HCID 20068714, compound → HCID 136027785, compound

Participants

Reaction Steps

A mixture of 2.25 g of 2-ethyl-4-hydroxydihydrothieno[3,2-d]pyrimidine and 2-ethyl-4-hydroxydihydrothieno[3,4-d]pyrimidine in phosphorus oxychloride (50 ml) was refluxed for 2 hours then cooled and concentrated under vacuum. The residue was dissolved in chloroform and poured into ice water. The mixture was basified with ammonia. The layers were separated and the aqueous phase extracted with chloroform. The combined organic extracts were washed with brine, dried (MgSO4) and concentrated. The residual orange oil was chromatographed on 140 g of silica eluting with ethyl acetate/hexane (1/4). Concentration of the first product fractions gave an oil, 1.05 g, shown by NMR to be 4-chloro-2-ethyldihydrothieno[3,4-d]pyrimidine. Concentration of the second product fractions gave an oil, 1.05 g, shown by NMR to be 4-chloro-2-ethyl-dihydrothieno-[3,2 d]pyrimidine.

Provenance & Evidence