2C03~ is extracted ~ith chloroform. After
; evaporating the so~vent, the product i8 recrystallised
from ~0 cm3 of a mixture of isopropyl ether (1 volume) and
benzene (1 volume). 2.8 g (8~%) of 2-piperazino-5-oxo-6-
carbethoxy-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine are
o,btained; melting point 155C.
,,, Analy8i~ for C16H21N53 (molecular weight 331-37)
Calculated % C 57.99 H 6.39 ~J 21,14
Found % C 57.98 ~ 6.23 1~ 21.39
Saponification of this e~ter (3,3 g) with 30 cm3 of
N/3 aqueous sodium hydroxide solution is camplete in 2
hours at ordinary temperature. After acidification (pH
about 6) with acetic acid, the precipitate i~ filtered off,
wa3hed with water and recry~tallised from 60 cm3 of a
, mixture of dimethylformamide (1 volume) and ethanol ~1
- 27 -
. .
.~ .
lQ59509
volume). 1.8 g of 2-piperazino-5-oxo-8-e~hyl-5,8-dihydro-
pyrido(2,3-d)pyrimidine-6-carboxylic acid are obtained;
melting point 264C.
Analy3i9 for C14H171~503 (molecular weight 303.32)
Calcula~ed % C 55.~3 H 5.65 1~ 23.09
Found % C 55.68 H 5.67 N 23.25
EXAMPLE IX
2-(4 ~ -PhenYl-~ipe~--azi-n- ? - 5-oxo- $~8-dihYdro-~vrido~2,3-d~-
p~rimidine-6-carboxYlic acid
(I, R C6 5 N ~ - , ~ = C2H5)
A solution of 3.2 g (O 02 mol) of N~phenyl-piperazine
in 30 cm3 of toluene i8 added to 2.8 g (0.01 mol) of 2-
chloro-5-oxo-6-car~etho~y-8-ethyl-5,8-dihydro-pyrido~2,3-d~
pyrimidine di~olved in 30 cm3 of toluene. Reaction takes
place practically instantaneously with evolution of heat
and the mixture sets ~olid due to formation of phenyl-
piperazine hydrochloride. me mixture i8 diluted with
100 cm3 of ethyl acetate, the solu~ion i~ filtered, washed
with water and dried (MgS04) and the solvent is evaporated.
The re3idue i~ recry~tallised from 110 cm3 of isopropanol
and yield~ 3 38 g (84%) of 2-(4'-phenyl-piperazino)-5-oxo-
6-carbetho~y-8-ethyl-5,8-dihydro-~yrido~2,3-d)pyrimidine;
melting point 186C.
Analv~is for C 2~2 ~53 (molecular weight ~07.~6)
2 5
Calculated % C 64.85 H 6.18 ~ 17.19
Found % C 64.97 H 6.0~3 N 16.7~
When 2 g o~ this e~ter are saponified as indicated
in Examl~le VIII, they yield, after acidification and
- 28 - -
l~)59S09
recrystallisation of the precipitate from 90 cm3 of a
mixture of dimethylformamide (1 volume) and ethanol (1
volume), 1.4 g ~77%) of 2-(4'-phenyl-piperazino)-5-oxo-5,8-
dihydro-pyrido(2,3-d)pyrimidine-6-carboxylic acid;
melting point 249C.
Analysis for C20H21Ns3 (molecular weight 379.41)
Calculated % C 63.31 H 5.58 N 18.46
Found % C 63.49 H 5.71 N 18.36
EXAMPLE X
2-(4'-Methyl-piperazino)-5-oxo-8-methyl-5,8-dihy~dro-
pyrido-(2,3-d)pyrimidine-6-carboxylic acid
Il, R - CH3 - ~ - , R = CH3)
26.2 g of ethyl N-methyl-~-aminopropionate,
dissolved in 150 cm3 of benzene, are added dropwise to
a solution, which is stirred and cooled to between 10
and 15C, of 22 g of 2,4-dichloro-carbethoxypyrimidine
in 150 cm3 of the same solvent. After standing over-
night, the solvent is evaporated in vacuo and the
residue is taken up in water tlOO cm3) and extracted
with ether. The organic solution is washed with water,
dried (MgS04) and evaporated. The residue is recrystall-
ised from 60 cm3 of hexane and yields 25 g (80%) of
2-chloro-4-(N-~-carbethoxyethyl-N-methyl)amino-5-carbo-
ethoxy-pyrimidine; melting point 60C.
