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Synthesis 2001; 2001(2): 0305-0311
DOI: 10.1055/s-2001-10821
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Synthesis of Triphenylene and Dibenzopyrene Derivatives: Vanadium Oxytrichloride a Novel Reagent

Sandeep Kumar* , Sanjay K. Varshney
  • *Centre for Liquid Crystal Research, P.O. Box 1329, Jalahalli, Bangalore-560013, India; Fax +91(80)8382044; E-mail: uclcr§giasbg01.vsnl.net.in
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Publication Date:
31 December 2001 (online)

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This paper presents an efficient synthetic procedure for the preparation of various triphenylene and dibenzopyrene derivatives using VOCl3 as a novel reagent. Symmetrically substituted hexaalkoxytriphenylenes are obtained from o-dialkoxybenzenes by oxidative trimerization with VOCl3 in high yields. The oxidative coupling of a 3,3′,4,4′-tetraalkoxybiphenyl and 1,2-dialkoxybenzenes or 1,2,3-trialkoxybenzenes affords unsymmetrically substituted derivatives of triphenylene. The reagent oxidizes 3,3′,4,4′-tetraalkoxybiphenyl efficiently to 2,5,6,9,12,13-hexaalkoxydibenzo[fg,op]naphthacene-1,8-quinone and its 1,10-quinone isomer. Both the quinones can be converted to liquid crystalline derivatives using well-established chemistry. Effects of solvent, reagent concentration, acid catalyst and temperature have been studied.

triphenylene - dibenzopyrene - vanadium oxytrichloride - oxidative coupling - discotic liquid crystals