68208-09-3Relevant articles and documents
Environment-friendly preparation method of substituted oxazole compound
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Paragraph 0142-0147, (2021/01/12)
The invention provides an environment-friendly preparation method of a substituted oxazole compound, which takes N-substituted formyl alpha-substituted glycine ester as an initial raw material; the substituted oxazole compound is obtained through a cyclization reaction under the action of a dehydrating agent such as trisubstituted phosphine dihalide, a combination of trisubstituted phosphine dihalide and an acyl halide reagent or a combination of trisubstituted phosphine oxide and an acyl halide reagent and organic amine. The obtained substituted oxazole compound can be further saponified anddecarboxylated to obtain a medical intermediate 4-substituent-5-substituent oxazole. The method can be carried out in a continuous flow manner, so that the production efficiency is improved, and the operation is reduced; a byproduct trisubstituted phosphine oxide is generated in the reaction process and can be recycled, so that the cost is reduced; phosphorus oxychloride and phosphorus pentoxide which are high in price and large in preparation process wastewater amount are not used as dehydrating agents, a high-temperature cyclization reaction is not needed, the process is simple, operation iseasy and convenient, no phosphorus-containing wastewater is discharged, and the method is environmentally friendly and low in cost. The method is high in atom economy, high in target product yield and purity and suitable for industrial application.
Synthesis of hydroxypiperidinecarboxylic acids from pyridinedicarboxylates
Damsgaard, Anders,Hazell, Rita,Bols, Mikael
, p. 521 - 527 (2007/10/03)
(3RS,4SR,5SR)-5-Hydroxy-3-hydroxymethyl-4-piperidinecarboxylic acid 4,3′-lactone was synthesised in eight steps from ethyl glycinate via selective hydrolysis and reduction of 4,5-di-(methoxycarbonyl)-3-hydroxypyridine. The regioisomer (3RS,4RS,5SR)-5-hydr
