Pyridone phenyl isocyanate

Substituted 2-pyridones were obtained from enamines with appropriate functional groups. Phenyl isocyanates and phenyl isothiocyanates... 

Cava and Saris591 refluxed the mesoionic selenazole 5 for a week with DM AD in benzene, and obtained 65% of the pyridone 6. This may be compared with the analogous mesoionic thiazole 49 (Section X,E). The easy loss of selenium from 6 contrasts with the loss of phenyl isocyanate from 49. 

Treatment of the pyrido-pyrimidines (346) with pyrrolidine gives the 1,8-naph-thyridines (347) (Scheme 133). The meso-ionic oxazines (349) that are formed by the reaction of chloroformyl-ketens with 2-pyridone undergo cycloaddition reactions with dimethyl acetylenedicarboxylate or with phenyl isocyanate, followed by loss of carbon dioxide, to yield quinolizines (350) and pyrido-pyrimidines (348), respectively (Scheme 134). Pyrido-pyrimidines (352) also result from the cycloaddition of anils of type (351) to ethyl vinyl ether (Scheme 135)."""... 

Copolymers of di5mes 8 with phenyl isocyanate afford poly(2-pyridones) 9. This copolymerization reaction uses nickel(O) complexes as initiators (63). 

Finally, the high efficiency of SIPr-Ni systems was applied to a three-component cycloadditions and the reaction of 3-hexyne and 2 equivalents of phenyl isocyanate afforded 2-pyridone in excellent isolated yield (Equation (10.21)). 

The acylation of G-alkyl groups in quaternary pyridinium salts has not otherwise been reported, but pyridone methides undergo substituted acylations with phenyl isocyanate and isothiocyanate. Some products of such reactions are recorded in Table 6.7. Some interesting examples of methide acylations are shown S ... 

On the other hand, the neutral iridium(I) catalyst is also effective for construction of the C—N axial chirality. In 2012, Takeuchi et al. reported that the reactions of malonate-linked internal 1,6-diyne 29 with ortho-substituted phenyl isocyanates 30 in the presence of the neutral iridium(I)/BINAP or Hg-BINAP catalyst furnishes enantioenriched A-aryl-2-pyridones 31, having a chiral C—N axis, with good yields and ee values (Scheme 9.12) [14]. 

The sodium salt of diethyl acetonedicarboxylate reacts with aryl isocyanates to give 1-aryl-4,6-dihydroxy-2-pyridones (XU-104)and with phenyl isothiocyanate to give 3-carbethoxy4-hydroxy-2-mercapto-l-phenyl-6-pyridone, Th e compound formed on treatment of XI-104 (R = H) with acetic anhydride has been proposed to be 3,5-diacetyl-4,6-dihydroxy-l-phenyl-2-pyridone. Characterization was based on the infrared spectrum, ... 

The rhodium-catalyzed chemo-, regio- and enantioselective [2-1-2- -2] cycloaddition of unsymmetrical alkynes to isocyanates leads to a wide range of 2-pyridones [123]. This method is used satisfactorily in the synthesis of axially chiral arylpyridones 2.196 by coupling alkylisocyanates with unsymmetrical a,to-diynes 2.195 that have one o-substituted phenyl group in one acetylene branch and terminal triple bond in another (Scheme 2.68) [123],... 

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