Pyridone dianions

Lithiation of l-methyl-4-pyridone at C-2 with n-butyllithium at — 78°C, followed by reaction with electrophiles, gives the 2-substituted l-methyl-4-pyridones in 34-78% yield (85CC1021). Pyridone dianion 139 is prepared by lithium-halogen exchange from bromopyridonecarboxylate 138 and two... 

Reactions via 2-pyridone dianions Side chain a-alkylation... 

Cyano-4-methyl-6-phenyl-2-pyridone, dianion of, 759 aroylated with, methyl benzoate, 759 benzophenone, 759... 

In the course of the reaction, Michael adduct 43 cyclizes initially under base catalysis to the dihydropyridone 45, which forms dianion 46. Electron transfer (an SET process leads to radical anion 47, which is finally transformed into pyridone 44 through an aromati/ation that includes hydrogen transfer and another SET process. 

Pyridones can be made by the condensation of nitriles with dianions of -diketones or 3-iminoketones (e.g.,... 

Some recent patents by Konishiroku refer to metallizable dyes of the dianionic type, with carboxyl groups as one of the hgands. A yellow pyridone (56) and a magenta naphthol dye (57) are two examples. Patents assigned to Agfa-Gevaert describe cyan metallizable dyes from imidazo[I,5-a]pyridine such as (58) and yellow dyes " from ethyl acetoacetate such as (59). A Fuji patent discloses a dye-releasing compound in which the dye is initially complexed with a metal... 

Pyridones The condensation of dianions of acyclic jS-enamino ketones with esters followed by acid treatment may lead to 4-pyranones (with HCl) or 4-pyridones (with PPA, 70°C). 

Cyclocondensation of dianions of p-dicarbonyl compounds 35 with nitriles offers a possibility for the formation of asymmetrically 2,6-disubstituted 4-pyridones 36, e.g. ... 

The recently developed dealkylation of phenol ethers with trimethylsilyl iodide has been shown to work well for OO -dialkyl-uracils. A number of ring transformations of uracils have been reported. The [2 + 2]cyclo-adducts (232) can be transformed into pyridones (233) by treatment with base overall yields of pyridines from the starting uracils (231) can be quite reasonable. The reaction is thought to proceed via electrocyclic ring-opening of the dianion of (232) (Scheme 92). 

The dicarbanion of acetoacetaldehyde is alkylated in the y-position to give salts and copper chelates of j3-ketoaldehydes (W-112 R = C6H5CH2, CH3, n-C Hg and n-CgHn), which are converted to 3-cyano-2-pyridones (XII-113 R = CH3, C6H5CH2, -C4H9) by reaction with cyanoacetamide. n-Butylation of the dianion of a-benzylacetoacetaldehyde followed by cyclization with aqueous cyanoacetamide gives 5-benzyl-3-carboxamido-6-n-pentyl-2-pyridone... 

Dianions of 4- and 6-alkyl-3-cyano-2-pyridones can be formed from the pyridone by treatment with two equivalents of potassium amide in liquid ammonia and can be alkylated, aroylated, or acylated selectively on the... 

The dianion of 3-cyano4,6-dimethyl-2-pyridone (XII-531) and benzyl chloride give only one product, which was not characterized. However, XII-531 and three equivalents of potassium amide and an excess of benzyl chloride give a 30% yield of stilbene and 35% each of a monobenzyl- (XII-532a or XII-S32b) and the dibenzyl- derivatives. This method gives better yields cf the... 

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