40923-58-8Relevant academic research and scientific papers
Synthesis of Lactones via C-H Functionalization of Nonactivated C(sp3)-H Bonds
Richers, Johannes,Heilmann, Michael,Drees, Markus,Tiefenbacher, Konrad
, p. 6472 - 6475 (2016/12/23)
An electron-deficient amide is utilized as a directing group to functionalize nonactivated C(sp3)-H bonds through radical 1,5-hydrogen abstraction. The γ-bromoamides formed are subsequently converted to γ-lactones under mild conditions. The method described is not limited to tertiary and secondary positions but also allows functionalization of primary nonactivated sp3-hybridized positions in a one-pot sequence. In addition, the broad functional group tolerance renders this method suitable for the late-stage introduction of γ-lactones into complex carbon frameworks.
Preparation of conformationally restricted β2,2- and β2,2,3-amino esters and derivatives containing an all-carbon quaternary center
Romanens, Alexandre,Blanger, Guillaume
, p. 322 - 325 (2015/01/30)
β-Amino acids are routinely incorporated into peptidic drugs to increase their stability and to incur conformational biases. However, the synthesis of highly substituted β-amino acids still represents a great challenge. A new approach to their preparation is reported involving a Vilsmeier-Haack reaction with nonaromatic carbon nucleophiles. The highly challenging preparation of contiguous tertiary and all-carbon quaternary centers was successfully used to generate several β2,2,3-amino esters, such as derivatives of homoproline, homoalanine, and homopipecolinic esters.
New syntheses on the basis of ethyl 2-oxotetrahydrofuran-3-carboxylates
Kochikyan,Arutyunyan,Arutyunyan,Avetisyan
experimental part, p. 849 - 854 (2009/06/08)
Alkylation of 5-substituted ethyl 5-methyl-2-oxotetrahydrofuran-3- carboxylates with alkyl halides in the presence of sodium ethoxide gave the corresponding 3-alkyl derivatives which were converted into 3,5-substituted 5-methyl-N-(4-nitrophenyl)-2-oxotetr
Metabolite pattern of valproic acid. I. Gaschromatographic determination of the valproic acid metabolite artifacts, heptanone-3, 4- and 5-hydroxyvalproic acid lactone
Schaefer,Luehrs
, p. 657 - 662,658,660 (2007/10/05)
Metabolites arising from enzymatic oxidation of valproic acid (VPA, Orfiril) are determined after incubating body fluids at 37°C with an equal volume of diluted mineral acid, such as 85% w/w H3PO4/1 N HCl (1 : 1, v/v) for 3 h. 3-Ketovalproic acid (3-keto-VPA, 2-propyl-3-ketovaleric acid), which appears as the main metabolite, is hereby converted into heptanone-3 by ketonic hydrolysis. 4-Hydroxyvalproic acid (4-hydroxy-VPA, 2-propyl-4-hydroxyvaleric acid) and 5-hydroxyvalproic acid (5-hydroxy-VPA, 2-propyl-5-hydroxyvaleric acid) are converted into their corresponding lactones (4-HVL, 5-HVL). The kinetics of these reactions was studied using synthesized reference substances. Ketonic hydrolysis and lactone formation under the conditions for extraction procedures were reproducible and almost quantitative. An accurate and rapid determination of these metabolites as well as VPA from body fluids, if necessary after treating with glucuronidase, is thus made possible. A preliminary study of the metabolite patterns of patients on VPA therapy is presented. 3-Keto-VPA, 4-hydroxy-VPA and 5-hydroxy-VPA are excreted predominantly as the non-conjugates. 4-Hydroxy-VPA is also occasionally detected in the serum in quantities of 1-2 μg/ml.
