Pyrido coumarines

Abdolmohammadi S (2013) Simple route to indeno[l,2-6]quinoline derivatives via a coupling reaction catalyzed by TiO nanoparticles. Chinese Chem Lett 24 318—320 Symeonidis TS, Lykakis IN, Litinas KE (2013) Synthesis of quinolines and fused pyrido-coumarins from N-propargylanilines or propargylaminocoumarins by catalysis with gold nanoparticles supported on TiO. Tetrahedron 69 4612 616... 

Base-catalyzed rearrangement of Af-(aryloxy)pyridinium salts (11) leads to 2-arylpyridines (12) via intramolecular attack on the ortho position of the aryloxy ring by the 2-pyridyl carbanion. When X was 3-CChMe, pyrido[3,2-J]coumarins (13 R = NO2, CN) were directly obtained in useful yields from this reaction. When in (11) X was 3-COMe and R was 4-NO2, 10-hydroxy- 10-methyl-6-nitropyrido[2,3-J]benzopyran (14) was obtained in 10.8% yield.89... 

Cycloaddition between electron-rich 6-[(dimethylamino)methylene]amino-1,3-dimethyl uracil 242 and various electron-deficient substrates such as quinones 243 and coumarins 244 was considered to take place by elimination of dimethyla-mine from the respective cycloadducts, followed by oxidative aromatization in a highly regiospecific manner to give pyrido[2,3-solvent-free conditions, the times were reduced to 6-7 min and the yields were increased from 70-80% to 85-94% (04SL1179). 

Khan et al. [69] synthesized pyrido[2,3-c]coumarin derivatives 52 from 3-ami-nocoumarins, aromatic aldehydes, and alkynes in the presence of 10 mol% of molecular iodine in acetonitrile under reflux conditions through one-pot Povarov reactions (Scheme 10.34). 

Khan AT, DasDK, Islam K, Das P (2012) A simple and expedient synthesis of functionalized pyrido[2,3-c] coumarin derivatives using molecular iodine catalyzed three-component reaction. Tetrahedron Lett 53 6418 5422... 

The chiral holmium(III)-complex-catalysed Diels-Alder cycloaddition of siloxyvinylindoles (70) with e-deficient olefins (71) formed exo-substituted hydro-carbazoles (72) in up to 99% yield and 94% ee. Alkylation of these cycloadducts gave tricyclic compounds (73) with four continuous chiral centres (Scheme 20). The thermal 4-i-2-cycloaddition reaction of 7-substituted 4-styrylcoumarins with A-phenylmaleimide and tetracyanoethylene in nitrobenzene yielded 3,4-annulated coumarins. The thermal Diels-Alder cycloaddition of ( )-l,3-dihydro-3-phenacylidene-2//-indol-2-ones (74) with l,2-dihydro-2-oxospiro[3//-indole-3,2 -[2H,9a//-pyrido[2,l-fe][l,3]oxazines]] (75) produced complex dispirooxindoline fused [l,3]oxazines (76) with high regio- and stereo-selectivity (Scheme 21). " ... 

The eco-friendly one-pot three-component reaction of 4-hydroxy-7-methylcoumarin, chalcones 130 and ammonium acetate as a source of ammonia was reported [106] to proceed in PEG 400 affording pyrido[3,2-c]coumarines 131 (Scheme 75). The reaction products demonstrated antibacterial and antifungal properties. 

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