Chelatbildende Enaminoketone I. Synthese von unsymmetrischen Liganden

Trathnigg, Bernd; Golob, Karl; Junék, H.; Perne, J.; Popitsch, Alois

doi:10.1007/bf00798314

Cited by 8 publications

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References 42 publications

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“…7 However, it has been reported that analogous reactions with trialkyl orthoacetates and trialkyl orthopropionates do not yield the corresponding enaminones. 8 Contrary to those data, we found that refluxing of a mixture of dimedone, triethyl orthoacetate (or triethyl orthopropionate), and p toluidine afford compounds 1a,b.…”

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Synthesis of new pyrido[2,3-d]pyrimidine derivatives by three-component condensation of 5-acetyl-4-aminopyrimidines, cyclohexane-1,3-diones, and orthocarboxylic acid esters

et al. 2006

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A three component condensation of 5 acetyl 4 aminopyrimidine derivatives with dimedone (or cyclohexane 1,3 dione) and triethyl orthoacetate (or triethyl orthopropionate) gave de rivatives of 7 (1,3 dioxocyclohex 2 ylidene) 7,8 dihydropyrido[2,3 d]pyrimidine. These heterocyclic compounds containing the enamino ketone fragment can form boron chelates under the action of butoxy(diphenyl)borane. Key words: 2,6 disubstituted 5 acetyl 4 aminopyrimidines, cyclohexane 1,3 diones, tri ethyl orthoacetate, triethyl orthopropionate, three component condensation, 7 (1,3 dioxo cyclohex 2 ylidene) 7,8 dihydropyrido[2,3 d]pyrimidines and their diphenylboron complexes. Easily accessible derivatives of 5 acetyl 4 amino pyrimidine (AAP) 1-3 can be effectively used for the de sign of the pyrido[2,3 d]pyrimidine system. Earlier, we have obtained substituted pyrido[2,3 d]pyrimidin 5(8H ) ones 2,4 by reactions of AAP with amide acetals and 5 oxo 5,8 dihydropyrido[2,3 d]pyrimidine 7 carboxylates 3 by condensation of AAP with diethyl oxalate. Heating of AAP with alkyl β oxo carboxylates gives the correspond ing 6 acylpyrido[2,3 d]pyrimidin 7(8H ) ones and that with ethyl malonate yields ethyl 7 oxo 7,8 dihydro pyrido[2,3 d]pyrimidine 6 carboxylates. 5In the present work, we proposed a new approach to the synthesis of pyrido[2,3 d]pyrimidines via three com ponent "one pot" condensation of AAP with dimedone (or cyclohexane 1,3 dione) and trialkyl orthoacetate and trialkyl orthopropionate.Three component condensation of cyclohexane 1,3 diones with trialkyl orthoformate and aromatic amines is known to produce 2 arylaminomethylenecyclohexane diones, 6 which are potential ligands for preparation of metal chelate complexes. 7 However, it has been reported that analogous reactions with trialkyl orthoacetates and trialkyl orthopropionates do not yield the corresponding enaminones. 8 Contrary to those data, we found that refluxing of a mixture of dimedone, triethyl orthoacetate (or triethyl orthopropionate), and p toluidine afford compounds 1a,b. According to 1 H NMR and IR spectroscopic data, they are structurally analogous to the condensation products obtained from triethyl orthoformate (Scheme 1). Scheme 1 R = H (a), Me (b)This result suggests that amines of the AAP type can be employed for the synthesis of the corresponding N sub stituted aminopyrimidines whose intramolecular cycliza tion can afford pyrido[2,3 d]pyrimidine derivatives.It turned out that reactions between 1,3 diketones 2 and 3, orthoesters 4 and 5, and aminopyrimidines 6a-c in boiling xylene without any catalysts give the corre sponding 7 (1,3 dioxocyclohex 2 ylidene) 7,8 dihydro pyrido[2,3 d]pyrimidines (7a-f) (Scheme 2).Obviously, the reaction intermediates vinylamino pyrimidines (VAP) are similar to compounds 1 and readily * Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday.

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