反应详情

The afore-mentioned process can not advantageously be employed to prepare cyanobisphenols wherein R1 is hydrogen. When R1 and all R2 are hydrogen, the following procedure is effective to prepare the cyanobisphenol. 4-Hydroxybenzaldehyde is reacted with sodium cyanide in the presence of sodium bisulfite to yield 4-hydroxymandelonitrile, a cyanohydrin which has the following formula. ##STR13## The reaction and conditions are described in Landenberg et al., "Synthesis of 3-Hydroxy-2(3)-Benzofuranone and of 4-Hydroxymandelic Acid", 58 J. Amer Chem Soc. 1292 (1936) and in Taylor, et al, "a-N,N-Dimethylaminophenylacetonitrile", 5 Organic Synthesis 437 (1962). 4-Hydroxymandelonitrile is then reacted with excess phenol in the presence of sulfuric acid at a temperature of about 55° C. to 60° C. to yield bis-(4-hydroxyphenyl)acetonitrile: ##STR14## A description of the reaction and its conditions is found in Schraufstatter, "Darstellung und Reaktionen von 4,4'-Dihydroxydiphenylacetonitril", 295 Arch. Pharm. 269 (1962).