Abstract: 1. An investigation was made of the lability of the hydrogen atoms of the methyl groups of 4-methylpyridine (I), 4-methylquinoline (II), 4-methyl-5,6-benzoquinoline (III), 4-methyl-7,8-benzoquinoline (IV), 9-methylacridine (V), 9-methyl-1,2-benzacridine (VI), 9-methyl-3,4-benzacridine (VII), 9-methyl-1,2,7,8-dibenzacridine (VIII) and 9-methyl-3,4,5,6-dibenzacridine(IX) in condensation reactions with m-nitrobenzaldehyde. A study was made of the photochemical reactions of the above compounds with carbonyl compounds. 2. It was found that in the condensations of the above compounds with m-nitrobenzaldehyde the activity of the methyl groups fall off on the one hand in the order: (I), >(II), >(III), ≥(IV), and on the other hand in the order: (V), > (VII), ≥ (VI), > (VIII), > (IX). 3. It was shown that, contrary to previously recorded views, the introduction of a benzene ring into the 4-methylpyridine molecule leads to a decline in the reactivity of the methyl group in condensation with o- and m-nitrobenzlaldehydes. 4. It was established that the most active of the investigated compounds toward m-nitrobenzaldehyde is 9-methylacridine. Passage from 9-methylacridine to its angular monobenzo derivatives (9-methyl-1,2- and 9-methyl,3,4-benzacridine) is accompanied by a fall in the reactivity of the methyl group. The activity of the methyl group is depressed to a still greater extent in the reaction of m-nitrobenzaldehyde with the angular dibenzo derivatives of 9-methylacridine. 5. It was established that the activity of the methyl group of benzo derivatives of 4-methylpyridine depends not only on the number of benzene rings but also on their position relative to the heterocyclic nucleus. This is particularly marked in the increased reactivity of 9-methylacridine and the low reactivity of the 5,6- and 7,8-benzo derivatives of 4-methylquinoline. 6. The great reactivity of 9-methylacridine in comparison with 5,6- and 7,8-benzo derivatives of lepidine is confirmed by the results of photocondensations of these compounds with m-nitrobenzaldehyde. 7. Several new styryl derivatives of the quinoline series were synthesized.

Cite: Mikhailov B.M. , Ter-Sarkisyan G.S.
The relative reactivity of the methyl groups of benzo derivatives of 4-methylpyridine
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science. 1954. V.3. N5. P.731-737. DOI: 10.1007/bf01170115 OpenAlex

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W2070619259

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