Epimino derivatives

D. H. Buss, L. Hough, and A. C. Richardson, Some ring-opening reactions of 2,3-epimino derivatives, J. Chem. Soc. (1965) 2736-2743. 

J. Kroutil, T. Trnka, M. Budesinsky, and M. Cerny, Preparation of 2,3-dideoxy-2,3-epimino and 3,4-dideoxy-3,4-epimino derivatives of l,6-anhydro-/8-D-hexopyranoses by Mitsunobu reaction, Collect. Czech. Chem. Commun., 63 (1998) 813-825. 

The 2, 3 -epimino derivative of ribostamycin (149) was prepared from the corresponding 3 -tosyl derivative 148, using sodium hydride for the cyclization step. However, no intrinsic antimicrobial activity was observed for this epimino analog [80] (compounds 147-149). 

Of the eight epimino derivatives possible, only three are thus far known. l,6-Anhydro-2,3-dideoxy-2,3-epimino-j3-D-mannopyranose (166) was prepared379 from the amino derivative 162 on acylation, followed by treatment of 163 or 164 with sodium isopropoxide, and catalytic debenzylation of 165. When a benzoyl group, which is more-... 

A vast majority of the amino derivatives used as substrates in the synthesis of carbohydrate aziridines are A-substituted, mostly as A-acylamines or A-aryl(alk-yljsulfonylamines. Reaction of free amines has rarely been reportedin the carbohydrate field and difficult and incomplete cyclization was generally encountered. Paulsen and Stoye, however, reported spontaneous cyclization of 6-hydrazino-5-C-mesyl-D-hexofuranoses, obtained from 5,6-di-C-mesyl-hexofura-noses by treatment with hydrazine, into the A-amino-5,6-epimino derivatives." ... 

Appel reported that various aziridines may be obtained by the reaction of triphenylphospine, carbon terachloride, and triethylamine with A-substituted vicinal amino alcohols. Reaction of adjacent -methoxybenzylamino and alcohol groups at the 2 and 3 positions of butirosin A and B under these conditions afforded epimino derivatives of both antibiotics. ... 

A detailed study on the structure of 2,3- and 3,4-epimino derivatives of 1,6-anhydro-p-D-hexopyranoses has been made employing NMR and IR spectros-... 

The results for eleavage reaetions of A -substituted epimino derivatives of d-manno and D-allo eonfigurations with halo aeids are summarized in Tables IV and V, respeetively. 

Cleavage reactions of epimino derivatives of methyl 4,6-0-benzylidene-2,3-epimino-2,3-dideoxy-a-D-allopyranosides with ammonium halides led either to diaxial or diequatorial isomers, or mixtures of both (Table VI). 

Free epimino derivative 44 afforded products of trara-diequatorial cleavage only, whereas A-substitution with an electron-withdrawing group led to the formation of mixtures of both stereoisomers, with the diaxial isomer predominant. In the cleavage of benzyl glycosides 53 and 255, the authors proved the existence of an equilibrium between the diaxial isomer and the starting epimine, which led to preponderant formation of the diequatorial isomer. 

Cleavage Reactions of X-Benzyl- and X-Tosyl-3,4-epimino Derivatives of 1,6-Anhydro-p-D-gala-... 

Similar product ratios of deoxybutirosins (3-deoxy 2-deoxy = 5 1) have been observed by Okutani et The corresponding epimino derivative (335) of butirosin was prepared in 58% yield by nucleophilic attack of an amino group at C-2 displacing a 3-(9-phosphoryl leaving-group in a 5 1 BSA-MesSiCl mixture. 

In 1969, the azidolysis of A-benzoyl-2,3-epimino derivative 20 by NaNs was published. The azidolysis afforded a mixture of regioisomers in which the 3-azido derivative 360 preponderated (3 1 ratio). 

Other 2,3-epimino derivatives based on o-lyxose were also opened by sodium azide (R = CH2NHBz, R = CH2NHCbz, R = H ), and the same regioselectivity was observed. Formation of the C-3 regioisomer corresponds to a cleavage pathway having minimum activation energy as documented by ab initio calculations. ... 

The reactions of an epimino derivative of lincosamine with sulphides and the... 

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