97308-36-6Relevant academic research and scientific papers
PYRIDINES. XIII - ACYLATION DE PYRIDYL-LITHIOENAMINES PRIMAIRES. SYNTHESE DE PYRIDYL-ENAMIDES ET DE NAPHTYRIDIN-1,6 ONES-5.
Compagnon, Paul-Louis,Gasquez, Francoise,Kimny, Tan
, p. 49 - 56 (2007/10/02)
The primary lithioenamine 4a is an ambivalent nucleophile resulting from the condensation of benzonitrile with 2-s-collidyllithium.Acylation of 4a by acetyl, benzoyl, N,N-dimethylcarbamoyl chlorides, ethyl chloroformate or methyl benzoate leads to β-C-acylated 5, N-acylated 6 (enamides) and β-C,N-diacylated 7 compounds.N-acylation predominates upon C-acylation with the studied aliphatic acid chlorides, contrary to benzoylation. 4,6-Dimethyl-2-pyridyl-acetate 17 and -acetamide 18 are formed and their origin is discussed.Thermocyclization of certain enamides, carbamates 6c, 7c and urea 6d leads to 2,4-dimethyl-7-phenyl-1,6-naphthyridin-5-(6H) ones 9a and 9b, and not to pyridopyrimidones 8.
PYRIDINES. XIV - ACYLATION DE PYRIDYL-LITHIOENAMIDINES. SYNTHESE DE PYRIDYL-N-ACYLENAMIDINES ET DE PYRIDYLPYRIMIDONES-4.
Compagnon, Paul-Louis,Gasquez, Francoise,Kimny, Tan
, p. 57 - 64 (2007/10/02)
The mixture of PhLi:di- or tri-methylpyridine 1:PhCN:RCOCl (R = Me, Ph, EtO, Me2N) or PHCO2Me (molar ratio 3:1:3:3) leads through the intermediates primary lithioenamines 3 and lithioenamidines 4, to acylated products, N-acylenamines (enamides) 5, β-diketones and β-ketoesters 6, C-acylenamides 7, N-acyleneamidines 8 and their cyclization derivatives, pyridylhydroxypyrimidines 10 (yield up to 60 percent) and pyridyldihydropyrimidones 11 (yield up to 10 percent).Distillation of the crude extract leads to naphthyridones 12 (yield up to 10 percent) which result from thermocyclization of the enamides 5f, 5g and 7f.Various by-products are isolated such as N,N-dimethyl-N',N'-diphenylmethyleneurea resulting from N-lithiodiphenylketimine and phenacylpyridines 13.Crotonization and oxidation of the latter compounds lead to the aza-analogues 14, 15 of dibenzoylstilbenes.
Condensed Heteroaromatic Ring Systems. III. Synthesis of Naphthyridine Derivatives by Cyclization of Ethynylpyridinecarboxamides
Sakamoto, Takao,Kondo, Yoshinori,Yamanaka, Hiroshi
, p. 626 - 633 (2007/10/02)
Four kinds of naphthyridinones, i.e. 1,6-naphthyridin-5-one, 1,7-naphthyridin-8-one, 2,6-naphthyridin-2-one, and 2,7-naphthyridin-1-one derivatives, were commonly synthesized by the intramolecular cyclization of pyridinecarboxamides having an ethynyl group or β,β-dimethoxyethyl group adjacent to the carbamoyl group.The syntheses of the starting pyridine derivatives were easily accomplished by cross-coupling of the corresponding halopyridines with acetylenes.Keywords-intramolecular cyclization; palladium catalyst; trimethylsilylacetylene; naphthyridinone; pyridineacetaldehyde; 1(2H)-isoquinolone
