Title
MM3(96) parameterization for camptothecin analogs: An ab initio and molecular mechanics study.
Abstract
Torsional parameters for MM3(96) were derived for the missing atom types present in thenatural product camptothecin (CPT). Potential energy curves were calculated via ab initiocalculations on representative compounds for dihedral angles containing these missingparameters. Gaussian 92 at the restricted Hartree–Fock level of theory using thestandard 6-31G** and 4-31G** basis sets, was used for all the quantum-mechanicscalculations. Missing MM3 torsional terms were obtained by optimizing the V1, V2 and V3parameters such that MM3 could reproduce the ab initio torsional profile. MM3 calculatedmolecular structures that compare well with the ab initio results. Using the newly developedparameters, conformational analyses and QSAR studies of camptothecin analogs wereundertaken. MM3 predicts two distinct ‘boatlike’ conformations for the α-hydroxy lactonemoiety. The low-energy lactone conformation predicted by MM3 is in general agreement withreported X-ray crystal structures of CPT iodoacetate and 7-ethyl-10-(4-piperidino)piperidinylcarbonyloxy CPT HCl as well as the ab initio structure of a CPT-likeα-hydroxy lactone.
Year
DOI
Venue
1997
10.1023/A:1008075411380
Journal of computer-aided molecular design
Keywords
Field
DocType
Molecular mechanics,MM3,Dihedral driver,Camptothecin,α-Hydroxy lactone
Quantitative structure–activity relationship,Crystallography,Camptothecin,Computational chemistry,Atom,Chemistry,Crystal structure,Lactone,Potential energy,Ab initio,Dihedral angle
Journal
Volume
Issue
ISSN
11
1
0920-654X
Citations 
PageRank 
References 
1
2.53
1
Authors
3
Name
Order
Citations
PageRank
Sean W. Carrigan135.12
Jenn-Huei Lii212725.25
J. Phillip Bowen31513.55