Analysis for C13H18ClN304 (molecular weight 315.5)
Calculated % C 49.45 H 5.74 N 13.31
Found % C 49.80 H 6.07 N 13.21
A solution of 10.5 g of this diester in 100 cm3
. , .
. ' .
105~5~9
of benzene is added, with stlrring and in the absence of
moisture, to a solution of potassium tertiary butylate
prepared from 1.4 g of potassium metal and 80 cm3 of
tertiary butanol. The potassium derivative of the
5 reaction product precipitates in the medium, which sets
solid. After 2 hours at ordinary temperature, 2.5 cm3
of acetic acid followed by 300 cm of iced water are
added, with stirring, The benzene phase is isolated by
decanting, washed with water and dried (MgSO4) and the
10 solvent is evaporated. The residue is recrystallised
from benzene and yields 5.7 g (63%) of 2-chloro-5-oxo-
6-carbethoxy-8 methyl-5,6,7,8-tetrahydro-pyrid~ (2,3-d)-
pyrimidine; melting point 175C,
Analysis for CllH12ClN3O3 (molecular weight 269.68)
Calculated % C 48.98 H 4.48 N 15.58 Cl 13.14
. .
Found % C 49.00 H 4.70 N 15,34 C1 13,10
A solution of 14 g of this ~-keto-ester,
dissolved in 100 cm3 of chloroform, is qtirred and cooled
to 10C. A solution of 2.8 cm3 of bromine in 100 cm3 of
20 chloroform is added to it, dropwise, at a rate such
that the temperature of the reaction mixture remains
between 10 and 15C. The solution is left to stand at
ambient temperature for one hour and is again cooled to
10C, and a solution of triethylamine (16 cm3) in
25 chloroform (100 cm3) is added to it dropwise.
After standing overnight at ordinary temperature,
the solvent is removed in vacuo at 40C. The residue
is taken up in water (100 cm3), filtered off, washed to
. remove the triethylamine hydrobromide and dissolved again
-- 30 --
1059509
in chloroform (100 cm3); the solution is dried (MgSO4),
the solvent is evaporated and the residue is recrystallised
from a mixture of isopropyl ether and benzene. 9.16 g
(65.5~) of 2-chloro-5-oxo-6-carbethoxy-8-methyl-5,8-
dihydro-pyrido(2,3-d)pyrimidine are obtained; melting
point 205C,
Analysis for Cl1HloClN3O3 ~molecular weight 267.67)
Calculated % C 49.34 H 3.76 N 15.69 Cl 13.24
Found % C 49.42 H 3.95 N 15.46 Cl 13.02
1.5 g of N-methylpiperazine are added to a
stirred suspension of 2 g of 2-chloro-5-oxo-6-carbethoxy-8-
methyl-5,8-dihydro-pyrido(2,3-d)pyrimidine in 20 cm3 of
absolute ethanol. The reaction takes place with
evolution of heat. After standing for 2 hours at room
temperature, the solvent is evaporated in vacuo, the
residue is taken up in water and the precipitate is
filtered off, washed, dried in vacuo and recrystallised
from benzene: 1.4 g (58~) of 2-(4'-methyl-piperazino)-
5-oxo-6-carbethoxy-8-methyl-5,8-dihydro-pyrido(2,3-d)-
pyrimidine are obtained.y 16H21N5O3 (molecular weight 331.37)
Calculated ~ C 57.99 H 6.39 N 21.14
Found ~ C 58,50 H 6.22 N 21.37
1.1 g of this ester are saponified by stirring
for 2 hours at ordinary temperature in an aqueous-
alcoholic solution of sodium hydroxide (NaOH 0.15 g,
water 2 cm3, ethanol 5 cm3). The solvents are
evaporated at 40C in vacuo, the residue is taken up
in 20 cm3 of water and the solution is acidified
- 31 -
.~ .
