|Systematic (IUPAC) name|
|(what is this?)|
Metazocine is an opioid analgesic related to pentazocine. While metazocine has significant analgesic effects, mediated through a mixed agonist–antagonist action at the mu opioid receptor, its clinical use is limited by dysphoric and hallucinogenic effects which are most likely caused by activity at kappa opioid receptors (where it is a high-efficacy agonist) and/or sigma receptors.
Thus, Rxn of the Grignard reagent from p-methoxybenzyl chloride (1) with the lutidine methiodide (2) affords the benzylated dihydropyridine (3). (The addition to the most hindered position is rather puzzling.) Reduction of the enamine π-bond leads to the tetrahydropyridine (4). Cyclization by means of acid leads directly to the benzomorphan ring system (5). Demethylation of the aromatic ring system affords the phenol. Although this last compound is in fact a relatively potent analgesic, it is not available commercially as a drug.
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