SUGAR LACTAMS AND LACTIM ETHERS, USEFUL PRECURSORS OF CYCLIC AMIDINES, FROM INTRAMOLECULAR NUCLEOPHILIC DISPLACEMENTS

The cyclisation of the conjugate base of O-isopropylidene-4-O-methanes ulfonyl-D-gulonamides gave the D-allonolactam acetals. Sodium methoxid e-promoted cyclisation of sopropylidene-4-O-methanesulfonyl-D-mannonon itrile gave the D-talonolactim ether. Tetrazole formation without isol ation of the intermediate azide was illustrated by the conversion of t he aforementioned nitrile sulfonate into the D-talonotetrazole. Cyclic amidines were prepared from the lactam and lactim ether derivatives. The D-allono derivatives were also converted into D-ribono-1,4 lactam and amidine derivatives. (C) 1997 Elsevier Science Ltd.