625-77-4Relevant articles and documents
Si· O proximity in imidosilanes - Absence of orbital interactions
B?hme, Uwe,Herbig, Marcus,Kroke, Edwin
, (2021/11/09)
New N-silylated phthalimides, succinimides, and 1,8-napthalimides were synthesised by reactions of the alkali imides with chlorosilanes in THF. Six different mono-, di-, tri- and tetra-iminosilanes of the type (CH3)4-nSi(imide)n were obtained and the products analysed with 1H, 13C, 29Si NMR, and Raman spectroscopy. The molecular structures of four imidosilanes have been determined by single-crystal X-ray diffraction. A characteristic structural feature of the compounds is the fact that all intramolecular Si· O distances are significantly below the sum of the van-der-Waals radii of silicon and oxygen of 3.62 ?. Experimentally found values for Si· O distances range from 2.813 to 3.030 ?. However, there are no significant orbital interactions between silicon and oxygen atoms, as shown by quantum chemical analysis with AIM and NBO methods. The short Si· O distances in these molecules are caused by the geometry of the rigid imide group bound to the silicon atom, and there is no evidence for an increase of the coordination number of the Si atoms.
Heterolytic (2 e) vs Homolytic (1 e) Oxidation Reactivity: N?H versus C?H Switch in the Oxidation of Lactams by Dioxirans
Annese, Cosimo,D'Accolti, Lucia,Fusco, Caterina,Licini, Giulia,Zonta, Cristiano
supporting information, p. 259 - 262 (2017/01/17)
Dioxiranes are powerful oxidants that can act via two different mechanisms: 1) homolytic (H abstraction and oxygen rebound) and 2) heterolytic (electrophilic oxidation). So far, it has been reported that the nature of the substrate dictates the reaction mode independently from the dioxirane employed. Herein, we report an unprecedented case in which the nature of the dioxirane rules the oxidation chemoselectivity. In particular, a switch from C?H to N?H oxidation is observed in the oxidation of lactams moving from dimethyl dioxirane (DDO) to methyl(trifluoromethyl)dioxirane (TFDO). A physical organic chemistry study, which combines the oxidation with two other dioxiranes methyl(fluoromethyl)dioxirane, MFDO, and methyl(difluoromethyl)dioxirane, DFDO, with computational studies, points to a diverse ability of the dioxiranes to either stabilize the homo or the heterolytic pathway.
Synthesis of 1,3,5-trisubstituted-1,2,4-triazoles by microwave-assisted N-acylation of amide derivatives and the consecutive reaction with hydrazine hydrochlorides
Lee, Jongbok,Hong, Myengchan,Jung, Yoonchul,Cho, Eun Jin,Rhee, Hakjune
experimental part, p. 2045 - 2051 (2012/04/10)
Facile and efficient procedures for the N-acylation reaction of amide derivatives with various acid anhydrides and the cyclization reaction of N-acylated amide derivatives with various hydrazine hydrochlorides were described. The reactions were carried out under microwave irradiation to give products in good yields in a few minutes. The synthesis of 1,3,5-trisubstituted- 1,2,4-triazoles from benzamides can also be accomplished in a simple one-pot sequential reaction.
