Note: Descriptions are shown in the official language in which they were submitted.
~5~
.
The invention relates to an unobvious one-stage process for the
preparation of N-substituted imido-dicarboxylic acid diaryl esters.
According to our prior copending Canadian patent application
No. 371,153 (corresponding to German Patent Application P 30 06 226.1), it is
possible to prepare N-substituted imido-dicarboxylic acid diaryl esters by
reacting corresponding carbamic acid aryl esters with carbonic acid aryl
ester halides, if appropriate in the presence of a diluent, at elevated
temperatures (100 to 300C). The carbamic acid aryl esters required must be
prepared from the corresponding primary amines in a separate process stage,
by react~on with carbon;c acid aryl ester hal;des or carbonic acid diaryl
esters.
The p,esent invention now provides a process for the production
of an N-substituted imido-dicarboxylic acid diaryl ester of the general formula
Rl _ N(C0-OR2~2 (I~
in which
R1 represents an optionally substituted aliphatic,
cycloaliphatic, araliphatic, or aroma~ic radical and
R represents an optionally substituted aryl radical,
in which a primary amine o~ the general formula
Rl _ NH2 (II)
in which
Rl has the aLovemeiltioned meaning,
is reacted with a carbonic acid aryl ester hal;de of the general formula
B5
~1.5~`0
X - C0 - oR2 (III)
ir, which
R2 has the abovementioned meaning and
X represents a halogen atom,
optionally in the presence of an additional dil~ert, at a
temperature between 100 and 300C.
The present invention further provides, as new
compounds N-substituted imido-dicarboxylic acid diaryl
esters cf the general formula (I), as defined above, in
which R1 represents a neopentyl (=2,2-dimethylpropyl)
radical and R2 represents a 4-methylphenyl or 4-chloro-
phenyl radical or in which R represents a phenyl radical
and R represents a methyl, l,l-dimethylpropyl, 1,2,2-
trimethylpropyl, 2,2-dimethylbutyl, 1-isopropyl-2-methyl-
prcpyl, l-ethyl-pentyl, l-methyl-octyl, allyl, 4-tert.-butyl-
cyclohexyl, (4-methyl-cyclohexyl)-methyl, cyclohex-3-enyl-
methyl, 3,4-dimethyl-cyclohex-3-enyl-methyl, cyclododecanyl,
cyclododecanyl-methyl, 2-(b~yclo[2.2.1]heptyl)-methyl,
6-(2,3,3a,4,5,6,7,7a-octahydro-4,7-methano-indenyl)-
methyl, 2-(1,2,3,4,5,6,7,~8a,4a-decahydro-1,4:5,8-
dimethano-naphthyl)-methyl, 2-chloroethyl, 3,3-dichloro-
3-fluoro-propyl, 3,3,3-trifluoro-propyl, 2,2-difluoro-
propyl, 2,2,2-trifluoro-1-methyl-ethyl, 6-chloro-hexyl,
2-methoxy-ethyl, 3-methoxy-propyl, 5-cyano-pentyl, 2-
ethoxycarbonyl-ethyl, phenyl, 3,4-dichlorophenyl, benzyl,
fur-2-yl-methyl or tetrahydropyran-2-yl-methyl radical.
It is to be described as surprising that the
reaction according to the invention, which very probably
proceeds via the int~rmediate stage of the corresponding
~0 carbamic acid aryl esters (Rl-~H-C0-OR2), leads smoothly,
and with high yields, to the desired imido-dicarboxylic
acid diaryl esters cf formula (I), since carbamic acid aryl
esters do not react with carbonic acid aryl ester halides
of formula (III) in the desired manner in the presence of
an acid-binding agent: it is indeed known that N-~ubstituted
Le A 20 566
_.,
QO
dialkyl imido-esters can be prepared by reacting N-
substituted carbamic acid alkyl esters with carbonic acid
alkyl ester chlorides in the presence of metallic sodium
(see J. Amer. Chem. Soc. 69, 2616 - 2618 (1947)).
