FORMATION OF PYRYLIUM SALTS IN THE ACYLATION OF STERICALLY HINDERED QUINONES
The reaction of 3,5-di-tert-butyl-o-benzoquinone and 2,6-di-tert-butyl-p-benzoquinone with solutions of 70percent HClO4 in acetic and propionic anhydrides and with boron trifluoride etherate in acetic anhydride leads to the formation of pyrylium salts in high yields.
Ukhin, L. Yu.,Dolgopolova, N. A.,Morkovnik, Z. S.,Kuz'mina, L. G.,Struchkov, Yu. T.