thefips
(Stranger) 01-28-04 00:29 No 484986 |
Substitutes for lithiumaluminiumhydride | |||||||
Hi! This is my first post,I am from Germany,and I am sorry,that my english is not very good but I hope,you can understand it. I have used the search engine,but iI did not find exactly,what I searched for. So I´ll ask you this way.I´m searching for substitutes for lithiumaluminiumhydride and I hope you can help me,because it is not easy to get LAH,because it is in the "monitoring system",which is for watching substances that can be used for drug synthesis.I think sodiumborohydride is watched,too. Are there other substances or reactions,that can be used instead of LAH and sodiumborohydride,for example for the reactions from PIHKAL or TIHKAL? I hope you can help me. :) |
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silenziox (Hive Bee) 01-28-04 02:28 No 485007 |
Regulated.. | |||||||
1. Aluminium hydride (AlH3) but unfortunately it seems that it's not from sale because of it's decomposing nature (it has to be synthed in situ from LiAlH4 and H2OH4 (if you know a place who's selling this, PM me ... 2. Sodium Aluminium hydroxide NaAlH4... I guess it's also on your list ike LAH... Why wouldn't you go with another reduction method? Holotna Pravda... Neskolko dnej iz zhizni siLENZiova |
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Jubrail (Introspecter) 01-28-04 03:32 No 485021 |
Depends | |||||||
On the synthesis you are doing. In some syntheses you just need a different reducing agent. Like sodium borohydride or sodium cyanoborohydride. NaBH4 is available for the creative man, though. Search the net. Hydrides are being researched for their uses as alternative fuel for the future. ;) Rainbows & Butterflies Forever :) |
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hest (Hive Adickt) 01-28-04 11:30 No 485064 |
Reduction | |||||||
NaBH4 is not watched. Use NaBH4 to reduce the dob.bond then use something else for the nitrogroup (like Al/Hg Zn/AcOOH Pd/c/COONH4) Read this ../rhodium /dob.htm Post 422844 (Bandil: "Verification of Bariums research", Methods Discourse) |
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Vitus_Verdegast (Hive Addict) 01-28-04 15:56 No 485097 |
OTC ways | |||||||
I would say dithionite reduction of a phenyl-2-nitropropene to the oxime, followed by a Al(Hg) or Zn/HCOOH reduction. UTFSE for posts by Barium and Bandil on these subjects. I must say however that a friend of mine tried the dithionite reduction as posted by Barium, and once in a basic medium (added 2 mol equiv. NaHCO3), but every time the yield was low, and during the reduction of this oxime a H2S like smell was noted coming from the reaction mixture (so be careful and use a fume hood). Still there are other ways to go from a P2NP to the oxime, like SnCl2 for example. Everything you need is in TFSE and on Rhodiums page. I believe these routes will not work for nitroethenes, because of hydrolysis of the oxime to the acetaldehyde, which is easily prone to polymerisation. http://tinyurl.com/28cek |
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thefips (Stranger) 01-29-04 01:55 No 485181 |
Thanks for the anwers.I could order LAH,but if | |||||||
Thanks for the anwers.I could order LAH,but if I would do it,I think I could get in trouble,because the shop cooperates with the police if they think that someone wants to make drugs or explosives or something else. Now I can look for the reactions,you said in Google,or in chemistry books,but it was hard to find the reactions without knowing the chemicals. So thanks @ all! |
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Sunlight (Pioneer Researcher) 01-29-04 13:52 No 485273 |
Direct Zn HCl | |||||||
If you want to reduce a nitrostyrene the more accesible way is Zn dust and HCl, it yields always >50 %. I've finished a 20 gr batch of 2,5 DMNS today and yield has been 68 %, with 5:1 Zn: nitro in weight, and about a 20 % of Zn didn't react (as usually). Search the Leminger procedure or others I've posted. Use good zinc. |
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gsus (Stranger) 02-12-04 20:42 No 488151 |
d.i.y. LAH | |||||||
or you could just make your own. if you can get NaAlH4, add LiCl for LAH. there must b something in TFSE for Na and NaH. make Na and blow H2 into the melt. divide into powder by shaking w/NaCl(dry!) while still hot. add AlCl3 and THF for NAH. the LAH is made the exact same way, exept w/et2o as solvent. et2o may work with NAH as well, but it isnt sol in it. the AlCl3 is made by blowing Cl2 onto hot Al. i recommend a "book" of foil with a little space between pages. this must be heated externally or otherwise to at least 150C. AlCl3 sublimes around 180C. go ahead and sublime it. it is very! sensitive! to atm. moisture. you will regret getting any on you. another way to make in mass qty is to blow Cl2 onto or into molten(600-750C) Al. the old school way is to powder Al, add clay and coal (or lignite) NaCl, mix as best you can (dry your coal and clay 1st, you'd b surprised how much H2O is in some coals and esp. lignite), grind and pelletize. heat to 900C in clay pots and catch the AlCl3 as it sublimes and b4 it hits humidity. Strike probably thought that Strike found a good recipe for LAH(JACS 69 p. 1199 1947) and Strike did. it is on page 131 of Total Synthesis |
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armageddon (Newbee) 04-17-04 19:03 No 501307 |
different OTC routes | |||||||
Thefips: If you are looking for OTC nitropropene reduction methods and want to avoid metalhydrides (and pressurized hydrogen gas/toxic mercury, too ), perhaps you find a good route here: Post 499607 (armageddon: "different routes starting from nitropropenes", Methods Discourse) Greetz A "..ein Trank von unterschiedlicher Farbe, in ihm ist Heilung für die Menschen." |
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