~owever, attempts to apply this methcd to the
corresponding car~amic acid aryl esters fail completely.
For example, neopentyl-carbamic acid phenyl ester reacts
with carbonic acid phenyl ester chloride under the reaction
conditions according to the state of the art to gi~e
exclusively neopentyl isocyanate and diphenyl carbonate.
Even with butyl-lithium as the acid-trappin~
agent, no neopentylimido-dicarboxylic acid diphenyl
ester is formed. It is all the more surprising that
the reaction according to the invention proceeds smoothly
at elevated temperature and in the absence of an acid-
trapping agent. According to the ~tate of the art,
it would have been expected that, at elevated temperature,
total re-splitting of the carbamic acid aryl ester
initially formed into isocyanate and phenol would take
place (see Houben-Weyl: Methoden der organischen Chemie
(Methods of Organic Che~istry), 4th Edition, ~olume 8,
page 127 (1952)).
If neopentylamine and carbonic acid phenyl ester
chloride are used as starting substances, the course of
the reaction for the production of compounds of the
present invention is illustrated by the following
equation:
(H3C)3C-cH2 NH2 2 Cl-CO-O
CO-O~
~ (H3C)3C-C~2-N
:~ CO-O~
Preferred primary amines to be used as starting
substances are those of formula (II) in ~-hich R represents
a straight-chain or branched alkyl ra~ical which has 1 to
10 carbon atoms and is opticnally substituted by lo~er
Le A 20 566
115~20~)
alkoxy, lower alkylmercapto, halogen (in particular fluorine or chlorine),
cyano or nitro; an alkenyl radical with 3 to ~ carbon atoms, an alkinyl
radical with 3 to 8 carbon atoms; a cyclo-aliphatic ring which has 3 to 8
carbon atoms and is optionally substituted by lower alkyl; an araliphatic
radical with a total of 7 to 12 carbon atoms, the aromatic ring system
optionally being substituted by halogen, nitro, trifluoromethyl, cyano,
lower alkyl and/or lower alkoxy; an aromatic radical which has 6 to 12
carbon atoms and is optionally substituted by halogen, nitro, trifluoromethyl,
cyano, lower alkyl and/or lower alkoxy~ The expressions "lower alkyl",
"lower alkoxy" and "lower alkylmercapto" in the context of this invention
are intended to denote appropriate radicals with in each case 1 to 4
carbon atoms~
The primary amines of the formula (II) which can be used according
to the invention are already known, or they can be prepared by customary,
known processes (see, for example, Houben-Weyl, Methoden der organischen
Chemie (Methods of Organic Chemistry), 4th Edition, Volume XI/l, pages 9 -
1033 (1957)~
Specific examples of primary amines of the formula (II) which may
be mentioned are: methylamine, ethylamine, propylamine, isopropylamine, 1,1-
dimethyl-propylamine, 1,2-dimethyl-propylamine, 2,2-dimethyl-propylamine
(neopentylamine), 1,2,2-trimethyl-propylamine, l-ethyl-propylamine, l-isoproyl-
2-methyl-propylamine, butylamine, isobutylamine, sec.-butylamine, tert.-
butylamine, l-methyl-butylamine, 2,2-dimethyl-butylamlne, 3.3-dlmethyl-
butylamine, l,3,3-trimethyl-butylamine, pentylamine, l-methyl-pentylamine,
2,2-dimethyl-pentylamine, 1,2,2-trimethyl-pentylamine, hexylamine, 2-ethyl-
hexylamine, l-methyl-octylamine, allylamine, 2-methyl-allylamine, propargyl-
