查询词典 Duff reaction

Methods 4-Hydroxy- benzonitrile was treated with sodium hydrogen sulfide and anhydrous magnesium chloride in dimethyl formamide to give thioamide, which was then directly cyclized with ethyl 2-chloroacetoacetate without separation to give ethyl 2-(4-hydroxyphenyl)-4-methylthiazole-5-carboxylate(2) in one-pot; then 2 was formylated with Duff reaction adopting hexamethylenetetramine in trifluoroacetic acid to give ethyl 2-(3-formyl-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate(3); finally, the target compound was obtained by the treatment of 3 with hydroxylamine hydrochloride and sodium formate in formic acid.

采用"一勺烩"方法，以4-羟基苯甲腈为起始原料，首先与硫氢化钠和无水氯化镁在N，N-二甲基甲酰胺中反应，所得中间体不经分离，直接加入2-氯乙酰乙酸乙酯进行环合反应，得到2-(4-羟基)苯基-4-甲基-5-噻唑甲酸乙酯（2）；然后通过六亚甲基四胺/三氟乙酸进行Duff反应，得到2-(3-甲酰基-4-羟基)苯基-4-甲基-5-噻唑甲酸乙酯（3）；再经盐酸羟胺/甲酸/甲酸钠体系脱水得到目标化合物。

Keywords 5-nitrosaicy|aldehyde polyphosphoric acid formylation Duff reaction

5-硝基水杨醛；多聚磷酸；甲酰化； Duff反应

Methods 4-Hydroxy- benzonitrile was treated with sodium hydrogen sulfide and anhydrous magnesium chloride in dimethyl formamide to give thioamide, which was then directly cyclized with ethyl 2-chloroacetoacetate without separation to give ethyl 2-(4-hydroxyphenyl)-4-methylthiazole-5-carboxylate(2) in one-pot; then 2 was formylated with Duff reaction adopting hexamethylenetetramine in trifluoroacetic acid to give ethyl 2-(3-formyl-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate(3); finally, the target compound was obtained by the treatment of 3 with hydroxylamine hydrochloride and sodium formate in formic acid.

采用&一勺烩&方法，以4-羟基苯甲腈为起始原料，首先与硫氢化钠和无水氯化镁在N，N-二甲基甲酰胺中反应，所得中间体不经分离，直接加入2-氯乙酰乙酸乙酯进行环合反应，得到2-(4-羟基)苯基-4-甲基-5-噻唑甲酸乙酯（2）；然后通过六亚甲基四胺/三氟乙酸进行Duff反应，得到2-(3-甲酰基-4-羟基)苯基-4-甲基-5-噻唑甲酸乙酯（3）；再经盐酸羟胺/甲酸/甲酸钠体系脱水得到目标化合物。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。