Note: Descriptions are shown in the official language in which they were submitted.
10~8SZ7
This invention relates to derivatives of 4'-
deoxy VLB "A" and 4'-deoxy VLB ~B" produced by hydrolysis
thereof.
The invention provides a process for the prep-
aration of a 4-desacetyl dimeric indole-dihydroindole of the
formula
~ ,
1e ~ Formula IV
H ~ 0
~ ~CH3
CH30-- H
R2 C~CH3
wherein R2 is CH3 or CHO; one of R3 and R4 i8 H and the
other is C2H5;
and pharmaceutically acceptable saltæ thereof
; : which comprises hydrolysing a 4-acetoxy dimeric indole-
~ dihydrbindole of the foz~ula
,
~ X-4730B -2-
10~
- R~
H l O
CHoO--~ ~
R I~CH~ :
11 ..
o
whereln R2, R3 and R4 aro a~ dsscribed above ln a reaction
mixture,
and rocovery of the ~-de~cetyl free ba~e or a pharm~ceu- ;
tlc~lly acceptable ~alt thereof.
Several nAturally-occurring alkalQids obtAinable
xom Vlnca xo~eA have been found acti~o in the treatment of
. .. ~ ~
oxperimental malignanctes in animals. Among the~e ~re
~-~ louro-ine ~U.~. P~tent No. 3,370,057), vincaleukoblastine
~vlnbl~stine~ to b~ referred to heroinafter a~ VL~ (U.S.
;~ Patent No. 3,097,137), lourosld~ne ~vlnrosidino) and leuro-
crlstine (YCR or vinçr'i~tine) ~both in U.S. Patent No.
3,205,220~, 4'-deoxy VLB "A" and "~", Tetrahedron Letter~,
783 (1968) (de~acotyl louro~ine hydra~tdo i~ al~o disclo~d
X-~ 7 30~ -3 -
10~
therein); 4-desacetoxy vinblastine (V.S. Patent No. 3,954,773);
4-desacetoxy-3'-hydroxyvinblastine (U.S. Patent No. 3,944,554);
leurocolombine (U.S. Patent No. 3,890,325~, leuroformine
(N-formylleurosine, see Belgian Patent No. 811,110) and
vincadioline (U.S. Patent No. 3,887,565). Two of these
alkaloids, VL~ and leurocristine, are now marketed as drugs
for the treatment of malignancies in humans, particularly
the leukemias and related diseases.
The dimeric indole-dihydroindole alkaloid~ ob-
tainable from Vinca rosea can be repre~ented by formula I.
3 ~ ~ormula I
~; CHnf ~1
R~
o
~ .
X-4730B -4_
lO~S'~:7
In formula I where Rl is acetoxy, R2 is methyl, R3 is
hydroxyl, R4 is ethyl and RS is H, VLB is represented; where
R is acetoxy, R2 is formyl, R3 is hydroxyl, R4 is ethyl and
R5 is ~, vincristine is represented; where R is acetoxy, R
is methyl, R3 is ethyl, R4 is hydroxyl, and RS is H, leuro-
sidine is represented; where Rl is acetoxy, R2 is methyl, R3
and R5 are H and R4 is ethyl, 4'-deoxy VLB "A" is repre-
sented; where Rl, R2 and R5 are the same as in 4'-deoxy VLB
"A" but R3 is ethyl and R4 is hydrogen, 4'-deoxy VLB "B" is
represented; and where Rl is acetoxy, R2 is methyl, R3 is
ethyl and R4 and R5 taken togethe~ form an a-epoxide ring,
leurosine is represented.
Of the above alkaloids, vincristine is the most
useful, and the least available, from vinca. Recently, ~ -
Jovanovics et al., U.S. Patent 3,899,493, have developed an
oxidative method for converting the relatively more abundant
VLB into vincristine by chromic acid oxidation at low
(-60C.) temperatures. There are other relatively abundant
alkaloids such as leu~osine in the dimeric indole-dihydro-
X-4730B - 4a -
S~7
indole fraction from vinca and it would be desirable to
convert these directly or indirectly to vincristine or to a
drug of comparable oncolytic activity. It is known that
leurosine can be converted to 4'-deoxy VLB ~B~ (along with
varying amounts of 4'-deoxy VLB "A") by treatment with Raney
nickel in refluxing absolute ethanol--see Neus~, Gorman,
Cone and Huckctep, Tetrahedron Let~ers 783-7 ~1968). While
leurosine demonstrated oncolytic activity in e~perimental
tumors in mice, clinical response was limited. 4'-Deoxy VLB
"A" and 4'-deoxy VLB "B" were reported to lack reproducible
activity in experimental tumors in mice.
