2-Amino-3,5-dicyano-4//-pyrans

Two molecules of aromatic j3-ketonitriles RCOCH2CN undergo a thermal cyclocondensation with one molecule of nalonitrile to give 2-amino-3,5-dicyano-4//-pyrans (90, 12 to 52%).137... [Pg.171]

Amino-3,5-dicyano-4//-pyrans 575 gave 1,4-dihydropyridines 576 in the same way, whereas analogous 3-esters were fully aromatized.441... [Pg.278]

Photorearrangements reported in six-membered cyclic systems include the dissociation of the cyclomers (50) into 1,1 -(1,2-ethanediyl)bis(pyrldinyl) blradicals,ring contraction of the 4-substituted 2-amino-3,5-dicyano-6-phenyl-4H-pyran (51)... [Pg.337]

Amino-3,5-dicyano-4/f-pyrans 241 were isomerized to cyclobutene carboxamides 242 on UV-illumination using a pyrex filter. This interesting conversion has been shown to proceed via excited triplet states of 241 and is thought to involve intermediate 243. The subsequent photoproducts were PhC=CCN and cyanocarboxamides R2C=(CN)CONH2 (87CC1231 89JOC3069). [Pg.94]

Amino-3,5-dicyano-4-isopropyl-6-methyl-4//-pyran 1598,1648,16 87JST19... [Pg.119]

Armesto D, Horspool WM, Martin N, Ramos A, Seaone C (1989) Synthesis of cyclobutenes by the novel photochemical ring contraction of 4-substituted 2-amino-3,5-dicyano-6-phe-nyl-4 77-pyrans. J Org Chem 54 3069-3072... [Pg.159]

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