Condensation of O-phthalaldehydic acid, part VI : synthesis of 3-arylphthalides and 1,3-diarylisobenzofurans

الملخص EN

The reaction of o-phtnalaldehydic acid (i) with thioanisole 3~niethylanisole, 2-bromo anisole and 4-tert-butyl thiophenol (2) in the presence of dilute acid afforded the corresponding 3-arylphthalides (3 a-c and 4) respectively, while with concentrated acid all these compounds except (2) afforded the corresponding 1,3-diarylisobenzofurans (6 a-c).

Compounds (6 a-c) show a dienic character and thus undergo fastly [4+2] cycloaddition reaction with maleic anhydride to afford, through Diels-Alder reaction, the adducts (8 a-c).

The structures of the products were confirmed through spectral and analytical data.