Chloroacetic Acid → 2-Cyclohexylideneacetic acid

Beteiligte Stoffe

Reaktionsschritte

A mixture of 4.0 ml (0.031 mole) of diethyl phosphite and 4.46 g (0.093 mole) of 50% sodium hydride in mineral oil in 100 ml of 1,2-dimethoxyethane under nitrogen was treated with a solution of 2.93 g (0.031 mole) of chloroacetic acid in 30 ml of 1,2-dimethoxyethane, and the mixture was stirred until hydrogen gas evolution ceased. Then 3.20 ml (0.031 mole) of cyclohexanone was added and the mixture was stirred for 1 h, after which it was quenched by the addition of 5 ml of ethanol and then poured into 500 ml of water. The strongly basic solution was washed with ether to remove mineral oil (ether extract discarded), then acidified to pH 4 with conc hydrochloric acid and extracted with ether. The ether extract was dried (over MgSO4) and evaporated in vacuo to yield 2.35 g (54%) of cyclohexylideneacetic acid which was recrystallized from methanol/water; mp 90°-91.5° (literature mp 90°-92°, Beesley, Thorpe, and Ingold, J. Chem. Soc., 107, 1099 (1915)); Ir (CHCl3) 3600-2400 (--OH), 1700 (C=O), and 1650 (C=C) cm-1 ; 1H NMR (CDCl3) δ 1.60 (6, s, CH2CH2CH2CH 2 CH2C=), ##STR8## 5.50 (1, s, =CHCO2H), and 11.40 (1, s, --CO2H); Anal Calcd for C8H12O2 : C, 68.55; H, 8.63; Found: C, 68.45; H, 8.61.

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