| 摘要 |
<p>The invention comprises glucosamine derivatives of the formulae: <FORM:0924985/IV(a)/1> <FORM:0924985/IV(a)/2> <FORM:0924985/IV(a)/3> (wherein R1 is a halogen atom, an alkyl or alkoxy radical of at most 6 carbon atoms, a trifluoromethyl radical or a nitro group, R2 and R3 are each hydrogen or halogen atoms or alkyl or alkoxy radicals, X is oxygen or sulphur and Ac is an acetyl group) and their preparation by reacting a - or b -1,3,4,6-tetraacetyl-D-pyrano-glucosamine with the appropriately substituted phenyl isocyanate or isothiocyanate to give compounds IV, treating these with ammonia in a low alkanol to give compounds I and exposing these to ring closing conditions, e.g. heating in water or an aqueous or anhydrous organic acid or treating with a dilute mineral acid, to give compounds II. Examples are given.</p> |
