Benzoic Acid → Acetophenone

Participants

Reaction Steps

Scheme 9 depicts synthesis of 2-amino-4-aryl thiazoles of the formula (37) (wherein R4, R5, R6, R7, R8 and R9 are as defined above in description) which is prepared from acetophenones of the formula (36) using known approaches. Certain di- and tri-substituted acetophenones were not commercially available and they were prepared from the corresponding benzoic acid derivative of formula (32) in three steps. Thus, acid of formula (32) was converted to the corresponding acid chloride of formula (33) using oxalyl chloride in the presence of catalytic amounts of DMF in dry dichloromethane. The acid chloride of formula (33) was converted to corresponding Weinerb amide of formula (35) by treating with N,O-dimethylhydroxylamine hydrochloride of formula (34) in the presence of a suitable base such as triethylamine. The addition of methyl magnesium iodide to Weinreb amide of formula (35) afforded acetophenone derivative of formula (36).

Provenance & Evidence