反应详情

A solution prepared from 5.0 mmol of 8-methyl-7-hydroxycoumarin and 6.0 mmol of 2-methyl-3-butyn-2-ol in 40 ml of xylene containing 0.095 g (0.50 mmol) of p-toluenesulfonic acid was refluxed with magnetic stirring for 4 hours. The solvent was distilled off in vacuo and the oily contents of the flask chilled in an ice-salt water bath to induce crystallization. The white microneedles, 33% yield, were recrystallized from methanol to analytical purity, m.p. 105°-107° C. (lit. m.p. 106°-107° C.). The 1H-NMR spectrum was also identical to that reported, see P. Rodighiero et al., reference cited above.

1. temperaturewas refluxed
2. distillationThe solvent was distilled off in vacuo
3. temperaturethe oily contents of the flask chilled in an ice-salt water bath
4. customcrystallization
5. customThe white microneedles, 33% yield, were recrystallized from methanol to analytical purity, m.p. 105°-107° C. (lit. m.p. 106°-107° C.)