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

Participants

Reaction Steps

2,4-Diamino-5-(7,8-dimethoxy-2H-1-benzopyran-5-ylmethyl)pyrimidine (3.35 g, 10.6 mmol) and potassium t-butoxide (2.5 g) were warmed in dimethyl sulfoxide (25 mL) at 80° for 1.5 hr. The mixture was diluted with water and filtered. Two fractional crystallizations from 10% acetic acid gave 92% pure 2,4-diamino-5-(7,8-dimethoxy-4H-1-benzopyran-5-ylmethyl)pyrimidine acetate (0.62 g, 18%). The NMR was consistent with the structure with an 8% impurity of 2,4-diamino-5-(7,8-dimethoxy-2H-1-benzopyran-5-ylmethyl)pyrimdine acetate. Anal. calcd for C16H18N4O3.C2H4O2 : C, 57.75; H, 5.92; N, 14.96. Found: C, 57.68; H, 5.93; N, 14.96.

Provenance & Evidence