- Diels-Alder cycloaddition of 2-azadienes to methyl 2-(2,6-dichlorophenyl)- 2H-azirine-3-carboxylate in the synthesis of methyl 4-oxo-1,3-diazabicyclo[4.1. 0]heptane-6-carboxylates
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A number of fused 4-oxo-1,3-diazabicyclo[4.1.0]heptane-6-carboxylates, a new type of compound, have been obtained by Diels-Alder cycloaddition between nucleophilic 2-azadienes and an electrophilic 2H-azirine. The reactions are completely endo- and regioselective, the azirine being added by its less hindered face to the diene. There are two isomers 7 and 8 formed from dienes 1 due either to isomerization of the cycloadducts 7 and 8 or by isomerization of the CN bond of the diene during the reaction. The isomer 10 is formed from diene 2e, and a single diastereoisomer structure 4a-i is formed from dienes 11. Some pyrimidones 8a, 7c/8c, 7e, 10, 11d have been hydrolyzed leading to functionalised aziridines 12, 13 and 15.
- Alves, M. José,Dur?es, M. Miguel,Fortes, A. Gil
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- 1,3-Oxazines and Related Compounds. XII. Facile Synthesis of 2,4-Disubstituted 6H-1,3-Oxazin-6-ones
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A convenient method for synthesis of 2,4-disubstituted 6H-1,3-oxazin-6-ones (8) was developed.Acylaminoalkylidene-1,3-dioxane-4,6-diones (5a-l), which were prepared from N-acylimidates (3a-l) and Meldrum's acid (4), readily underwent thermolysis upon heating, leading to a variety of 2,4-disubstituted 6H-1,3-oxazin-6-ones (8a-l).Keywords - 6H-1,3-oxazin-6-one; Meldrum's acid; acylaminoalkylidene-1,3-dioxane-4,6-dione; N-acylimidate; thermolysis
- Yamamoto, Yutaka,Morita, Yasuo,Minami, Keiko
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p. 1980 - 1986
(2007/10/02)
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