الفهرس 
General trends in Chemistry of ketene dithioacetalsOnly 14 pages are availabe for public view
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Abstract
Part (I) Novel N-substituedamino -4- methylthio -2- pyridines and deazapurine analogues from ketene dithioacetals Ketene dithioacetals 2 reacted with 1- cyanoacetyl-4-substituted-thiosemi-carbazides 3 a,b at room temperature in the presence of pulverized KOH-dioxan to give the corresponding N-(4-methylthio-2-oxo-1-pyridyl) thiourea derivatives4. Structure of compounds 4 were established and confirmed on the basis of their elemental analysis and spectral data (MS. 1H NMR and IR). Similarly, when compounds 2 reacted with cyanoacetohydrazide under the same reaction condition, the corresponding N-amino-4-methylthio-2-pyridones 5a,b were isolated. The structure of compounds 5 were elucidated according to their elemental analysis and spectral data (MS, 1H NMR and IR). Reaction of ketene dithioacetals 2 with 1-cyanoacetyl-4-arylidenesemicarbazide in the presence of KOH-dioxan was reported to afford the corresponding N-schiff bases 7. The latters were subjected to the reaction with hydrazine hydrate in refluxing ethanol to give the corresponding pyrazolo[3,4-c]pyridines 8. Both the structures of compounds 7 and 8 were confirmed and established based on their elemental analysis and spectral data (MS, 1H NMR and IR). Part (II) Novel synthesis of N-arylsulfonylamino-2-pyridones: Cyanoacetohydrazide 1 reacts with arylsulfonyl chloride in ethanol to afford the corresponding N-cyanoacetyl-arylsulfonylhydrazides 2 in good yields. The structures of 2 were established and confirmed for the reaction products on the basis of their elemental analysis and spectral data (MS, IR, 1H NMR). Compounds 2 reacted with arylmethylenemalononitriles 3 in refluxing ethanol containing catalytic amounts of piperidine to give the corresponding N-arylsulfonylamino-2-pyridones 6 in good yields. The structures of compounds 6 were established on the basis of their elemental analysis and spectral data. The formation of 6 from 2 and 3 is assumed to proceed via addition of active methylene of 2 to the double band in 3 to give the intermediate 4. This Michael adduct then cyclises to give the intermediate dihydropyridine derivative 5, which is oxidized under reaction conditions to the novel N-arylsulfonylamino-2-pyridone derivatives 6. This result indicate that the reaction of N-cyanoacetyl-arylsulfonylhdrazides with α,β unsaturated nitriles can be utilized as an excellent route for the synthesis of several N-sulfonated aminopyridine derivatives, which are otherwise accessible only with difficulty. The obtain compounds are now under biological evaluation studies.