反应详情

A solution of 4-toluenesulphonylmethyl isocyanide (4.9 g, 25.2 mmol) and methyl trans-cinnamate (4.0 g, 24.7 mmol) in diethyl ether (40 ml) and dimethyl sulphoxide (20 ml) was added drop-wise over 30 minutes to a stirred suspension of sodium hydride (60% dispersion, 1.25 g, 31.3 mmol) in diethyl ether (100 ml) under nitrogen. After 20 minutes a further portion of dimethyl sulphoxide (25 ml) was added to the reaction vessel. The mixture was stirred for 1 hour then water (200 ml) was cautiously added. The product was extracted into dichloromethane (1×400 ml and 1×250 ml) then the combined dichloromethane layers were dried (Na2SO4) and the solvent removed in vacuo. The residue was purified by flash chromatography over silica gel eluting with a gradient of heptane:ethyl acetate:dichloromethane 2:1:0→1:1:1. Appropriate fractions were combined and the solvents removed in vacuo to leave 4-phenyl-1H-pyrrole-3-carboxylic acid methyl ester as a white solid (1.55 g, 31%). TLC (single spot, Rf=0.25, heptane:ethyl acetate 2:1), HPLC-MS (main UV peak with Rt=7.849 mins, 202.1 [M+H]+, 425.1 [2M+Na]+).

1. extractionThe product was extracted into dichloromethane (1×400 ml and 1×250 ml)
2. dry with materialthe combined dichloromethane layers were dried (Na2SO4)
3. customthe solvent removed in vacuo
4. customThe residue was purified by flash chromatography over silica gel eluting with a gradient of heptane:ethyl acetate:dichloromethane 2:1:0→1:1:1
5. customthe solvents removed in vacuo