Triethylamine → 3-(4-chloro-3-nitrobenzylidene)-3H-isobenzofuran-1-one

Participants

Reaction Conditions

Reaction Steps

A stirred solution of dimethyl 3-oxo-1,3-dihydroisobenzofuran-1-ylphosphonate (4.84 g, 0.02 mol; prepared in a manner similar to that described in Example 23) and 4-chloro-3-nitrobenzaldehyde (3.71 g, 0.02 mol) in tetrahydrofuran (30 ml) was cooled to 15° C. and a solution of triethylamine (2.02 g, 0.02 mol) in tetrahydrofuran (3 ml) was added dropwise at <25° C. The mixture was stirred at ambient temperature for 1 hour, allowed to stand at this temperature for a further 16 hours and the resulting solid was collected by filtration. The filtrate was concentrated in vacuo, the residue was triturated with water (5 ml) and the resulting solid was collected by filtration. The two crops of solid were combined and suspended in water (30 ml). The mixture was stirred at ambient temperature for 30 minutes and the resulting solid was collected by filtration and dried in vacuo for 24 hours to give crude 3-(4-chloro-3-nitrobenzylidene)-3H-isobenzofuran-1-one as a pale yellow solid, m.pt. 198–204° C., still slightly wet with water, which was used directly in the next stage.

Provenance & Evidence