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Effects of introduction of α‐carboxylate, N ‐methyl, and N ‐formyl groups on intramolecular cyclization of o ‐quinone amines: Density functional theory‐based study
Author(s) -
Kishida Ryo,
Saputro Adhitya Gandaryus,
Arevalo Ryan Lacdao,
Kasai Hideaki
Publication year - 2017
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25445
Subject(s) - chemistry , intramolecular force , quinone , steric effects , methylene , density functional theory , carboxylate , ring (chemistry) , photochemistry , stereochemistry , methyl group , medicinal chemistry , homo/lumo , intramolecular reaction , computational chemistry , molecule , organic chemistry , group (periodic table)
o ‐Quinone amines, which are relevant to various biological processes, can undergo spontaneous intramolecular cyclization (ring closure reaction by amino‐terminated hydrocarbon side chain) that deactivates them toward another possible reactions, that is, thiol binding. Density functional theory‐based calculation is employed for obtaining the potential energy curves along the CN bond formation in the intramolecular cyclization of various o ‐quinone amines, viz., dopaminequinone, dopaquinone, N ‐methyl‐dopaminequinone, N ‐formyl‐dopaminequinone, and the corresponding methylene‐inserted analogues. The activation barrier is decreased by introduction of α‐carboxylate and N ‐methyl group whereas increased by introduction of N ‐formyl group. A negative correlation between the activation barriers and the level of highest occupied molecular orbital is pointed out. Furthermore, the methylene‐inserted analogues show decreased activation barriers. This is explained by reduction of steric repulsion in the transition state.