Patent ID: 7595400

Claim:
A process for the preparation of a compound of the formula [1], wherein R 1 and R 2 are independently hydrogen, halogen, (C 1 -C 5 )-alkyl or (C 1 -C 5 )-alkoxy; R 3 is hydrogen; (C 1 -C 5 )-alkyl optionally substituted with one to three moieties independently selected from the group consisting of (C 1 -C 5 )-alkoxy, hydroxy, halogen, amino, (C 3 -C 7 )-cycloalkyl, heterocyclic ring and aryl in which the aryl ring is optionally substituted with one to three moieties independently selected from the group consisting of hydroxy, (C 1 -C 5 )-alkoxy, amino, mono-(C 1 -C 5 )-alkylamino or di-(C 1 -C 5 )-alkylamino; R 4 is hydrogen; (C 1 -C 10 )-alkyl, optionally substituted with one to three moieties independently selected from the group consisting of (C 1 -C 5 )-alkoxy, hydroxy, halogen, amino, mono-(C 1 -C 5 )-alkylamino, di-(C 1 -C 5 )-alkylamino and (C 3 -C 7 )-cycloalkyl, a heterocyclic ring and aryl in which the aryl ring is optionally substituted with one to three moieties independently selected from the group consisting of hydroxy, alkoxy, halogen, amino, mono-(C 1 -C 5 )-alkylamino and di-(C 1 -C 5 )-alkylamino; or a pharmaceutically acceptable salt thereof, which comprises condensing a compound of the formula [2] or its salt, wherein R 1 , R 2 , R 3 , R 4 are the same as defined above and R 5 is —OH or —O—(C 1 -C 5 )-alkyl, with a compound of formula [3], wherein R 6 is a chlorine or bromine.