Triethylamine → Trans-6-cyano-4-(ethoxycarbonylamino)-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-ol

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Reaction Steps

To trans-4-amino-6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-ol (1.09 g) and triethylamine (0.77 ml) in dichloromethane (20 ml), cooled in an ice bath, was added ethylchloroformate (0.67 ml). The mixture was allowed to attain room temperature and stirred for 2 days. The reaction mixture was washed with water and dried over anhydrous magnesium sulphate. Filtration and evaporation and chromatography (chromatotron, gradient elution: 10-30% Ethyl acetate-pentate) gave one fraction (456 mg) which was recrystallised from ethyl acetate-pentane to give the compound of this example (319 mg); mp 147°-148° C.

Provenance & Evidence