Polyphosphate esters as synthetic agents. II. Bischler-Napieralski reaction by means of polyphosphate esters and synthesis of 5H-2-benzazepine derivatives was written by Kanaoka, Yuichi;Sato, Eisuke;Yonemitsu, Osamu;Ban, Yoshio. And the article was included in Tetrahedron Letters in 1964.Reference of 52250-50-7 This article mentions the following:
Polyphosphate ester (I, prepared from P2O5 and Et2O in CHCl3 and used in situ, 5 parts) refluxed with 3,4-R2C6H2CH2CH2NHCOR’ (R = MeO, R’ = Me; R = MeO, R’ = Ph; R = H,R’ = Me; R = H, R’ = Ph) 0.5-1.5 h. yielded 78-89% of the corresponding dihydroisoquinolines. Similarly, 3,4-(MeO)2C6H3(CH2)3NHCOR (R = H, Me, Ph) were cyclized to yield the corresponding benzazepines (II, R = H, Me, Ph) (III, IV, V), in 76, 63, and 93% (crude) yields, resp., reduced by NaBH4 to the resp. dihydro compounds (VII, VIII, IX). Phys. data are tabulated (compound, m.ps. of base, picrate, perchlorate, and methiodide given): III, 165-6掳, 197-8掳, 234掳 (decomposition), 182-5掳; IV, 140-3掳, 183-4掳, 190-1掳, 190-1掳; V, -, 222掳 (decomposition), 246-7掳 (decomposition), 206-6.5掳 (decomposition); VII, 172-3掳, 197-8, -, -; VIII, 115-20掳 (b. 3掳), 163-5, -, -; IX, 114-15, -, -, -. In the experiment, the researchers used many compounds, for example, 1-Phenyl-3,4-dihydroisoquinoline (cas: 52250-50-7Reference of 52250-50-7).
1-Phenyl-3,4-dihydroisoquinoline (cas: 52250-50-7) belongs to isoquinoline derivatives. Being an analog of pyridine, isoquinoline is a weak base, with a pKa of 5.14. Lewis acid activation and nucleophilic attack can produce multiple regioisomers in quinolines and pyridines; isoquinolines generally only undergo attack at the 1-position.Reference of 52250-50-7
Referemce:
Isoquinoline – Wikipedia,
Isoquinoline | C9H7N – PubChem