- Dialkyl (1,2-Epoxy-3-oxoalkyl)phosphonates as Synthons for Heterocyclic Carbonyl Compounds: Synthesis of Acyl-Substituted Thiazoles, Indolizines, Imidazopyridines and Imidazopyrimidines
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Dialkyl phosphonates (1) react with H2O2/Na2CO3 to give the corresponding trans-1,2-epoxy derivatives 2.These, on reaction with thioamides 4-7, afford (1-hydroxy-1-thiazolylalkyl)phosphonates 8-11, with ethyl α-pyridylacetate (indolizinylalkyl)phosphonates 19, with 2-aminopyridine (imidazopyridinylalkyl)phosphonates 20 (together with the α-amino compounds 22) and with 2-aminopyrimidine the (imidazopyrimidinylalkyl)phosphonates 21.On treatment with alkali or by pyrolysis the (1-hetaryl-1-hydroxyalkyl)phosphonates 9-11 and 19-21 yield the corresponding acyl-substituted heterocycles (thiazoles 13-15 and bicyclic acyl compounds 23-25). - The structure of the bicyclic derivatives 19-25 is assigned from the considerable deshielding of their 5-H NMR signals caused by the electron-rich substituents in peri-3-position.Condensation of the epoxyketones 2 with cytosine results in the isomeric (imidazopyrimidinylalkyl)phosphonates 27 and 28, which can be cleaved to the corresponding aldehydes 29 and 30, respectively.
- Oehler, Elisabeth,El-Badawi, Mahmoud,Zbiral, Erich
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p. 4099 - 4130
(2007/10/02)
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- A NOVEL AND VERSATILE SYNTHESIS OF HETEROCYCLIC ALDEHYDES USING DIALKYL 3-OXO-1-ALKENYL-PHOSPHONATES.
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Dialkyl 1,2-epoxy-3-oxoalkyl-phosphonates, easily prepared from the corresponding 1-alkenyl-phosphonates, react with ambident nucleophiles to dialkyl 1-hetaryl-1-hydroxymethyl-phosphonates, which can be transformed to heterocyclic aldehydes.
- Oehler, Elisabeth,Zbiral, Erich,El-Badawi, Mahmoud
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p. 5599 - 5602
(2007/10/02)
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