It is an object of this invention to convert
leurosine via 4'-deoxy VLB "A" and "B" to oncolytically
active derivatives of 4'-deoxy VLB "A" and "B", thereby
converti~g indirectly the relatively abundant alkaloid
leurosine into a drug of greater potential clinical utility. -
compound of formula I in which R4 is ethyl, Rl
is acetoxy, R2 is CHO, and R3 and R5 are hydrogen is named
4'-deoxyvincristine; a compound where Rl is hydroxy but the
2Q other groups are the same is named 4'-deoxy-4-desacetyl-
~ vincristine. $ince the companion alkaloid to vincristine
;~ having a reverse configuration of hydrogen and ethyl at 4'
from that found in vincristine is not known, those compounds
in which R3 is ethyl, and R4 is hydrogen will be referred
; back ~o leurosidine which has the same ~onfiguration at 4'
as 4'-deoxy VLB "B" and will be referred to as derivatives
of l-formylleurosidinet i.e., 4'-deoxy-1-formylleur~sidine
(or ~'-deoxyepivincristine) and 4'-deoxy-4-desacetyl-1-
ormylleurosidine where Rl is acetoxy or hydro~y, respectively.
X-4730B _5_
-
S;~
In each of the above names, it will be under stood that the
l-methyl group of leurosidine has been replaced by a formyl
group and that the "l-desmethyl" term has been omitted to
simplify the nomenclature.
Non-toxic acids useful for forming pharmaceu-
tically-acceptable acid addition salts of the compounds of
this invention include salts derived from inorganic acids
such as: hydrochloric acid, nitric acid, phosphoric acid,
sulfuric acid, hydrobromic acid, hydriodic acid, nitrous
acid, phosphorus acid and the like, as well as salts of
non-toxic organic acids including aliphatic mono and di-
carboxylic acids, phenyl-substituted alkanoic acids hydroxy
alkanoic and alkandioic acids, aromatic acids, aliphatic and
aromatic sulfonic acids, etc. Such pharmaceutically-
acceptable salts thus include the sulfate pyrosulfate, --
bisulfate, sulfite, bisulfite, nitrate, phosphate, mono-
hydrogenphosphate, dihydrogenphosphate, metaphosphate,
pyrophosphate, chloride, bromide, iodide, acetate, pro-
pionate, decanoate, caprylate, acrylate, formate, iso-
butyrate, caprate, heptanoate, propiolate, oxalate, malonate,
succinate, suberate, sebacate, fumarate, maleate, benzoate, ~-
chlorobenzoate, methylbenzoate, dinitrobenzoate, hydroxy-
benzoate, methoxybenzoate, phthalate, terephthalate, ` !
benzenesulfonate, toluenesulfonate, chlorobenzenesulfonate,
xylenesulfonate, phenylacetate, phenylpropionate, phenyl-
butyrate, citrate, lactate, 2-hydroxybutyrate, glycollate,
malate, tartrate, methanesulfonate, propanesulfonate,
naphthalene-l-sulfonate, naphthalene-2-sulfonate and the
like salts. -`
`.
X-4730B -6-
8S;~7
The compounds of this invention according to
Formula I above wherein R2 is formyl are prepared by low
temperature chromic acid oxidation of either 4'-deoxy VLB
"A" or 4'-deoxy VLB "B" under acidic condition, e.g. chromium
trioxide and acetic acid.
4'-Deoxy VLB "A" and "B" or their l-formyl deriva-
tives can be hydrolyzed to the corresponding 4-desacetyl
derivatives under acidic or basic conditions. These 4-
desacetyl derivatives of 4'-deoxy VLB ~A" and "B~ can then
be oxidized at low temperature (-60C) with chromium tri-
oxide without converting the 4-hydroxy group to a ketone to
yield 4'-deoxy-4-desacetylvincristine and 4'-deoxy-4-
desacetyl-l-formylleurosidine.
