The dimerisation of some 4-hydroxyindenes

Studies on 5-Bromo-4,7-dimethylindene, an Intermediate in the Synthesis of 6-Bromo-5,8-dimethylisoquinoline

“…Several conditions have been described previously for the dehydration of indanols. 3Y4 However the formation of this type of dimer was also observed during the acid-catalysed dimerisation of indenes when treated with 5% TFA in chloroform, 4 with 85% phosphoric acid 5 or with 48% r P y R . 6 Recently it was reported 7 that the best conditions for the dehydration of 4-methylindan-1-ol, under which the yields of the dimer or the indene could be maximised, were the use of benzene with toluene-p-sulfonic acid.…”