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Journal of the Brazilian Chemical Society

Print version ISSN 0103-5053On-line version ISSN 1678-4790


SRIVASTAVA, Rajendra M. et al. Synthesis of Cyclohexyl 6-O-Trityl-a-D-Threo-Hexopyranosid-4-ulo-(2,3:3',4')-2-Pyrazoline. J. Braz. Chem. Soc. [online]. 2002, vol.13, n.2, pp.158-164. ISSN 1678-4790.

Reaction of tri-O-acetyl-D-glucal (1) with cyclohexanol (2) using Ferrier's method provided the unsaturated cyclohexyl glucoside 3, which furnished the title compound 12 in a sequence involving hydrolysis, selective tritylation of oxygen at C-6, allylic oxidation with MnO2 and 1,3-dipolar cycloaddition with diazomethane. Starting from 6, product 17 was obtained in four steps. Semi-empirical molecular orbital calculations (AM1) were carried out for compound 12 which gave an idea about its stable conformation, and also supported the existence of the anomeric effect. Attempts to open the pyrazoline ring in 12 and 17 failed. Partial negative charge at C-3 was responsible for the lack of reactivity of 12 towards reduction of C=N bond.

Keywords : aminodeoxy sugars; Ferrier's rearrangement; 1; 3-dipolar cycloaddition; diazomethane; allylic oxidation.

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