1-Bromo-3,3-<i>bis</i>(2-bromoethyl)alkanes: Precursors to 4-Substituted Quinuclidines and 1-Phosphabicyclo[2.2.2]octanes
作者:Kerim A. Bairamov、Andrew G. Douglass、Piotr Kaszynski
DOI:10.1080/00397919808005108
日期:1998.2
Abstract 1-Bromo-3,3-bis(2-bromoethyl)octane has been synthesized from tetrahydro-4H-pyran-4-one in 6 steps and 18% overall yield. This method is more convenient, gives higher overall yields and is potentially more general than those previously reported for related tribromides.
In the context of formation of camptothecinssubstituted by a carbonyl function on position 5 of cycle C, synthesis of a new keto tetrahydroindolizine was realized. This compound was obtained from the reaction of Bredereck's reagent with an indolizine derived from pyroglutamic acid. That yielded a dimethylaminovinyl group whose NaIO4 oxidation gave a ketone. The indolizinone obtained was reacted in
Total Synthesis of Premithramycinone H and Related Anthrapyran Antibiotics
作者:Karsten Krohn、Jürgen Vitz
DOI:10.1002/ejoc.200300451
日期:2004.1
Two approaches are described for the preparation of 2-(1′,3′-dioxoalkyl)-substituted 1-hydroxyanthraquinones 10a−d and 20a−c, which were cyclized in a biomimetic-type reaction to the anthra[1,2-b]pyran skeletons 11a−d and 21a−c of the heydamycin- or pluramycin-type antibiotics. Cleavage of the methyl ethers afforded the natural product premithramycinone H (2). The simple derivative 11b showed inhibition
Dimethyl 7-methoxycarbonylmethyl-5-oxo-1,2,3,5-tetrahydro-indolizine-3,8-dicarboxylate was synthesized starting from methyl pyroglutamate. A study was made of the reactions of this highly functionalized pyridone with ethyl iodide, selenium oxide, isoamyl nitrite and formaldehyde. Literature reports that reaction of 4-(1-carbomethoxypropyl)-5-carbomethoxy-1,6-cyclopentano-2-pyridone with formaldehyde