Abstract
The pyridoquinolines and pyrroloquinolines obtained by the Skraup and Conrad-Limpach-Knorr e quinoline cyclization and Fischer's indole cyclization carried out on 4, 6-diaminoquinoline and 4-methyl-6-aminocarbostyril were all found to be angular cyclized product. Skraup's quinoline cyclization was carried out newly on 5-methyl-6-aminocarbostyril, protecting the 5-position with an alkyl group, to find whether angular and linear cyclizations took place. The starting 5-methylcarbostyril was prepared by the rearrangement reaction of 5-methylqui noline 1-oxide with tosyl chloride and the intermediate tosyl derivative was hydrolyzed to 5-methylcarbostyril. Since the rearrangement of quinoline 1-oxide with tosyl chloride results in variety of reactions, it was important that the tosyl derivative was obtained as an intermediate. Nitration of 5-methylcarbostyril gave the 6-nitro compound and 5-methyl-6-aminocarbostyril derived from it was submitted to the Skraup cyclization. The product was chromatographed through alumina and three kinds of product were obtained; pale yellow needles (A) of m.p. 316-317°, pale yellow needles (B) of m.p. 303-304°, and colorless needles (C) of m.p. 124°. From the comparison of their ultraviolet spectra and preparation of their derivatives, it was confirmed that (A) is the linear cyclized product, (B) the angular cyclized product, and (C) is the hydrate of (A).
