Oxidation and ring cleavage reactions of 3-benzhydrylchromones. Generation of triarylmethine cations from methylidenechroman-4-ones and benzopyrano[4,3-c]pyrazoles

GABBUTT, Christopher; HARGROVE, Tessa; HERON, B.; JONES, David; POYNER, Carley; Yildiz, EMEL; HORTON, Peter; HURSTHOUSE, Michael

doi:10.1016/j.tet.2006.08.090

Oxidation and ring cleavage reactions of 3-benzhydrylchromones. Generation of triarylmethine cations from methylidenechroman-4-ones and benzopyrano[4,3-c]pyrazoles

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GABBUTT C. D., HARGROVE T. F. L., HERON B. M., JONES D., POYNER C., Yildiz E., ...More

TETRAHEDRON, vol.62, no.47, pp.10945-10953, 2006 (SCI-Expanded)

Publication Type: Article / Article
Volume: 62 Issue: 47
Publication Date: 2006
Doi Number: 10.1016/j.tet.2006.08.090
Journal Name: TETRAHEDRON
Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
Page Numbers: pp.10945-10953
Çukurova University Affiliated: No

Abstract

The oxidation of 3-[bis-(diaryl)methyl]chromones 2 with p-chloranil affords novel acetals, 3-[bis-(diaryl)methylene]-2-methoxychroman-4-ones, 4 through interception of a pyrylium type intermediate. Oxidation of 3-(2-hydroxyphenyl)-4-[bis-(diaryl)methyl]pyrazoles 8, derived from 2 and hydrazines, gave 4,4-diarylbenzopyrano[4,3-c]pyrazoles 15. The electronic absorption spectra of 4 and 15 upon protonation are comparable with those of triarylmethine cationic dyes. (c) 2006 Elsevier Ltd. All rights reserved.