Patent ID: 6166243
Filing Date: 2000-12-26
Classification: C07C

Abstract:
A method for making a compound of the structural formula ##STR25## wherein R is selected from the group consisting of H, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.3 -C.sub.6 cycloalkoxy, haloalkyl, alkoxyalkyl, arylalkoxy, alkenyl, alkylthio, alkoxycarbonyl, alkylamino, heteroaryl, arylalkyl, haloalkoxy, aryloxy, and C.sub.3 -C.sub.6 cycloalkyl and R' is C.sub.1 -C.sub.6 alkyl, the wherein the method comprises the steps of:A) selecting as a starting material a compound of the structural formula ##STR26## B) reacting compound III with sodium nitrite in the presence of HCl to form the diazonium salt IV ##STR27## C) adding compound IV to freshly prepared alkali metal sulfite prepared by purging sulfur dioxide into an alkali metal hydroxide until the pH is between 7.3 and 7.5, thereby forming compound V ##STR28## D) reducing compound V with an alkali metal dithionite to form compound VI ##STR29## E) hydrolyzing compound VI under acid conditions to form compound VII ##STR30## and F) acylating compound VII to form compound I.