2-Mercaptoethanol → Ammonia

Participants

Reaction Steps

A solution (32 ml) of 0.53 g 2-ethyl-8-methyl-1-oxa-8-azaspiro[4,5]decane-3-one in dichloromethane was cooled in ice, 384 μl 2-mercaptoethanol and 2.05 ml boron trifluoride/ether complex were added in that order in an argon atmosphere, and the mixture was stirred at room temperature for 16 hours. The reaction mixture was poured into 23 ml of 20% aqueous solution of caustic soda, stirring was continued for about 15 minutes, and the two separate layers were collected. The aqueous layer was extracted with chloroform, the extract was joined to the organic layer separated above, and the combined solution was washed with saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate. The dried solution was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography using, as eluent, a mixed solvent of chloroform/methanol/conc. ammonia (20:1:0.1 by volume), giving 460 mg of 14-ethyl-10-methyl-1,13-dioxa-4-thia-10-aza-dispiro[4,1,5,2]tetradecane as oil. It was then converted to maleate by treatment with maleic acid in isopropanol.

Provenance & Evidence