And the hypothesis that the cause of PMA being made, likewise PMMA is easier to obtain the precursors for compared to more desirable compounds such as MDxx, MMDAs, TMA and analogs, nobody is really interested in controlling anethole. It is present in many essential oils, and easy to obtain. Whereas safrole-containing plants are more difficult to get hold of, parsely and its essential oils are not difficult or extremely regulated. The same types of syntheses are used for either, and various other propenylbenzenes and allylbenzenes are present in essential oils of many plants, its not like they are going to be able to eradicate availability of parsely (the allylbenzenes can be isomerized to the propenylbenzenes usable for production of the 'essential amphetamines' as Sasha Shulgin termed the ten or so amphetamines produced from such essential oils) and there are many present in nature, in essential oils of many common plants. Unfortunately safrole is one of the ones present in plants more difficult to obtain.
Although even things like cork, and oilseed rape residues after extraction of the oil from oilseed rape could provide better, more useful polyalkoxlated phenolics for production of those of greater items, various such entities are hosted, some in multiple mixtures of varying concentrations per phenylpropenoid, and at greater or lesser levels to others.
Sadly it seems anethole is the easiest to obtain by clandestine chemists, along with eugenol from clove oil, which if ring-methylated would give interesting things, or if first formed into an amphetamine, and the ether linkage cleaved to give a diol type moiety could then be methylenated with methylene bromide or better, methylene iodide (iodide is a better leaving group and ought to give a bit better yield than bromide), if simply made into an amphetamine then the result from eugenol would be 2,4-dimethoxyamphetamine, after methylating its remaining phenolic group using fr.ex MeI (before forming the amphetamine, so as to avoid formation of secondary/tertiary amine derivatives from the primary aminated amphetamine derivatives. The entactogens can tolerate a sec. amine, and the simple stimulants (E.g methamphetamine) it works, but the psychedelic amphetamine pharmacophore will not tolerate well a secondary or tertiary amine. Secondary amine versions of, just for example, picking one or two at random, DOx, or TMA-x lead to dramatically reduced potency and effectiveness, and effects closer to antidepressants, a tertiary amine would probably kill it right off or damn close to it.