1059509
with acetic acid and then extracted with chloroform.
Evaporation of the solvent leaves a residue which, after
- recrystallisation from a mixture of alcohol and dimethyl-
formamide, yields 0.5 g of 2-~4'-methyl-piperazino)-5-oxo-
8-methyl-5,8-dihydro-pyrido(2,3-d)pyrimidine-6-carboxylic
acid; melting point 280C.
Analysis for C14H17N5O3 (molecular weight 303.32)
Calculated % C 55.43 H 5.65 N 23.09
Found % C 55.25 H 5.67 N 23.24
EXAMPLE XI
2-(4'-~-HvdroxYethyl-piperazino)-5-oxo-8-methyl-5,~-
dihydropyrido(2~3-d)pyrimidine-6-carboxylic acid.
(I, R = HOCH2 - CH2 - ~ - , R' = CH3)
; As described in Example X, reaction of N-~-
hydroxyethyl-piperazine (2.1 g) with a suspension of 2 g
of 2-chloro-5-oxo-6-carbethoxy-8-methyl-5,8-dihydro-pyrido-
(2,3-d)pyrimidine in 20 cm3 of ethanol (for 2 hours at
ordinary temperature) yields, after evaporation of the
solvent, a residue which is recrystallised from water,
2.14 g of 2-~4-~-hydroxyethyl-piperazino)-5-oxo-6-carb-
ethoxy-8-methyl-5,8-dihydro-pyrido(2,3-d)pyrimidine
dihydrate are obtained; it has two melting points:
melting point 160C, solidification, followed by
melting point 170C.
Analy_ s for C H~ N O . 2 H2O (molecular weight
17 ~3 5 4
397.43)
Calculated % C 51.37 H 6.85 N 17.62
Found ~ C 51.60 H 6.53 N 18.01
- 32 -
,
,~ ~ ,, .
~059509
1 94 g of this ester are saponified for 2 hours at
ordinary temperature (NaOH 0.25 g, water 5 cm , ethanol
10 cm3). After evaporating the solvent ln vacuo, the
residue is taken up in 20 cm of water and the solution
is brought to pH 6 by adding acetic acid. The precipitate
is filtered off, washed with water and recrystallised
from a mixture of ethanol (1 volume) and dimethylformamide
(2 volumes). 1.25 g of 2- (4,~-hydroxyethyl-piperazino)-5-
oxo-8-methyl-5,8-dihydro-pyrido(2,3-d) pyrimidine-6-
carboxylic acid are obtained; melting point 245CAnalysis for ClsH1sN504 (molecular weight 333.34)
Calculated % C 54.04 H 5.75 N 21.01
Found ~ C 54.14 H 5.88 N 21.21
EXAMPLE XII
2-(4'-Ethyl-piperazino)-5-oxo-8-ethyl-5,8-dihydro-pyrido-
(2~3-d)pyrimidine-6-carboxylic acid.
(I, R - H5C2 ~ ~ ~ ~ R' = C2H5)
3.8 g of 2-chloro-5-oxo-6-carbethoxy-8-ethyl-5,8-
dihydro-pyrido(2,3-d)pyrimidine and 2.9 g of l-ethyl-
piperazine, dissolved in 50 cm3 of chloroform, are heated
under refl~x for 2 hours. After cooling, the organic
solution is washed with water and dried over MgS04;
the solvent is evaporated and the residue is recrystallised
from a mixture of isopropyl ether (15 cm3~ and benzene
(25 cm3) and gives 4.4 g (yield: 93%) of 2-(4'-ethyl-
piperazino)-5-oxo-8-ethyl-6-carbethoxy-5,8-dihydro-pyrido-
(2,3-d)pyrimidine; melting point 161C.
.
