Iodine → HCID 14541576, compound

Participants

Reaction Steps

This procedure is an adaptation of a general iodopyrrole formation procedure (Collman, J. P.; Chong, A. O.; Jameson, G. B.; Oakley R. T.; Rose, E.; Schmittou, E. R.; Ibers, J. A. J. Am. .Chem. Soc. 1981, 103, 516-533) where pyrrole (13) has been substituted for ethyl 5-carboxy-3-ethyl-4-methylpyrrole-2-carboxyate. A solution of NaHCO3 (15.7 g, 0.19 mol) in 60 ml H2O was heated to 50° C. in a 1 L round bottom flask. To this was added 700 ml of 1,2-dichloroethane followed by ethyl 3-ethyl-4-methylpyrrole-2-carboxylate (13) (Barton, D. H. R.; Zard, S. Z. J. Chem. Soc. Chem. Comm. 1985, 1098-1100. Sessler, J. L.; Johnson, M. R.; Creager, S.; Fettinger, J.; Ibers J. A. to be submitted to J. Am. Chem. Soc.) (10 g, 55 mmol). A solution of I2 (15.7 g, 62 mmol) and NaI (19.8 g, 0.13 mol) in 60 ml H2O was then added portionwise to the mixture over a 5 minute period. Undissolved I2 was washed into the mixture with H2O and the resulting mixture was heated at reflux for one hour. The mixture was then cooled to room temperature and crystalline Na2S2O3 (4 g) added to discharge excess iodine. The mixture was then transferred to a separatory funnel, the organic layer separated, and the aqueous phase washed with CHCl3 (3×50 ml). The combined organic layers were washed with a 5% solution of Na2S2O3 (3×50 ml), a 5% solution of NaHCO3 (3×50 ml), a saturated brine solution (3×50 ml), and dried over Na2SO4 before the solvent was removed on the rotorary evaporator to leave an off-white solid which was recrystallized from CH2Cl2 /hexanes giving a first crop of 11.8 g (70%) with m.p. 122°-124° C. (lit. Collman, J. P.; Chong, A. O.; Jameson, G. B.; Oakley R. T.; Rose, E.; Schmittou, E. R.; Ibers, J. A. J. Am. Chem. Soc. 1981, 103, 516-533 m.p. 120°-121° C.).

Provenance & Evidence