amine, cyclopropylamine, cyclopropyl-methylamine, cyclobutylamine, cyclopentyl-
amine, cyclopentyl-methylamine, cyclohexylamine, cyclohexyl-
ZO~)
methylamlne, 3-~ethyl-cyclohexylamine, 4-methyl-cyclohexylam me, 4-tert.-butyl-
cyclc~lexylamine, 4-methyl-cyclohexyl-methylamLne, 3,3,5-trimethyl-cyclohexyl-
a ne, cyclohex-3-enyl-methylamine, 3,4-di~ethyl-cyclohex-3-enylamine, 3,4-
dimet~lyl-cyclohex-3-enyl-methylamine, cycloheptanylamine, cycloheptanyl-methyl-
amine, cyclooctanyl-amLne, cyclooctanyl-methylamine, cyclododecanylamine, cyclo-
dodecanyl-methylamine, adamantyl-methylamine, 2-(bicyclo[2.2.1]heptyl)-methyl-
amine, 6-(2,3,3a,4,5,6,7,7a-octahydro-4, 7-methano-indenyl-methylamine, 2-(1,2,3,
4,5,6,7,8,8a,4a-decahydro-1,4:5,8-dimethanonaphthyl)-methylamine, 5-(4,5,6,7,7a,3a-hexahydrorindenyl)-methylamine, 2-chloro-ethylamine, 2,2,2-trifluoro-ethyl-
amine, 3,3-dichloro-3-fluoro-propylamine, 3,3,3-trifluoro-propylamine, 2,2-
difluoro-propylamine, 2,2,2-trifluoro-1-methyl-ethylamine, 6-chloro-hexylamine,
3-trifluoromethyl-cyclohexylamine, 4-trifluoromethyl-cyclohexylamine, 3-tri-
fluoromethyl-cyclohexyl-methylamine, 4-trifltloromethyl-cyclohexyl-methylamine,
2-methoxy-ethylamine, 3-methoxy-propylamine, 5-cyano-pentylamine, 2-ethoxy-
carbonyl-ethylamine, aniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline,
2,4-dichloroaniline, 3,4-dichloroaniline, 3,5-dichloroaniline, 2,4,5-trichloro-
aniline, 3-nitroaniline, 4-nitroaniline, 3-chloro-4-nitroaniline, 2-methyl-
aniline, 2-chloro-6-methylaniline, 4-chloro-2-trifluoramethylaniline, 3-methyl-
aniline, 3-trifluoromethylaniline, 4-methylaniline, 2,6-dimethylaniline, 2-
ethylaniline, 2-ethyl-6-methylaniline, 2,6-diethylaniline, benzylamine, l-phenyl-
ethylamine, 2-phenyl-ethylamine, 2-chloro-~enzylamine, 2,4-dichloro-benzylamine,
fur-2-yl-methylamine, tetrahydro-fur-2-yl-methylamine, tetrahydro-pyran-2-yl-
methylamine and tetrahydro-pyran-3-yl-methylamine.
Preferred carbonic acid aryl ester halides also to be used as starting
substances are those of formula (III) in which R2 represents a phenyl or
naphthyl radical which is optionally substituted by chlorine, methyl and/or
methoxy; and X represents a chlorine or fluorine atom.
115120~
me carbonic acid aryl ester halides of the formula (III) which can be
used according to the invention are known, or they can be prepared by known pro-
oesses. m us, for example, the carbonic acid phenyl ester chlorides can be pre-
pared in a manner which is in itself kncwn, by phosgenation of phenols (see
Houben-Weyl, Methoden der organischen Chemie (Methods of Organic Chemistry), 4th
~;tion, Volume 8, page 103 (1952)); the corresponding carbanic acid phenyl
ester fluorides can be obtained analogously from phenols and difluorophosgene
(see J. Chem. Soc. [London] 1948, page 2183).
Specific examples of starting ccmpounds of the formula (III) which may
be mentioned are: the carbonic acid ester chlorides of phenol, 4-chlorophenol,
4-cresol and l-naphthol and the carbonic acid ester fluoride of phenol. A part-
icularly preferred oombination of starting compounds of formula (II) and (III)
is neopentylamine hydrochloride and carbonic acid phenyl ester chloride.
The reaction according to the invention may be carried out using a
diluent for the primary amine of formula (II).
