A solvent-free, catalytic, one-potsynthesis of β-lactams is described. The reaction involves the reaction between silyl ketene thioacetals derived from 2-pyridyl thioesters and imines at room temperature in the presence of catalytic amounts of Sc(OTf)3 and in the absence of solvent. Extension of this procedure to the synthesis of an enantiomerically pure azetidinone, a precursor of industrially relevant
Preparation of 2-azetidinones by cyclocondensation of carboxylic acids and imines via diphosphorustetraiodide
作者:Maaroof Zarei、Fatemeh Maaqooli
DOI:10.1080/00397911.2016.1148165
日期:2016.3.18
ABSTRACT One-pot mild synthesis of 2-azetidinones was carried out by the reaction of imines and carboxylic acids in dry dichloromethane at room temperature using diphosphorus tetraiodide. It was also applied for synthesis of 3-spiro-2-azetidinones. The synthesized compounds were characterized by analytical and spectral (infrared, 1H NMR, 13CNMR, and elemental analysis) data. GRAPHICAL ABSTRACT
An improved method for the stereoselective synthesis of β-lactams from carboxylic acids and imines
作者:Gunda I. Georg、Peter M. Mashava、Xiangming Guan
DOI:10.1016/s0040-4039(00)74832-5
日期:1991.1
Carboxylic acids activated with Mukaiyama's reagent (2-chloro-N-methylpyridinium iodide) reacted with imines to produce β-lactams in good yields and with high stereoselectivity. The utilization of three equivalents of tripropylamine as the base was necessary to obtain high chemical yield and good stereoselectivity.
Synthesis of β-lactams via Staudinger reaction using <i>N</i>-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline as a carboxylic acid activator
作者:Saleheh Zavar、Maaroof Zarei、Mahnaz Saraei
DOI:10.1080/00397911.2016.1244691
日期:2016.12.16
ABSTRACT N-Ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) has been used as an efficient and convenientreagent for the one-pot synthesis of β-lactams by [2+2] ketene–imine cycloaddition (Staudinger reaction). Cleanliness, simplicity of method, and good to excellent yields of products are some advantages of this method. GRAPHICAL ABSTRACT
Reductive ring opening of 2-azetidinones promoted by sodium borohydride
作者:Paola Del Buttero、Giorgio Molteni、Maurizio Roncoroni
DOI:10.1016/j.tetlet.2006.01.103
日期:2006.3
Variously substituted 2-azetidinones 3 and 4 were reacted with sodiumborohydride in aqueous isopropanol giving 3-aminopropan-1,2-dioles 5 and 7. Reaction extent was dependent upon the substitution pattern in the 3- and 4-positions of the 2-azetidinone ring and revealed good correlation with carbonyl LUMO energies of starting 3.