- 33 -
~ :. : ,. - - -
~ os~so~
Analysis for C18H25N5O3 (359.42)
Calculated ~ C 60.15 H 7.01 N 19.49
; Found ~ C 60.22 H 6.81 N 19.66
Saponification of this ester (3.6 g) with a
2N solution of sodium hydroxide in alcohol, at ordinary
temperature, yields, after the treatments described in
the preceding examples, 2 23 g (67%) of 2-(4'-ethyl-
piperazino)-5-oxo-8-ethyl-5,8-dihydro-pyrido(2,3-d)-
pyrimidine-6-carboxylic acid; melting point 229C,
after recrystallisation from a mixture of ethanol ~1
volume) and dimethylformamide (1 volume).
Analysis for C16H21N53 (molecular weight 331.37)
Calculated % C 57.99 H 6.39 N 21.14
Fou~d % C 58.27 H 6.39 N 21.14
EXAMPLE XIII
2-~4'-Propyl-piperazino)-5-oxo-8-ethyl-5,8-dihydro-pyrid
(2,3-d)pyrimidine-6-carboxylic acid.
(I, R = (n) C3H7 - N ~ - , R C2 5)
As described in Example XII, the condensation of
2.8 g of 2-chloro-5-oxo-6-carbethoxy-8-ethyl-5,8-dihydro-
pyrido(2,3-d)pyrimidine with 2.2 g of l-propyl-piperazine,
in chloroform (40 cm3) gives, after the treatments
described in Example XII, 3.14 g of 2-(4'-propyl-
piperazino)-5-oxo-6-carbethoxy-8-ethyl-5,g-dihydro-pyrido-
; 25 (2,3-d)pyrimidine (yield 84%); melting point 149C,
after recrystallisation from ethyl acetate.
Analysis for ClgH27NsO3 (molecular weight 373.45)
Calculated % C 61.10 H 7.29 N 18.75
Found % C 61.50 H 7.22 N 18.91
`:~;
- 34 -
,
:` ~
~r
.,:. . , ~ .
~oS9509
Saponification of this ester (2 g) as indicated in
the preceding examples, yields, after recrystallisation
from a mixture of ethanol ~1 volume) and dimethylformamide
(2 volumes), 1,32 ~ (71%) of 2-(4'propyl-piperazino)-5-
oxo-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine-6-
carboyxlic acid: melting point 226C.
Analysis for C17H23N5O3 (molecular weight 345.39)
Calculated % C 59.11 H 6.71 N 20.28
Found 4 C 58,75 H 6,73 N 20.00
EXAMPLE XIV
2-(4'-Allyl-piperazino)-5-oxo-8-ethyl-5,8-dihydro-pyrido-
(2,3-d)pyrimidine-6-carboxylic acid.
(I, R z H2C=CH-CH2- ~ - , R C2H5)
.:
2-(4'-Allyl-piperazino)-5-oxo-6-carbethoxy-8-
ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine is prepared,
~' in a yield of 79%, by condensing 2-chloro-5-oxo-6-carb-
ethoxy-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine with
l-allyl-piperazine, as indicated in the preceding
Examples. It is a solid which melts in two stages;
melting point 131C, solidification, followed by melting
point 143C [after recrystallisation from a mixture of
benzene (1 volume) and isopropyl ether (1 volume)].
Analysis for ClgH N O3 (molecular weight 371.43)
25 5
Calculated % C 61.44 H 6.78 N 18.86
Found % C 61.10 H 6.75 N 18.75
Saponification of this ester with a 2 N solution
of sodium hydroxide in alcohol gives 2-(4'-allyl-
piperazino)-5-oxo-8-ethyl-5,8-dihydro-pyrido(2,3-d)-
- pyrimidine-6-carboxylic acid. When recrystallised from
~" .
- 35 -
.''. ' .
~' :
iossso9
a mixture of ethanol (2 volumes) and dimethylfor~amide
(1 volume), it is o~tained in a yield of 64%; melting
point 203C.
AnalysiS for C17H21N53 (molecular weight 343.38)
Ca~culated ~ C 59.46 H 6.16 N 20.40
Found % C 59.47 H 5.98 N 20.38
EXAMPLE XV
2-(4'-p-Chlorobenzyl-piperazino)-5-oxo-8-ethyl-5,8-
dihydro-pyrido(2,3-d)pyrimidine-6-carboxylic acid.
