Sodium Hydroxide → 5-(3-ethoxy-2-thienyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one

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Reaction Conditions

Reaction Steps

A mixture of 3 (1.15 g, 3.42 mmol), NaOH (284 mg, 7.1 mmol) in ethanol (11 mL) and water (34 mL) was heated at 80° C. for 65 h. After cooling to r.t. a white precipitate was formed. Filtration and drying under vacuum gave 0.625 g of the product. The filtrate was extracted with CH2Cl2, and the organic phase was washed with 1N HCl and brine, dried with MgSO4. Evaporation of the solvent gave additional product; mp: 151-152° C.; 1H NMR (CDCl3) δ 1.00 (t, J=7 Hz, 3 H), 1.54 (t, J=7 Hz, 3 H), 1.82 (sxt, J=7 Hz, 2 H), 2.86 (t, J=7 Hz, 2 H), 4.23 (s, 3 H), 4.34 (q, J=7 Hz, 2 H), 6.87 (d, J=6 Hz, 1 H), 7.37 (d, J=6 Hz, 1 H); MS (m/z): 319 (MH+).

Provenance & Evidence