@article { ISI:000227615900006, title = {Microwave assisted rapid synthesis of 4-amino-3,4-dihydroquinolin-2-ones from azetidin-2-ones}, journal = {Arkivoc}, number = {1}, year = {2005}, month = {JAN}, pages = {53-64}, publisher = {ARKAT USA INC}, type = {Article}, address = {C/O ALAN R KATRITZKY, UNIV FLORIDA, DEPT CHEMISTRY, PO BOX 117200, GAINESVILLE, FL 32611 USA}, abstract = {

An efficient one-pot synthesis of 4-amino-3,4-dihydroquinolin-2-ones from 3-(2-nitrophenyl)-1, 4-disubstituted azetidin-2-ones is described. Microwave assisted transfer hydrogenation of a nitro group followed by in situ beta-lactam ring opening by the newly formed amino group is the key step in this synthesis.

}, keywords = {4-amino-3, 4-dihydroquinolin-2-ones, azetidin-2-ones, imines, ketenes, Microwave, transfer hydrogenation}, doi = {10.3998/ark.5550190.0006.106}, author = {Shirode, N. M. and Kulkarni, K. C. and Gumaste, V. K. and Deshmukh, A. R. A. S.} } @article { ISI:000227267300021, title = {Synthesis of cis bis-beta-lactams via Staudinger cycloaddition reaction using C-2-symmetric 1,2-diamines}, journal = {Tetrahedron}, volume = {61}, number = {9}, year = {2005}, month = {FEB}, pages = {2441-2451}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An efficient stereoselective synthesis of bis-beta-lactams via cycloaddition reaction (Staudinger reaction) of ketenes with bisimines derived from C-2-symmetric 1, 2-diamines is described. The reaction provided diastereomeric mixture of meso and C-2-symmetric cis-bis-beta-lactams with higher selectivity for meso-bis-beta-lactams. (C) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {imines, ketenes, Staudinger cyclo-addition reaction, stereoselective synthesis}, issn = {0040-4020}, doi = {10.1016/j.tet.2005.01.031}, author = {Shaikh, A. L. and Puranik, Vedavati G. and Deshmukh, A. R. A. S.} } @article { ISI:000239289800036, title = {Gamma-heteroatom directed stereocontrolled staudinger cycloaddition reaction of vinylketenes and imines}, journal = {Tetrahedron Letters}, volume = {47}, number = {33}, year = {2006}, month = {AUG}, pages = {5993-5996}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Vinylketenes possessing a gamma-heteroatom, on Staudinger cycloaddition reaction with imines gave trans-3-vinyl-beta-lactams in very good yields. The vinyl side chain stereoselectively adopts the Z-configuration in the transition state to stabilize the vinylketene and produces, exclusively, trans-3-vinyl-beta-lactams. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {imines, Staudinger reaction, stereoselective synthesis, vinylketenes}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2006.05.189}, author = {Shaikh, Aarif L. and Puranik, Vedavati G. and Deshmukh, A. R. A. S.} } @article { ISI:000249394900019, title = {Efficient synthesis of azetidine-2,3-diones from L-(+)-diethyl tartrate}, journal = {Synlett}, number = {14}, year = {2007}, month = {SEP}, pages = {2242-2246}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A convenient route to enantiopure azetidine-2,3-diones is described. The chiral ketene generated from commercially available L-(+)-diethyl tartrate on Staudinger cycloaddition with different imines gave spiro-beta-lactams in good yields. These spiro-beta-lactams were transformed into azetidine-2,3-diones in excellent yields in a two-step process.

