Rearrangement Gabriel-Colman

The Gabriel-Colman rearrangement entails reaction of the enolate of a maleimidyl acetate (2) to provide isoquinoline 1,4-diol 3.  

In 1900, Gabriel and Colman reported the preparation of phthalimidoyl acetate 4 They had anticipated saponifying 4 with sodium ethoxide and were surprised to find, rather than hydrolysis, rearrangement to 5. The identity of the product was confirmed by hydrolysis of the newly formed ester and concomitant decarboxylation to provide 6, which was hydrogenated to the known isocarbostyril (7). 

The Gabriel-Colman reaction has been used to prepare 3-alkyl isoquinoline 1,4-diols. Phthalimides 8 and 9 rearrange as expected when treated with alkoxides. Further treatment with sodium ethoxide results in decarboxylation and the expected isoquinolinone 1,4-diols 12 and 13. 

The Gabriel-Colman reaction involves rearrangement of phthalimidoyl acetates to 4-hydroxy isoquinoline cores by the use of hydrolytic basic conditions. 

The reaction is postulated to invoke alkoxide attack on one of the amide carbonyls, furnishing amide anion. Enolate formation and Dieckmann 

The rearrangement was found to be substrate specific, and several factors have been found to contribute in the yield of the product, such as the polarity of the solvent, the temperature, and, in some cases, the pressure. 

Gabriel-Colman Rearrangement In Name Reactions in Heterocyclic Chemistry, Li, J. J. Corey, E. J., Eds. Wiley Sons Hohoken, NJ, 2005, 416—422. (Review). 

Name Reactions, 4th ed., DOI 10.1007/978-3-642-01053-8 107, Springer-Verlag Berlin Heidelberg 2009 

Name Reactions A Collection of Detailed Mechanisms and Synthetic Applications, DOI 10.1007/978-3-319-03979-4 115, Springer International Publishing Switzerland 2014 

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GABRIEL COLMAN Rearrangement Synthesis of isoquinolines by rearrangement ol phthahmides. 

Gabriel-Colman rearrangement. Formation of isoquinoline derivatives by the action of sodium ethoxide on phthalimidoacetic esters. 

GABRIEL - COLMAN Rearrangement Synthesis of tsoqumolines by rearrangement ot phthahmides. 

Other references related to the Gabriel-Colman rearrangement are cited in the literature. ... 

Gabriel-Colman Rearrangement (Phthalimidoacetic Ester- Isoquinoline Rearrangement, Gabriel Isoquinoline Synthesis)... 

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