PROCESS FOR THE PREPARATION OF DERIVATIVES OF CYSTAMINE HAVING ONCOSTATIC ACTIVITY

PROCEDE DE PREPARATION DE DERIVES DE LA CYSTAMINE AYANT UNE ACITVITE ONCOSTATIQUE

English Abstract

ABSTRACT OF THE DISCLOSURE
"A process for the preparation of derivatives of
cystamine having oncostatic activity"
This invention relates to a process for the
preparation of compounds having oncostatic activity corresponding to the formula:
< IMG >
wherein one of the radicals A' or B' and A or B represents
-NO and the other radical represents a hydrogen atom,
which comprises effecting nitrosation of a carbamate
corresponding to formula (I):
(I)
< IMG >
wherein R represents a protective radical for the alcohol
function which may be hydrolysed in an acid medium.

Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined as
follows:
1. A process for the preparation of compounds
corresponding to the formula:
< IMG >
wherein one of the radicals A' or B' and A or B represents
-NO, and the other radical represents a hydrogen atom,
which comprises effecting nitrosation of a carbamate
corresponding to formula (I):
(I)
< IMG >
wherein R represents a protective radical for the alcohol
function which may be hydrolysed in an acid medium.
2. A process according to claim 1, wherein nitro-
sation is effected by sodium nitrite in formic acid.
-9-

3. A process according to claim 1, wherein R
represents the trityl radical.
4. A process according to claim 1, wherein the
reaction is carried out at a temperature of from 5 to
20°C.
5. A process according to claim 1, wherein the
carbamate corresponding to formula (1) is obtained by
the reaction of 2-chloroethyl isocyanate on the
corresponding S-cysteamine derivative.
6. The process for the preparation of the compounds
as claimed in claim 1 corresponding to the formula:
< IMG >
which comprises subjecting the mixture which is obtained
by carrying out the process according to claim 1 to
fractional crystallisation.
-10-

7. The process for the preparation of compounds
as claimed in claim 1 corresponding to the formula:
< IMG >
-11-

Description

This invention relates to a process for the
preparation of derivatives of cystamine having onco-
static activity.
French Patent No. ?,459,231, published
January 9, 1981 in the name of l'AGENCE NATIONALE DE
VALORISATION DE LA RECHERCHE (ANVAR), describes in
particular new compounds which have oncostatic activity
and which correspond to the following formula:
10 S-(CH2)2-NII-C-N-(CH2)2Cl and I-(CH2)2-~-C-NH-(CH2)2Cl
S-(CH2)2-NH-17-1N-(CH2)2 -(CH~)2-1N-Il-Nll-(CH2)2C
O NO NO
These products are equally active in mixtures, as
has been shown in the Examples of the above-mentioned
French patent.
This invention relates to a new process for the
" ~

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preparation Or this type of compound and to a particular
process which makes it possible to separate one of these
products which has particularly advantageous properties.
According to the process of the present
invention, compounds corresponding to the formula:
A 0 B
l 11 1
S-(CH2)2-N-C-N-(CH2)2G1
S-(CH2)2-N-ICI-N-(CH2)2C1
A'0 B'
wherein one of the radicals A' or B' and A or B represents
-N0, and the other represents a hydrogen atom, are
prepared by the nitrosation of the carbamate corres-
ponding to formula (I):
R_S-(CH2)2-NH-II-NH-(C~2)2 (1)
wherein R represents a protective radical for the alcohol
function which may be hydrolysed in an acid medium.
Detailed Description of the Invention
In the process according to the present invention,
nitrosation is preferably carried out by means of an

--3--
alkali rnetal nitrite in forrnic acid.
Among protective radicals for the alcohol function,
the trityl radical in particular should be mentioned.
This nitrosation reaction is preferably carried out
at a temperature of from 5 to 20C.
The carbamate corresponding to formula (I) may
i~ particular be prepared by the action of the cysteamine
derivative corresponding to formula (II):
R-S-(CH2)2-NH2 (II)
on 2-chloroethyl isocyanate.
The direct nitrosation product consisting of a
mixture of isomers may be used as a medicament for its
oncostatic properties, for the same reason as the mixtures
which are mentioned in the previously quoted ~rench
patent.
The different components of the nltrosation mixture
may be separated by known processes, in particular by
f`ractional crystallisation.
According to this invention, by means of fractional
crystallisation in a mixture of ether and ethyl acetate,
it is possible to isolate the mixed isomer corresponding
to the formula:

