Development of One-Pot Synthesis of New Antiarthritic Drug Candidate S-2474 with High E-Selectivity

A one-pot synthesis of S-2474 was developed to overcome the problems of a large number of steps, low stereoselectivity, low yield, a large amount of waste, and severe reaction conditions. Aldol-type condensation of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and N-ethyl-γ-sultam was carried out with LDA and then quenched with water. Dehydration proceeded under basic conditions, providing S-2474 directly as a single isomer on the benzylidene double bond. The reaction mechanism appears to involve a quinone methide intermediate. Environmental assessment of the development of this compound is also discussed in this paper.