It is appropriate to follow a procedure in which the carbonic acid
aryl ester halide of formula (III) is initially introduced into the reaction
vessel and is warmed to the reaction temperature, and a solution of the primary
amine in a suitable diluent is slcwly added. Suitable diluents for the amine to
be added are low-boiling inert organic solvents, such as hydrocarbons and
chlorinated hydrocarbons (for example petroleum ether, cyclohexane, methylene
chloride, chloroform or difluorodichloro-methane, preferably petroleum ether
(boiling range 30 - 50&)); these solvents evaporate at the reaction temperature
and thereby simLltaneously serve as "entraining agents" for removal of the
hydrogen halide formed.
It is also possible, and in many cases particularly advantageous, to
OE ry out the reaction in an exoess of the carbonic acid aryl ester halide of
1~5~%~
formula (III) used as a reactant, as the alternative to using the additional
diluellt.
me carbonic acid aryl ester halide of formula (III), which is in
general initially introduced, can also be employed in the form of a dilute solu-
tion. Diluents which are suitable for this are high-boiling inert organic sol-
vents, such as chlorinated or nitrated aromatic hydrocarbons (for example chloro-
benzene, the dichlorobenzenes, the trichlorobenzenes or nitrobenzene). However,
using such an additional diluent in general provcdes no noticeable advantage.
It has proved to be more appropriate to carry out the reaction without such an
additional diluent, and instead to employ the carbonic acid aryl ester halide of
formula (III) in excess amDunts.
If the reaction according to the invention is carried out without using
an additional diluent for the (initially introduced) carbonic acid aryl ester
halide of formula (III), up to 20 moles, but appropriately 4 to 15 moles and pre-
ferably 8 to 12 moles, of carbonic acid aryl ester halide can be employed per
mole of a primary amine of the formula (II).
If a diluent is also used for the carbonic acid aryl ester halide of
formwla (III), in general 2 to 15, preferably 3 to 12, moles of carbonic acid
aryl ester h~l;de of form~la (III) are employed per mole of the primary amine of
formula (II). In the latter case, it is thus also advisable to employ the car-
bonic acid aryl ester halide of fornula (III) in amounts which are greater than
the stoichiometric am~unt.
me process according to the invention is ried out without the addi-
tion of an acid-binding agsnt. However, by usin~ a low-boiling, inert orqanic
solvent a~ the diluent for the primary a~ me, it is possible for a large propor-
tion of the hydrogen halide formed in the course of the reaction to be removed
from the reaction
~s~zo~
mixture, since, as mentioned above, the solvent simultaneously serves as an
"entraining agent". In order to expel all of the hydrogen halide formed, it
is a~visable additionally to pass a continuous stream of air or nitrogen
through the reaction mixture (see the Preparative Examples).
The reaction temperatures can be varied within the substantial
range, as indicated above, of between 100 and 300C, preferably between 170
and 250C.
The reaction according to the invention is in general carried out
under normal pressure.
The reaction products are isolated in a simple manner by separating
the reaction mixture by distillation. Solid, higher-melting imido-dicarboxylic
acid diaryl esters can also be easily purified by recrystallisation.
The new N-substituted imido-dicarboxylic acid diaryl esters (I)
according to the present invention and the compounds produced by the process
of the present invention can be used as intermediate products for the prepara-
tion of known herbicidal active compounds from the l,3,5-triazine-2,4-(lH,3H)-
dione series (see, for example, DE-OS (German Published Specification) 2,254,200
and U.S. Patent Specification 4,056,527).
