Ethanol → N-Methyl-3-pyrrolidinyl Cyclopentylmandelate

Participants

Reaction Steps

A solution of 2 (2.20 g, 9.4 mmol) and N-methyl-3-pyrrolidinol (3, 1.30 g, 13 mmol) in 40 ml of n-heptane was heated until 20 ml of heptane had been distilled. About 0.003 g of sodium was added, and the solution was stirred and heated for 2 h as the distillation was continued. More heptane was added at such a rate as to keep the reaction volume constant. Additional sodium was added at the end of an hour. The solution was then cooled and extracted with 3N HCl. The acid extract was made alkaline with concentrated NaOH and extracted three times with ether. Removal of the dried ether solution gave a crude oil. Flash chromatography of the crude product on silica gel with 8:1 EtOAc:EtOH gave pure product 4 (2.053 g, 72%). Analysis for C18H25NO3. Calcd: C, 71.26; H, 8.31; N, 4.62. Found: C, 71.55; H, 8.44; N, 4.68. 1H NMR (CDCl3, 500 MHz): 1.27-1.35, 1.40-1.47, 1.54-1.60, 1.75-1.90 [8H, m, (CH2)4], 2.12-2.30, 2.52-2.57, 2.64-2.81 (6H, m CH2NCH2CH2), 2.33, 2.36 (3H, 2s, NCH3), 2.93 [(1H, p, CHC(OH)], 3.83 (1H, bs, OH), 5.23 (1H, m, CO2CH), 7.23-7.36, 7.64-7.67 (5H, m, Ph) ppm.

Provenance & Evidence