Turkish Journal of Chemistry
Construction of a Homonaphthazarin Skeleton and Synthesis of Hydroquinone-annelated Cycloheptatriene Derivatives
1,4-Dihydroxy-7,8-dihydro-5H-benzo[a]cycloheptene-5,9(6H)- dione (7) was synthesised from hydroquinone and glutaric acid chloride via an acylation reaction. The reaction of dione (7) with bromine followed by treatment with NEt_3 gave homonaphthazarin 8 as well as the brominated derivatives 9 and 10. Reduction of 1,4-dimethoxy-7,8-dihydro-5H-benzo[a]cycloheptene-5,9(6H)-dione (16) with LiAlH_4 gave 2 isomeric alcohols, 17 and 18. Reaction of these alcohols with SOCl_2 followed by HCl elimination with NEt_3 afforded dimethoxybenzocycloheptatriene 19 as the sole product. For the synthesis of the isomeric cycloheptatriene 20, the double bond in 19 was isomerised with KOt-Bu.
Naphthazarin, homonaphthazarin, benzocycloheptatriene, acylation, bromination
ŞENGÜL, EMİN; MENZEK, ABDULLAH; and BALCI, METİN (2006) "Construction of a Homonaphthazarin Skeleton and Synthesis of Hydroquinone-annelated Cycloheptatriene Derivatives," Turkish Journal of Chemistry: Vol. 30: No. 2, Article 1. Available at: https://journals.tubitak.gov.tr/chem/vol30/iss2/1