Tin, reduction of nitro groups

Other possibilities are the reduction of nitro groups by applying the sample solutions to adsorbent layers containing zinc dust and then exposing to hydrochloric acid vapors [110] 3,5-Dinitrobenzoates and 2,4-dinitrophenylhydrazones can also be reduced in the same way on tin-containing silica gel phases [111] Cellulose layers are also suitable for such reactions [112] Seiler and Rothweiler have described a method of trans-salting the alkali metal sulfates to alkali metal acetates [113]... 

Catalytic hydrogenation of alkenes 3. Reduction of nitro groups. Catalytic hydrogenation or reaction with iron or tin and aUtynes is discussed in Section 6.3.2.4... 

Reduction to aminophenol. Reduce about 0 5 g. of o-nitrophenol with cone. HCl and tin as described on p. 385. After a few minutes the yellow molten o-nitrophenol disappears completely, the solution becoming homogeneous and colourless due to the formation of 0-aminophenol (which is soluble in HCl). Cool and add 30% aqueous NaOH solution note that a white precipitate is first formed and then redissolvcs in an excess of NaOH, and that the solution does not develop an orange coloration, indicating that the nitro-group has been reduced. 

Nitro groups are readily reduced to primary amines by a variety of methods Cat alytic hydrogenation over platinum palladium or nickel is often used as is reduction by iron or tin m hydrochloric acid The ease with which nitro groups are reduced is especially useful m the preparation of arylamines where the sequence ArH ArN02 ArNH2 IS the standard route to these compounds... 

Reduction of aryl nitro compounds (Sec tion 22 9) The standard method for the preparation of an arylamine is by nitra tion of an aromatic ring followed by reduction of the nitro group Typical re ducing agents include iron or tin in hydro chloric acid or catalytic hydro genation... 

Subjecting 8-chloro-5-iiitro-l,7-iiaphthyridiiie (97) to reduction with tin(II) chloride leads, besides loss of the chloro atom and reduction of the nitro group, i.e., formation of 5-amino-l,7-naphthyridine (131, 22%), to the formation of small amounts of 5-amino-6,8-dichloro- (132, 1.5%) and 5-amino-6-(or 8-)chloro-l,7-naphthyridine (133, 2.5%) (88PJC305). 

The property of being converted by energetic reduction into primary amines belongs to the nitro-compounds both of the aliphatic and of the aromatic series. Six atoms of hydrogen are required for the reduction of each nitro-group. In industry nitrobenzene is reduced, not with expensive tin, but with iron filings or iron powder according to the old method of Bechamp, which is still in use at the present time. The amount of hydrochloric acid indicated by the equation... 

The reduction of carbazole nitro groups to the primary amines is straightforward stannous chloride, tin-hydrochloric acid, iron-hydrochloric acid" hydrogen-palladium/charcoal," hydrogen-nickel,hydrazine-palladium,and hydrazine-nickeP have all been employed. 3,6-Dichloro-l,8-dinitrocarbazole was partially reduced with sodium hydrogen sulfide to give l-amino-8-nitro-3,6-dichloro-carbazole. ... 

Fused pyrroles have been prepared by the condensation of an amino group with a suitably positioned carbonyl function. Thus, reduction of ethyl (3-nitro-2-thienyl)pyruvate (226) with tin(IV) chloride gave 5-ethoxycarbonyl thieno[3,2-6]pyrrole (47), by the spontaneous cyclization of the intermediate amino derivative (227 Scheme 76) (64JOC2160). The formation of indolo[3,2-6]indole (229), a dibenzannelated pyrrolopyrrole, by the cyclization of (228) with tin(IV) chloride (Scheme 77) is an example of a case where reduction of the imino function in the starting material is necessary before cyclization will occur (78AHC(22)183). 

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