Patent ID: 6689896
Filing Date: 2004-02-10
Classification: A61P,C07C,C07D

Abstract:
A method for the preparation of a compound of the formula in which R4 is aryl; R2 is hydrogen, halogen or lower alkyl; R3 is halogen or lower alkyl; and n represents zero, 1 or 2; or a pharmaceutically acceptable salt thereof; which method comprises:(a) reacting a compound of the formula in which R4 has meaning as defined for formula A1 with a compound of the formula in which R2 and R3 have meaning as defined for formula A1 to obtain a compound of the formula (b) converting the nitro compound of formula D to a corresponding amine of the formula in which R2, R3 and R4 have meaning as defined for formula A1;(c) condensing the amine of formula E with an acylating agent corresponding to a carboxylic acid of the formula R1(CO)â€”(CH2)nâ€”COOHâ€ƒâ€ƒ(F) in which R1 is optionally substituted alkoxy, aryloxy, heteroaryloxy, aralkoxy, cycloalkoxy or heteroaralkoxy; and n has meaning as defined for formula A1 to obtain a compound of the formula in which R2, R3 and R4 have meaning as defined for formula A1; andd) hydrolyzing the compound of formula A2 to obtain the compound of formula A1 in which R2, R3, R4 and n are as described above; and if desired converting the compound of formula A1 to a pharmaceutically acceptable salt thereof.