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Synthesis of Iminosugars from alfa,beta-Unsaturated Lactones and N-Benzyl Nitrone

Panfil I., Urbańczyk-Lipkowska Z., Chmielewski M.

Polish Journal of Chemistry

2005

Vol. 79 / nr 2

239-249

1,3-Dipolar cycloadditions of N-benzyl nitrone 12 to D-glycero _-lactone 13 and to D-threo _-lactone 14 proceed with excellent stereoselectivity to provide only one adduct in each case, 16 and 17, respectively. The same reaction performed with L-erythro _-lactone 15 afforded two stereoisomers 18 and 19 in the ratio ca. 2.5:1. Cycloadducts 16-19 were subsequently subjected to a sequence of reactions involving hydrogenolysis of the N-O bond and intramolecular alkylation of the nitrogen atom by C-4 or C-5 carbon atom of the sugar backbone to afford 1,2-dideoxy iminosugars 25, 31, 38, 44 and 50 with a protected hydroxymethyl group at C-2 carbon atom.

A,B-unsaturated sugar D-lactones : Preparation and conjugate addition of hydroxylamines and hydrazines

Panfil I., Mostowicz D., Chmielewski M.

Polish Journal of Chemistry

1999

vol. 73 nr 7

1099-1110

Oxidation of 2,3-unsaturated glycosides with hydrogen peroxide in the presence of molybdenum trioxide as catalyst provides corresponding A, B-unsaturated sugar d-lactones via the anomeric hydroperoxide stage. Conjugate addition of N-substituted hydroxylamines and hydrazines to these d-enealdonolactones proceeds anti to the C-6 carbon atom. The adducts undergo rearrangement consisting in opening of the lactone ring and formation of 3-substitued isoxazolidin-5-one or 5-substitued pyrazolidin-3-one, respectively. Introduction of a leaving group to the polyol side chain of both heterocycles induces further rearrangements.