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The Synthesis of 4-Ethyl-2-propyl-3-substitutedpyrrolo[ 3,4-b]quinoline-1,9-dione Derivatives from 3,3-Dichloro-4-ethyl-thieno[3,4-b]quinoline-1,9-dione and Propylamine
Abstract
The preparation, spectral properties and structure elucidations of the hitherto undocumented 3-oxo-, 3-thioxo-, 3-propylimino-, 3-imino-, and 3-propylamino- derivatives of 4-ethyl-2-propyl-2,3-dihydro-pyrrolo[3,4-b]quinoline-1,9-dione are described. Mechanistic aspects relating particularly to the formation of the latter two unprecedented products are considered. Magnetic anisotropic effects (deshielding/line broadening of signals) are exhibited by the α-methylene protons of the 4-ethyl moiety in the 1H NMR spectra of the first four of the above, and in several 3,3-dichloro-thieno[3,4-b]quinoline-1,9-diones and intramolecular H-bonded, 1,2-dialkyl-4-oxo-3-quinolinecarboxylic acid precursor substrates.
KEYWORDS: 3-Imino-, 3-propylamino-, 3-propylimino-, 3-oxo-, 3-thioxo-substituted 4-ethyl-2-propyl- 2,3-dihydro-pyrrolo[3,4-b]quinoline- 1,9-diones, 4-methyl-, 4-propyl-substituted-3,3-dichloro-thieno[3,4-b]quinoline-1,9-diones, intramolecular H-bonding, magnetic anisotropic effects.