The preferred method of carrying out ~he above
hydrolysis reaction, uses sodium carbonate in methanol
at reflux temperature. Hydrazine hydrate may be used.
Other bases which can be employed include potassium t-
butoxide, sodium or potassium methoxide or ethoxide,
pyridine, triethylamine (or other tertiary amine), urea and
the like in polar organic solvents such as the lower
alkanols. Dilute sodium and potassium hydroxide can also be
employed, in methanol for example, but precautions must be
taken not to operate with base concentrations or reaction
~; temperatures at which other hydrolysable groups in 4'-deoxy-
vincristine or 4'-deoxy-1-formylluerosidine are affected.
Bases which operate only in non-polar solvents can also be
` used; i.e., sodium or lithium hydride in benzene, ether,
THF, etc. or the sodium salt of dimethyl-sulfoxide in DMSO.
Temperatures varying from ambient temperature (25C.) to
. ~ ' '
X-4730B _7_
-
l~S~'7
boiling point of the particular solvent may be used. On the
other hand hydrolysis can be carried out under acidic
conditions, e.g., absolute methanol saturated with anhydrous
hydrogen chloride at 0C.
More specifically, the compounds of this invention
can be prepared according to the following examples.
Example 1
Preparation of 4'-Deoxyvincriqtine
582 mg. of chromium trioxide are dissolved in
10 5.8 ml. of acetic acid and 0.6 ml. of water. m is oxidizinq --
solution is added in dropwise fashion over a five-minute `
period to a stirred solution of 462 mg. of 4'-deoxy VLB "A
in 58 ml. of acetone and 2.9 ml. of glacial acetic acid at a
temperature of about -50C. m e reaction mixture is stirred
at this temperature for about 30 minutes and then cooled
to -65C. at which temperature the reaction mixture is
quenched with 12 ml. of 14 N aqueous ammonium hydroxide.
m e alkalinized reaction mixture is then poured onto 400 ml.
of an ice-water mixture and the aqueous layer extracted with
20 150 ml. of ether followed by three extractions with 150 ml. `
of chloroform each. The organic layers are combined and the
combined layers washed with dilute aqueous sodium bisulfite,
` separated and dried. Evaporation of the organic solvents ~
leaves, as a residue, 4'-deoxyvincristine. Chromatography -`
of the residue over 50 gm. of activity I silica is employed
- to further purify the desired compound. The chromatogram is
developed as follows: 300 ml. of 3:1 ethyl acetate-methanol
followed by 300 ml. of 1:1 ethyl acetate-methanol. After an
: ` ~
initial 100 ml. fraction, 20 ml. fractions are collected. ~
X-4730B -8- -`
10885~7
Fractions 8-20 are combined. Evaporation of the solvents
from the combined fractions yields 279 mg. of a light tan
solid which is substantially one spot (pure) material by
thin-layer chromatography.
4'-Deoxyvincristine free base thus prepared has
the following physical characteristics:
Mass spectrum: m/e 808 (M ), 806,707
Infrared spectrum: 3465, 1745, 1687, 1220 cm 1
Ultraviolet spectrum: 210, 222, 255, 290, 298 nm
100 MHz NMR spectrum: methyl singlets at 3.88,
3.67 and 2.07 ~.
4'-Deoxyvincristine, as a tan solid is dissolved
in acetone and the acetone solution treated with 0.96 ml. of
0.36 M (2 percent volume/volume) sulfuric acid in absolute
ethanol. A green solution results which is maintained at
about 0C. overnight. Crystallization is induced by
scratching or seeding, and the solid crystalline 4'-deoxy-
vincristine sulfate is separated by filtration. The filter
cake is washed with cold acetone. The sulfate salt is
somewhat soluble in acetone so the filtrate is evaporated to
dryness and the resulting residue recrystallized from
ethanol. Crystalline 4'-deoxyvincristine sulfate thus
obtained from ethanol was filtered and the filter cake
washed with ethanol. Total yield of 4'-deoxyvincristine
sulfate is 266 mg. "
~ ' .
