Cesium carbonate → tert-butyl 5'-(4,4,4-trifluoro-3-(3,4,5-trichlorophenyl)but-2-enoyl)-3'H-spiro[azetidine-3,1'-isobenzofuran]-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

In 100 mL two neck RBF fitted with dean-stark apparatus, a stirred solution of tert-butyl 5′-acetyl-3′H-spiro[azetidine-3,1′-isobenzofuran]-1-carboxylate (Preparation 1, 7 g, 23.1mmol) in toluene (21 mL) and trifluoro methyl benzene (21 mL) was added followed by addition of 2,2,2-trifluoro-1-(3,4,5-trichlorophenyl)ethanone (7.37 g, 26.6 mmol) and Cs2CO3 (0.751 g, 2.31 mmol) at room temperature. Resulting reaction mixture was stirred at 110° C. for 16 hours. Reaction was monitored by TLC, after complete consumption of starting material; reaction mixture was dissolved in tert-butyl methyl ether (50 mL), and filtered through celite bed. The filtrate was concentrated under reduced pressure to get crude compound as brown sticky oil 14.1 g. Purification was done by column chromatography using silica gel 230-400 mesh. Desired compound was eluted in 20% ethyl acetate in n-hexane to give compound as light yellow solid (8.6 g, 66.15%). 1H NMR (400 MHz, CDCl3) δ: 1.47 (s, 9H), 4.11 (d, J=9.6 Hz, 2H), 4.32 (d, J=9.52 Hz, 2H), 5.12 (s, 2H), 7.28 (s, 1H), 7.40 (m, 1H), 7.54-7.56 (m, 1H), 7.66 (s, 1H), 7.83 (d, J=7.92 Hz, 1H). VETERINARY (m/z): 560.0 (M−H).

Provenance & Evidence