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Ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate : synthesis and reactivity with di...
Alves, M. José; Fortes, A. Gil; Lemos, Américo; Martins, Cristina I.Ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate, the first example of an 3-heteroamatic-2H-azirine, was prepared and its reaction with conjugated 1,3-dienes, under mild conditions and in the absence of Lewis acid catalyst, produced cycloadducts in good yield and high stereoselectivity.
Ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate : synthesis and reactivity with di...
Alves, Maria José Chão; Fortes, Gil; Lemos, A.; Martins, Cristina I.Ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate, the first example of an 3-heteroamatic 2H-azirine has been prepared. The reaction of ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate with conjugated 1,3-dienes, under mild conditions and in the absence of Lewis acid catalyst, afforded cycloadducts in good yield and high stereoselectivity.
Structural elucidation of the red dye obtained from reaction of 1,8-naphthalene...
Campos, Ana M. F. Oliveira; Carvalho, Luís H. Melo de; Silva, Artur M. S.; Martins, Cristina I.; Coelho, Paulo J.The structure of the intensely coloured red product obtained through the reaction of 1,8-naphthalenediol with 1,1-diphenylprop-2-yn-1-ol was reinvestigated. Instead of the expected permanent open form of the naphthopyran, the dye presents the alpha,beta-unsaturated chain at a different position of the naphthalene nucleus. The structure of this compound was elucidated on the basis of detailed spectral analysis,...
First report of a permanent open form of a naphthopyran
Campos, Ana M. F. Oliveira; Martins, Cristina I.; Coelho, Paulo J.; Carvalho, Luís H. Melo deThe synthesis of a permanent open form of a naphthopyran is described for the first time. The open form of the 10-hydroxy-2H-naphtho[1,2-b]pyran, obtained by reaction of 1,8-dihydroxy-naphthalene with 1,1-diphenylprop-2-yn-1-ol under acid catalysis, is stable due to the establishment of an intramolecular hydrogen bond.
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