Crystal structure of (Z)-ethyl 2-{5-[(2-benzyl-idene-3-oxo-2,3-di-hydro-benzo[b][1,4]thia-zin-4-yl)meth-yl]-1H-1,2,3-triazol-1-yl}acetate.

The title compound, C22H20N4O3S, features two fused six-membered rings linked to a 1,2,3-triazole ring which is attached to an ethyl acetate group. The heterocycle in the benzo-thia-zine residue has an envelope conformation with the S atom being the flap. The conformation of the ethyl acetate side chain, which is directed to the same side of the mol-ecule as the C6 ring of the fused-ring system, may be partially established by a pair of weak intra-molecular C-H⋯O(carbon-yl) inter-actions. The three-dimensional packing is aided by inter-molecular C-H⋯O and C-H⋯N inter-actions.

Crystal structure of 4-benzyl-2H-benzo[b][1,4]thia-zin-3(4H)-one.

In the title compound, C15H13NOS, the thia-zine ring adopts a twisted boat conformation and the dihedral angle between the aromatic rings is 86.54 (4)°. In the crystal, mol-ecules are linked by weak C-H⋯O inter-actions, resulting in chains along [010].

Thermochemistry and kinetics for 2-butanone-1-yl radical (CH2·C(═O)CH2CH3) reactions with O2.

Thermochemistry of reactants, intermediates, transition state structures, and products along with kinetics on the association of CH2·C(═O)CH2CH3 (2-butanone-1-yl) with O2 and dissociation of the peroxy adduct isomers are studied. Thermochemical properties are determined using ab initio (G3MP2B3 and G3) composite methods along with density functional theory (B3LYP/6-311g(d,p)). Entropy and heat capacity contributions versus temperature are determined from structures, vibration frequencies, and internal rotor potentials. The CH2·C(═O)CH2CH3 radical + O2 association results in a chemically activated peroxy radical with 27 kcal mol(-1) excess of energy. The chemically activated adduct can react to stabilized peroxy or hydroperoxide alkyl radical adducts, further react to lactones plus hydroxyl radical, or form olefinic ketones and a hydroperoxy radical. Kinetic parameters are determined from the G3 composite methods derived thermochemical parameters, and quantum Rice-Ramsperger-Kassel (QRRK) analysis to calculate k(E) with master equation analysis to evaluate falloff in the chemically activated and dissociation reactions. One new, not previously reported, peroxy chemistry reaction is presented. It has a low barrier path and involves a concerted reaction resulting in olefin formation, H2O elimination, and an alkoxy radical.