Potassium Carbonate → HCID 14867563, compound

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To a suspension of 6-cyclohexyl-4,7-dihydro-2-phenyl-5H-pyrazolo[1,5-a]pyrrolo[3,4-d]pyrimidine-5,8(6H)dione (2.00 g, 5.75 mmole) and potassium carbonate (795 mg, 5.75 mmole) in dry dimethylformamide (DMF, 30 mL) was added methyl idodide (0.72 mL, 12 mmole). The flask was stoppered tightly and stirred at room temperature for 24 hours. The mixture was diluted with water (150 mL), stirred for 10 minutes and suction filtered. The collected solid was washed once with water and once with 95% ethanol. Drying under vacuum left 1.91 g of white powdery solid. Crystallization from 95% ethanol (500 mL) afforded the titled product as fine white needles (1.73 g, 83%, m.p. 276°-279°). 1H NMR (CDCl3, δ) 8.05 (m, 2H, 2-phenyl H), 7.45 (m, 3H, 3,4-phenyl H), 6.45 (s, 1H, pyrazole-H), 4.33 (s, 2H, lactam CH2), 4.16 (s, 3H, CH3), 4.15 (m, 1H, cyclohexyl CH), 1.1-2.0 (m, 10H, cyclohexyl CH2); IR (mull, cm-1) 1693, 1627, 1590, 1574; UV (ethanol) λmax (ε) 206 (27,300), 226(23,920), 268(33,740), 285sh(15,570), 295(10,940), 338(6,090); MS m/e (rel. intens.) 363 (M+1, 25) 362 (M+, 100), 319(35), 280(66); Analysis calc'd for C21H22N4O2 =C, 65,59; H, 6.12 N, 15.46; Found=C, 69.64; H, 6.21; N, 15.43. TLC (silica, ethylacetate) Rf 0.80.

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