Some azido- and epimino-sugars.
thesisposted on 19.11.2015, 08:46 by David Murphy
The chemistry of azido- and epimino-compounds, with particular reference to alkyl compounds, and to the sugar derivatives, has been reviewed. Methyl 2-azido-4, 6-0-benzylidene-2-deoxy-?-D-altroside, and the corresponding 3-azidoaltroside have been prepared by reaction of the corresponding 2,3-anhydromannoside and -alloside with sodium azide. The two azidoaltrosides have been converted, via their sulphonate esters to methyl 4,6-0-benzylidene-2,3- dideoxy-2,3-epimino-?-D-mannoside, and the corresponding alloside, respectively. The reaction of the 2,3-epiminoglycosides and their N-acyl derivatives with sodium azide has been studied. In all cases but one, trans-diaxia1 opening to give amino-azido-derivatives of D-altrose was observed; the 2,3-benzoylepiminoalloside gave a derivative of 3-azido-2-benzamido-D-glucose via trans-diequatorial opening. A degradative proof of configuration of these amino-azido-derivatives is described. The displacement of secondary sulphonyloxy groups in the probable absence of anchimeric assistance has been studied. Reaction of methyl 2-azido-4, 6-0- benzylidene-2-deoxy-?-D-altroside 3-toluene-p-sulphonate with sodium azide gave methyl 2,3-diazido-4,6-0-benzylidene 2,3-dideoxy-?-D-mannoside. Attempts to similarly displace the sulphonate group in the corresponding 3-azidoaltroside 2-toluene-p-sulphonate failed; reaction with hydrazine led to unsaturated product. The mechanism of this elimination is discussed. A number of attempts to prepare thio-aminosugar derivatives by reaction of sulphur-containing nucleophiles with the epiminoglycosides failed due to the stability of these products to attack by nucleophilic reagents. Methyl 4,6-0-benzylidene-2,3-dideoxy-2,3-epithio-?-D-mannoside has been prepared from the 2,3-anhydro-alloside by a convenient one step synthesis; this product and the corresponding epithioalloside were not attacked by azide ion.