(I, R = Cl ~ CH2 - ~ _ , R = C2H5)
Condensation of l-p-chlorobenzyl-piperazine with
2-chloro-5-oxo-6-carbethoxy-8-ethyl-5,8-dihydro-pyrido-
(2,3-d)pyrimidine, as de~cribed in Example VII, gives, in
a yield of 74%, 2-(4'-p-chlorobenzyl-piperazino)-5-oxo-6-
carbethoxy-8-ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine;
melting point 150C, after recrystallisation from ethyl
acetate.
Analysis for C23H26ClN5O3 (molecular weight 455.5)
Calculated % C 60.59 H 5.70 N 15.36 Cl 7.79
Found % C 60.29 H 5.72 N 15.38 Cl 7.76
Saponification of this ester gives the carrespond-
ing acid; melting point 216C, when purified by
recrystallisation from dimethylformamide (yield 68%).
Analysis for C21H22ClN5O3 (molecular weight 427.5)
Calculated % C 58.94 H 5.14 N 16.37 Cl 8.30
Found % C 58.88 H 5.15 N 16.42 Cl 8.40
:
- 36 -
.
- ,: ~ : . :.. ,
.
so9
EXAMPLE XVI
2-~4'-p-Methoxybenzyl-piperaZinO)-5-oxo-8-ethYl-5,8 d~
hydro-pyrido~2,3-d)pyrimidine-6-carboxylic acld.
(I, ~ = CH3-0 ~ CH2 ~ ~ ' C2 5)
By condensing 2-chloro-5-oxo-6-carbethox~-~-ethyl-
5,8-dihydro-pyrido(2,3-d)pyrimidine with l-p-methoxybenzyl-
piperazine, follo~ing the procedure described in Example
VII, 2-(p-methoxybenzyl-piperazino)-5-oxo-6-carbethoxy-8-
ethyl-5,8-dihydro-pyrido(2,3-d)pyrimidine is obtained and
is purified by recrystallisation from a mixture of iso-
propyl ether (1 volume) and benzene (1 volume); melting
point 136C; yield 70%.
Analysis for C24H29N5O4 (molecular weight 451.51)
Calculated % C 63.84 H 6.47 N 15.51
Found % C 63.75 H 6.41 N 15.31
Saponification give~ the corresponding acid;
melting point 200C when purified by recrystallisation
from dimethylformamide; yield 60%.
Analysis for C H N O (molecular weight 423.46)
22 25 5 4
Calculated % C 62.40 H 5.95 N 16.55
Found % C 62.42 H 5.93 N 16.55
The anti-microbial activity of the compounds of
the invention has been demonstrated in vitro on two
different nutrient media: :
: 25 a) Trypticase soya medium (T.S.A.), which is
very suitable for culturing the majority of micro-
organisms; it has the following composition:
Trypsin-produced peptone from casein .............. 15 g
Papain-produced peptone from soya ................. 5 g
~059509
Sodium chloride .,.... ,.,...... ~,.................. ..,. 5 g
Agar ~ Q~ 15 g
~ater, q.~.p. ...~....,...,.,...,...~...,.... 1,000 cm3
After sterilisation, the pH i~ 7.3.
b) Ordinary nutrient agar (N.A.), which is
les~ rich in nutrient~, corre~ponds to the following
formulations
Meat extract ....... ,,.,....... ,....... ,.. ,.. ,.- 3 g
Peptone ......... ...~........................ .........5 gAgar .,,,.,...... ,.. .,....................... ........15 9
~ater, q.s,p, .. ,,.,.. ,..................... .....1,000 cm
A~ter sterilisation at 120C~ tile pH is 6.8.
Table I gives the minLmurn inhibitory
concentration~ (~xpressed in ~g/cm3) ~or the various
microorgani3m~ tested on each medium.
; The products were t~ted on three Gram po~itive
microorganisma (1 to 3) and on 10 Grarn negative micro-
organ~sms (~ to 13).
