The 2-chlorobenzophenone (of formula VI) is brought to react with methylethanolamine in the presence of e.g.
48% HBr in hot chloroform to afford the target benzoxazocine The reaction of 2-benzoylbenzoic acid (I) with refluxing SOCl2 gives the corresponding acyl chloride (II), which is condensed with 2-(methylamino)acetic acid (III) in benzene to yield the N-(2-benzoylbenzoyl)-N-methylglycine (IV).
Nefopam is contraindicated in people with convulsive disorders, those that have received treatment with irreversible monoamine oxidase inhibitors such as phenelzine, tranylcypromine or isocarboxazid within the past 30 days and those with myocardial infarctionpain, mostly due to a lack of safety data in these conditions.
Less common side effects include vomiting, blurred vision, drowsiness, sweating, insomnia, headache, confusion, hallucinations, tachycardia, aggravation of angina and rarely a temporary and benign pink discolouration of the skin or erythema multiforme.
A pure reaction product is obtained when the ethanol is evaporated from the solution and the product is crystallized as a hydrochloride salt from a mixture of diethylether and alcohol.
The yield is 10.7 g (95 %) of 2- methylbenzophenone as a crystalline powder, m.p. This compound, as the free base, shows the following N M R spectrum (in c DC1 using T M S as internal reference): 7.8 – 7.1 (aromatic), 3.5 (singlet), 3.4 (triplet), about 2.6 (singlet), 2.3 (triplet),1.9 (singlet).