Hydrazine hydrate (1:1) → 5-[3-(Cyclopentyloxy)-4-methoxyphenyl]pyrazolidin-3-one

Participants

Reaction Steps

To a suspension of 3-cyclopentyloxy-4-methoxycinnamic acid (7.9 g, mmol) in toluene (25 ml) is added hydrazine hydrate (2.91 n-A, 60 mmol). The reaction mixture is heated to 100° (bath temperature) for 24 hours. Toluene is partially removed and ether carefully added, and the product allowed to crystallize. The solid is filtered to give crude product (6 g). A crystallization from chlorofom-hexane gives the pure product (5 g) m.p. 185°-186°. 1H NMR (CDCl3) δ 7.02 (1H, s, NH--CO), 6.88 (3H, m, arom), 4.79 (2H, m, carbinolic and benzylic), 4.28 (1H, m, NH), 3.84 (3H, s, CH3O--), 2.79 (2H, d, --CH2CO), 1.9 (5H, m, cyclopentyl C-H), 1.61 (3H, m, cyclopentyl C-H); IR(KBr),3420,3220,3160,2960,1700,1660 cm-1 ; MS m/z 276 (M)+.

Provenance & Evidence