Diazotization 3-aminoisoquinoline

Electrocyclization reactions are often used to synthesize fused thiophenes. Diazotization of an aminoisoquinoline gave a mixture of products including a 6-thiaellipticine and a pyrazolo[3,4-A]isoquinoline in 34% and 41% yields, respectively (Eq. 30) <96CC2711>. A diazotization... 

Diazotization of 1-hydrazinoisoquinolines <67UC403) and reaction of p-toluenesulfonyl azide with 1-aminoisoquinoline (79JHC1579) are two methods that have been described for preparing tetrazolo[5,1 -a ]isoquinolines. 

If the structure of the dienone above were 133, the product 134 from 2 -aminoisoquinoline 131 should be different. However, the products obtained by diazotization of the two aminoiso quinolines 130 and 131, followed by decomposition, were proved to be identical by extensive spectral data. 

The Baltz-Schiemann reaction is still one of the most common methods for direct ring fluorination because of the accessibility to aminated isoquinoline derivatives. The original conditions, which involve the use of tetrafluoroboric acid (fluoroboric acid), are still often employed, [23-27] even though several modified procedures have been reported. For example, Myers synthesized 1-fluoroisoquinoline 2 by the dealkylative diazotization of 1-fcrt-bntyl-aminoisoquinoline 1 with pyridine hydrofluoride instead of HBF4 (Scheme 8) [28]. 

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