X-4730B -9-
:
1~8S27
In similar fashion, 794 mg. of 4'-deoxy VLB "B~
can be oxidized with 900 mg. of chromium trioxide in 10 ml.
of glacial acetic acid and 1 ml. of water to yield 4'-deoxy-
l-formylleurosidine. Thin-layer chromatography of the
residue obtained directly from the oxidation mixture prior
to purification indicates the presence of a major and a
minor spot plus traces of other components. Recrystal-
lization of the residue from anhydrous ethanol yields
substantially one spot crystalline material which is isolated
by filtration and the crystals washed with cold ethanol.
Chromatography of the crystalline free base thus
obtained over 50 g. of silica using a 1:1 methylenedi-
chloride-ethyl acetate solvent system containing 20, 30, 45
and 60 percent by volume of methanol as the eluant as follows:
SystemQuantity
1:1 20%Z00
1:1 30%100
1:1 45%100
1:1 60%400 -
yields the following fractions:
FractionVolume of Eluate
1160 ml.
2100 ml.
~ 350 ml. ~;
- 450 ml. t`` `
~; 550 ml.
;~ 6120 ml.
7120 ml.
X-4730B -10-
~ .
S;~'~
Fractions 4-7 are combined to yield 597 mg. of a
tan residue which in turn yields 435 mg. of white crys-
talline 4'-deoxy-1-formylleurosidine (from ethanol). The
compound has the following physical characteristics:
Mass spectrum: m/e 808 (M+), 806, 777, 775,
336, 138, 136.
Infrared spectrum: v (CHC13) 3470, 1743, 1690,
1222 cm 1.
Ultraviolet spectrum: (C2H5OH) 210, 222, 254,
290, 298.
100 MHzNMR spectrum: methyl singlets 3.87,
3.65 and 2.07 ~.
pKa = 9~0 and 4.9 (in 66% DMF~. -
The sulfate salt is prepared by dissolving 435 mg. of the
free base in 10 ml. of hot ethanol and adding 1.5 ml. of 2
percent sulfuric acid in ethanol thereto. Crystalline
4'-deoxy-1-formylleurosidine sulfate deposits on cooling.
EXAMPLE 2
Preparation of 4'-Deoxy-4-desacetyl-1-formylleurosidine
About 744 mg. of 4'-deoxy-1-formylleurosidine are ~
mixed with 10 ml. of anhydrous methanol and the mixture
heated to refluxing temperature, at which temperature the
compound dissolves to give a clear solution. 200 mg. of
solid sodium carbonate are added and the reaction mixture is
stirred for about 7.2 hrs. at which time TLC of the crude
reaction components shows that virtually all starting 4'-
~; deoxy-l-formylleurosidine has disappeared. The solvent is
removed ~y evaporation and the residue containing 4'-
deoxy-4-desacetyl-1-formylleurosidine formed in the above
reaction is partitioned between water and methylene di-
X-4730B -11- `
S;~7
chloride. The organic layer is separated and dried and the
solvent is removed by evaporation yielding 506 mg. of a
white solid which is substantially pure 4'-deoxy-4-desacetyl-
l-formylleurosidine.
The compound had the following physical char-
acteristics:
mass spectrum: m/e 766~M+), 764, 735, 254, 252,
20~, 138 -
infrared spectrum: v (CHC13) 3450, 1734, 1680,
1596, 1495, 1456, 1434 cm 1.
100 MHz pmr spectrum: (CDC13) includes N-formyl
at ~8.80, methyl singlets at 3.89 (C16-OCH3) and 3.66
(C18-CO2CH3), broadened multiplet at 3.82 (C3-CO2CH3), and
no N-CH3 around 2.75 (or OCOCH3 around 2.06). -
The corresponding sulfate salt is formed as in the
previous examples using acetone as a solvent and 0.26 ml. of -
2% sulfuric acid in ethanol. Other solvents can be used and j~-
it is preferred to use a solvent in which the base is
readily soluble but the sulfate salt substantially insoluble. -
4'-Deoxy-4-desacetylvincristine and its sulfate
salt are prepared in entirely analogous fashion from 4'- ``
deoxyvincristine.
