反应详情

温度

60 °C

The 4-(3-carboxyacetyl-phenyl)-thiazole-2-carboxylic acid ethyl ester was prepared from 4-(3-chlorocarbonyl-phenyl)-thiazole-2-carboxylic acid ethyl ester [prepared by the following sequence: i.) A mixture of 3-(2-bromo-acetyl)-benzoic acid [CAS-no. 62423-73-8] (2.43 g) and ethyl thiooxamate [CAS-no. 16982-21-1] (1.6 g) in THF (40 mL) was heated to 60° C. for 4 h and then partitioned between EtOAc and brine. The organic layer was dried and evaporated and the residue was crystallized from EtOAc/hexane to give 4-(3-carboxy-phenyl)-thiazole-2-carboxylic acid ethyl ester (2.2 g) as off-white crystals, mp 225-228° C. ii.) This carboxylic acid (2.1 g) was heated with thionyl chloride in toluene and the resulting carboxylic acid chloride was used directly in the next step.] (2.24 g) and bis(trimethylsilyl)malonate with n-BuLi in ether at −60° C. to 0° C. according to general procedure K (method c2). The crude material was transformed into the title compound by stirring in isopropenyl acetate and conc. H2SO4 according to general procedure L (method a). Obtained as yellow oil (2.7 g).

1. customprepared by the following sequence
2. custompartitioned between EtOAc and brine
3. customThe organic layer was dried
4. customevaporated
5. customthe residue was crystallized from EtOAc/hexane