Takahiro Torii

Syntheses of 3-fluoro-, 3-epi-3-fluoro-, and 3,3-difluoro-3-de(methoxy)sporaricin A☆

Abstract 3-Fluoro- ( 4 ), 3-epi-3-fluoro- ( 3 ), and 3,3-difluoro-3-de(methoxy)sporaricin A ( 5 ) have been prepared by reaction of diethylaminosulfur trifluoride with the corresponding precursors: 1,2′,6′-tris( N -benzyloxycarbonyl)-4- N , 5- O -carbonyl-3-de( O -methyl)sporaricin B ( 6 ), its 3-epi-3-hydroxy isomer ( 10 ), and the 3-oxo derivative ( 9 ). The structures of 3,4, and 5 were determined by 1 H-, 13 C-, and 19 F-n.m.r. spectroscopy.

Syntheses of methyl 6-deoxy-6-hydroxyamino-α-d-glucopyranoside, 6′-N-hydroxykanamycin A, and 6′-N-hydroxydibekacin

Abstract Methyl 6-deoxy-6-hydroxyamino-α- d -glucopyranoside has been prepared from methyl 6-amino-6-deoxy-α- d -glucopyranoside via oxidation with hydrogen peroxide in the presence of sodium tungstate [to give the corresponding 6-aldoxime ( 2 )], followed by reduction with sodium cyanoborohydride in an acidic medium. Acetylation of the Z isomer of 2 gave a nitrile derivative. The above oxidation-reduction procedure was applied to kanamycin A and dibekacin, starting from the corresponding 6′-amino- N -tosyl derivatives. On treatment with sodium in liquid ammonia, 6′-deamino-6′-hydroxyimino-1,3,3″-tri- N -tosylkanamycin A gave the corresponding N -detosyl derivative in good yield with the 6′-aldoxime group remaining intact, but, with 6′-deamino-6′-hydroxyimino-1,3,2′,3″-tetra- N -tosyldibekacin, the N -detosyl derivative ( 17 ) was obtained only by a very short reaction period. The antibacterial activities of 17 and 6′- N -hydroxydibekacin were demonstrated.