It is shown that the acylative decarboxylation reaction of phenylacetic acid, a method used in clandestine laboratories for synthesizing phenyl-2-propanone, is accompanied by side reactions that produce characteristic neutral compounds. Some of these compounds include cis and trans 1,3-diphenyl-2-methylpropene and enol acetates derived from dibenzylketone and phenyl-2-propanone. An unskilled chemist would have difficulty separating neutral substances from phenyl-2-propanone; therefore, illicit phenyl-2- propanone is likely to be an impure product. The use of crude phenyl-2-propanone in reductive amination reactions aimed at amphetamine production causes a complex mixture of amines and characteristic neutral compounds. Likely origins of N-acetylamphetamine and amphetamine benzaldimine are discussed. 10 references and 6 figures