Aluminium lithium hydride → 5-Benzyl-2-(4-fluorophenyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine

Participants

Reaction Steps

To a solution of Intermediate 1D (23.00 g, 71.6 mmol) in THF (230 mL) under N2 at −10° C. was added LAH (59.6 mL, 2.4 M solution in THF, 143 mmol). Reaction mixture was allowed to stir at room temperature for 12 h. Reaction mixture was quenched with ice-cold water and filtered through CELITE® pad and the filtrate was extracted with chloroform (3×150 mL) The combined organic layer was washed with brine, dried over Na2SO4, filtered and concentrated. The residue was triturated with diethyl ether (2×150 mL) and the resulting solid was filtered, rinsed with diethyl ether and dried to afford Intermediate 1E (17 g, 77%). MS(ES): m/z=308 [M+H]+; 1H NMR (300 MHz, CDCl3) δ ppm 7.67-7.82 (m, 2H), 7.31-7.47 (m, 514), 7.01-7.14 (m, 2H), 6.19 (s, 1H), 4.22 (t, J=4.2 Hz, 2H), 3.73 (s, 2H), 3.70 (s, 2H), 2.97 (t, J=5.6 Hz, 2H).

Provenance & Evidence