The reaction of 2(1H)-pyridinone and some of its derivatives with substituted propynenitriles was studied.
The aromatic character of I-methyL2(lH)-pyridinone is reflected in its failure to give a 4+2 adduct.
Instead, reaction occurs at lactam carbonyl function to give 1,2dihydropyridine-2-methides.
The O-methyl derivatives are dealkyiated during reaction with propynenitriles to give N-substituted pyridones which are otherwise accessible in good yields from 2(1H)-pyridinone. R. YADLA et al. R' CH$/PTC/NaOH CH2CIz H I R-CEC-N _6 o-d b) R=CH,O -0 / ' R'=R2=H, X=OCH, b) R!=CeH5, RsH,X=OCH3 c) R$CeHb, &CH3,X=OCH3 d) R!=f?=H, X-Cl e) R'rCeH5, =H ,X=CI K f) R&Hb, &CH3, X=CI SCHEME a mixture of N-and O-methyl derivatives. More authentic methods were then employed to prepare N-and O-methyl derivatives. The alkylation of lactams lb,c with methyl iodide using in one case sodium hydroxide under phase transfer catalysis9 and in the other silver carbonate 10 m dry benzene gave exclusively the N-and O-methyl derivatives respectively. During the course of this study we observed an interesting reaction between O-methyl derivatives and substituted propynenitriles and these results are also described here. The reaction of l-methyl-la, I-methyl-4-phenyl-1p and 1,6-dimethyl-4-phenyl-2(1H)-pyridinone zc with different substituted propynenitriles was carried out under identical conditions used in the case of DMAD. However, no reaction was observed under these conditions. The reactions were then carried out in neat phase in a sealed tube at 110". I-Methyl-Icphenyl-lb and 1,6-dimethyl-4_phenyL2(1H)-pyridinone zc did not undergo any reaction. However, I-methyl-2(IH)-pyridinone 3a reacted with phenyl-, Cnitrophenyl-, 4-methoxyphenyl-and adamantane-I-yl-propynenitrile to give the corresponding 1,2-dihdyro-pyridine-Z-methide derivatives ga-d (see Scheme) which were isolated in trace yields and characterised. It appears that the case of substituted propynenitrile is different found M+ at m/e 266.1055 (calcd. for C16H14N202 266.