Synthesis of 2-Carbamoyl-2-Deoxy Glycosides |
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Authors: | Danuta Mostowicz Czesław Bełzecki Marek Chmielewski |
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Institution: | Institute of Organic Chemistry, Polish Academy of Sciences , 01-224, Warsaw, Poland |
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Abstract: | Abstract Recently we have reported the addition of trichloracetyl isocuyanate to glycals 1 1,2,3. The reaction led to the highly stereoselective formation of a mixture of unstable 2+2] and 4+2] cycloadducts 2 and 3. The isocyanate adds to the glycal moiety anti to the substituent at C-3. The addition of benzylamine to the reac6tion mixture led to N-deprotection of 2 and allowed us to isolate stable bicyclic β-lactams 4 1-3. We have shown also that 2 (a mixture of α-L-gluco and β-L-manno isomers) obtained from L-rhamnal 1 (R1dbnd]Ac, R2dbnd]CH3 under high pressure, when treated with methanol, underwent a rapid trans opening of the four-membered ring to give respective glycosides 5(β-L-gluco and α-L-manno isomers). On the other hand 3 (R1dbnd]Ac, R2dbnd]CH3) under the same conditions added a molecule of methanol to the Cdbnd]N double bond affording 6. |
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