5-[3-(CYCLOPENTYLOXY)-4-METHOXYPHENYL]PYRAZOLIDIN-3-ONE synthesis

Yield:-

Reaction Conditions:

with hydrazine hydrate in toluene;

Steps:

1 5-[3-(Cyclopentyloxy)-4-methoxyphenyl]-3-pyrazolidinone

EXAMPLE 1 5-[3-(Cyclopentyloxy)-4-methoxyphenyl]-3-pyrazolidinone To a suspension of 3-cyclopentyloxy-4-methoxycinnamic acid (7.9 g, 30 mmol) in toluene (25 ml) is added hydrazine hydrate (2.91 ml, 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 chloroform-hexane gives the pure product (5 g) m.p. 185°-186°. ¹ H NMR (CDCl₃) δ7.02 (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, CH₃ O--), 2.79 (2H, d, --CH₂ CO), 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)⁺. Analysis for: C₁₅ H₂₀ N₂ O₃: Calculated: C, 65.22; H, 7.29; N, 10.14. Found: C, 65.45; H, 7.30; N, 9.97.

References:

US5191084,1993,A