Tetrahydrofuran → cyclopropyl(1-(4-vinylphenyl)-1H-1,2,4-triazol-5-yl)methanone

Reaction equation

[CH:1]([C:3]1[CH:8]=[CH:7][C:6]([N:9]2[CH:13]=[N:12][CH:11]=[N:10]2)=[CH:5][CH:4]=1)=[CH2:2].[Li]CCCC.[CH2:19]1[CH2:23][O:22][CH2:21][CH2:20]1>>[CH:19]1([C:23]([C:13]2[N:9]([C:6]3[CH:5]=[CH:4][C:3]([CH:1]=[CH2:2])=[CH:8][CH:7]=3)[N:10]=[CH:11][N:12]=2)=[O:22])[CH2:20][CH2:21]1

Participants

Reactant 3

HCID 8028Tetrahydrofuran2×

HCID 585499641-(4-vinylphenyl)-1H-1,2,4-triazole

HCID 178418339Butyllithium

Product 1

HCID 86675220cyclopropyl(1-(4-vinylphenyl)-1H-1,2,4-triazol-5-yl)methanone

Procedure

To a stirred solution of 1-(4-vinyl-phenyl)-1H-[1,2,4]-triazole (1 g, 5.8 mmol) in 25 mL of THF, was added n-BuLi (0.37 g, 5.8 mmol) at −78° C. and stirred for 30 min. To this N-methoxy N-methylcyclopropoxide in THF (0.82 g, 6.4 mmol) was added and the resultant reaction mixture was stirred at ambient temperature for 16 h. The reaction mixture was quenched with a saturated aqueous NH4Cl solution and extracted with EtOAc (3×25 mL). The combined EtOAc layer was washed with brine and dried over sodium sulphate and concentrated under reduced pressure. The crude compound was purified by flash chromatography (SiO2, 100-200 mesh, 40% EtOAc in Pet ether) to afford the title compound as an off white solid (420 mg, 30%): mp 90-91° C.; 1H NMR (400 MHz, CDCl3) δ 8.12 (s, 1H), 7.50 (d, J=7.8 Hz, 2H), 7.38 (d, J=7.8 Hz, 2H), 6.75 (dd, J=16.3, 10.7 Hz, 1H), 5.81 (d, J=16.3 Hz, 1H), 5.35 (d, J=10.7 Hz, 1H), 3.22 (m, 1H), 1.27 (m, 2H), 1.18 (m, 2H); ESIMS m/z 240.18 ([M+H]+); IR (thin film) 2922, 1630 cm−1.