The synthesis and investigation of impurities found in Clandestine Laboratories: Baeyer–Villiger Route Part I; Synthesis of P2P from benzaldehyde and methyl ethyl ketone

The synthesis of impurities detected in clandestinely manufactured Amphetamine Type Stimulants (ATS) has emerged as more desirable than simple "fingerprint" profiling. We have been investigating the impurities formed when phenyl-2-propanone (P2P) 5, a key ATS precursor, is synthesised in three steps; an aldol condensation of benzaldehyde and methyl ethyl ketone (MEK); a Baeyer-Villiger reaction; and ester hydrolysis. We have identified and selectively synthesised several impurities that may be used as route specific markers for this series of synthetic steps. Specifically these impurities are 3-methyl-4-phenyl-3-buten-2-one 3, 2-methyl-1,5-diphenylpenta-1,4-diene-3-one 9, 2-(methylamino)-3-methyl-4-phenyl-3-butene 16, 2-(Methylamino)-3-methyl-4-phenylbutane 17, and 1-(methylamino)-2-methyl-1,5-diphenylpenta-4-ene-3-one 22.