6-Allyloxy-2-methylbenzothiazole, Claisen rearrangement

A heterocyclic ring induces partial double-bond fixation in a fused benzene ring. Hence, for example, diazo coupling occurs at the 7-position of 6-hydroxyindazole (349), and Claisen rearrangement of 6-allyloxy-2-methylbenzothiazole (350) gives the 7- and 5-allyl products in a ratio of 20 1. 

Similar studies of the relationship between bond structures and the Claisen rearrangement have been made with allyloxy derivatives of other aromatic compounds, among them anthracene,60 phenanthrene,61 hy-drindene,62 fluorene,68 chromone,64 flavone,64 fluorenone,66 and 2-methylbenzothiazole.660... 

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