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Molecular mechanics calculations of conjugated amides and an ab initio investigation of acrylamide and its β‐amino derivative: Conformational analysis and rotational barriers
Author(s) -
Berg Ulf,
Bladh Nina
Publication year - 1996
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/(sici)1096-987x(199603)17:4<396::aid-jcc2>3.0.co;2-p
Subject(s) - conjugated system , chemistry , amide , ab initio , nitrogen atom , conformational isomerism , computational chemistry , molecular mechanics , force field (fiction) , nicotinamide , molecular orbital , nicotinamide adenine dinucleotide , nad+ kinase , molecule , organic chemistry , molecular dynamics , polymer , ring (chemistry) , enzyme , artificial intelligence , computer science
Conformations and rotational barriers in a series of conjugated primary and tertiaryamides have been analyzed by a modified MM2(91) force field, which treats the amide nitrogen as part of the conjugated system by redefining the atom type for the nitrogen. Ab initio molecular orbital calculations at the MP2/6‐31G* level have been performed on the stable conformers and transition structures of acrylamide and β‐ trans ‐aminoacrylamide. The results have been used, with published experimental and computational data, to generate parameters for the MM2 force field. The force field has been applied to various conjugated amides, such as reduced nicotinamide adenine dinucleotide (NADH) and NAD + analogues, nicotinamide, urea, vinylogous urea derivatives, and nucleic acid bases. The fundamental difference between primary and tertiary conjugated amides with respect to both conformation and barrier is highlighted. © 1996 by John Wiley & Sons, Inc.