Author Topic: Ephedrine to desoxyephedrine - NaBH4 -Rhodium  (Read 2853 times)

0 Members and 1 Guest are viewing this topic.

dormouse

  • Guest
Ephedrine to desoxyephedrine - NaBH4 -Rhodium
« on: April 20, 2000, 02:36:00 AM »

   the Hive BB
  Novel Discourse
  Ephedrine to desoxyephedrine - NaBH4
  
profile | register | preferences | faq | search
 
 next newest topic | next oldest topic 
Author  Topic:   Ephedrine to desoxyephedrine - NaBH4 
Rhodium
Administrator   posted 05-11-98 06:28 PM          
--------------------------------------------------------------------------------
Synthetic Communications. 19(17), 3051-3054 (1989)
(pseudo)Ephedrine, or rather its O-Acetyl ester, is reduced with a large excess of NaBH4/NiCl2 for 30-60 min at room temp to yield desoxyephedrine in 80-90% yield.

Interesting. Sure beats HI/P. Maybe something for TS II if someone gets it to work.


CyderJack
unregistered   posted 05-11-98 09:27 PM           
--------------------------------------------------------------------------------
Do you mean Sodium Borohydride which I have seen as NaBH3 , is this different from the NaBH4 you are referring to ?

Thanks ,

CyderJack


Osmium
Member   posted 05-12-98 04:13 AM          
--------------------------------------------------------------------------------
NaBH3 does not exist.
 
Osmium
Member   posted 05-12-98 04:13 AM          
--------------------------------------------------------------------------------
NaBH3 does not exist.
 
quirks
Member   posted 05-12-98 08:50 AM          
--------------------------------------------------------------------------------
And the best (standard) way to obtain the ester??
(from the journal)

a. solvent: anyhyrous MeOH
b. Rx temp: room temp
c. Molar ratio: Substrate / NaBH4 / NiCl2 = 1 / 14 / 7

This would work, with crappy yeilds, for just ephedrine too no?


quirks
Member   posted 05-12-98 08:50 AM          
--------------------------------------------------------------------------------
And the best (standard) way to obtain the ester??
(from the journal)

a. solvent: anyhyrous MeOH
b. Rx temp: room temp
c. Molar ratio: Substrate / NaBH4 / NiCl2 = 1 / 14 / 7

This would work, with crappy yeilds, for just ephedrine too no?


Osmium
Member   posted 05-13-98 05:20 AM          
--------------------------------------------------------------------------------
Prepare the ester with acetic anhydride, when you can locate some, or use glac. AcOH/H2SO4.
 
Osmium
Member   posted 05-13-98 05:20 AM          
--------------------------------------------------------------------------------
Prepare the ester with acetic anhydride, when you can locate some, or use glac. AcOH/H2SO4.
 
Rhodium
Administrator   posted 05-13-98 03:48 PM          
--------------------------------------------------------------------------------
How would you prevent acetylation of the amine? It cannot be too sterically hindered, can it?
 
Rhodium
Administrator   posted 05-13-98 03:48 PM          
--------------------------------------------------------------------------------
How would you prevent acetylation of the amine? It cannot be too sterically hindered, can it?
 
Lone Ranger
unregistered   posted 05-13-98 09:19 PM           
--------------------------------------------------------------------------------
I have read of NaBH4 or KBH4 used to supposedly fully reduce the ester formed with H2SO4 in Ephedrine. I doubt it, and have not 'dreamed' of this. I do have a great interest in any possiblilities in this direction...
However, I am wondering if the acid chloride will reduce with either of the fore mentioned reagants. I have had many pleasant dreams about direct hydrogenolys in alkaline over Pd, and high yield dreams of catalytic dehalogenation. I would happily share dreamy details if anyone could help me fiqure out something to do with a few hundred grams of borohydride....


Lone Ranger
unregistered   posted 05-13-98 09:19 PM           
--------------------------------------------------------------------------------
I have read of NaBH4 or KBH4 used to supposedly fully reduce the ester formed with H2SO4 in Ephedrine. I doubt it, and have not 'dreamed' of this. I do have a great interest in any possiblilities in this direction...
However, I am wondering if the acid chloride will reduce with either of the fore mentioned reagants. I have had many pleasant dreams about direct hydrogenolys in alkaline over Pd, and high yield dreams of catalytic dehalogenation. I would happily share dreamy details if anyone could help me fiqure out something to do with a few hundred grams of borohydride....


All times are CT (US)
 next newest topic | next oldest topic


Administrative Options: Close Topic | Archive/Move | Delete Topic
    Hop to: Select a Forum or ArchiveList of Forums:General DiscussionAcquisition DiscourseChemistry DiscourseMethods DiscourseNovel DiscourseCrystal MethSerious Chemistry ForumThe Hive CouchSerious Tryptamine DiscourseAdmin Chill-out TentList of Archives:Couch ArchivesClassics!Law and OrderThe litter box.misc. PEAs  

Contact Us | the Hive

Powered by: Ultimate Bulletin Board, Version 5.39a
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 1999.