Carbon‐13 nuclear magnetic resonance spectra of phencyclidine analogs substituted in the piperidine and aromatic rings

Abstract

Natural abundance carbon‐13 chemical shifts are reported for the hydrochloride salts of phencyclidine (1a) and twelve analogs substituted in the piperidine and aromatic rings. The signals are assigned on the basis of chemical shift theory, SFORD multiplicities, signal intensities, and comparisons with related compounds.

Preparation and analytical characterization of 1‐(1‐phenylcyclohexyl)piperidine (PCP) and 1‐(1‐phenylcyclohexyl)pyrrolidine (PCPy) analogues

“…This was observed with 3-MeO-PCP and 3-Me-PCP and was consistent with that reported previously by Brine et al [20] where these shifts were also observed in the HCl salts of 4a-4c. One such effect included the observation of coalescence, e.g.…”

“…The impact of amine substitution on chemical shifts presented here were essentially consistent with those reported previously for unsubstituted PCP, PCPy and PCA hydrochlorides [20] and this was also observed by Iorio et al with related arylcyclohexylamine hydrochlorides and freebases. For example, a Δ b of 8.82 ppm was observed between the C 1' chemical shifts of 4-MeO-PCA (3b) and 4-MeO-PCP (4b) hydrochlorides and a 10.13 ppm Δ b between freebases.…”

“…[20,43] Similar to these earlier reports 13 C chemical shift values of the present series were largely consistent between d 6 -DMSO and CDCl 3 . The 13 C data for hydrochlorides reported here were consistent with that reported by Brine et al [20] but an exception was also observed with regards to the C c value of 4-MeO-PCP (4b). This was reported at 51.21 ppm but was observed here at 55.35 ppm (CDCl 3 ).…”

“…One such effect included the observation of coalescence, e.g. [20] The effect was only seen with 3-MeO-PCP and 3-Me-PCP hydrochlorides (d 6 -DMSO) and all remaining compounds gave two separate chemical shifts for C 3,5, C b,b carbons independent of protonation and solvent. This was observed with 3-MeO-PCP and 3-Me-PCP and was consistent with that reported previously by Brine et al [20] where these shifts were also observed in the HCl salts of 4a-4c.…”

“…Syntheses of the three primary amine intermediates 3-MeO-PCA (3a), 4-MeO-PCA (3b) and 3-Me-PCA (3c) has been described [17] and the preparation of 3-MeO-PCP (4a), 4-MeO-PCP (4b) and 3-Me-PCP (4c) also exist in the literature. [12,[18][19][20] Data for the PCPy series is less available, with only a single publication describing the synthesis of 4-MeO-PCPy (5b) from the iminium salt. [21] To the best of the authors' knowledge it would also appear that 3-MeO-PCPy (5a) and 3-Me-PCPy (5c) have not yet been described in the scientific literature and information on the potential to be psychoactive in humans is absent.…”