Ephedrine to desoxyephedrine - NaBH4 -Rhodium , Hive Novel Discourse


		dormouse (Member) 04-20-00 02:36 No 108325				Ephedrine to desoxyephedrine - NaBH4 -Rhodium	Bookmark
						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.