Patent GB-1348289-A (GB)
Title: Thiopyrimidine nucleotide derivatives processes for their pre paration and compositions containing them
IPC: C07H19/10
Filed: 1971-08-10
Abstract: 1348289 Thiopyrimidine nucleotide derivatives MERCK PATENT GmbH 10 Aug 1971 [22 Aug 1970] 37535/71 Heading C2P [Also in Divisions A5 and C3] The invention comprises thiopyrimidine derivatives of the general formula in which R is B is the radical of a pyrimidine or purine base, X is S or NH, m is an integer from 1 to 3 and n is a whole number from 0 to 2000 and in which the sum of m and n is at least 2 and different B radicals may be present in the same molecule, their metal and ammonium salts, and the disulphides of the derivatives in which X is sulphur. They may be obtained by (a) reacting 2,4 - dithiouridine monophosphate or 2- thiocytidine monophosphate or a compound of the above general Formula (I) in which m=1 with an inorganic or organic ortho- or pyrophosphate, one of the reactants being in activated form, (b) treating a compound of Formula I but in which the XH group is replaced by a radical which can be substituted by XH with a compound of formula H 2 X, or (c) treating a compound I but in which at least one OH, SH or NH 2  group is present in a functionally modified form or in which a reducible functional group is present with a solvolysing or reducing agent respectively in order to liberate one of the groups OH, SH or NH 2 . The products I may be subjected to the action of a polymerizing enzyme, if desired in the presence of a further nucleotide, to form oligo- or poly-nucleotides and/ or treated with an oxidizing agent and/or treated with an ammonolysing agent to convert an SH group when present therein to an NH 2  group, if necessary in a multistage reaction. The substituent B is preferably a 2,4-dithiouracilyl, 2-thiocytosyl, or adenylyl radical. In method (a) one of the reactants must be present in activated form, e.g. as an imidazolidate, morpholidate, anilide, or activated ester, e.g. pnitrophenyl ester or 2-pyridyl ester. In method (b) the radical replacing the XH group is suitably a C 1 -C 4  alkyl mercapto or benzyl mercapto radical, a sulphonic acid radical (or salt thereof), a sulphonic alkyl or aryl ester radical, or a halogen atom, e.g. Cl or Br. In method (c) the functionally modified group may suitably be an acyloxy, acyl-mercapto or acylamido group, benzyloxy or triphenylmethoxy or may comprise neighbouring OH groups in acetal, ketal or orthoester-like form. Such groups are preferably solvolytically split off in an aqueous alkaline or weakly acid medium which may also contain an organic solvent. When an additional nucleotide is added during the above referred to enzyme polymerization it becomes incorporated in the polynucleotide formed which may thus contain different nitrogen base radicals, e.g. 2,4-dithiouracilyl and adenylyl. Suitable enzymes for the polymerization are polynucleotide phosphorylases and the polymerization is preferably effected in an aqueous medium at pH 5À5 to 9À5 preferably in the presence of a buffer and of an inorganic salt such as magnesium-, manganese (II)- or calcium chloride. The mono or polynucleotide products can be oxidized to the corresponding disulphides by means of oxidizing agents, e.g. iodine. When an SH group is present in a compound of Formula I it may be converted to an NH 2  group, e.g. treating a trialkylammonium salt of I (X=S) with gaseous ammonia in a solvent. Reducible functional groups such as benzyloxy, triphenylmethoxy, NO 2  or azido present in compounds corresponding to those of Formula I can also be converted to free OH or NH 2  groups by means of reducing agents, thus the disodium salt of 4-azido-2-thiopyrimidyl-(1<SP>1</SP>#,D-ribose)- 5<SP>1</SP>-diphosphate is converted to the disodium salt of 2 - thiocytidine - 5<SP>1 </SP>- diphosphate by reaction with zinc dust in aqueous acetic acid (see Example 7). Examples are also given for the production of 2,4-dithiouridine-5<SP>1</SP>-di-(and tri)phosphates and 2-thiocytidine-5<SP>1</SP>-di-(and tri- ) phosphates which are isolated in the form of their di-(or tri-)sodium salts, and of various polynucleotides. The products have antiviral and antitumour activity and may be used as active ingredients in pharmaceutical compositions of conventional type.