63086-84-0

Upstream product

• 63086-85-1 N-(mesityl)diphenylketenimine 
• 1450-31-3 Thiobenzophenon 

Relevant academic research and scientific papers

Selectivity in Ketenimine-Thioketone Cycloadditions. 2. Kinetic and Theoretical Studies of the Mechanism of the 1,2- and 1,4-Cycloadditions

The kinetics of the thermal 1,2- and 1,4-cycloadditions of thiobenzophenones to ketenimines to give four-membered adducts, 2-iminothietanes, and six-membered adducts, 4H-3,1-benzothiazines, respectively, has been studied with respect to changes of solvents and substituents as well as at different temperatures.Both reactions show the typical features of concerted processes, viz., little change of rate with the polarity of the solvent, small activation energies, and large and negative activation entropies, but have some substantial differences.The results are consistent with a scheme where the products are formed from two site-selective additions of the reactants through independent pathways, very likely by concerted mechanism.The formation of intermediates such as an open-chain zwitterion or a four-membered cycloadduct involving the C=N bond of the cumulene appears unlikely for both processes.Perturbational molecular reasonings coupled with SCF-MO computations indicate as most probable a ?2s + ?2a> pericyclic process between the C=S bond of the thione and the C=C of the cumulene for the 1,2-cycloaddition and a ?4s + ?2s> process between the C=S bond of the thione and the heterodiene system which consists of the C=N bond of the ketenimine and the C=C of the N-phenyl ring for the 1,4-cycloaddition.

Selectivity in Ketenimine-Thioketone Cycloadditions. 1. 1,4- and 1,2-Addition Pathways and the Synthesis of 4H-3,1-Benzothiazines, 2-Iminothietanes, and Thioacrylamides

The cycloadditions of thiobenzophenones to ketenimines take place at different sites of the cumulene depending on the extent of substitution and the nature of the substituents.C,C-Disubstituted ketenimines whose nitrogen bears an alkyl or an ortho,ortho'-