Pyrolysis of trifluoromethyl sulfonyl dihydropyridines. Thermolysis vs. Photolysis

GUADALUPE FIRPO; COOKE, M. V.; PELÁEZ, W. J.; GUILLERMO M. CHANS; ARGÜELLO G. A.; ELIZABETH GÓMEZ; CECILIO ÁLVAREZ TOLEDANO

Concón

Conferencia; 14th Latin American Conference on Physical Organic Chemistry; 2017

14th Latin American Conference on Physical Organic Chemistry.

2017- ?Pyrolysis of trifluoromethyl sulfonyl dihydropyridines. Thermolysis vs. Photolysis?. G. Firpo, M. V. Cooke, W. J. Peláez, G. M. Chans, G. A. Argüello, E. Gómez, C. Alvarez-Toledano. 14th Latin American Conference on Physical Organic Chemistry. P20. 7th-11th May 2017. Concón, Chile.As part of our ongoing project on sulfonyl derivatives as bioactive heterocyclic compounds, our research has been focused on exploring the consequences of an N?SO2?R linkage on the stereoelectronic properties of some sulfonyl-tetrahydroquinolines.1In this case, we are interested in the reactivity of some trifluoromethyl sulfonyl-dihydropyridines2 and how the trifluoromethanesulfonic moiety can be removed. Here, we describe a comparison of three methodologies: static gas phase pyrolysis, microwave induced pyrolysis (MIP) and photolysis reactions of these non-aromatic compounds, scheme 1. We demonstrated that it is possible to achieve the rearomatization process by elimination of the trifluoromethyl sulfonyl moiety through the three processes, being the static pyrolysis the best method to obtain the desired compounds. In turn, the products proved to be substituted pyridines that are known to be difficult to prepare by other methods. We propose the 1,4-elimination (CF3SO2 + H) as the first step, since it is the less energetic process - corroborated by calculations. A competitive reaction (CO2 extrusion) also occurs, yielding undesired products.