Abstract

A search of the literature revealed that almost nothing is known concerning the class of compounds known as decahydroquinoxalines. Since this posed a problem involving a search for a systematic synthetic method of general application as well as a method for establishing the characteristic class and individual properties, a research project under the guidance of Dr. H. Smith Broadbent was initiated. Of particular interest aside from matters of purely chemical interest was the recognition that the hydroquinoxalines possess obvious structural similarities with atropine and other well-known drugs which have valuable application as hypotensive agents, analgesics, spasmolytic agents, parasympathetic depressants, antihistaminics, bronchodilators, etc. A catalyst consisting of 5% rhodium on alumina powder was reported by Baker and Co., Inc., to have certain special activity toward nitrogen heterocycles. This catalyst was applied in hydrogenation of alcohol solutions of quinoxaline and some of its substituted derivatives. At hydrogen pressures which ranged from 2000-5500 p.s.i. and temperatures of 100-200° C it was found that a variety of quinoxalines could be reduced completely to the decahydro compounds. The following decahydroquinoxalines were synthesized, described, and identified for the first time: decahydroquinoxaline, 6-methyldecahydroquinoxaline, 2,3,5,7-tetramethyldecahydroquinoxaline, 6-methoxydecahydroquinoxaline, 2,3-dimethyl-6-methoxydecahydroquinoxaline, and 6,7-dimethoxydecahydroquinoxaline. The existence of stereoisomeric forms of the decahydroquinoxalines is indicated, and it is believed that a separation of the cis and trans forms can be successfully accomplished by a combination of fractional crystallization and solvent recrystallization. Another method of separation depending on the differences of picrate solubilities in ethyl alcohol and in water is suggested. During the course of investigation five additional new compounds not previously reported in the literature were prepared and identified by elemental analysis. These were 6-phenylquinoxaline, 2,3,5,7-tetramethylquinoxaline, 6-phenyl-1,2,3,4-tetrahydroquinoxaline, 6-amino-1,2,3,4-tetrahydroquinoxaline, and 6,7-dimethoxy-1,2,3,4-tetrahydroquinoxaline. This fundamental research has opened up a convenient synthetic route for a whole new class of compounds and has in part indicated their characteristic properties.

Degree

College and Department

Physical and Mathematical Sciences; Chemistry and Biochemistry

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