3.4- Quinolyne

The reaction of 3-bromo-4-chloro- and 3-bromo-2-chloro-quinoline with lithium amalgam in the presence of furan gives phenanthridine (83, 9% yield) and acridine (85, 0.1% 3deld), respectively, via 3,4-(82) and 2,3-quinolyne (84). 

In the addition of piperidine to 3,4-quinolyne, the orienting effect of the nitrogen atom manifests itself in bringing the ratio of the 3- and 4-substituted derivatives formed to 49 51 (cf. 86), whereas the ratio is 69 31 in the case of 3,4-naphthalyne (cf. 87). 

Kaneko, C., Yamamoto, A. and Hashiba, M. (1979) Ring contraction reactions of methyl quinolyne 1-oxide 5-carboxylates via the corresponding benz[d]-3,l-oxazepines. A facile synthesis of methyl indole 4-carboxylate and its derivatives. Chemical e[ Pharmaceutical Bulletin, 27 (4), 946-952. 

The intermediates (66), (67), upon in situ oxidation, afford 2(or 3)-pyridynes or 2(or 3)-quinolynes <71JCS(C)3948> which are highly reactive in Diels-Alder reactions, as shown in Schemes 10 and 11 for syntheses of ellipticine (69), isoellipticine (70) (84JOC4518,92T10645), and furo[3,4-c]pyridine (72) (77TL1741). Nitrosation of the aminotriazolopyridines affords the parent triazolopyridines. 

In the addition of piperidine to 3,4-quinolyne, the orienting effect of the nitrogen atom manifests itself in bringing the ratio of the 3- and... 

Finally, an example of a 1,3-dipolar cycloaddition has appeared. Reaction of pyridynes and quinolynes with pyridazine-A-oxides 747 gave pyrido-oxepins 750 in 20-30% yields. The reaction is thought to involve cycloaddition to give 748 which, after a 1,3-shift of the oxygen from N to C and nitrogen loss, gives the product. The pyridynes were produced by lead tetraacetate oxidation of 1-aminotriazolopyridines. 

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