To a solution of 4.7 g. (0.022 m) of 2,4-dihydroxybenzophenone and 2.5 ml. of pyridine in 35 ml. of ether in a 4 neck 100 ml. round bottom flask containing a thermometer, condenser and magnetic stirring bar was added 4.0 g. (0.0218 m) of 4-t-butylazo-4-cyanovaleryl chloride dropwise with cooling so the temperature did not rise above 25° C. After completion of the addition the reaction mixture was stirred 1/2 hour at room temperature and then diluted with 100 ml. of water. The ether layer was separated, washed consecutively with 5% HCl, water, and 10% NaHCO3 solution and saturated sodium chloride solution. The ether was evaporated off and the residue dissolved in methylene chloride, dried over anhydrous sodium sulfate, filtered and the methylene chloride stripped off under reduced pressure. The product weighted 8.8 g. (99% yield) and was a viscous syrup. The infrared spectrum was in agreement with the structure of the desired product.