The minimum inllibitory concentrations (M.I,C.)
were determined by dilution in the ayar media, the
range~ of concen*ration e~ctending ~rom 0~2 to 100 ~ ~ cm3
as a geometric progression with a ratio of 2.
Inoculation of the di31les was carried out by means of a
multiple inoculator with 10 3 dilutions of 18 hour broth
cul~ures. The di3hes are placed in an oven at 37C and
readings are made after 18 hour~' incubatîon. The M.I.C.
i~ the lowcst concentration which completely ir~lbits
the culture.
The compounds of EY~mples IV~ V~ Vl, VII~ VIII~ X
_ 38 -
.
~0 59 5 g
and XI to XVI are particularly active against Gram-ne~ative
microorganism~, the minimum inhibitory concentration
being generally ~ubstantially lower in the ordinary
medium (N.A.) than in the trypticase-~oya medium (T.S.A.).
The compounds of the invention can be used in
human or veterinary therapy, especially as anti-
bacterial agents, in pharmaceutical form~ which enable
them to be admini~tered orally or parenterally, The oral
form preferably consist~ o~ tablets or gelatine-coated
0 pill3 each containin~ 50 to 500 mg of active ~rinciple.
For the parenteral ~orms, it i9 po~sible to use
aqueous ~olutions containing 5 to lo~ o~ active product,
and having a pH between 6 and 7~ isotonicity i8 achieved
by adding sodium chloride if necessary. ~ith compounds
lS which are less ~oluble in water than the limits fixed
above~ aqueous solution3 of polyethylene glycol ~300 or
600) or propylene glycol~ at concentrations 10 to 4o~
may be u9ed as the solvent, Tertiary amides of lower
alipllatic acids such as ,~dimethylacetamide and ~diethyl-
acetamide and lactamide, or 5~' strength aqueou~ solutions
of benzyl alcohol can also be used as oolubiliaation
adjuvants. The solutions thus produced can be sterilised
either by sterile filtration or by autoclaving. They
may bo disp~naed Into S or 10 cm3 ampoulos.
~ '
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Table (II) gives the minimum inhibitory
concentrations of the compounds of Examples XII to XVI,
determined on the agar medium, N.A~, and expressed in
~g/cm .
TABLE II
Microorganism Ex. XII Ex. XIII Ex. XIV Ex. XV Ex. XVI
1) Staphylo-
coccus 20 P 1.66.2 3.10.8 0.4
2) Strepto-
coccus Group
A 3.16.2 1.61.6 0.8
3) B. subtilis 1003.1 3.11.6 50
4) 9Ord. bronchi-
,.~
septica 100 12.5 3.13.1 12.5
5) B. pyocyaneus
A 22 100100 25 50 12.5
6) Esch. coli
~.
0.8 5050100 3.1
7) Klebs
pneumoniae 0.41.6 0.40.8 0.2
8) Salm. typhi 0.81205 3.112.5 1.6
9) Sh. sonnei 0.81.6 0.81.6 0.8
10) Pr. vulgaris 0.86.2 3.112.5 6.2
11) Pr. mirabilis 6.2 12.5 6.2 12.5 12.5
12) Pr. morganii 0.86.2 1.66.2 1.6
The compound o~f Example VIII appears to be the
most valuable for therapeutic use. It has been tested
on 25 bacterial strains, in comparison with nalidixic acid
and with the acid of Example III containing a pyrrolidino
.,~ ,
;~ - 42 -
~. '
~ t, ' ~ ' ~ . . ' '
1059S09
ring in the 2-position, l~he minimum inhibitory
concentration~ were determined ~ive time~ on each strain
by the 301id medium (nutrient agar) dilution method.
Table III give~ the average value~ ~ound for the three
5 compounds.
It is apparent from this table that the compound
of Example VIII i~ more active on ~he laajority of the
Gram negative microorganism3 than the 2 other substance~.
