INFLUENCE OF ULTRASOUNDS ON DIASTEREOSELE CTIVITY - SYNTHESIS OF CHIRAL IMIDAZOLIN-4-ONES

A three-step synthesis of imidazolidine-4-one has been realized. Sodiu m dithionite was a very efficient reagent for the last step, the reduc tion of a ketone. The reaction is slow under the normal conditions of heating and its diastereoselectivity is poor. Under the influence of u ltrasound, the selectivity and the yield are very good. The use of sod ium dithionite makes it possible to work in water and to avoid the use of hydrides.