According to a process which has not hitherto belonged to the state
of the art (and which is the subject of our copending Canadian patent applica-
tion No. 371,154),1,3,5-triazine-2,4-(lH,3H)-diones of the general formula
R R3
Rl _ N"-" N N : C
R4 tIV)
N ~ SR5
o
~ 5~ZOO
n w~Lch
Rl has the abovementioned meaning and
R3, R4 and R5 in each case represent identical or different alkyl
radicals,
can be prepared with a high yield and purity when the N-substituted imido-
dicarboxylic acid diaryl esters according to the invention, of the general
formula
1 ~CO-OR
R -N 2 (I)
~CO-OR
in which
Rl and R2 have the abovem~ntioned meaning,
are reacted with an isothiosemicarbazone of the general formula
,R3
HN-N2C ~ 4 (V)
HN=C-S-R
in which
R3, R4 and R5 have the akovem~ntioned meaning,
in approximately stoichiometric am~unts, without using a diluent and without
adding a base as an auxiliary, at temperatures between 50 and 150&, preferably
between 70 and 120&.
m e triazinediones of form~la (IV) can be worked up and isolated, for
example, ,by a prooedure in which the (optionally substituted~ phenol formed in
the condensation reaction - (I) + (V) ~ (IV) - is distilled off in vacuo and the
residhe is purified, if necessary, by distillatiQn under a high vacuum or by
recrys~llisation.
The 1,3,5-triazine-2, 4(1H,3H)-diones of form~la (IV) thus prepared
are themselves herbicidal active oompounds; hcwever, they can also be easily con-
verted into the corresponding l-amino-1,3,5-triazine-2, 4(IH,3H)-diones of the
general formula
., ~
115~200
--~o --
o
/~1 i~ 5
s~
in which
Rl and R5 have the abovementioned meaninG, ~Jhich
are likewise excellent.herbicides, by hydrolytic spli~tinc
off of the alkylidene radical ~=CR3R4) which serves as a
protective group. Furthermore, the S-alkyl radicals
(-SR5) in compounds of formulae (I~) and ~Vl) can be
replaced by alkylamino or dialkylamino groups by reactior.
with primary or secondary amines, herbicidal active
compounds which are also known being obtained ~see likewise
DE-OS ~German Published Speci~ication) 2,254,200 and U.S.
Patent Specification 4,056,527).
The new process ~iven here for the preparation of
the herbicidal active compounds of the general formulae (IV)
and tVI) and 6-amino derivati~es thereof, in wbich the
' ::imido-dicarboxylic acid diaryl esters of formula (I)
according to the invention are used as starting compounds,
has considerable and surprising advantages compared with the
processes already known, for example from DE-OS (German
Published Specification) 2,254,200. Thus, the cycli-
æation reaction can be carried out in the mQlt of the
starting materials without using solvents. No ~her
auxiliaries, such.--as organic bases, are required in this
procedure. The.only by-products are phenols tno hydrogen
halides being p~oduced), which can easily be separated off
and re-used. Finally, the imido-dicarbox~lic acid
diaryl ester~ o~ formula (I) employed as starting
substances can be prepared' in high'yiel'ds in an industrially
simple manner from readily accessible precursors by the
process claimed-in-the-above-mentioned copending patent
application.
The isothiosemicarbazones o~ the'general formula (~)
.are'known or. they-can be prepared by known processes, for
~ example by S-alkylation of thiosemicarbazones (see
Le A 20 56 6
11 5~?~
Houben-Weyl, Methoden der or~anischen Che~.ie ~lethods
. of Org2nic Chemis~ry)~ 4th Edition, Volume 9, page 912).
The synthesis of the particularly effecti~e
herbicidal active compound l-amino-6-ethyl'hio-3-nec-
pentyl-1,3,5-triazine-2, 4(1H,3~)-dior.e cf formula (Vlz)
(see for example, ~anish Patent Specification 136,C67),
starting from the co~pound N-neopentylimi~o-dicarboxylic
acid diphenyl ester of formula (Ia) accordins to t~e
in~ention, is described below by way of example; the
course of the reaction can be represented by the following
equation:
H3~3c-cH2-N 6Hs HN-N=C ~
COOC6H5 1 , CH3
HN SC H
(lo ) . 2 5
~Va~
.
