One-pot synthesis of fused 1,2-dihydropyridines

Dihydropyridines (DHP) are among the most beneficial scaffolds that have revolutionised pharmaceutical research with unprecedented biological properties1. DHPs are versatile intermediates in the synthesis of various alkaloids and important bioactive products such as aza-sugar derivatives and anti-influenza drug Tamiflu. Major synthetic routes to 1,2-dihydropyridine derivatives include condensation reactions, reduction of and nucleophilic addition to pyridines and pyridinium salts, and ericyclic reactions2,3. The zwitterionic intermediates, generated in situ from triphenylphosphine and dialkyl acetylenedicarboxylates, are trapped by N-H acidic 2-(alkylamino)-2-(1,3-dioxo-1H-inden-2(3H)-ylidene)acetonitriles in refluxing toluene to afford dialkyl 2-alkyl-1-cyano-9-oxo-3,9-dihydro-2H-indeno[2,1- c]pyridine-3,4-dicarboxylates in good yields. Various features of these transformations will be presented and discussed.

کلیدواژه ها:

1 ، 2-Dihydropyridines ، Acetylenic esters ، Triphenylphosphine ، Alkylamines ، Ninhydrin