Von richter rearrangement

rearrangement

1. BY Dr . Gurumeet.C.Wadhawa DEPARTMENT OF CHEMISTRY K. B. P . College,Vashi,Navimumbai Von Richter Rearrangement

2. When aromatic nitro compounds are reacted with potassium cyanide to generate a carboxylic acid ortho to the existing nitro group is known as Victor Von Richter reaction (in 1871). When aromatic nitro compounds are treated with cyanide ion, the nitro group is displaced and a carboxyl group enters with cine substitution , always ortho to the displaced group, never meta or para . The von Richter reaction can be inhibited in the presence of potassium ferricyanide (K3Fe(CN)6) and sodium sulfite .

3. The rearrangement reaction of aromatic nitro-compounds with KCN or NaCN giving carboxylation on ortho - position of the nitro groups. The  von Richter reaction , also named  von Richter rearrangement , is a name reaction in the organic chemistry. It is named after Victor von Richter, who discovered this reaction in year 1871. It is the reaction of aromatic nitro compounds with potassium cyanide in aqueous ethanol to give the product of  cine  substitution (ring substitution resulting in the entering group positioned adjacent to the previous location of the leaving group) by a carboxyl group .  Although it is not generally synthetically useful due to the low chemical yield and formation of numerous side products, its mechanism was of considerable interest, eluding chemists for almost 100 years before the currently accepted one was proposed.

4. This reaction is the example of cine aromatic nucleophilic substitution reaction in which nitro group is replaced by carboxylic group. The position of carboxylic group is always ortho - to the nitro group. As with other aromatic nucleophilic substitution reaction, the reaction gives best results when electron withdrawing group are present on ortho - or para - position with respect to the nitro group. This reaction has limited application in organic synthesis and yield of the reaction is very poor. The yield is usually ranging in between 20-50%.