Preparation and mass spectrometric analysis of 5,6- dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1,2-dione and 1,1'- (1,2-dioxoethane-1,2-diyl)bis-1,2,3,4-tetrahydroquinoline

Abstract

According to thin layer chromatography (eluent - chloroform) found to that the reaction of 1,2,3,4-
tetrahydroquinoline hydrochloride with oxalyl chloride in refluxing toluene exhaustively occurs for 1.5 h.
The product of this interaction is a mixture of 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1,2-dione (Rf 0,52),
and 1,1'-(1,2-dioxoethane-1,2-diyl)bis-1,2,3,4-tetrahydroquinoline (Rf 0,38) at a ratio of 3: 1. Purification of
the reaction mixture and separating the obtained compounds was performed by column chromatography. The
optimal eluent for the separation of the individual products was a mixture of carbon tetrachloride: chloroform
in the ratio 3: 1, the transmission rate of 2 cm3 / min. Product structure uniquely proved by means of mass
spectrometry. Mass spectrometric investigation of 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1,2-dione,
showed that of two cycles - hydropyridine and pyrroledione less stable is the last one. Under electron impact
in the ion-radical 1,1'-(1,2-dioxoethane-1,2-diyl)bis-1,2,3,4-tetrahydroquinoline symmetrically breaks up the
C-C bond dioxoethane moiety. Thus obtained radical cation emits a neutral molecule of CO to form ion
tetrahydroquinoline having maximum intensity (100%).