Phosgene → 9(+)-Fluorenylethyl chloroformate

Participants

Reaction Steps

N-[9H-(Fluorenyl-9-ethoxycarbonyl)]amino-4-benzoic acid was prepared from a solution of 2-(9-fluorenyl) ethanol (1.5 g, 7.1 mmol) in 10 ml of toluene to which was added dropwise with stirring a solution of phosgene in toluene (12.4 ml, 1.93M). After 0.5 hours, the solution was put under vacuum to remove excess phosgene, and concentrated to yield 2-(9-fluorenyl)ethyl chloroformate. This was then dissolved in 10 ml of dioxane and add to a solution of 4-aminobenzoic acid (1.0 g, 7.3 mmol) in 15 ml water. After 5 hours, the dioxane was evaporated, the solution diluted with an equal amount of water, rendered basic with sodium carbonate solution, and filtered to remove insoluble materials. Acidification with 10% HCl yielded a white precipitate, which was filtered and dried. Crystallization from aqueous DMF gave a white solid (1.22 g, 46%), mp 202° C. IR(KBr) 3342, 2964, 2666, 2543, 2363, 1699, 1676, 1609, 1594, 1524, 1509, 1477, 1414, 1313, 1293, 1266, 1177, 1069, 1049, 938, 853, 768, 750, 735 cm-1. 1H NMR (300 MHz, DMSO) δ 2.3(q, 2H, J=7.0), 400(t, 2H, J=7.0), 4.12(t, 1H, J=6.0), 7.29-7.88(m, 13H, 9.97(s, 1H). Anal. calcd for C23H19NO4 0.25H2O: C, 73:10; H, 5.20; N, 3.71. Found: C, 73.32; H, 5.23; H, 3.70.

Provenance & Evidence