N monosubstituted derivative of tetra-hydro-quinoxaline

Abstract

The following research was carried outprimarily owing to the interest of the compounds obtained in 1920 by moore and Doubleday from the viewpoint of the stereochemistry of the nitrogen atom, and the lack of knowledge of the simple derivatives of the tetrahydroquinoxaline bases, and consisted mainly ofattempts to obtain from tetrahydroquinoxaline bases of the above type, where a, b, and c, are carbon chains.The direct condensation of tetrahyroquisoxaline with other substances was investigated A compound of the desired type was obtained only with acetaldehyde, when was obtained, examined and identified. The failure to obtain a similar actios with other reagents was attributed to the presence of two reactive imidic hydrogen atoms in the tetrahydroquinoxaline molecule, and attempts were made to replace one of these, with a less reactive group.This was successful, andwere obtained. The next step was to substitute for the imidic hydrogen atom remaining in these compounds a carbon chain containing a reactive, group, and after a trial experiment giving five of such compoundswere obtained. The next stage, more difficult, was the. elimination of the inactive group first substituted, so that the desired condensation could occur. This was successful, and in all cases the toluolsulpho group was removed from the molecule; the two compounds were obtained. It was found impossible to bring about the desired condensation with either of these compounds; all attempts to cause them to react resulted in the loss of carbon dioxide from the molecule.In the other cases, the subsequent condensation occurred so readily after the removal of the toluolsulphe group from the molecule that it was impossible to isolate the intermediate products. The two compounds were obtained and identified.Thus three new compounds of the type where a, b, and o are carbon chains have been obtained, identified and examined, and a method of preparation of such compounds worked out. In audition, derivatives of tetrahydroquinoxaline and its methyl derivative in which another group has been substituted for one only of the two imidic hydrogen atoms have been obtained and examined.