Patent ID: 6897307

Claim:
A process for preparing 2,6-diaminopurine derivatives or an acid addition salt thereof comprising (i) reacting a purine compound having formula (V) with an amine compound having formula (VI) in the presence of a tertiary amine at a pH of 7 to 14 to form a 6-substituted aminopurine derivative having formula (I) wherein X and Y are independently a halogen; and (ii) reacting the 6-substituted aminopurine derivative with an aromatic amine having formula (II) in the presence of an acid catalyst at a pH of 0.1 to less than 7 to form 2,6-diaminopurine derivative having formula (III) or acid addition salt thereof wherein X is a halogen; R 1 and R 2 are independently selected from the group consisting of hydrogen, alkyl, alkenyl, cycloalkyl, benzocycloalkyl, cycloalkylalkyl, aralkyl, heterocyclic group, alkoxy, and a group having formula (IV) R 3 , R 4 , R 5 , R 6 , R 7 R 8 , R 9 , R 10 , R 11 and R 12 are independently selected from the group consisting of hydrogen, halogen, alkyl, alkoxy, —N(R 13 )R 14 , —SO 2 N(R 15 )R 16 , C 1 -C 4 -alkylene-SO 2 N(R 15 )R 16 and —CON(R 17 )R 18 ; or, when R 1 and R 2 , or two of R 3 , R 4 , R 5 , R 6 , R 7 R 8 , R 9 , R 10 , R 11 and R 12 , are attached to adjacent carbon atoms on the indicated benzene rings, they denote, together with the carbon atoms to which they are attached, a carbocyclic group having 5- to 10-ring atoms or a heterocyclic group having 5- to 10-ring atoms of which one, two or three are hetero atoms selected from the group consisting of nitrogen, oxygen and sulfur; R 13 is alkyl; R 14 is alkyl or —COR 19 wherein R 19 is selected from the group consisting of alkyl, haloalkyl, alkoxy, alkoxyalkyl, alkoxycarbonyl, and alkoxycarbonylalkyl; or R 13 and R 14 , together with the nitrogen atom to which they are attached, denote a heterocyclic group having 5- or 6-ring atoms of which one or two are hetero atoms selected from nitrogen, oxygen and sulfur; R 15 is hydrogen or alkyl; R 16 is selected from the group consisting of hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, and alkoxycarbonylalkyl; or R 15 and R 16 together with the nitrogen atom to which they are attached denote a heterocyclic group having 5- or 6-ring atoms of which one or two are hetero atoms selected from nitrogen, oxygen and sulfur; and R 17 and R 18 are independently hydrogen or alkyl.