反应详情

A 750-ml 4-necked flask equipped with a mechanical stirrer, a thermometer, a dropping funnel and an argon inlet, cooled with a CO2/acetone bath, was charged with a solution of 49.15 g of crude methyl 2-(5-methyl-2-phenyl-4-oxazolyl)acetate (ca. 0.16 mol) and 90 ml of toluene and stirred. 400 ml of diisobutyl aluminiumhydride 1.2 M in toluene were added under argon at ca. −20 to −25° C. during 60 min. After additional 15 min a solution of 191 g of citric acid monohydrate in 400 ml of deionized water was added with cooling during 30 min, so that the temperature did not exceed 5-10° C. The aqueous phase of the clear biphasic mixture was extracted with 200 ml of toluene. The combined organic phases were washed twice with 40 ml, a total of 80 ml of deionized water, twice with 40 ml, a total of 80 ml of brine and dried (Na2SO4). Rotary evaporation (50° C., 8 mbar, 1 h) afforded 38.5 g of crude 2-(5-Methyl-2-phenyl-4-oxazolyl)ethanol (theor. amount 32.4 g) which was used in the next step without further purification.

1. customA 750-ml 4-necked flask equipped with a mechanical stirrer
2. temperaturea thermometer, a dropping funnel and an argon inlet, cooled with a CO2/acetone bath
3. temperaturewith cooling during 30 min, so that the temperature
4. customdid not exceed 5-10° C
5. extractionThe aqueous phase of the clear biphasic mixture was extracted with 200 ml of toluene
6. washThe combined organic phases were washed twice with 40 ml
7. dry with materiala total of 80 ml of deionized water, twice with 40 ml, a total of 80 ml of brine and dried (Na2SO4)
8. customRotary evaporation (50° C., 8 mbar, 1 h)