O
~J~sc H
tIVa)
,,. ,, O
.H20
'tCH ) C C~C2H5
A mixture o~ 65.4-g(0.2 mole) of ~-neopentyli~ido-
dicarboxylic acid diphenyl ester (see Preparative Example
1) and 31.8g (0.2 mola) o~ acetone S-ethyl-
is.othiosemicarba~one of formula.(Va.) is ~elted and the ~e1t
is stirred..at:100C fo~-5 hours. The phenol for~èd is
Le A 20 566
.
.
~5Sl200
then distilled off in v~cuo. The residue~ which
. essentially consists of l-isopropylideneamino-6-ethylthio-
3-neopentyl-1,3,5-tria71ne-2, 4(1H,3H)-dione of formula
(IVa), is dissolved in 200 ml of isopropanol. To split
off the isoprop~lidene protecti~e group hydrolyticall~-,
2.8g of p-toluenesulphonic acid are added, and 14.4 ml of
water are added drcpwise at a temperature of 60C and under
a pressure of 200 - 300 mbar in the course of half an hour.
The acetone formed is distilled off during the reaction,
together with about 100 ml of isoprop~no~l. The l-amino-6
-ethylthio-3-neopentyl-1,3,5-triazine-~, 4(1H,3H)-dione o~
formul~ (VIa) which has crystallised out is filtered off ? t
0C and washed with methanol. 38.2g of the compound of
formula (~tIa) of melting point 202C are obtained,
corresponding to a yield of 74% of theory.
Herbicidally active l-amino-3-isobutyl-6-methy~nio
-1,3,5~triazine-2, 4(1H,3H)-dione of formula (VIb), which
is known (see, for example, Danish Patent Specification
-136,067), can be prepared in an analogous manner startin~
~rom the compound N-isobutyl-imido-dicarboxylic acid
diphenyl ester offormula (Ib) according to the invention, it
being possible for the interFIediate product l-isoprop~lidene
-amino-3-isobutyl-6-methylthio-1,3,5-triazine-2, 4(1H,3~)-
dione of formùla (IVb) to be isolated:
1~st s~age:' ~
(cH3)2c~-cN2-N p~~=CtCH3)2 (IVb)
~ ~ N SCH3
34.6g (O.lI mole) of N-isobutyl-imido-dicarboxylic
acid diphenyl ester of formula (IB) (see Preparative Example
5) and 16.0g (O.ll..mole) of acetone ~-methyi-isothi`osèmi-
carbazone'are' meIted at 50C and the melt is stirred for 4hours in an oil ba~h of 100C. The phenol ~ormed is
distilled off under a pressure of 18 mbars, the bath
temperature being increased to 14QC. The res'idue (30.3g)
.solidi~ies:; it-.is boiled up wi'th 150 ml of
Le A 20 56-,
. ~
~15~00
cyclohexane, 22.4 g of pure 1-isopropylidenea~.ino-3-
isobutyl-6-methylthio-1,3,5-tria~ine-2,4(1H,3H)-dione o
formula (IVb) of melting point 125 -127C remaining as
undissolved material. A further 6.4g of the compound
of formula (IVb) crystallise frcm the filtrate of the
~.ixture. The total yield is 28.8g (97% of theory). The
compound of formula (IVb) can be distilled: boilin~ point:
165C under 0.38 mbar.
2nd sta~e . o
Jl
~CH3)2cH-cH2-N `N NH2 (VIb)
o SCH3
27.0g (0.1 mole) of the compound of formula (IVb)
are dissolved in 200 ml of isopropanol at 60C in a
distillation apparatus and a pressure of 260 to 200 mbars
is established, so that the solvent starts to boil and is
condensed in the descending condenser. The internal
temperature is 45 - 50C. A solution of 0.4 ml of
concentrated sulphuric acid in 7 ml of water is then added
dropwise in the course of 15 minutes, about 70 ml of
isopropanol, together with the acetone formed, being
distilled off during this period. 14.5g of 1-amino-3-iso-
butyl-6-methylthio-1,3,5-triazine-2,4(1H,3H)-dione of
formula (VIb) of melting point 167 - 169C crystallise out,
at 0C, from the solution which remains; a further 4.5g are
obtained from the concentrated filtrate of the mixture.
