Morpheridine (Morpholinoethylnorpethidine)[2] is a 4-phenylpiperidine derivative that is related to the clinically used opioid analgesic drug pethidine (meperidine).

It is a strong analgesic with around 4 times the potency of pethidine,[3] and unlike pethidine, does not cause convulsions, although it produces the standard opioid side effects such as sedation and respiratory depression.

[5] The key intermediate, normeperidine, is obtained by a scheme closely akin to the parent molecule.

Thus, alkylation of benzyl cyanide (1) with the tosyl analog of the bischloroethylamine (2) leads to the substituted piperidine (3).

Alkylation of that amine by means of N-(2-chloroethyl)morpholine gives morpheridine.