Photochemistry of 3-alkoxychromones I — Photocyclisation of 6-chloro-3-alkoxy-2-(furan-3-yl)-4H-chromen-4-ones

2009 ◽  
Vol 87 (2) ◽  
pp. 422-429 ◽  
Author(s):  
Ramesh C. Kamboj ◽  
Urmila Berar ◽  
Surinder Berar ◽  
Mandeep Thakur ◽  
Rita Arora ◽  
...  
Keyword(s):  
Mm2 Calculations

3-Alkoxy/allyloxy-6-chloro-2-(furan-3-yl)-4H-chromen-4-ones yield angular tetracyclic products involving the 2-furyl group on photoirradiation through the intermediacy of 1,4-biradicals. The nature of the 3-alkoxy/allyloxy group influenced the photoproduct distribution. The stereochemical dispositions of the products have been established using the J/Φ relationship and were corroborated by MM2 calculations.

MM2 calculations with atomic point charges modelling AM1 energy surfaces

1993 ◽  
Vol 291 (1) ◽  
pp. 105-121 ◽  
Author(s):  
Immaculada Dinarés ◽  
Carlos Jaime ◽  
Ermitas Alcalde
Keyword(s):  
Mm2 Calculations ◽  
Energy Surfaces

scholarly journals Unsymmetrical Schiff Base Functionalized as Monobasic Tridentate Ligand on Complexation with Some Transition Metal Ions

2012 ◽  
Vol 9 (2) ◽  
pp. 532-544
Author(s):  
Bibhesh K. Singh ◽  
Narendar Bhojak ◽  
Anant Prakash
Keyword(s):  
Schiff Base ◽  
Transition Metal Ions ◽  
Tridentate Ligand ◽  
Planar Geometry ◽  
Physico Chemical ◽  
Square Planar ◽  
Unsymmetrical Schiff Base ◽  
Mm2 Calculations ◽  
Microbial Potential

Cu(II), Co(II), Ni(II) and Mn(II) complexes of Schiff base derived from 2-aminophenol and pyrrole-2- carbaldehyde have been prepared. The complexes are formed by coordination of N and O atoms of the ligand. Their structures were characterized by physico-chemical and spectroscopic methods. Molecular structure of the complexes has been optimized by MM2 calculations and suggests a tetrahedral/ square planar geometry. The bio-efficacy of the ligand and their complexes has been examined against the growth of bacteriain vitroto evaluate their anti-microbial potential.

A novel method of ring formation with functionalized angular methyl groups. Limitations and MM2 calculations

1988 ◽  
Vol 29 (6) ◽  
pp. 715-718 ◽  
Author(s):  
Alfred Hassner ◽  
Ananda S. Amarasekara ◽  
Albert Padwa ◽  
William H. Bullock
Keyword(s):  
Ring Formation ◽  
Methyl Groups ◽  
Novel Method ◽  
Mm2 Calculations

Approaches to the Synthesis of Retronecine From Some Pyrrolidine Precursors

1993 ◽  
Vol 46 (6) ◽  
pp. 805 ◽  
Author(s):  
BW Clare ◽  
V Ferro ◽  
BW Skelton ◽  
RV Stick ◽  
AH White
Keyword(s):  
Structure Determination ◽  
Am1 Calculations ◽  
X Ray ◽  
Bicyclic System ◽  
Alternative Procedures ◽  
Mm2 Calculations

Procedures are described for the attempted conversion of the pyrrolidine (2) into a bicyclic system that would ultimately lead to retronecine (3). The only molecule to be isolated from these attempts was the epimeric ketone (6), and AM1 and MM2 calculations were used to probe this apparently favoured isomerization. Alternative procedures were then investigated that sought to convert the pyrrolidine (1) into precursors to retronecine, and notable successes were obtained with the addition of the amine (21) to both nitroethene and ethyl 2-diethylphosphonoacrylate. However, not only were these precursors resistant to further transformations into retronecine , but also the problem of epimerization again arose. Consequently, AM1 calculations were again employed, and an X-ray structure determination of ethyl (7R,8R)-7-benzyloxy-1-benzyloxymethyl-5,6,7,8-tetrahydro-3H-pyrrolizine-2-carboxylate (39) is reported. Attempts to convert (39) into a diastereoisomer of retronecine were unsuccessful.

Molecular mechanics (MM2) calculations and cone angles of phosphine ligands

1994 ◽  
Vol 470 (1-2) ◽  
pp. 73-85 ◽  
Author(s):  
Mian Chin ◽  
Gregory L. Durst ◽  
Simone R. Head ◽  
Paul L. Bock ◽  
John A. Mosbo
Keyword(s):  
Molecular Mechanics ◽  
Phosphine Ligands ◽  
Mm2 Calculations

1,n-Radical ions. Photosensitized (electron transfer) carbon–carbon bond cleavage. Formation of 1,6-radical cations

1991 ◽  
Vol 69 (2) ◽  
pp. 225-233 ◽  
Author(s):  
Donald R. Arnold ◽  
Laurie J. Lamont ◽  
Allyson L. Perrott
Keyword(s):  
Electron Transfer ◽  
Radical Cation ◽  
Bond Cleavage ◽  
Radical Cations ◽  
Dimethyl Acetal ◽  
Mercury Vapour ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Mercury Vapour Lamp ◽  
Mm2 Calculations

The reactivity of the radical cations of methyl 2,2-diphenylcyclohexyl ether (7), 6,6-diphenyl-1,4-dioxaspiro[4.5]decane (8), methyl cis- and trans-2-phenylcyclohexyl ether (9cis and trans), and 6-phenyl-1,4-dioxaspiro[4.5]decane (10), generated by photosensitized (electron transfer) irradiation, has been studied. Solutions of the ethers and acetals in acetonitrile–methanol (3:1), with 1,4-dicyanobenzene (2) serving as the electron acceptor, were irradiated with a medium-pressure mercury vapour lamp through Pyrex. The diphenyl derivatives 7 and 8 were reactive; 7 gave 6,6-diphenylhexanal dimethyl acetal (11) and 8 gave 2-methoxy-2-(5,5-diphenylpentyl)-1,3-dioxolane (12). These are the products expected from the intermediate 1,6-radical cation, formed upon carbon–carbon bond cleavage of the cyclic radical cation. The monophenyl derivatives 9cis and trans and 10 were stable under these irradiation conditions. The mechanism for the carbon–carbon bond cleavage and for the cis–trans isomerization is discussed. An explanation, based upon conformation, is offered for the lack of reactivity of 9 and 10. Molecular mechanics (MM2) calculations were used to determine the preferred conformation of 9cis and trans, and 10. Key words: photosensitization, electron transfer, radical cation, carbon–carbon bond cleavage, conformation.

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