Dr_Sister (Hive Bee)
01-20-02 19:46
No 258712
      dill apiole cyclisation during demethylation?  Bookmark   

this may well be a fools errand and a waste of apiole, and i know some bees will be skeptical, but humour me. k?

ideally this might be manifest in a basic demethylation as acidic conditions seem to promote cylisation of a furan ring with the 2MeO. Yet dillapiole survives a buffered performic in good yeilds, so maybe just a mild de-methylation is called for.

what it would be nice to be able to do is go from
2,3-diMeO,4,5MDallybenzene
to
2,3-diHO,4,5MDallybenzene
to
2,3,4,5-diMDallybenzene (one of the 3 fabled bis-methylenedioxy paths to valhalla)

i like the idea of demethylating w AlCl3, but that 210C reflux afterwards is going to hurt. the reflux w/ 48%HBr RXN is one i am very leary of, and would save it as last ditch.

bees have any thoughts on how this might be successfully accomplished? last thing, any idea as to what properties might be expected of 2,3-diHO,4,5MDallybenzene. muchos gratias bees.




7.10.01
 
 
 
 
    terbium
(Old P2P Cook)
01-21-02 01:31
No 258786
      Re: dill apiole cyclisation during demethylation?  Bookmark   

Why not demethylate with pyridine hydrochloride?
 
 
 
 
    Dr_Sister
(Hive Bee)
01-21-02 02:05
No 258791
      Re: dill apiole cyclisation during demethylation?  Bookmark   

you mean similar to the one pychokitty posted for her eugenol >> safrole  peice? how likely do you think it is that the MD bridge would survive the pyridine demethylation?  or any other of the demethylation rxns for that matter.

7.10.01
 
 
 
 
    Antoncho
(Official Hive Translator)
01-21-02 02:08
No 258794
      Re: dill apiole cyclisation during demethylation?  Bookmark   

ummmm... please enlighten the ignorant - how you're gonna demethylate it w/out demethylenating - i always thought the MD bridge was more sensitive...

Welll at least boiling it w/HBr will tear the shit out of it, AFAIK.

Well as i said i'm no expert about this.

Antoncho
 
 
 
 
    Dr_Sister
(Hive Bee)
01-21-02 03:01
No 258812
      Re: dill apiole cyclisation during demethylation?  Bookmark   

well, ideally there is way that that won't, but in the event all four substitutions were reduced to HO's, then perhaps one could double the amount of reagnets used in the subsequent methylenation and hope that a 3,4-MD ring doesn't form leaving 2,5-HO,3,4-MD allybenzene, even if it did form it could be isolated by distillation and is only a methylation away from tasty parsley camphor. can you taste it yet?

7.10.01
 
 
 
 
    blue
(Delicioso!)
01-23-02 02:28
No 259633
      sweet mutha o hesu  Bookmark   

this one looks like it might leave the MD bridge intact, and the opiate chemists been holding out on ya

Known methods of converting codeine to morphine by demethylation (codeine is morphine 3-methyl ether). Cleavage of aromatic ethers are commonly effected by reflux with concentrated HBr or HI. This relatively simple method can unfortunately not be used on codeine, as the oxygen bridge at the 9,10 position on the morphinan carbon skeleton would also rupture, causing the rearrangement of the molecule to the very potent emetic apomorphine, completely devoid of opiate-like effects.

5) Using L-Selectride (Lithium tri-sec-butyl Hydride) [6,7] 482 mg (1.6 mmol) of codeine was dissolved in 4 ml of an 1 M solution of L-selectride in THF (4.0 mmol) and was refluxed for 3.5h. The reaction was quenched with water (5ml), followed by 2ml of 15% NaOH solution and removal of the THF. The resulting mixture was washed twice with CH2Cl2, cooled to 0-5C and acidified to pH 1 with 10% HCl. After basification with ammonium hydroxide to pH 9, the mixture was extracted into CHCl3, the organic phase was washed with brine and dried over Na2SO4. Removal of the solvent, followed by recrystallization from water gave 355mg (73%) of morphine hydrate. Unreacted codeine was recovered from the non-phenolic extracts, and after purification by recrystallization from water, it amounted to 71mg (14%). The method i have suggested and outlined works well in the lab if the required reagents are attainable, there are easier ways i can think of to performing this convertion but for obvious ethical and moral reasons i have not placed this information on to this page  to prevent any negative use of my knowledge.


http://www.geocities.com/taylex18/


this one looks promsing to avoid cyclisation, and possibly MD cleavage, as well seems to inhibit AlCl3 from bonding to and cleaving oxygen atoms. and to make it even sweeter it lives next door to otc, (reduce your DMSO to DMS with Al/Hg and simply bubble the evolved DMS into your DCM smile. similar rxns without DMS involved cyclisation

Osthenol(condensed version)
DMS (2,5ml) added to a suspension of anhydrous AlCl3 (0.33g, 2.5mmol) in CH2Cl2 (5ml) at 0degC with stirring until in solution. to this solution, osthol (0.24g, 1,0mmol) was added over 10 minutes at same temp. Allow temp to reach RT and stir 24hours, rxn was quenched in 1N HCl and extracted with CH2Cl2 and purifiied on column, yeild 62%

 Molecules 2000, 5, 880-885, Gopalakrishan, Kasinath

www.mdpi.org

is this what you meant by mild? any other got an opinion of whether or not these rxns would be sufficient to the task?



as in cobalt