... [13b] J. March, in Ad- vanced Organic Chemistry, 3rd ed., Wiley Interscience, 1985, chapter 9, pp. ... of copper(II) salt [Cu(NO3)2 or Cu(OAc)2], at 100 °C for 3 hours. The reaction was carried out both in the absence of 4- toluic acid and with 5 equivalents of 4-toluic acid. ...