Diisopropylethylamine → HCID 86643335, compound

Participants

Reaction Conditions

Reaction Steps

Cis(±)4-{[(3,4-Dichloro-5-methyl-1H-pyrrol-2-yl)carbonyl]amino}piperidine-3-carboxylic acid hydrochloride (Intermediate 79; 1.84 g) was dissolved in anhydrous DMF (20 ml) under an argon atmosphere in a 100-ml round bottom flask. Methyl 2-bromothiazole-5-carboxylate (1.43 g) was added followed by N,N-diisopropylethylamine (3.6 ml) at room temperature. The reaction was heated to 55° C. for 14 h cooled to room temperature. The reaction mixture was diluted with EtOAc (250 ml) and washed with a saturated aqueous ammonium chloride solution (125 ml), followed by a saturated aqueous sodium chloride solution (100 ml). The EtOAc solution was dried over anhydrous MgSO4 and concentrated in vacuo. The crude product was purified by silica gel chromatography using 0-10% CH3OH in DCM. The recovered product was recrystallised from EtOAc to further enhance the diastereomeric excess, increasing it from a 90:10 cis:trans mixture to a 96:4 cis:trans mixture (by HPLC analysis). The recrystallised product was carried on to the next reaction (2 g). MS (ES−(M+H)+): 461, 463 for C17H18Cl2N4O5S; NMR: 1.71 (m, 1H), 1.91 (m, 1H), 2.16 (s, 3H), 2.81 (dt, 1H), 3.42 (m, 2H), 3.74 (s, 3H), 3.86 (m, 1H), 4.34 (m, 2H), 7.43 (d, 1H), 7.88 (s, 1H), 8.50 (brs, 1H), 12.06 (s, 1H).

Provenance & Evidence