[CH:1]([C:3]1[NH:7][C:6]([C:8]([OH:10])=O)=[C:5]([CH3:11])[CH:4]=1)=[O:2].C1C=CC2N(O)N=NC=2C=1.C(Cl)CCl.[NH:26]1[CH2:31][CH2:30][O:29][CH2:28][CH2:27]1>CN(C=O)C.C(OCC)(=O)C>[CH3:11][C:5]1[CH:4]=[C:3]([CH:1]=[O:2])[NH:7][C:6]=1[C:8]([N:26]1[CH2:31][CH2:30][O:29][CH2:28][CH2:27]1)=[O:10]
To a solution of 5-formyl-3-methyl-1H-pyrrole-2-carboxylic acid (306.3 mg, 2 mmol) in DMF (5 mL) was added HOBt (324.3 mg, 2.4 mmol), EDC (460.1 mg, 2.4 mmol) and then morpholine (0.21 mL, 2.4 mmol). The mixture was stirred at room temperature under nitrogen for overnight. The reaction was diluted with ethyl acetate and washed with sodium bicarbonate. The aqueous layer was extracted several times with ethyl acetate. The combined organic layer was washed with brine, dried, concentrated and column chromatographed (MeOH/DCM) to give 395 mg (89%) of 4-methyl-5-(morpholine-4-carbonyl)-1H-pyrrole-2-carbaldehyde as a light yellow foam solid. 1H NMR (360 MHz, DMSO-d6) δ 12.18 (br s, 1H, NH), 9.46 (s, 1H, CHO), 6.79 (s, 1H), 3.43 (m, 4H, 2×CH2), 2.29 (m, 4H, 2×CH2), 2.17 (s, 3H, CH3), 2.01 (s, 3H, CH3).
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