Thionation of β-lactams to β-thiolactams by silica-supported P2S5
摘要:
In this paper, an improved method for the thionation of -lactams is described. Using a solid-supported P2S5 reagent and heating under reflux conditions, -thiolactams were obtained in good to excellent yields. Also the reaction time reduced significantly compared with that achieved under the more conventional method using P2S5 alone. Furthermore, inexpensive and easily available starting materials simple reaction conditions and a simple purification process are some other advantages of this method.[GRAPHICS].
The Vilsmeier reagent: a useful and versatile reagent for the synthesis of 2-azetidinones
作者:Aliasghar Jarrahpour、Maaroof Zarei
DOI:10.1016/j.tet.2009.02.005
日期:2009.4
and oxalyl chloride or thionyl chloride, works as a versatile acid activator reagent for the direct [2+2] ketene–imine cycloaddition of substituted acetic acid and imines in one-pot synthesis under mild conditions. Monocyclic, spirocyclic and 3-electron-withdrawing group β-lactams were synthesized by this method and optimization of conditions were performed.
Utilization of DMF–PhCOCl Adduct as an Acid Activator in a New and Convenient Method for Preparation of β-Lactams
作者:Maaroof Zarei
DOI:10.1246/bcsj.20110323
日期:2012.3.15
An efficient one-potsynthesis of β-lactams by the reaction of imines with acetic acid derivatives in the presence of DMF and benzoyl chloride adduct, a cheap reagent, has been described. Optimizat...
The Vilsmeier reagent as an efficient acid activator for the synthesis of β-lactams
作者:Aliasghar Jarrahpour、Maaroof Zarei
DOI:10.1016/j.tetlet.2007.10.012
日期:2007.12
The Vilsmeier reagent (chloromethylenedimethylammonium chloride) has been used as an efficient and cheap acid activator for the one-step Staudinger reaction of substituted acetic acids and imines under mild conditions. This reaction is clean and the by-products are DMF and triethylamine hydrochloride which were removed by simple aqueous work-up. (c) 2007 Published by Elsevier Ltd.
Solid‐Solid Phase and Solvent‐Free Oxidative Removal of<i>N</i>‐(4‐Alkoxyphenyl) Groups of Monocyclic β‐Lactams with Ceric Ammonium Nitrate as a Cheap, Simple, and Efficient Method
作者:Aliasghar Jarrahpour、M. Zarei
DOI:10.1080/00397910801981326
日期:2008.5
Five N-(4-methoxyphenyl)- and five N-(4-ethoxyphenyl)-beta-lactams were prepared by ketene-imine [2+2] cycloaddition (Staudinger reaction). Then these 2-azetidinones were N-dearylated by grinding together with ceric ammonium nitrate without hazardous solvents in good to excellent yields. The solid-solid phase N-dearylation is easier, simpler, and more efficient than the general method in solution. The pure N-unsubstituted beta-lactams obtained by a nontedious workup and without further purification.
Argentic oxide mediated N-dearylation of β-lactams
作者:Maaroof Zarei、Aliasghar Jarrahpour
DOI:10.1016/j.tetlet.2011.01.022
日期:2011.3
A method is described for the N-dearylation of N-(4-methoxy- or 4-ethoxyphenyl)-2-azetidinones with argentic oxide. The yields are good-to-excellent and the reaction is simple, efficient, and fast. (C) 2011 Elsevier Ltd. All rights reserved.