EXAMPLE 3
Alternate preparation of 4'-deoxy-4-desacetyl-1-formyl-
leurosidine
A reaction mixture was prepared containing 1.48 g.
of 4'-deoxy VLB "B", 1 g. of sodium carbonate and 100 ml. of
methanol and was heated to reflux under a nitrogen atmosphere.
Thin-layer chromatography of an aliquot taken at two hours
X-4730B -12-
laws;~7
indicated that the hydrolysis reaction to remove the 4-
acetyl group was about half completed. The reaction mixture,
after standing overnight at room temperature, was heated to
reflux again for eight and one-half hours. Thin-layer
chromatography of an aliquot using a 20:1:1:1 ether/di-
ethylamine/toluene/methanol solvent indicated that the
reaction had gone to completion. The solvent was removed
from the reaction mixture by evaporation and the resulting
residue was dissolved in a mixture of methylene dichloride
and water. The methylene dichloride phase was separated and
dried. Evaporation of the methylene dichloride yielded a
residue comprising by TLC a very polar substance plus the
expected 4'-deoxy-4-desacetylleurosidine. The residue which
weighed 1.33 g. was dissolved in benzene. The highly polar
material was substantially insoluble in benzene and was
separated by filtration. The filtrate was evaporated to
dryness and the residue weighing 500 mg. was chromatographed
on Woelm silica gel using a 20:1:1 ether/diethylamine/toluene
solvent system (with increasing quantities of methanol) as
20 the eluant. The progress of the chromatography was followed `~
by thin-layer chromatography and fractions shown to contain
4'-deoxy-4-desacetylleurosidine were combined and yielded
348 mg. of base on evaporation of the solvent. The residue
was treated with 1.28 ml. of 2 percent sulfuric acid in
methanol (0.36M) and the resulting solution was filtered to
yield 315 mg. of 4'-deoxy-4-desacetylleurosidine sulfate.
4'-Deoxy-4-desacetylleurosidine had the following `
physical characteristics: "
X-4730B -13-
.~
Mass spectrum: m/e 752 (M+), 750, 693, 691, 555,
338, 240, 138
Infrared spectrum: v (CHC13) 3455, 1724, 1610,
1497, 1457, 1431 cm~l
100 MHz pmr spectrum: ~ CDS13 9.43 (br s, 1,
C3-OH), 7.92 (brs, 1, indole N-H), 7.47-7.63 (m, 1, Cll,
' ' C12~-14- H)~ 6-58 (s, 1, C14-H)~ 6 10
(s, 1, C17-H), 5.78-5.87 (m, 2, C6 7-H), 4.10 (m, 1, C4-H),
16 3), 3.78 (s, 3, C3-CO2CH3), 3.70 (s, 1 `
C2-H), 3.58 (s, 3, C18,-CO2CH3), 2-75 (s, 3, N-CH3), 0.76-1.06 --`
( ~ ~ C21,21~ H)- -~
4'-Deoxy-4-desacetylleurosidine (834 mg.) obtained
rom filtrates and including solid filtered material was -`
combined. The combined material probably contained 30-40
percent of the highly polar material referred to above. The
combined material was dissolved in 100 ml. of acetone con- `,t""
taining 7 ml. of acetic acid. The solution was stirred for
15 minutes at room temperature and then cooled to -65C. in
a dry-ice acetone bath under a nitrogen atmosphere. 1110 mg.
. ~ .
20 of chromium trioxide were dissolved in 13 ml. of glacial
acetic acid and 2 ml. of water. This solution was added in
dropwise fashion to the solution of 4'-deoxy-4-desacetylleuro- `
, , ~
sidine. The reaction mixture was stirred in the temperature -
range -60 to -65C. for one hour and then quenched by the
addition of 35 ml. of 14 M aqueous ammonium hydroxide. The
reaction mixture was next poured onto ice and the resulting
aqueous suspension extracted several times with chloroform.
The chloroform extracts were combined, washed with water,
and dried. Removal of the chloroform in vacuo yielded
~ ~ .
".~ ~ .
