Passerini- Smiles reaction

Scheme 19.40 Mercaptobenzothiazoles and benzoxazoles in Ugi-Smiles couplings. Scheme 19.41 Passerini-Smiles reaction of 2-nitrophenol.

The related Passerini-Smiles reaction, an analogous three-component coupling performed in the absence of the amine parmer, affords O-aryl carboxamides 76 via O to O aryl transfer fScheme 19.411. ... 

Recendy, different enol sources have been investigated to replace the starting phenol. For instance, Charton and coworkers reported a similar reaction using squaric acid 83 instead of an electron-deficient phenol fScheme 19.47T Similarly, Ramazani and coworkers described the application of tropolone 84 in Ugi-Smiles or Passerini-Smiles couplings to synthesize substituted cycloheptatrien-l-one derivatives 85 fScheme 19.48T... 

A three-component reaction comprising of Phenol-Passerini-Smiles rearrangement sequence of o-nitrophenol, cyclohexylisocyanide and propionaldehyde at 40 for 3 days provided the amide 158. In the course of the reaetion, a final Smiles rearrangement displaces all the equilibria to result in the product. Various aldehydes and isocyanides were employed to investigate the scope of this new reaction. It has been found that hindered isocyanides and aromatic aldehydes gave the desired product, whereas a,P-... 

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