That reference & some more gibberish
Hello once again.
The reference you seek is JOC 'A practical High Yielding Synthesis of Dihydromorphine from Tetrahydrothebaine & Efficient Syntheses of of 8(S) 8 -Bromomorphide' by Anna K. Anna K. Przybyl, Judith L. Flippen-Anderson, Arthur E. Jacobson and Kenner C. Rice of NIH.
Basically, 15% by weight of HBr is dissolved in GAA. The DHC is added to this mixture and the whole lot in a Parr Hydrogenation vessel. The mixture is held at 100C (should be at about 20 psi) for 1 hour. Yield is 97% 6 acetyl dihydromorphine hydrobromide. Deacetylation & freebasing can be achieved simply by adding NaOH.
DHM is pretty good, but K t-butoxide yields Hydromorphone in similarly high yields.
I suggest that replacing the N-Methyl with an N-phenylethyl would produce an analogue 18x stronger than the parent compound. Phenylethyl Bromide & K2CO3 would add the phenylethyl, but I've not found a good, high-yielding way of chopping off the N-methyl in the first place. I mean, Cyanogen Bromide will do it, but I don't like using that stuff. Any comments?
Also, it's worth noting that noroxymorphone is not controlled in many places and if you added an N-phenylethyl to that (x18) and acetylating the 6 & 14 positions (x2.5) would produce a compound with a LOT of mu agonist activity (sort of in the hundreds of times morphine) OR one may make the hydromorphone and use a Wittig-Horner reaction the 6 =O with q 6 =CH2 which is 80x morphine (see nalmefene). Now, swap the N-methyl with N-phenylethyl and voila. Gentlemen, I give you the wheel...