RE: ORGLIST:Nitrogroup reduction

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From: Yuehui Zhou (yuehuizhou$##$hotmail.com)
Date: Fri May 07 2004 - 04:09:40 EDT


Krishna,

It seems the Pd/C hydrogenation is the best of all. Try higher pressure and larger vessel. It helps often for my works.

Y. Zhou

>From: Maringanti Krishna <maringanti9@yahoo.com>
>To: everybody@orglist.net
>Subject: ORGLIST:Nitrogroup reduction
>Date: Thu, 6 May 2004 05:49:53 -0700 (PDT)
>
>Hi All:
>I need to reduce an aromatic nitro group to -NH2. It is a large molecule and I have an Acetal and t-BOC protections elsewhere. I have tried the following methods.
>1. Raney Nickel, Hydrogenation:  Several spots on TLC (after complete disappearance of starting material, and after 48 hours)
>2. Pd/C Hydrogenation...very low yield after 48 hours
>3. Pd/C hydrazine hydrate. Reaction is OK but, the yield is  verylow. Difficult to get pure product. Also, acetal deprotection
>4. Electrolytic iron/ ammonium acetate and ammonium chloride. Acetal deprotection is occuring. At rt. reaction is extremely sluggish. At reflux, acetal deprotection is taking place.
>
>Can someone suggest an alternative method?
>Krishna
>
>
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