Gabriel–Colman rearrangement

The Gabriel–Colman rearrangement

.

Mechanism

The

of this reaction is the attack of the carbanion on the carbomethoxy group.

The displacement of the methoxide is analogous to the displacement seen in the

, as it is also a result of a ring closure.

Furthermore,

form.

Applications

The major application of the Gabriel–Colman rearrangement is in the formation of isoquinolines, due to the relatively high yield of the desired products. Therefore, studies in which either the product or an

Phthalimide derivatives were seen to be inactive, while saccharin derivatives were seen to be fair inhibitors of these enzymes.

In a study

(1,1-dioxido-3-oxo-1,2-benzothiazol-2(3H)-yl)acetate to Isopropyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide, as shown above. This reaction has shown a percent yield of 85%.

In another study,^[10] N-phthalimidoglycine ethyl ester was used to synthesize 4-hydroxyisoquinoline through use of a Gabriel–Colman rearrangement, as shown above. This reaction has shown a percent yield of 91%. The formation of this product was an important step in the study of the synthesis of 4,4′-functionalized 1,1′-biisoquinolines.

See also

• Dieckmann reaction
• Claisen condensation
• Chan rearrangement

References