The total yield of l9.0g corresponds to 83% of theory.
The Preparative Examples which follow illustrate
the process of the present invention in more detail.
Preparative Examples
Example' 1
(CH3)3C-CH2-N(co-o-c6H5)2 (1)
A 4 litre three-necked flask was provided with a
stirrer and reflux condenser, to which a descending
distillation bridge was connected via a Reitmeler
attachment. A coarse-pored gas inlet frit was immersed
as low as possible into the flask. A dropping funnel,
Le A 20 566
00
with pressure compensation, was connected ~o the gas inlet
frit via a grcund glass joint. The gas inlet tube o~
the frit was ccnnected tc a nitrogen line and to a ~lercury
bubbler. The reflux condenser was operated at 90 -
100C and the descending condenser at ~20C. All theground glass connections before the frit were ~.&de secure
towards excess pressure.
2.54 litres = 3.13 kg (20 moles) of carbonic acid
phenyl ester chloride were initially introduced and were
heated to the reflux temperature, and a solution of
174.0g (2 moles) of neopentylamine in 500 ml of petroleum
ether was uniformly added dropwise into the gas inlet frit
in the course of 8 to 9 hours, whilst stirrin~ ~igorously.
In addition, a vigorous stream of nitrogen was passed
through. The internal temperature was not allowed to
exceed 185C; towards the end of the reaction a temperature
of 189 to 190C was reached. Because of encrustation of
the frit, a gauge pressure of up to 60 mm Hg t80 mbars)
was established in the frit during the initial phase (5 to
30 minutes after the start of the drcpwise addition), and
finally fell to 10 to 15 mm Hg (about 13 to 20 ~hars).
The petroleum ether used was condensed in the descending
condenser, to~ether with some neopentyl isocyanate`and a
little carbonic acid phenyl ester chloride.
At the end of the dropwise addition period, the
mixture was boiled under reflux for another hour~ whilst
passing further nitrogen through.
Analysis of this reaction solution by gas
chromatography gave the following values, without taking
into consideration the carbonic acid phenyl ester chloride
employed in excess: 14.3% of diphenyl carbonate, ~3.9%
of N-neopentyl-imido-dicarboxylic acid diphenyl ester (1)
and 0.7% of orthocarbonic acid tetraphenyl ester.
The resulting reaction solution was worked up by
distillation: after separating off a small amount of first
runnings, most of the excess carbonic acid phenyl ester
Le ~ 20 566
-
0
chloride (boiling pcint: 76-78C/l9 mbars) was distilled
off, until the bottom tem~erature reached 140C. 1.94
litres (=2.39 kg) of a 99.5% ~ure ester chloride, which
could be re-used for the same reaction, were recovered in
this manner.
Residual amounts of the carbonic acid phenyl ester
chloride as well as the diphenyl carbonate were then
distilled o~f under a high vacuum over a short Vigreux
column, until a boiling point of 160GC under 0.2 mbar was
reached. 578 g of a residue which solidified and had
a purity, determined by gas chromatography, of 98.5%
were obtained, cerresponding to a yield of 87% of theory
of N-neopentyl-imido-dicarboxylic acid diphenyl ester (l);
melting point 81C (from petroleum ether), boiling point:
156C/0.02 mbar.
The compounds listed in the following Table were
prepared in an analogous manner:
Le A 20 566
512~0
- 16 -
O ~
S~ ~ ~ I` ~ O ~
O O ~ O O
rl O ~ : O -- O O O O
o~ ~ I
~_ u~ u~ o o
. u~
u~
. o
.
bO '
~ u~ o ~ _
~1 ~ O ~ ~r ~ ~ ~ c~
~ ~ _
H 0 00
~7
: ' ~ _\
. U U U U U
C~ ~ .
.
.
~:; . 5
.
