反应详情

Four portions each of 0.99 ml 5.4 M methanolic sodium methylate solution (21.4 mmol) are stirred into a solution of 2.957 g (21.4 mmol) 4,5,6,7-tetrahydro-1(3H)-isobenzofuranone (for preparation see J. Am. Chem. Soc. 118, 1-12 [1996]), 2.02 ml (21.4 mmol) pyridine-4-carbaldehyde, and 10.7 ml (93.2 mmol) ethyl propionate in 17.4 ml methanol at intervals of 5 min respectively and at 0° C. The reaction mixture is stirred for 20 min at RT, heated for 2 h under reflux, and then evaporated under vacuum. Stirring of the residue in 5 ml water, filtration, washing of the filter residue with water, and drying under HV (8 h, 100° C.) yields the title compound; m.p. 258-261° C.; ESI-MS: (M+H)+=228. A further, slightly impure batch of title compound may be obtained by extracting the aqueous filtrate with diethylether, adjusting the aqueous phase to pH 7 with glacial acetic acid, filtering, and washing the filter residue with water.

1. customat 0° C
2. temperatureheated for 2 h
3. temperatureunder reflux
4. customevaporated under vacuum
5. stirringStirring of the residue in 5 ml water
6. filtrationfiltration
7. washwashing of the filter residue with water
8. customdrying under HV (8 h, 100° C.)