Oxazolo quinolines, synthesis

H,4H-Oxazolo[5,4,3-y]pyrido[3,2-g]quinolin-4-one, 8-hydroxymethyl-6-methyl — see Nybomyein 5H-Oxazolo[2,3-[Pg.731]

The isoxazole-to-oxazole rearrangement has been also used in the synthesis of benzocondensed derivatives. The irradiation of benzisoxazoles 81 in water (high-pressure Hg lamp) produces almost quantitative yields of the corresponding ben-zoxazoles 82 (Scheme 12.24) [53]. Benzoxazolin-2-ones 83 are similarly obtained [54], Furthermore, oxazolo[5,4-b]pyridines 84 and oxazolo[5,4-b]quinoline 85 are obtained by preparative-scale photolysis in ether with a high-pressure Hg lamp of the corresponding isoxazolo[5,4-b]pyridines or isoxazolo[5,4-b]quinoline, respectively (Scheme 12.24) [55]. 

An efficient, diverse synthesis of oxazolo[4,5-c]quinoline-4-ones and thiazolo[4,5-c]quinolines-4-ones is carried out in two steps from readily available starting materials <03OL2911>. The Suzuki-Miyaura coupling reaction was employed. 

M. Yamato, K. Hashigaki, S. Ishikawa, N. Qais, Syntheses of chiral oxazolo[2,3-a]tetrahydroiso-quinoline and its asymmetric alkylation. Synthesis of (S)-(-)- and (R)-(-l-)-salsolidines, Tetrahedron Lett. 29 (1988) 6949. 

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