Potassium Carbonate → Indole

Reaction equation

N([C:3]1[CH:8]=[CH:7][C:6]([CH2:9]N2C=NC=N2)=[CH:5][CH:4]=1)N.COC(OC)CC[CH2:20][N:21]1CCC1.C([O-])([O-])=O.[K+].[K+]>OS(O)(=O)=O>[NH:21]1[C:5]2[C:6](=[CH:7][CH:8]=[CH:3][CH:4]=2)[CH:9]=[CH:20]1

Participants

Procedure

A solution of 1-(4-hydrazinophenyl)methyl-1,2,4-triazole (0.92 g, 4.1 mmol) and 4-(1-azetidinyl)butanal dimethylacetal (0.65 g, 3.8 mmol), in 4% H2SO4 (30 ml), was refluxed for 4.5 h. The solution was cooled to room temperature, basified with K2CO3 and extracted with EtOAc (4×100 ml). The combined extracts were dried (Na2SO4) and evaporated and the residue chromatographed on silica-gel eluting with CH2Cl2 /MeOH/NH3 (40:8:1) to give the title-indole. The hydrogen oxalate hemihydrate salt was prepared (30 mg); m.p. 128°-129° C. Found: C, 57.28, H, 5.95; N, 18.05. C16H19N5.C2H2O4.0.45 H2O requires C, 56.97; H, 5.82; N,18.45%). δ (360 MHz, D2O) 2.30-2.54 (2H, m, CH2), 3.07 (2H, t, J=7.0 Hz, CH2), 3.52 (2H, t, J=7.0 Hz, CH2), 3.94-4.13 (4H, m, 2 of CH2), 5.51 (2H, s, CH2), 7.20 (1H, dd, J=1.5 and 8.4 Hz, Ar--H), 7.30 (1H, s, Ar--H), 7.51 (1H, d, J=8.4 Hz, Ar--H), 7.62 (1H, s, Ar--H), 8.05 (1H, s, Ar--H), 8.56 (1H, s, Ar--H).