反应详情

The required starting compound may also be prepared as follows: 1.8 g of 2,6-dioxo-5-phenoxy-1,2,3,6-tetrahydro-pyrimidine-4-carboxylic acid (preparation described in: Khim Geterotsikl. Soedin., 1974, p1527) are emulsified in 65 ml of ethanol, 0.92 ml of conc. H2SO4 and 0.92 ml of SOCl2 are subsequently added and the mixture is heated at reflux for 12 hrs. Subsequently, the mixture is concentrated on a rotary evaporator and the seperated solid is filtered off under suction and chromatographed on silica gel (eluent: CH2Cl2 /ether: 3/1). There are obtained 520 mg of ethyl 2,6-dioxo-5-phenoxy-1,2,3,6-tetrahydro-pyrimidine-4-carboxylate as a solid. MS: M=276.

1. custommay also be prepared
2. temperaturethe mixture is heated
3. temperatureat reflux for 12 hrs
4. concentrationSubsequently, the mixture is concentrated on a rotary evaporator
5. filtrationthe seperated solid is filtered off under suction
6. customchromatographed on silica gel (eluent: CH2Cl2 /ether: 3/1)