Freeman, Fillmore’s team published research in Journal of Physical Chemistry A in 112 | CAS: 20662-83-3

Journal of Physical Chemistry A published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Category: oxazolidine.

Freeman, Fillmore published the artcileSubstituent Effects on Singlet-Triplet Gaps and Mechanisms of 1,2-Rearrangements of 1,3-Oxazol-2-ylidenes to 1,3-Oxazoles, Category: oxazolidine, the publication is Journal of Physical Chemistry A (2008), 112(37), 8775-8784, database is CAplus and MEDLINE.

Electronic structures, partial at. charges, singlet-triplet gaps (ΔEST), substituent effects, and mechanisms of 1,2-rearrangements of 1,3-oxazol-2-ylidene (5) and 4,5-dimethyl- (6), 4,5-difluoro- (7), 4,5-dichloro- (8), 4,5-dibromo- (9), and 3-methyl-1,3-oxazol-2-ylidene (10) to the corresponding 1,3-oxazoles were studied using complete-basis-set methods (CBS-QB3, CBS-Q, CBS-4 M), second-order Moller-Plesset perturbation method (MP2), hybrid d. functionals (B3LYP, B3PW91), coupled-cluster theory with single and double excitations (CCSD) and CCSD plus perturbative triple excitations [CCSD(T)], and the quadratic CI method including single and double excitations (QCISD) and QCISD plus perturbative triple excitations [QCISD(T)]. The 6-311G(d,p), 6-31+G(d,p), 6-311+G(d,p), and correlation-consistent polarized valence double-ξ (cc-pVDZ) basis sets were employed. The carbenes have singlet ground states, and the CBS-QB3 and CBS-Q methods predict ΔEST values for 5-8 and 10 of 79.9, 79.8, 74.7, 77.0, and 82.0 kcal/mol, resp. CCSD(T), QCISD(T), B3LYP, and B3PW91 predict smaller ΔEST values than CBS-QB3 and CBS-Q, with the hybrid d. functionals predicting the smallest values. The concerted unimol. exothermic out-of-plane 1,2-rearrangements of singlet 1,3-oxazol-2-ylidenes to their resp. 1,3-oxazoles proceed via cyclic three-center transition states. The CBS-predicted barriers to the 1,2-rearrangements of singlet carbenes 5-9 to their resp. 1,3-oxazoles are 41.4, 40.4, 37.8, 40.4, and 40.5 kcal/mol, resp. During the 1,2-rearrangements of singlet 1,3-oxazol-2-ylidenes 5-9 there is a decrease in electron d. at oxygen, N3 (the migration origin), and C5 and an increase in electron d. at C2 (the migration terminus), C4, and the partially pos. migrating hydrogen.

Journal of Physical Chemistry A published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Category: oxazolidine.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem