Michael Henry Hockley

Novel Preparation of 1-Aryl-3-(2-hydroxyphenyl)-2-pyrazolin-5-ones and their Conversion into 2-Aryl-4-methyl[1]benzopyrano[4,3-c]pyrazol-3(2H)-ones†

1-Aryl-3-(2-hydroxyphenyl)-2-pyrazolin-5-ones are prepared from 4-hydroxycoumarin and arylhydrazines and then cyclised with triethyl orthoacetate to give 2-aryl-4-methyl[1]benzopyrano[4,3-c]pyrazol-3(2H)-ones.

Regioselective Addition of Grignard Reagents to Isoxazole-4,5-dicarboxylate Esters

Regioselective mono-addition of a range of Grignard reagents with the 5-esters of 3-methylisoxazole-4,5-diesters affords 5-keto derivatives instead of tertiary alcohols which is explained by the complexing ability of the isoxazole oxygen atom and by the electron withdrawing effect of the isoxazole ring.