--4 --
O NO
Il I
lS-(CH2)2-NH-C-N-(CH2)2C1
S-(CH2)2-N-ICl-NH-(CH2)2C
N00
it being impossible to prepare this isomer by direct
synthesis.
This invention also relates to the use as a
medicament of the mixtures which are obtained by carrying
out the process according to the present invention, as
well as the use of the mixed isomer. These different
elements have oncostatic properties and they may be used
for the same reason as, and under the conditions which
have been described in, the previously mentioned French
patent.
Other characteristics of the process according
to the present invention will be revealed frorn reading
the ~ollowing Example.
EXAMPLE
Process for the synthesis of a mixture of various isomers
according to the present invention
S-trityl-N-(?-chloroethylcarbamoyl) cysteamine

-
--5--
A solution of 100 cm3 of anhydrous ether and 2.8 g
(88 x 10 mols) of S-trityl cysteamine is agitated at
about 0C and mixed dropwise with 0.77 cm3 ~9 x lO mols)
of 2-chloroethyl isocyanate. After the addition, the
mixture is left to return to ambient temperature and
agitation is maintained over a period of 12 hours.
The resulting cream precipitate is drained, washed
with iced ether and dried in a vacuum desiccator over
phosphoric anhydride. M.P. = 80-85C. 3 g of cream
1~ powder are recovered which crystallise from dichloromethane
in the f`orm of cream needles. M.P. = 96-97C.
Y 24 25 2 ( 5)
calculated (%) : C 67.84 H 5.88 N 6.59
found (%) : C 67.52 H 5.92 N 6.27
Production of CNCC by nitrosation of S-trityl N-(2-chloro-
.
ethylcarbamoyl) cysteamine
424.5 mg (10 3 mols) of the S-trityl carbamate
mentioned above are dissolved in 5 cm3 of pure formic
acid at ambient temperature. This results in a yellow
colouring of the solution and in the formation of a
triphenylcarbinol precipitate.
The reaction mixture is then brought to about
10C and thereafter mixed with 276 mg (4 x 10 3 mols) of
sodium nitrite over a period of 1 hour. I'he triphenyl-

--6--
carbinol precipitate is drained and the mother liquors
are mixed with 50 cm3 of iced distilled water. The resulting
orange oil is extracted using 3 x 50 cm3 of ethyl acetate.
~he organic phases which are collected are washed
with distilled water (2 x 50 cm3), with an iced saturated
solution of aqueous sodium bicarbonate (50 cm3), then
with distilled water up to a neutral pH. The organic
solution is then dried over sodium sulphate and evaporated
to dryness under vacuum. Two ~V visible spots are detected
in ccm (eluant; ether-hexane 8-2), Rf = 0.15 and 0.4.
The two products (total yield 70D~) are separated
over a column of dry silica ~Kieselgel 60, 70-230 mesh,
Merck) with an eluant consisting of a mixture of ether
and hexane 7-3.
The first majority product (Rf - 0.4) crystallises
in a mixture of ether and hexane tv/v). Yellow crystals
M.P. _ 77-78C. Yield 60%.
Compared to CNCC, this product is identical in
all points to the one described in the previous French
patent (analysis I~, NMR, IH, HPLC). It is possible to
isolate the pure mixed isomer by five successive
recrystallisations of this CNCC, consisting of a mixture
of isomers, in ether-ethyl acetate ~15-1).
A compound corresponding to the empirical formula
C1oH18S2N~04C1 is then obtained, having a melting point
of from 83 to 84C and having an infrared spectrum (KBr)V
~ r~ rk

cm of : (NH) 3325; (CH) 3000, 2960, 2930, 2910; (C-0)
1690 ; (amide) 1525 ; (N-N0) 1480 ; and an NMR spectrum
( 3)
NH : (m) centred at 7.40 ppm ; 2 H exchangeable ir D20
2 N0 : (m) centred at 4.17 ppm ; 4 H
NH-CH2 ; CH2C1 (with N0 on the side of sulphur) ; (m)
centred at 3.80 ppm ; 6 H
CH2Cl (with N0 on the side Or chlorine) : (t) centred at
3.49 ppm ; 2 H
S CH2 (N0 on side of chlorine) : (t) centred at 2.99 ppm ;
2 H
S CH2 (N0 on side of sulphur) : (m) centred at 2.71 ppm ;
2 H.
The second product Rf = 0.15 which is obtained
during the nitrosation of the S-trityl carbamate was also
successfully isolated by chromatography over silica. The
yield thereof is less than 5%. It was identified by proton
NMR as being a nitroso derivative of cysteamine.
NMR spectrum (CDC13) HS : (t) 1.15 ppm
Formula: HS - CH2~ CH2 ~ X ~ ~ CH2 C 2
1) A = H, B = N0
2) A = N0, B - H.
Pharmacodynamic tests made it possible to
determine for the mixed isomer an acute LD 50 by an

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intraperitoneal rnethod of 95 mg/kg.
1 0 '
1~