methoxyacetyl chloride

[Cyrax]

Is it suspicious to buy methoxyacetyl chloride? Is it a watched chemical?

[Rhodium]

I'd say that is obscure enough to be safe.

[PrimoPyro]

Methoxyacetyl chloride...

CH3-O-CH2-CO-Cl correct?

What use would this have clandestinely? Just curious.

                                                  PrimoPyro

[Cyrax]

Well, you can use it instead of propionyl chloride or propionic anhydride to acylate 1-phenethyl-4-(N-phenylamino)-piperidine to get a nice fentanyl analog with an ED50 of 0.08 mg / kg.  Propionyl chloride is suspicious (right?), so I think this is a good alternative.

Or you can use 2-furoyl chloride to the amine.  That compound will certainly not be suspicious.  Then the ED50 is 0.02 mg / kg.

[Rhodium]

Cyrax: Very interesting! Refs?

[Nemo_Tenetur]

Very good idea!
Although somewhat weaker, you can get around U.K. generic definition (and maybe same in some other countries)

[Cyrax]

Check it out: US patent 4584303.  You will find a real treasure of fentanyl analogs.  It is one of the best fentanyl patents I have read. 

Too weak: I think it is strong enough to not kill yourself during the synthesis.  If you want a stronger compound: simply use o-fluoroaniline instead of aniline.  Then the ED50 will be 0.0077 mg / kg.  But I forsee that the yield of the acylation will be lower, since that lovely little fluorine atom will suck the free electron pair of the nitrogen into the aryl ring    (resonance)