GB744869A - Improvements relating to 2-substituted-mercapto-6-disubstituted-amino-8-mercaptopurines and salts thereof - Google Patents

Abstract

The invention comprises purine derivatives of the formula <FORM:0744869/IV(a)/1> where R1 is alkyl or mononuclear aralkyl and R2 and R3 are alkyl, mononuclear aryl or mononuclear aralkyl or with the N atom form a 6-membered ring. These are made by treating 2-alkylthio (or aralkylthio)-4:5-diamino-6-NR2R3-pyrimidines with carbon disulphide in an inert solvent, preferably at 25-100 DEG C. They form salts with strong acids such as hydrochloric, sulphuric, phosphoric and picric, and also with alkali, alkaline earth and heavy metals. The mercapto group may be alkylated and the products then alkylated in the 7- or 9-position; if desired the sulphur groups can be removed by reduction. The products of the invention may also be used for making the purine derivatives of Specification 744,865. Examples show the production of the following substituted purines: 2-methylthio-6-dimethylamino - 8 - mercapto, 2 - methylthio - 6 - diethylamino - 8 - mercapto, 2 - methylthio - 6-N - methylanilino - 8 - mercapto, 2 - methylthio - 6 - butylbenzylamino - 8 - mercapto and 2 - benzylthio - 6 - piperidino - 8 - mercapto. Other radicals specified for R1 are ethyl, propyl, butyl and substituted benzyl; R2 and R3 may also be propyl, substituted phenyl or substituted benzyl and NR2R3 may be morpholino. 2 - (Substituted mercapto) - 4:5 - diamino - 6-NR2R3-pyrimidines are obtained from the corresponding 2:4:6-trisubstituted pyrimidines by treatment with nitrous acid to give the 5-nitroso derivatives and reduction of the latter. 2- (Substituted mercapto) - 4 - amino - 6-NR2R3-pyrimidines are made as in Specification 744,867 from 2 - mercapto - 4 - amino - 6-hydroxypyrimidine by alkylation or aralkylation of the mercapto group, replacement of hydroxyl by halogen and reaction with HNR2R3.