3-Bromothiophene → 1-butyl-alpha-(3-thienyl)-1H-benzotriazole-5-methanol

Participants

Reaction Steps

To a stirred and cooled (-78° C.) solution of 7.2 parts of 3-bromothiophene in 70 parts of 1,1'-oxybisethane were added 30 parts of a 1-butyllithium solution 1.6M in hexane. After stirring for 20 minutes at this low temperature, a solution of 6 parts of 1-butyl-1H-benzotriazole-5-carboxaldehyde in 1,1'-oxybisethane was added to the previous mixture. The reaction mixture was stirred for 2 hours at -78°~-'° C. The whole was poured into 200 parts of ice water and the product was extracted three times with 56 parts of 1,1'-oxybisethane. The combined extracts were dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (98:2 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from 2,2'-oxybispropane. The product was filtered off and dried, yielding 5 parts (58.9%) of 1-butyl-α-(3-thienyl)-1H-benzotriazole-5-methanol; mp. 80° C. (int. 58).

Provenance & Evidence