. I I ~ U C~
:: V ~ U U U U U
,~ ~ IU ~ U ~ ~ ~ r~
., . :~ U ~ U ~ U U U
U -- U -- ~
~ '
'I
~ * * * *
.' ,~ . ~ ~ ~ L'~ C~
' ~O
:
. Le A 20 566
~5~200
- 17 -
~1~ N
O O
O O ~ o ~ o ~ ~ c~ N
_~ O O O ~ O O
I I ~
O G~ I ~ o
U~ In0 r~ er
. ~ .
b~
v r ~ o
H~ O . a~
~ :
.,
~ .
^
.,
O
O
c> O
V
~ z; : u~ u~ ~ ~n Lr~ ~ In
rl N . S~
n I P;
' Y Y y y y y c~
:
:
~ . I ~ I 1~ ~
.
~' I5~ N ~ ~ U - U ~
. . I ^ I t'~ I Ir) U')
:' , In ~ ~ 5 ~ -- --
r~ U ~ U ~ u~
P; ~ -- U ~ C)
. o
,, :
~ ~o
. ~Z
~ ~c
;
Le ~A 20 _66
l~lZOO
- 18 -
!
, ..
~ O ~G~ r-
b~ ~ O O O O
o o o o
'I~rl O -- O O C~ O L~
~ o ~ o 0 o ~
o PO, o o o ~ ~ ~ o
m ~, ~ ~ ~ I I I I ~
. ~ o ~ ~ ~ ~ o o
. 1` ~ ~ C~ O
.
bO
~ ~rlO . '~
_~~1 o
Ha) ~ t~
_,
~_ .
~0
J~ .
.
~0
_~ O
_ u~ L~ L~ n L~
~1 Z ~ ~ . X
I
~ ~1~;
. 1~ 1
~ ;
.
CO G~ O
~ ' _ --'
k O
X Z'
Le A 2~ 566
- 19 -
~o ~ ~ o o o
o o o o o
Q,-- O
. ~
.
~ oo ~ ~ ,
~ ~--
,_ . CO C~
o
: .,1 ,
^
.,,C~l
o
o
V o
V
a) z . -~
~1
~ I :
~ l l l l l l l
~ tr; ~ '
.
~' .
U
*
~ U~~D!`COG~ O
,1 : ~ ~ ~ ~ ~ ~ -'~
~d Z
Le A 20 566
' ., : -
r~
1151200
-- 20 --
~1 o co
: ~ o O
co o o o o
~0 ~ o ~ ~ _ o u~
o ~ _ o o o _ ~
,~ O ~ ~`1` O o a~ c~ o
O ~ ~ ~r~D Ul -- ~ U~ ~
_ _ _ _ N . _ N
1~ O C~ N
H a~ 00 CO~0 O
O
~ :
.~1 .
.
N ~U u-)~)11'1 1~ n u~ U~
~ P; :L: ~ m ~ -
~1 O . ~O ~ ~ ~O ~ ~ ~ ~D
~ o Y Y y y y y y lU
Z
I
: ~tl; ~ I I
. ~1 I N
. _ I N ~
. t`l N 5: 1 ~`1 C~ I
.~ . ~ ^ V
. V ~ I -- U C~
. -- m N I ~ N -- `-- N
. I ~ ~ m 5~
_ y y C~ ~ o o U
.. . ~ U ~ U
.
.
~ o
X
:
Le A 20 566
-
OO
- 21 -
I
CoO ` ~
_ O C 1` ~ ~
~d _ ~ o ~J'
o o ~
-- o ~3 o o ~
O 00' -- C ~ ~D
m ~_ a~
_ ~ _ _ N
00
.~ .`
W U~ O O ~
O CO ~ C~
, ~ I~ ~ O
~-- ~D 00 ' ~a~ ~ ~ 1` ~q
--` H~ ~--' _ _ ~ C~
. . ~
.,1 .
O N O
V ^.
_~ N
N~ U~ a
~D
I ;'o
~~ I u~ oo
*
~1 O _ ~ D ,~
o
s
~ E~
Le A 20 566
.: ' ~ ' .
