washing with dichloromethane the filtrate was concentrated to yield 0 43 g 88 of orange solid 1 ms m z 395 m 23 373 m 1 cleavage of carboxylic ester 5 r 2 2 4 dimethylphenyl r 3 h r 4 me to a suspension of ester 5 2 75 g 6 94 mmol in acetone 50 ml was added aqueous 1 m naoh 100 ml after stirring at room temperature for 24 hours the reaction mixture was diluted with 100 ml of water and washed with dichloromethane 2 u00d7 100 ml the aqueous layer was cooled to 0 u00b0 c and acidified with concentrated hcl the mixture was filtered and washed with water to yield 1 84 g 77 yellow solid 6 ms m z 366 m 23 343 m 1 preparation of amide 7 r 2 2 4 dimethylphenyl r 3 h r 4 me r 5 u2550 h r 6 me a solution of carboxylic acid 6 0 337 g 0 98 mmol in thionyl chloride 10 ml was heated at reflux for 1 hour the solution was cooled and concentrated in vacuo the residue was diluted with ccl 4 and concentrated to remove the residual thionyl chloride the residue was then dissolved in thf 3 5 ml and added to a 0 u00b0 c solution of methylamine 1 47 ml of 2 0 m solution in thf 2 94 mmol in 6 5 ml thf the reaction was warmed to room.