Diisopropylethylamine → HCID 178451904, compound

Participants

Reaction Conditions

Reaction Steps

To a dry 1000 mL round bottom flask under Nitrogen, is added 4-iodo-benzene-1,2-diamine (45 g), (S)-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester (41.39 g) and THF (450 ml). The reaction mixture is stirred until complete dissolution then cooled to 0-2° C. DIPEA (50.17 ml) is added dropwise to control the exotherm then HATU (80.38 g) is added in one portion. The reaction mixture is stirred in an ice bath for 3 hours and followed by HPLC to monitor completion of reaction. To this solution are added 500 ml of water and 500 ml of ethyl acetate. The aqueous phase is extracted twice with ethyl acetate. The organic phases are combined and evaporated half. To the organic phase is added 450 ml of acetic acid and the mixture is evaporated to 300 ml. This procedure is repeated 3 times for a residual of −470 ml, and the mixture is then heated at 50° C. over night. Toluene (200 ml) is added and evaporated to a small residue (repeated 6 times). To this solution is added 450 ml of ethyl acetate. The organic phase is washed with saturated sodium carbonate, dried over sodium sulfate, filtered and evaporated to dryness. The residue is purified on a pad of silica using 25% ethyl acetate/hexane mixture to give (S)-2-(5-Iodo-1H-benzoimidazol-2-yl)-pyrrolidine-1-carboxylic acid tert-butyl ester (67 g) as a beige powder.

Provenance & Evidence