superreductant
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Reduction of Nitro > Amine: Sodium Aluminum Hydride (NaAlH4)/Lithium Borohydride (LiBH4)?
Hello all, first time poster, long time lurker, etc.,
I'm posting as I've managed to find myself on the endless rabbit hole of insanity inducing proportion for many users before me - that of access to
hydride reagents.
Of course, there's tonnes of dissolving metal reactions which will reduce a nitro to an amine, but let's just pretend I'm a shill exclusively for
hydrides which will accomplish this.
I'm aware that the usual choice is LiAlH4 or Red-Al/Vitride, however I was curious as to whether anyone had personal experience for proof/any
literature showing that LiBH4 and/or NaAlH4 will reduce nitro groups to the amine? A preliminary Google Scholar search turned up empty, though I am
new to this sort of thing.
Reason for these hydrides in particular is that I imagine they'll be more likely to arrive okay from overseas in comparison to a big fat "LiAlH4"
sticker on the box.
Any help would be amazing, thanks so much!
Two hoes on me, call that dihydroxy
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B(a)P
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Hello and welcome, great to see another Australian on the forum!
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andyloris
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I found a paper on the reduction of nitro groups with sodium borohydride and copper sulfate...
Attachment: s-1990-21113.pdf (132kB)
This file has been downloaded 63 times
Always trust your first idea, especially if you only have one.
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Lionel Spanner
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If you're reducing aromatic nitro compounds, using sodium dithionite is an easier and more practical method; metal hydrides tend to produce azo compounds instead.
If you're reducing aliphatic compounds, sodium/lithium borohydride are not effective on their own, and need to be combined with something like TMS chloride. Lithal tends to produce hydroxylamines and oximes as by-products.
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walruslover69
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I have tried several reduction reactions of nitro compounds into amines with both LiAlH4 and NaBH4. The details on the specific compound are usually
pretty important for the conditions if you want to achieve reasonable yields. NaBH4 on it's own isn't going to reduce a nitro group in most
circumstances, but I have had very good success using either nickel or copper chloride along with NaBH4 to reduce compounds you would only expect LAH
to work on. The mechanism is complex and not fully understood, but I think of it as the NaBH4 reducing the copper or nickel chloride into metal
nanoparticles, which make the make the hydrogen more active.
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