It was found that the reaction of 5-arylfurfurilamines with maleic anhydride leads to the formation of 6-aryl-3a,6-epoxyisoindole-7-carboxylic acids (the cyclic form), which in solution are in dynamic equilibrium with N-furfurylmaleinamides… Click to show full abstract
It was found that the reaction of 5-arylfurfurilamines with maleic anhydride leads to the formation of 6-aryl-3a,6-epoxyisoindole-7-carboxylic acids (the cyclic form), which in solution are in dynamic equilibrium with N-furfurylmaleinamides (the open form). During the esterification of these tautomeric mixtures with methanol in the presence of a catalytic amount of sulfuric acid, methyl esters of 5-aryl-7a-hydroxy-7-methoxy-3-oxo-2,3,3a,4,7,7a-hexahydro-1H-isoindole-4-carboxylic acids, unexpected cleavage products of the 3a,6-oxo bridge of the cyclic form, are formed diastereospecifically. The structure of the obtained products was confirmed by X-ray structural analysis.
               
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