Ethanol → HCID 131717469, compound

Participants

Reaction Steps

To a suspension of potassium carbonate (9.65 g, 69.9 mmole) in cyclohexylamine (8.0 mL, 69.9 mmole) was added ethyl 4-bromobutyrate (10.0 mL, 69.9 mmole) and the mixture was stirred at room temperature for 24 hours. The resulting solid mass was dissolved in methylene chloride (100 mL) and washed with water (100 mL). Evaporation of the organic phase under vacuum left a turbid oil which was dissolved again in methylene chloride (100 mL) and to it added 1 N aq. NaOH (100 mL). While cooling the mixture in a cold water bath, ethyl oxalyl chloride (7.8 mL, 70 mmole) was added and the reaction was stirred for 15 minutes. The methylene chloride layer was separated, dried over MgSO4, and evaporated under vacuum, leaving an amber oil. This was dissolved ini absolute ethanol (50 mL) and to it added a solution of ethanolic sodium ethoxide (21 wt.%, 26 mL, 70 mmole). The solution was refluxed on a steam bath for 1.5 hours, cooled and then most of the solvent removed under vacuum. The resulting tan chunky solid was suspended in water (250 mL) which had been made acidic with concentrated HCl (5 mL) and stirred vigorously at room temperature overnight, turning into a flocculent, lighter colored solid. This was collected by suction filtration, washed with water, and air dried. Crystallization from 1/1 ethanol/water (100 mL) gave, after cooling to 0° C., gave the subtitled ester, 1.80 g (15%) of light tan needles (m.p. 88°-89°). A second crop from 50 mL of the same solvent gave an additional 0.55 g of the ester for a total yield of 3.35 g (18%). 1H NMR (CDCl3, δ) 4.3 (m, 1H, NC-H), 4.25 (q, 2H, J= 7 Hz, OCH2), 3.30 (t, 2H, J=7 Hz, NCH2), 2.46 (t, 2H, J=7 Hz, NCH2CH2), 1.30 (t, 3H, J=7 Hz, CH3), 1.1-1.9 (m, 10H); IR (mull) 1658, 1613, 1242, 1226 cm-1 ; UV (ethanol) λmax (68 ) 251 (8180), 290(6730); MS m/e (rel. intens.) 267 (m+, 34), 221 (25), 193 (31), 186 (25), 150 (17), 140 (100); Exact mass calc'd for C14H21NO4 =267.1470; Found=267.1461; TLC (silica, 10% methanol/chloroform) Rf 0.7.

Provenance & Evidence