~ X-4730B -14-
10~8S~7
794 mg. of a residue shown by thin-layer chromatography to
contain essentially one-spot material besides the original
very low Rf impurity. This residue was chromatographed over
Woelm silica gel using an initial eluant of 20:1:1 ethyl
ether/diethylamine/toluene solvent mixture containing
0.9 percent methanol. The eluant was employed in 150 ml.
portions. The percent of methanol was increased for each
successive 150 ml. eluant portion up to 15 percent. Frac-
; tions shown to contain 4'-deoxy-4-desacetyl-1-formylleuro-
sidine by thin-layer chromatography were combined and
yielded 293 mg. of pure 4'-deoxy-4-desacetyl-1-formyl-
leurosidine after evaporation of the solvent. The sulfate
salt was prepared as before.
4'-Deoxy-4-desacetylvincristine can be prepared as
above by hydrolysing 4'-deoxy VLB "A" to yield 4'-deoxy-
4-desacetyl VLB and then oxidizing this compound with CrO3
in acetic acid at -60C.
The compounds of this invention, as represented by
Formula I above, particularly those in which Rl is acetoxy,
are powerful anti-tumor agents. The compound 4'-deoxy-
4-desacetylleurosidine is also an oncolytic agent. In -`-
demonstrating the activity of these drugs against trans-
planted tumors in mice, a protocol was used which involved
the administration of the drug by the intraperitoneal route
at a given dose level for 7-10 days after innoculation with
the tumor or alternatively, on the first, fifth, and ninth
days after innoculation.
Table I gives the results of several experiments
in which transplanted tumors in mice were treated successfully
with a compound of this invention.
X-4730B -15-
1~8SZ'~
In the table, column 1 gives the name of the
compound; column 2, the transplanted tumor; column 3, the
dose level or dose leve~ range and the number of days the
dosage was administered; column 4, the route of admini- -;
stration, and column 5, the percent inhibition of tumor
growth or percent prolongation of qurvival time, e.g., B16.
(ROS is an abbreviation of Ridgeway osteogenic sarcoma; GLS
for Gardner lymphosarcoma; P1534(J) and L1210 are leukemias;
CA755 is an adenocarcinoma; and B16 is a melanoma.).
`''` :
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X-47 30B -18-
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1~88S'~7
In utilizing the novel compounds of this invention
as anti-tumor agents, either the parenteral or oral route of
administration may be employed. For oral dosage, a suitable
quantity of a pharmaceutically-acceptable salt of a ba~e
according to Formula II formed with a non-toxic acid, such
as the sulfate salt, is mixed with starch or other excipient
and the mixture placed in telescoping gelatin capsules each
containing from 7.5 to 50 mg. of active ingredients.
Similarly, the anti-neoplastically active salt can be mixed
with starch, a binder and a lubricant and the mixture
compressed into tablets each containing from the 7.5-50 mgs.
of salt. The tablets may be scored if lower or divided
dosages are to be used. Parenteral administration is
preferred however. For this purpose, isotonic solutions are
employed containing 1-10 mg./ml. of a salt of an indole-
dihydroindole of Formula II such as the sulfate salt. The
compounds are administered at the rate of from 0.01 to
1 mg/kg. and preferably from 0.1 to 1 mg./kg. of mammalian
body weight once or twice a week or every two weeks de-
pending on both the activity and the toxicity of the drug.An alternative method of arriving at a therapeutic dose is
based on body-surface area with a dose in the range 0.1 to
10 mg./meter squared of mammalian body surface every 7 or 14
days being administered.
In utilizing a compound of this invention clin-
ically, the clinical physician would administer the compound
initially by the same route and in the same vehicle and
probably against the same types of tumors as are indicated
for vincristine or VLB. The dose levels employed would
:
X-4730B -19-
1088SZ7
reflect the difference in do~e levels found in the treatment
of experimental tumors in mice, the dose levels of the
compounds of this invention being less than those used with
vincristine and VLB. In clinical tests, as with other
anti-tumor agents, particular attention would be paid to the
effect of the oncolytic compounds of this invention again~t
the ten "signal" tumors set forth at page 266 of "The Design
of Clinical Trials in Cancer Therapy" edited by Staquet
(Futura Publishing Company, 1973)
,
.'`'` .
. X-4730~ -20- ~`
~ .
'