Furthermore~ thi~ product i~ characterised by a
very low toxicity~ when administered orally at doses
as high as ~ g per kilogr~n, no deaths were observed
amongst the rodent~ (rat3 and mice) and a dog was
able to undergo a 6 wee]~s' treatment at 100 mg/kg/day
without showing any toxic sign~.
1~ Wben administered orally~ the compound of Example
VIII is a~sorbed rapidly and i8 eliminated principally
in ~lle urine. Even with low dose~, urinary ccncentrations
are obtained which are very much greater than the
minimum inhibitory concentrations effective again~t the
majority of Gram negative rnicroorgani~,ls,
In an experim~nt involving a 20 kg dog, 50 mg of
the compound o E~ample VIII, corresponding to 2.5 mg/kgJ
were administered by means of a probang. m e ur~ne of
the ani~al Wa8 removed by catheterisation a~ the 3rd and
at tlle 7th hour, and the anti-bacerial activity of these
~ample9 Wa9 measured~ taking the compound admini~tered
as ~he reference produc~-. Respective concentrations
- of 1~5 ~g/cm3 (3 hour~) and 90 ~g/cm3 (7 hours) were thu9
found~ the latter concentration being still very much
:,
_ ~3 -
.
.,
~ . .
~0 59 50 9
gxeater than the minLm~n inhibitory concentrations for
the majority of the Gram negative microorgani$m inve~ti-
gated~ especially the Colibacilli and Pxoteu~.
TABLE III
Micro- Nalidixic acid ~. III Ex. VIII
organism average stan- average stan- averaqe stan-
dard dard dard
devi- devi- devi- .,
ation ation ation
~taphylo-
coccu~ 209P 16.24 8.~ 3.42 1.68 6.22 3.5
" 91~4 25 ~.34~,04 2.06 6.22 3.5
" SIM 56.25 31.45 14,98 8,42 12.48 3.33
Strepto-
coccu3 A561 18,74 19.65 2,82 ~,1 13,74 6.86
" DMQ9 100 o 100 0 100 o
. ~ubtili~ .
6633 7~ 0,75 1 0.6 8,1 9.54
Bord~bronCbL 2S 17.67 80 27.36 75 35.3S
~17 .
P~. aeru-
ginosa A22 60 37.91100 o 12,5 o
" 72-3~5 60 37.91 75 35.35 13,74 6.86
Esch. coli.
. 95 I.S,M. 21.87 6.25 32.5 16,77 5,14 4.57
" 5~127 0M 2.15 1.14 15.625 9.5 5.66 5
" LRB 45 3.12.1615.625 9.5 2.04 1.019
" LRB 67 2.70.7512.5 o 1.2 0.565
o 4.04 2.~1 32.5 16.77 2.66 2.15
:.
.,..... . . -... - . - :
~ 59509
T~BLE III (Continued)
_ .
rlicro- Nalidixic aci ¦ Ex, III Ex. VIII
organism average stan-average stand- average stan-
dard dard dard
devi- devi- devi-
ationation ation
. . _ ~ . . -
E~ch
111 B~ 2,34 1,1~ lS.62 9,38 1.64 1,3~'~
~Clebs. .
pneumoniae
10.031 1.4 0.~ 7.2 0.33 1.88 1.03
Salrn.
typ~~ 0901 2.7 0.75 23.7~ 16.77 2.06 2.06
S. enteri-
tid~ 8 I~NYZ 2.75 2.3 21.9 18.75 1.2 0.565
S~ oranien-
burg 10-66 100 0 100 o 27.5 7.5
Arizona 621~ 3.12 1.7 27.5 13.7 1.26 1.138
Providen-
cia 0223 L00 o 100 0 16.24 8.
Sh. sonnei
I.P.S. 1.58 0.77 10.6 8.74 0.56 0.22
Pr, vulgari~8
12-53 0.88 0,~38 5.6 ~.08 0.36 0.09
Pr, mira-
bilis Nig 3.42 1.68 30 11.18 1.58 0.3
Pr. morganii
A236 ____ 0.5 6 0,22 0.4 0
.
~ ~5 --
.~ , . - , .
,: .
. ........ . . . .
