反应详情

7.085 g of methyl carbamate, 0.275 g of p-toluenesulfonic acid monohydrate and 10.000 g of 2-oxo-4-(hydroxymethylphosphinyl)-butanoic acid prepared by the method described in Japanese Patent Laid-Open No. 92897/1981, were added to 16 mL of acetic acid to be suspended. After being dissolved by heating, 64 mL of toluene was added thereto and then the solution was refluxed with vigorous stirring. The internal temperature of the reaction solution was from 106 to 108 deg. C. One and a half hours later, 8 mL of toluene was further added to the reaction solution and continued stirring. Three hours later, dissipation of almost all the raw materials was confirmed by HPLC measurement. At this point, the area ratio of Z form to E form was 94:6. After removing about 60 mL of the solvent under a reduced pressure, followed by adding 20 mL of acetic acid, and then the resultant was stirred for 1 hour at 80 deg. C. The precipitate which was obtained by cooling the solution gradually to room temperature and stirring over-night, was filtered and then the filtrate was washed with acetic acid. After being washed with acetone, dried for 5 hours from 40 to 50 deg. C. under a reduced pressure, 10.625 g of the objective compound was obtained (80.7% yield, Z:E=99.6:0.4). mp 254-256 deg. C.

1. dissolutionAfter being dissolved
2. temperatureby heating
3. temperaturethe solution was refluxed with vigorous stirring
4. customwas from 106 to 108 deg. C
5. customThree hours
6. customAfter removing about 60 mL of the solvent under a reduced pressure
7. additionby adding 20 mL of acetic acid
8. stirringthe resultant was stirred for 1 hour at 80 deg. C
9. customThe precipitate which was obtained
10. stirringstirring over-night
11. filtrationwas filtered
12. washthe filtrate was washed with acetic acid
13. washAfter being washed with acetone
14. customdried for 5 hours from 40 to 50 deg. C