1-N-acylation of gentamicin C1a by a cyclic, chiral .GAMMA.-amino-.ALPHA.-hydroxy acid related to the (S)-4-amino-2-hydroxybutyric acid.

Abstract
A semisynthetic aminoglycoside antibiotic 15, containing a cyclic .gamma.-amino-.alpha.-hydroxy acid, related to the 1-N-4-amino-2-hydroxybutyric acid (AHBA) side chain of butirosins and amikacin, was prepared. Conveniently protected 3,2'',6''-tris-N-tert-butoxycarbonylgentamicin C1a (12) was condensed with the phtalimido active ester 10 to give, after catalytic reduction and deprotection, the hitherto unknown 1-N-substituted gentamicin C1a 15. The requisite side chain was synthesized from the readily available D-(.sbd.)-quinic acid. The antibacterial properties of 15 are given.