Synthesis of 6,7-dideoxy-7-isothiocyanatoheptoses: stable fully unprotected monosaccharide isothiocyanates.
Methyl 6,7-dideoxy-7-isothiocyanato-alpha-D-gluco (manno)(galacto)-heptopyranosides have been synthesized in four steps by homologation of the respective methyl hexopyranosides via the corresponding heptopyranosydurononitriles. Neither intra- nor intermolecular thiocarbamate formation was observed, even under rather strenuous acidic or basic conditions. The reducing derivative 6,7-dideoxy-7-isothiocyanato-alpha-D-gluco-heptopyranose was also a stable compound in aqueous solution in the absence of base. Formation of a six-membered intramolecular cyclic thiocarbamate was achieved in DMF solution in the presence of triethylamine. The title compounds are the first examples of stable fully unprotected monosaccharide isothiocyanates.
Benito
J M
JM
Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Spain.
Oriz Mellet
C
C
García Fernández
J M
JM
D004126:Dimethylformamide / Q000737:chemistry; D006027:Glycosides / Q000138:chemical synthesis*; D006539:Heptoses / Q000138:chemical synthesis*; D017879:Isothiocyanates / Q000138:chemical synthesis*; D013696:Temperature
D006027:Glycosides; D006539:Heptoses; D017879:Isothiocyanates; D004126:Dimethylformamide