Bradsher cyclization

Other references related to the Bradsher cyclization are cited in the literature. 

The mechanism for forming acridizinium salt is similar to the Bradsher Cyclization when a carbonyl group exists in the reaction system. However, the mechanism for forming oxazole[3,2-a] pyridinium is different from what is proposed here. 

The intramolecular Bradsher cyclization refers to the acid-catalyzed aromatic cyclodehydration of ort/zo-acyl diaryImethanes to form anthracenes. On the other hand, the intermolecular Bradsher cycloaddition often involves the Diels-Alder reaction of a pyridium with a vinyl ether or vinyl sulfide. 

Yamato and co-workers introduced dichloromethyl methyl ether in the presence of titanium tetrachloride as a reagent for one-pot formylation followed by in situ Bradsher cyclization. In this way anthracene regioisomers 25 and 26 were obtained from diaryImethane 24 in good yield. The initially formed anthracene derivative presumably reacts with excess dichloromethyl methyl ether to yield 9- or 10-formylanthracene derivative 25 or 26. 

Diol epoxide metabolites of DMBA such as tra 5-3,4-dihydroxy-a //-1,2-epoxy-1,2,3,4-tetrahydro-DMBA (41) or rra 5-3,4-dihydroxy-s y -1,2-epoxy-1,2,3,4-tetrahydro-DMB A (42) has been implicated as the principle active form of DMBA which binds covalently to DNA in vivo. The intermediacy of 41 and 42 was further supported by the development of methods for their synthesis by using the Bradsher cyclization for the construction of the DMBA moiety, coupled with studies of their mutagenicity, tumorigenicity and DNA binding. ... 

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