Synthesis of 2-substituted 9,10-anthraquinones

Abstract

A convenient preparation of racemic 2-substituted 9,10-anthraquinones that included 2-triazoylethyl skeleton 1 and 2-alkylethyl skeleton 6 is reported. The products were obtained in good yields by a three- or four-step synthetic route based on a sequence of N-bromosuccinimide (NBS)–mediated bromination of 2-ethyl-9,10-anthraquinone 2, nucleophilic substitution, and CuI-catalyzed 1,3-dipolar cycloaddition or alkylation/reductive desulfonylation.

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GRAPHICAL ABSTRACT

Keywords:

• Alkynes
• azides
• dipolar cycloaddition
• heterocycles
• nucleophilic substitution

ACKNOWLEDGMENT

The authors thank the National Science Council of the Republic of China for financial support.

Notes

^a The products 1a–h were >95% pure as judged by ¹HNMR analysis.

^a The products 8a–e and 9a–e were >95% pure as judged by ¹HNMR analysis.