You could get the bromo derivative with the 1,4-addition probably without problems, but the benzoate anion is such a poor nucleophile that it would require heathing and this would readily cause the elemination of the bromide even in just slightly basic conditions. The reaction would result back to arecoline, benzoic acid and NaBr.
Even though piperidine analogues are mentioned by Shulgin in his Drugs of Abuse in the Future he actually says: "Another, yet simpler, series of potential cocaine substitutes might be found in the open-chain piperidine analogs such as (23). A number of these extremely easily synthesized esters have been employed in imitation of cocaine as contact anaesthetic agents, or in imitation of atropine as mydriatic agents, but there is little information at hand concerning their abuse potential using the parenteral routes employed with cocaine."
https://www.thevespiary.org/rhodium/Rhodium/chemistry/shulgin.futuredrugs.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/shulgin.futuredrugs.html)
Looks like what slappy wrote is true.
If you think that these potential analogues are centraly active as stimulants you can make a WIN 35428 type analogue by adding a phenylmagnesiumbromide (from PhBr+Mg in THF) to arecoline. The 1,4-addition is probable if equimolar amount is used. You would also avoid making a new bio-labile ester group making the new compound longer lasting (if active at all!). But making a Gringnard reagent is so tedious that I would not even try it for something that may be just a local anesthetic without any CNS effects.
Anyway, I think the compound 23 mentioned in Drugs of Abuse in the Future is realy simple to make starting from diethyl acetonedicarboxylate, acetone and methylamine.
Nicodem, look in my fentanyl thread at the last post. I just happened to read about how that funny piperdone is made. Maybe you just said that? But it is made by aldol reaction of acetone to diacetone, followed by michael reaction with ammonia and cyclization. Hang on, here it is::
Molecule: (https://www.the-hive.ws/forum/faq.pl?Cat=#applet)
aldol reaction ("CC(=O)C.CC(=O)C.CC(=O)C>>CC(C)=CC(=O)C=C(C)C")
Molecule: (https://www.the-hive.ws/forum/faq.pl?Cat=#applet)
Michael reaction ("CC(C)=CC(=O)C=C(C)C>>CC(C)(N)CC(=O)CC(C)(N)C")
Molecule: (https://www.the-hive.ws/forum/faq.pl?Cat=#applet)
Spontaneous cyclization ("CC(C)(N)CC(=O)CC(C)(N)C>>CC1(C)CC(=O)CC(C)(C)N1")
So of course, if you used methylamine, you would very likely get the substituted compound you desire. Better still, since this is a dehydrating aldol, rather than a strong base, you could probably use concentrated sulfuric acid and acetone, making this a two-step to the TEMPO/piperidone of your desire. Then a reduction to alcohol and esterification with benzoic acid. This sounds very yummy....
If desired, I will hunt down that info more. I was already thinking about it because that piperidone REALLY looks like TEMPO, which our bleach oxidation papers tell us is a Very Useful Thing to have around.