Patent ID: 6680384
Filing Date: 2004-01-20
Classification: C07D

Abstract:
A process for preparing a 4,6-diaminopyrimido[5,4-d]pyrimidine of the formula I, whereinR1 is a hydrogen atom or a C1-C6 alkyl group, R2 is an optionally substituted C6-C10 aryl group, R3 is a hydrogen atom or a C1-C6 alkyl group, and R4 is a hydrogen atom or an optionally substituted C1-C6 alkyl, C3-C6 alkenyl, C3-C8 cycloalkyl or a 4- to 7-membered, nitrogen-containing heterocycle group, or R3 and R4 together with the nitrogen atom linked to them are an optionally substituted saturated 5- or 6-membered nitrogen-containing heterocyclic group containing one or two nitrogen atoms or one nitrogen atom and one oxygen or sulfur atom, which process comprises the following steps: (a) treating a compound of formula II, wherein R1, R2, R3, and R4 are as herein defined and PG1 is a suitable protecting group, so as to cleave the protecting group, (b) treating the deprotected species formed by the preceding step with a reducing agent, to form a reduced intermediate, and (c) treating the reduced intermediate with an oxidising agent, to form the compound of the formula I.