5331-43-1Relevant articles and documents
Method for preparing benzyl carbazate
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Paragraph 0018-0026, (2021/09/04)
The invention provides a method for preparing benzyl carbazate. The method comprises the following steps: (1) adding a dichloromethane solvent and hydrazine hydrate into a reaction kettle, stirring until the dichloromethane solvent and hydrazine hydrate are dissolved, adding a catalyst, and stirring for at least 5 minutes; (2) slowly dropwise adding benzyl chloroformate into the reaction kettle, and carrying out heat preservation reaction for 2 hours; (3) carrying out heat preservation and water separation on the obtained reaction liquid through a liquid separation device, and recycling hydrazine hydrate after water separation; (4) adding hydrochloric acid into an organic phase obtained after water separation, and carrying out acidification refining; (5) adding a sodium carbonate aqueous solution into the acidified and refined solution for neutralization, carrying out cooling crystallization on the neutralized solution, centrifuging, separating the filtrate to remove water, recycling the organic phase, and collecting the crystallized solid for later use; and (6) recrystallizing the collected crystal solid with water to obtain benzyl carbazate. The benzyl carbazate with higher purity is obtained by adding a cooling crystallization method, and the cooling crystallization method is simple, easy to operate and safer for operators.
Synthesis and application of a novel asymmetric azo reagent: 1-(tert-butyl)-2-(4-chlorobenzyl) azodicarboxylate (tBCAD)
Xie, Jian,Xu, Cai,Dai, Qianjin,Wang, Xiaozhong,Xu, Gang,Chen, Yingqi,Dai, Liyan
, p. 5321 - 5326 (2017/08/04)
A series of novel asymmetric azo reagents, 1-(tert-butyl)-2-(4-substituted benzyl) azodicarboxylate, were prepared. The synthetic process has the advantage of simpleness, easy operation, mild reaction condition and high yield. The 1-(tert-butyl)-2-(4-chlorobenzyl) azodicarboxylate (tBCAD) was selected for its stability and convenience to handle, and its precursor can be recycled by recrystallization with toluene. The tBCAD and DIAD were applied to a wide variety of Mitsunobu reactions. The experimental results showed that the performance of tBCAD in Mitsunobu reaction was comparable to that of DIAD, while the stability of tBCAD was much better than DIAD. Thus, tBCAD can be a novel, stable, effective azo-reagent for the Mitsunobu reaction.
Gold-catalyzed three-component spirocyclization: A one-pot approach to functionalized pyrazolidines
Wagner, Bernd,Hiller, Wolf,Ohno, Hiroaki,Krause, Norbert
supporting information, p. 1579 - 1583 (2016/02/10)
An efficient, highly atom economic synthesis of hitherto unknown spirocyclic pyrazolidines in a one-pot process was developed. The gold-catalyzed three-component coupling of alkynols, hydrazines and aldehydes or ketones likely proceeds via cycloisomerization of the alkynol to an exocyclic enol ether and subsequent [3 + 2]-cycloaddition of an azomethine ylide. A library of 29 derivatives with a wide range of functional groups was synthesized in up to 97% yield. With this new method, every position in the final product can be substituted which renders the method ideal for applications in combinatorial or medicinal chemistry.