Arylquinolin/4 -ones

Nucleophilic ring-opening of benzoxazinones by enolates of arylacetic esters followed by deacylation of the amine group resulted in cyclization to the desired 3-arylquinolin-2-ones <03JOC4567>. 

The reaction of Al-methyl-Al-phenylcinnamamides with phenyliodine bis (trifluoroacetate) in the presence of Lewis acids provides 3-arylquinolin-2-ones and involves a metal-free oxidative C(sp )-C sp ) bond formation and a 1,2-aryl migration (Scheme 89). " ... 

Zhao et al. utilized the remarkable oxidative property of FIFA in a C-C bond formation to prepare an array of 3-arylquinolin-2-ones 120 (Scheme 26). FIFA-promoted oxidation of N-methyl-N-phenylcinnamamides 119 in the presence of a Lewis acid afforded 3-arylquinolin-2-ones in good yields. Formation of 3-arylquinolin-2-ones was realized through the FIFA-promoted simultaneous C-C bond formation and 1,2-aryl migration. This simple and metal-free FIFA-mediated green approach for the biologically important 3-arylquinolin-2-ones also widen the synthetic utility of hypervalent iodine reagents [42]. 

L. Liu, H. Lu, H. Wang, C. Yang, X. Zhang, D. Zhang-Negrerie, Y. Du, K. Zhao, PhI(OCOCF3)2-mediated C-C bond formation concomitant with a 1,2-aryl shift in a metal-free synthesis of 3-arylquinolin-2-ones, Org. Lett. 15 (2013) 2906-2909. 

AT-Arylquinolin-2(lff)-ones have been prepared in a four step process from commercially available coumarins, utilizing a Buchwald-Hartwig ami-... 

Hewawasam, P. and Starrett, J. E. (Bristol-Myers Squibb) 3-Substituted-4-arylquinolin-2-one derivatives as potassium channel modulators, W00034244. 

A mild, highly efficient, scalable synthesis of 4-arylquinolin-2-ones from 2-aminobenzophenones was reported <03TL4271>. By reacting the starting material with lactones and two equivalents of LiHMDS, the desired compounds are formed in good to excellent yields. 

A route to 4-(l-alkenyl)isoquinolines and 4-alkyl-3-arylquinolines via palladium(II)-catalyzed cyclization, followed by olefination, was developed through many trials. Substrates were chosen for their ability to stabilize the Pd(II) intermediate, and to promote the Pd-catalyzed cyclization. An o-methoxy substituent on the aryl group was found to be necessary <03JOC980>. Forty-one examples are given. 

Alkaloids 164a and 164b have been prepared accordingly from 2 and the pyrrolidine enamines of 2-pentanone and 2-heptanone <1998CPB332>, and a series of 2-arylquinoline and 2-arylquinol-4-one alkaloids have been prepared from 2 and its 6-methoxy derivative with suitably designed enamines <1999CPB1038>. 

Table 24.25 Occurrence of 2-arylquinolin (l//)-one alkaloids in the Rutaceae species...

More recently, Jiang and coworkers used 3-arylquinolin-4(l//)-one as the substrates and realized the construction of 6//-isochromene[4,3-c]-quinolin-6-ones by palladium-catalyzed C-H carbonylation and cyclization (Scheme 3.27) [52]. 

Blaschke-Cobet and co-workers (212) have shown that the non-anthranilate portion of the 2-arylquinolin-4(lH)-one of graveoline of Ruta graveolens is derived from the decarboxylation and deamination of phenylalanine. Feeding experiments with labeled isotopes in R. graveolens indicated that hydroxylation of the aromatic ring precedes cyclization to the quinolin-4(lH)-one system. A (3-keto ester and a 3-carboxyquinolin-4(lH)-one are probable intermediates in the biosynthesis of graveoline (Do) (Scheme 11). 

The Flindersioideae is a smaller sub-family of two genera, and only Flindersia has been reported to contain a 2-arylquinolin-4(lH)-one alkaloid (Do). The presence of only one alkaloid is of little chemosystematic value to clarify the classification of the subfamily. However, it does begin to reinforce its position close to the Toddalioideae in Waterman s diagram (Figure 2a). 

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