2,4-diamino-5-(7,8-dimethoxy-2-methyl-2H-1-benzopyran-5-ylmethyl)pyrimidine → 2,4-Diamino-5-(7,8-dimethoxy-2-methyl-4H-1-benzopyran-5-ylmethyl)pyrimidine

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Reaction Steps

A solution of 2,4-diamino-5-(7,8-dimethoxy-2-methyl-2H-1-benzopyran-5-ylmethyl)pyrimidine (967 mg, 2.94 mmol) and potassium t-butoxide (991 mg, 8.83 mmol) in dimethyl sulfoxide was maintained at 60°-70° for 0.5 hr under nitrogen. The solution was cooled and diluted with water (50 mL). The resulting precipitate (920 mg) was recrystallized from 95% ethanol to give the title compound as white crystals (820 mg, 85%), mp 215°-217° dec., structure confirmed by NMR spectrum. Anal. Calcd for C17H20N4O3 : C, 62.18; H, 6.14; N, 17.06. Found: C, 61.95; H, 6.20; N, 17.00.

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