Chloroacetyl chloride → 2-Chloro-1-[5-(2,4-Dichlorobenzoyl)-1,2,4-trimethyl-1H-pyrrol-3-yl]-ethanone

Participants

Reaction Steps

A solution of 48.65 g (0.17 mole) of (2,4-dichlorophenyl)(1,3,5-trimethyl-1H-pyrrol-2-yl)-methanone (5) in 480 mL 1,2-dichloroethane was cooled in an ice bath and 53.5 g (0.425 mole) of AlCl3 was added in four portions. A 33.5 mL portion of (0.425 mole) chloroacetyl chloride was added dropwise. The ice bath was removed and the reaction allowed to stir for 3 h under argon. A 10 g sample of AlCl3 was added and the reaction was stirred overnight. The mixture was poured into 1N HCl/ice and the organic layer was separated. The aqueous layer was extracted twice with methylene chloride. The organics were combined and washed with water, NaHCO3, water, brine, and dried (MgSO4). The solvent was evaporated in vacuo and the residue recrystallized from methylcyclohexane to give 53.50 g of product: mp 100-102° C.; mass spectrum (Cl—CH4) m/z=358 (M+1); NMR 300 MHz (CDCl3) d 7.55 (s, 1H); 7.4 (s, 2H); 4.4 (s, 2H); 3.7 (s, 3H); 2.5 (s, 3H); 1.9 (s, 3H). Anal Calcd for C16H14NO2: C, 53.58; H, 3.93; N, 3.91. Found: C, 53.48; H, 3.81; N, 3.93.

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