3-Benzazepine ring

H-3-Benzazepines ring contractions, 7, 506 2H-2-Benzazepine- 1-thione synthesis, 7, 532... 

In the presence of a catalytic amount of concentrated hydrochloric acid, dimethyl 1 -methyl-1 H-l-benzazepine-3,4-dicarboxylate (1) undergoes addition of 1-methylindole, probably via initial protonation of the enaminic 3-position of the benzazepine ring, to give the indolyldihydrobenz-azepine 2.21 In fact, adduct 2 is the major product from the reaction of 1-mcthylindole with dimethyl acetylenedicarboxylate in acetonitrile. Similar adducts are obtained with indole. 

This kind of reactivity is usually limited to substitution on the nitrogen of benzazepine ring and the nitrogen of pyrrole (or indole) fused to the heteropine core. 

Varenicline (used as the tartrate salt as CHANTIX, Pfizer Inc.) is a smoking cessation dmg containing a benzazepine ring structure. 

Intramolecular cyclization to form tetracyclic ring systems has been reported wherein a 7-membered benzazepine ring was formed by the... 

Ring closure by making a C—C bond is a common synthetic method for rings of all sizes. Scheme 7 gives a few examples of displacement reactions. Other examples are found in the preparation of benzazepines (Section 5.16.4.1.2) and oxepins (Section 5.17.3.2.1). 

H-2-Benzazepine, (halophenethyl)-ring expansion, 7, 528 3H-2-Benzazepine, 1-phenyl-synthesis, 7, 540... 

The aldehyde functionality present in 3-phenyl-2H-azirine-2-carbox-aldehyde reacts selectively with amines and with Qrignard and Wittig reagents to give a variety of substituted azirines. These azirines have been used, in turn, to prepare a wide assortment of heterocyclic rings such as oxazoles, imidazoles, pyrazoles, pyrroles, and benzazepins. ... 

Fenoldopam (76) is an antihypertensive renal vasodilator apparently operating through the dopamine system. It is conceptually similar to trepipam. Fenoldopam is superior to dopamine itself because of its oral activity and selectivity for dopamine D-1 receptors (D-2 receptors are as.sociated with emesis). It is synthesized by reduction of 3,4-dimethoxyphenylacetonitrile (70) to dimethoxyphenethylamine (71). Attack of diis last on 4-methoxystyrene oxide (72) leads to the product of attack on the epoxide on the less hindered side (73). Ring closure with strong acid leads to substituted benzazepine 74. O-Dealkylation is accomplished with boron tribromide and the catechol moiety is oxidized to the ortho-quinone 75. Treatment with 9NHC1 results in conjugate (1,6) chloride addition and the formation of fenoldopam (76) [20,21]. 

Likewise, the isomeric fused aziridines 22 and 24, obtained from 1,4,5,6,7,8-hexahydronaph-thalene, undergo bromination. dehydrobromination and ring expansion to the 6,7,8,9-tetra-hydro-3//-3-benzazepine 23 and the 2,7-bridged azepine 25, respectively.61... 

X-ray analysis of 2-methoxy-4-hydroxy-5//-l-benzazepin-5-one (a benzazatropolone), prepared by methylation of the corresponding 4-hydroxy-l-benzazepin-2,5-dione with Meerwein s reagent, demonstrates the presence of a planar seven-membered ring but, in contrast to tropolone, little 71-electron delocalization.17 Likewise, ll//-dibenz[f>,e]azepin-ll-ones display no significant aromatic character.18 In contrast, 7-chloro-8//-thieno[3,2-c]azepin-8-one (12) has azepine ring hydrogen resonances at 8.7 and 9.02 ppm that indicate a substantial contribution from the polar zwitterionic mesomer 13.19... 

Partial reduction of the acetylenes 1 over 10 % palladium on barium sulfate yields the ra-alkenes 2 which ring close spontaneously to the 3//-2-benzazepines 3.78 Reduction with Raney nickel is less successful and produces mixtures of the 3-benzazepines and their 4,5-dihydro derivatives. 

The 2-(2-pheriylvinyl) derivative 18 and the thienyl compound 20 cyclize exclusively at the alkene carbon, and at the thiophene ring, to give 3,4-diphenyl-l//-2-benzazepine (19) and 4-phenyl-6-//-thieno[3,2-e]-2-benzazepine (21), respectively.48 A mechanistic rationale for these results has been offered. This method has been extended to the synthesis of 7Z7-pyrido[3,4-t/]-, 7//-pyrido[2,3-t/]- and 77/-pyrido[4,3-r/]benzazepincs and to other thieno- and furo-fused 2-benzazepines.244... 

Benzoyl-l-methyl-3,4-benzo-2-azabicyclo[3.2.0]hepta-3.6-diene (3) at 250"C yields exclusively l-benzoyl-2-mcthyl-l//-l-benzazepine (4).23 In contrast, silvcr(I) ion catalyzed ring expansion of 3 yields a mixture of the rearranged bicycle 5 (43 %), starting material (43 %), and the isomeric 1 H-l-benzazepines 4 (8%) and 6 (4%).23... 

The structure of the product obtained by the silver(I) ion catalyzed ring expansion of anti-1-chloro-2,3-benzo-7-azabicyclo[2.2.l]hepta-2,5-diene, formulated tentatively as 1-methoxy-l/f-1-benzazepine,140 has been shown to be 2-methoxy-6,7-benzo-l-azabicyclo[3.2.0]hept-3-ene... 

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