}, keywords = {Cycloaddition, imines, lactams, spiro compounds, stereoselective synthesis}, issn = {0936-5214}, doi = {10.1055/s-2007-985563}, author = {Chincholkar, Pinak M. and Puranik, Vedavati G. and Deshmukh, Abdul Rakeeb A. S.} } @article { ISI:000252091800019, title = {Stereoselective synthesis of spiro-beta-lactams using D-(+)-glucose derived chiral pool: remarkable influence of the torquoelectronic effect}, journal = {Tetrahedron}, volume = {63}, number = {37}, year = {2007}, month = {SEP}, pages = {9179-9187}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Diastereoselective synthesis of spiro-beta-lactams via [2+2] cycloaddition reaction of imines and chiral ketenes is described. The chiral ketene was prepared from commercially available, inexpensive D-glucose. Although, theoretically four diastereomers are possible, the reaction yielded only two diastereomers stereoselectively in good to moderate yields. The stereochemical outcome of the reaction was in accordance with the torquoelectronic model. (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {imines, ketenes, spiro-beta-lactams, Staudinger reaction, stereoselective synthesis}, issn = {0040-4020}, doi = {10.1016/j.tet.2007.06.073}, author = {Chincholkar, Pinak M. and Puranik, Vedavati G. and Deshmukh, A. R. A. S.} } @article {46021, title = {N-Heterocyclic carbene-catalyzed umpolung of imines for the enantioselective synthesis of dihydroquinoxalines}, journal = {ACS Catalysis}, volume = {9}, year = {2019}, month = {MAY}, pages = {4065-4071}, type = {Article}, abstract = {

N-heterocyclic carbene (NHC) organocatalysis is widely employed for the umpolung of aldehydes and recently to the umpolung of Michael acceptors and aldimines. Described herein is the NHC-organocatalyzed umpolung of aldimines for the enantioselective synthesis of nitrogen heterocycles. The bisimines generated from the condensation of 1,2-phenylenediamines and salicylaldehydes undergo intramolecular cyclization in the presence of a chiral NHC catalyst, resulting in the formation of dihydroquinoxalines in moderate to good yields and er values. Detailed DFT studies shed light on the role of -OH groups in stabilizing the initially generated aza-Breslow intermediates via intramolecular hydrogen bonds. Preliminary photophysical studies on the synthesized dihydroquinoxalines revealed that these molecules can be used for the sensing of various acids and bases.

}, keywords = {dihydroquinoxalines, imines, N-heterocyclic carbenes, organocatalysis, umpolung}, issn = {2155-5435}, doi = {10.1021/acscatal.9b00737}, author = {Das, Tamal Kanti and Ghosh, Avik and Balanna, Kuruva and Behera, Pradipta and Gonnade, Rajesh G. and Marelli, Udaya Kiran and Das, Abhijit Kumar and Biju, Akkattu T.} } @article {48458, title = {Imine oxidation catalyzed by zinc hydroxyapatite: kinetic studies}, journal = {ChemistrySelect}, volume = {8}, year = {2023}, month = {MAY}, pages = {e202203503}, type = {Article}, abstract = {

The synthesis of N,N-diphenylformamide from N-benzylideneaniline and urea hydrogen peroxide is investigated using a zinc hydroxyapatite (ZnHAP) catalyst. It was found that the catalyst resulted in the highest activity of 91 \% conversion and 40 \% selectivity at 130 degrees C in 2 h. A kinetic model was validated by Langmuir-Hinshelwood-Hougen-Watson (LHHW) at different temperatures and the absence of mass transfer resistance was proved by the Weisz Prater criterion. Effect of different catalysts, catalyst loading, temperature, mole-ratio, and speed of stirring was studied. The as-synthesized catalyst is characterized by FTIR, BET nitrogen adsorption-desorption, TEM, EDX, TPD-NH3, XPS, ICP-MS and XRD. ZnHAP catalyst was found to be stable up to three recycles with no loss in activity.

}, keywords = {heterogeneous catalysis, hydroxyapatite, imines, Oxidation, Reaction kinetics}, issn = {2365-6549}, doi = {10.1002/slct.202203503}, author = {Vishwakarma, Rakhi and Vinod, C. P. and Rathod, Virendra K. and Kantam, Mannepalli Lakshmi} }