Phosphorus oxychloride → (R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine

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Reaction Steps

A mixture of (R)-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-ol (5.8 g, 38.6 mmol) in POCl3 (20 mL) was refluxed for 5 minutes. Excess POCl3 was removed under vacuum, and the residue was dissolved in DCM (50 mL). The mixture was then added to a saturated NaHCO3 solution (200 mL). The aqueous phase was extracted with DCM (3×100 mL), and the combined organic phases were dried and concentrated. The resulting residue was purified by silica gel chromatography, eluting with ethyl acetate to give (R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine (3.18 g, 49%). 1H NMR (CDCl3, 400 MHz) δ □8.81 (s, 1H), 3.47 (m, 1H), 3.20 (m, 1H), 3.05 (m, 1H), 2.41 (m, 1H), 1.86 (m, 3H), 1.47 (m, 3H).

Provenance & Evidence