Synthesis of alkyl glyco-pyranosides and -furanosides of 2-amino-2-deoxy-d-glucose. Crystal structure of 2-deoxy-2-[(4,4-dimethyl-2,6-dioxocyclohexylidenemethyl)amino]-α-d-glucopyranose

✍ Scribed by Ma de Gracia García-Martín; Consolación Gasch; Antonio Gómez-Sánchez; Ma Jesus Diánez; Amparo López Castro

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 984 KB
• Volume: 162
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(87)80214-8

✦ Synopsis

The reaction of 2-amino-2-deoxy-D-glucose hydrochloride with 5,5-dimethyl-2-phenylaminomethylene-1 ,fcyclohexanedione in MeOH in the presence of Et,N afforded 2-deoxy-2-[(4,4-dimethyl-2,6-dioxocyclohexylidenemethyl)amino]-~-~ucase (6) in yields >75%. Glycosidation of 6 with different alcohols (MeOH, CH,=CH-CH,OH, BnOH) under the Fischer conditions afforded mixtures of the corresponding aIky1 2-deoxy-2-[(4,4-dimethyl-2,6-dioxocyclohexylidenemethyl)amino]-a#-D-glucopyranoside and -a-D-ghicofuranoside.

Removal of the Nprotecting group gave high yields of the free aminodeoxyglyco-pyranosides and -furanosides. In addition to other known glycosides, ally1 and benxyl 2-amino-2deoxy-a-o-glucopyranoside and ethyl and ally1 2-amino-2-deoxy-a-D-glucofuranoside were obtained. An X-ray crystallographic study of 6 indicated that, in the solid state, it has the ar-~ cotiguration and that the pyranoside ring adopts the 4C, conformation.

INTRODUCITON

We have reported'** on the utility of the 2,2-dimethoxy-and 2,2-diethoxycarbonylvinyl groups for protecting the amino function of amino sugars during Fischer glycosidation. For example, using derivatives 1 and 2, methyl and ethyl