6-OXO-TETRAHYDROPYRAN DERIVATIVES AND CYANOMETHYL-AZETIDINONES

摘要

The invention relates to a process for the preparation of the compound of the formula I, I which comprises (a1) splitting off the ethylene ketal protecting group from the azetidinone derivative of the formula IVa, IVa reducing the compound of the formula III thus obtained, III treating the resulting compound of the formula II II with concentrated aqueous hydrogen chloride solution; or (a2) reducing the compound of the formula III, treating the compound of the formula II thus obtained with concentrated aqueous hydrogen chloride solution; or (a3) treating the compound of the formula II with concentrated aqueous hydrogen chloride solution; and isolating the compound of the formula I thus obtained from the reaction mixture. The compound of the formula I is useful as an intermediate in the production of thienamycin, a highly potent antibiotic.