SYNTHESIS OF HETEROCYCLIC-SYSTEMS WITH A CARBOHYDRATE FRAGMENT .4. UNUSUAL REACTIVITY OF LEVOGLUCOSENONE WITH RESPECT TO ALPHA-AMINOAZOLES AND BETA-DICARBONYL COMPOUNDS

Levoglucosenone reacts with alpha-aminonzoles to yield azolo[1,5-a]pyr imidine systems fused with a carbohydrate fragment. The reaction oocur s much more smoothly than in the case of other alpha,beta-unsaturated ketones, The reactions of levoglucosenone with beta-dicarbonyl compoun ds (dimedone, barbituric acid) in the presence of a base results in th e pyran ring closure. which has never been observed earlier in reactio ns of beta-dicarbonyl compounds with alpha,beta-unsaturated ketones un der the conditions of basic catalysis. The structures of products were established by IR and NMR spectroscopy.