Ethyl Acetate → 2-(2-Ethyl-4-formylphenylimino)-1-cyclopentyl-3-thia-1-azaspiro[4.4]nonane

Participants

Reaction Conditions

Reaction Steps

2-(4-Cyano-2-ethylphenylimino)-3-thia-1-azaspiro[4.4]nonane was prepared in a manner analogous to Method C2a and the thiazolidine was alkylated in a manner analogous to Method D2b to give 2-(4-cyano-2-ethylphenylimino)-1-cyclopentyl-3-thia-1-azaspiro[4.4]nonane. To a solution of 2-(4-cyano-2-ethylphenylimino)-1-cyclopentyl-3-thia-1-azaspiro[4.4]nonane (0.21 g, 0.60 mmol) in anh. toluene (20 mL) at −78C. was added DIBAL (1.0M in toluene, 1.20 mL, 1.20 mmol). The reaction mixture was stirred at −78° C. for 3 h, then EtOAc (3 mL) was added at −78° C., stirring was continued for 0.5 h, and wet silica gel (5% water, 2 g) was added. The reaction mixture was warmed to room temp., stirred for 3 h, then filtered through a pad of through Celite®. The filtrate was concentrated under reduced pressure, and the residue was purified by preparative TLC (30% EtOAc/hex) to give 2-(2-ethyl-4-formylphenylimino)-1-cyclopentyl-3-thia-1-azaspiro[4.4]nonane as a white solid (0.16 g, 75%): mp 104-105° C.

Provenance & Evidence