- Syntheses of 4-[(1H,3H)-pyrimidine-2,4-dion-1-yl]- and 4-[(1H,3H)-5- methylpyrimidine-2,4-dion-1-yl]-1,6-heptadienes
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Heptadienes containing nucleic bases are attractive building blocks for the synthesis of carbocyclic oligonucleotide analogs. Herein, we report an alternative synthetic route to 4-[(1H,3H)-pyrimidine-2,4-dion-1-yl]-1,6- heptadiene and 4-[(1H,3H)-5-methylpyrimidine-2,4-dion-1-yl]-1,6-heptadiene via building the pyrimidine ring utilizing 4-isocyanato-1,6-heptadiene intermediate.
- Bouhadir, Kamal H.,Zhou, Jing-Lan,Shevlin, Philip B.
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p. 1003 - 1010
(2007/10/03)
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- Highly Efficient Syntheses of Alkyl 3,3-Dialkoxypropanoates, Alkyl 4-Ethoxy-2-oxo-3-butenoates, and Monoprotected Malonaldehydes
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Haloform reaction of 4-alkoxy-1,1,1-trichloro-3-buten-2-ones, which can be obtained by acylation of enol ethers, gives 3,3-dialkoxypropanoic esters.Transacetalization of ethyl 3,3-diethoxypropanoate with 2,2-dimethyl-1,3-propanediol, followed by reduction and oxidation with DMSO/oxalyl chloride yields a monoprotected malonaldehyde. 4-Ethoxy-2-oxo-3-butenoates are synthesized either by acylation of enol ethers with alkoxalyl chlorides or by Claisen condensation of alkyl pyruvates with orthoesters.
- Tietze, Lutz-F.,Meier, Heinrich,Voss, Edgar
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p. 274 - 277
(2007/10/02)
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- Unnatural nucleosides and nucleotides. III. Preparation of 2-14C and 4-14C labelled 5-alkyluracils and 5-alkyl-2'-deoxyuridines
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2-14C Labelled 5-alkyluracils were prepared by condensation of the diethylacetals of α-formyl-carbonic acid esters with 14C-thiourea. Compounds labelled at 4-C were synthesized by condensation of the labelled carboxylic acid derivatives with thiourea. β-Anomers of 5-alkyl-2'-deoxyuridines were obtained in a fairly good radiochemical yield. Alkyl substituents ranged from methyl to tetradecyl, isopropyl and tert-butyl.
- Szabolcs,Kruppa,Sagi,Otvos
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p. 713 - 726
(2007/10/08)
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