NaHSO4/SiO2 catalyzed generation of o-quinone/o-thioquinone methides: synthesis of arylxanthenes/arylthioxanthenes via oxa-6π-electrocyclization

被引：7

作者：

Karthick, Muthupandi ^{[1
]}

Abi, Edwin Konikkara ^{[1
]}

Someshwar, Nagamalla ^{[1
]}

Anthony, Savarimuthu Philip ^{[2
]}

Ramanathan, Chinnasamy Ramaraj ^{[1
]}

机构：

[1] Pondicherry Univ, Dept Chem, Pondicherry 605014, India

[2] SASTRA Deemed Univ, Sch Chem & Biotechnol, Thanjavur 613401, India

来源：

ORGANIC & BIOMOLECULAR CHEMISTRY | 2020年 / 18卷 / 42期

关键词：

FRIEDEL-CRAFTS HYDROXYALKYLATION; ONE-POT SYNTHESIS; EFFICIENT SYNTHESIS; COUPLING REACTION; ORTHO-HYDROXY; SOLID ACIDS; ALCOHOLS; DERIVATIVES; ACTIVATION; CONVENIENT;

D O I：

10.1039/d0ob01868f

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

ortho-Quinone methides, very reactive transient intermediates, are utilized successfully in synthesizing complex organic molecules of natural and biological significance. Among several synthetic protocols, the acid catalyzed generation of ortho-quinone methides from suitably substituted phenols is a promising method for further exploitation in organic synthesis. Such an interesting reactive species is conveniently employed in the synthesis of conformationally restricted triarylmethane derivatives such as 12/9-arylxanthenes/arylthioxanthenes starting from symmetrical/unsymmetrical 2-(hydroxydiarylmethyl)phenol/thiophenol, respectively, using SiO2-NaHSO4. Conformationally restricted 12/9-arylxanthenes/arylthioxanthenes were obtained in 52 to 96% yields using this protocol, which is believed to involve the formation of o-quinone methides followed by electrocyclic ring closure and isomerization at elevated temperature. Photophysical studies of selected examples in acidic media showed turn-on fluorescence by hydride ion transfer mediated pi-conjugated xanthylium salt formation and suggested the application potential in bio-imaging and fluorescent sensors.

引用

页码：8653 / 8667

页数：15

共 95 条

[1] Direct, regioselective synthesis of 2,2-dimethyl-2H-chromenes. Total syntheses of octandrenolone and precocenes I and II [J].