Verfahren zur Herstellung des cancerostatisch wirksamen 5-Azacytidins

1,050,899. 5-Azacytosines. CESKOSLOVENSKA AKADEMIE VED. Dec. 21, 1964 [Dec. 22, 1963], No. 51786/64. Heading C2C. 5-Azacytosines of the general formula where R1 is a peracylglycosyl group or the glycosyl group, R2 is H or a C 1-4 alkyl group, R3 and R4 are either or both H and/or aralkyl and/or C 1-4 alkyl groups, are prepared by reacting a peracylglycosyl isocyanate with an S-alkylisothiourea where R5 is a C 1-4 alkyl group or an aralkyl group, condensing the resultant peracylglycosylisothiobiuret with an ortho ester of an aliphatic acid, where R6 is methyl or ethyl and reacting the resultant triazine with a compound and converting the product into the corresponding 1-glycosyl-5-azacytosine, e.g. by alcoholysis or ammonolysis.