TY - JOUR
AU - Grandberg, I.
AB - Chemistry of Heterocvclic Compounds, Vol. 30, No. I, 1994 LETTERS TO THE EDITOR G. P. Tokmakov and I. I. Grandberg 3-Alkyl and 3-arylindoles rearrange to the corresponding 2-substituted indoles in acid media [1,2]. The driving force for this rearrangement is thought to be the increased basicity of the 2-substituted indole and the consequent stability of its cation in comparison with that of the 3-substituted indole [2]. If this is true then 1,2-migration of these substituents should be possible in acid media since, for example, a 2-alkylindole is more basic than the 1-alkylindole. We have encountered a rearrangement of this type. When an attempt was made to synthesize 2-alkyl-l-benzylindoles by rearrangement of the corresponding 3-alkyl-1- benzylindoles by heating in polyphosphoric acid (PPA) by the method described previously [2] a mixture of isomeric indoles was formed. Apart from the expected 2-alkyl-l-benzylindole, the reaction mixture contained 3-alkyl-2-benzylindole. The two isomers were obtained by concurrent 3,2- and 1,2-migration of the substituents. We carried out the isomerization of 1- benzylindole (I) to observe the 1,2-migration in pure form and to verify its preparative potential. Heating 1-benzylindole in PPA gave 2-benzylindole (II) in 74% yield. PPA = ~~. CH~Ph I H CII,Ph I II A 
TI - 1,2-Migration of the benzyl group in indoles
JF - Chemistry of Heterocyclic Compounds
DO - 10.1007/BF01164747
DA - 2005-01-30
UR - https://www.deepdyve.com/lp/springer-journals/1-2-migration-of-the-benzyl-group-in-indoles-hg4qtHh1Tc
SP - 121
EP - 121
VL - 30
IS - 1
DP - DeepDyve
ER -