Phendimetrazine

Phendimetrazine (Bontril, Adipost, Anorex-SR, Appecon, Melfiat, Obezine, Phendiet, Plegine, Prelu-2, Statobex) is a stimulant drug of the morpholine chemical class used as an appetite suppressant.
Pharmacology
Phendimetrazine functions as a prodrug to phenmetrazine; approximately 30 percent of an oral dose is converted into it. Phendimetrazine can essentially be thought of as an extended-release formulation of phenmetrazine with less potential for abuse. Phendimetrazine is an anorectic drug which acts as a norepinephrine-dopamine releasing agent (NDRA).
As an amphetamine congener, its structure incorporates the backbone of methamphetamine, a potent CNS stimulant. While the addition of an N-methyl group to amphetamine significantly increases its potency and bioavailability, methylation of phenmetrazine renders the compound virtually inactive. However, phendimetrazine is a prodrug for phenmetrazine which acts as the active metabolite. Phendimetrazine possesses preferable pharmacokinetics over phenmetrazine as a therapeutic agent because its metabolization by demethylases produces a more steady and prolonged exposure of active drug within the body. This decreases abuse potential as the peak blood-concentration of active phenmetrazine that's produced from a single dose of phendimetrazine is lower than a single therapeutically equivalent dose of phenmetrazine.
Indicated as a short-term secondary treatment for exogenous obesity, phendimetrazine immediate-release 35mg tablets are typically consumed one hour before meals, not to exceed three doses daily. Phendimetrazine is also manufactured as a 105mg extended-release capsule for once daily dosing, typically consumed 30 to 60 minutes before a morning meal. Whereas the immediate-release formulation has a maximum daily dosage of 210mg (6 tablets), the extended-release capsules have a maximum daily dosage of 105mg (one capsule).
Legality
According to the List of Psychotropic Substances under International Control published by the International Narcotics Control Board, phendimetrazine is a Schedule III controlled substance under the Convention on Psychotropic Substances.
Synthesis
Alkylation of ephedrine (1) with oxirane (2) gives the diol, N-(2-Hydroxyethyl) Pseudoephedrine [54275-43-3] [91688-17-4] (3). (The secondary nature of the amine in 1) eliminates the complication of dialkylation and thus the need to go through the amide.) Cyclization affords phendimetrazine (4).
The halogenation of Propiophenone [93-55-0] (1) with bromine gives 2-Bromopropiophenone [2114-00-3] (2). Further reaction with N-Methylethanolamine [109-83-1] (3) goes on to five CID:232614 [902267-47-4] (4). Cyclization with formic acid completed the synthesis of phendimetrazine (5).
The reaction between Ephedrine [299-42-3] (1) and ethyl chloroacetate [105-39-5] (2) in the presence of sodium hydride gives 4,5-dimethyl-6-phenylmorpholin-3-one, [5493-96-9] (3). The optional reduction of the lactam carbonyl with lithium aluminium hydride.
Additional method:
See also
2-Phenyl-3,6-dimethylmorpholine
3-Fluorophenmetrazine
Fenbutrazate
G-130
Morazone
Manifaxine
Radafaxine
Phenmetrazine
Fenmetramide
References
Antiobesity drugs
Anorectics
Phenylmorpholines
Substituted amphetamines
Euphoriants
Norepinephrine-dopamine releasing agents