Synthese von Glutaconaldehyden aus Quadrats�ure-Pyridiniumbetainen
摘要:
The pyridinium ring of squaric acid betaines (2) is opened by hydroxide ions. Electronegative substituents (R = Cl, CN) at C-3 promote this reaction. The stereochemistry of the resulting 5-(2-hydroxy-3,4-dioxocyclobut-1-en-1-yl) aminopenta-2,4-dienales (3) is confirmed by NMR-spectroscopy. Treatment of 3 with sodium hydroxide results in further hydrolysis to the sodium salts of glutaconaldehydes (5) and 3-amino-4-hydroxycyclobut-3-ene-1,2-dione (6). These products are also directly obtained from the nicotinic acid derivates 2d (R = COOEt) and 2e (R = CONH2), in the latter case cyclisation of the glutaconic acid derivate to the known 3-formylpyrid-2-one (10) is observed.
Amino Substituted Bisketenes: Generation, Structure, and Reactivity
作者:Nanyan Fu、Annette D. Allen、Shinjiro Kobayashi、Thomas T. Tidwell、Sinisa Vukovic、Selvananthan Arumugam、Vladimir V. Popik、Masaaki Mishima
DOI:10.1021/jo062090h
日期:2007.3.1
factor of 7.5 × 104, and the bis(Me2N) bisketene 14 is the most reactive in ringclosure that has been reported. Rate constants for ringclosure of these and previously observed bisketenes vary by a factor of 1013. The dialkylamino bisketenes 16 (R = Me, n-Bu) with tethered substituents and restricted geometries are less reactive than the bis(Me2N) bisketene 14 by factors of 1700 and 540, respectively
[EN] KYNURENINE-3-MONOOXYGENASE INHIBITORS, PHARMACEUTICAL COMPOSITIONS, AND METHODS OF USE THEREOF<br/>[FR] INHIBITEURS DE KYNURÉNINE-3-MONOOXYGÉNASE, COMPOSITIONS PHARMACEUTIQUES ET PROCÉDÉS D'UTILISATION DE CES COMPOSITIONS
申请人:COURTNEY STEPHEN MARTIN
公开号:WO2013033068A1
公开(公告)日:2013-03-07
Certain chemical entities are provided herein. Also provided are pharmaceutical compositions comprising at least one chemical entity and one or more pharmaceutically acceptable vehicle. Methods of treating patients suffering from certain diseases and disorders responsive to the inhibition of KMO activity are described, which comprise administering to such patients an amount of at least one chemical entity effective to reduce signs or symptoms of the disease or disorder are disclosed. These diseases include neurodegenerative disorders such as Huntington's disease. Also described are methods of treatment include administering at least one chemical entity as a single active agent or administering at least one chemical entity in combination with one or more other therapeutic agents. Also provided are methods for screening compounds capable of inhibiting KMO activity.
Development of N,N-bis(perfluoroalkanesulfonyl)squaramides as new strong Brønsted acids and their application to organic reactions
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1016/j.tet.2010.03.120
日期:2010.6
l groups have been developed and applied to several organic reactions. These squaramides are bench-stable and exhibit much higher reactivities in several organic reactions than squaric acid itself. N,N-Bis(trifluoromethanesulfonyl)squaramide 2a was applied to the Mukaiyama aldol reaction and Mukaiyama Michael reaction. Mechanistic studies revealed that the Brønsted acid might be the predominant catalyst
Unexpected Squaramide-Induced Cleavage of Benzils: Synthesis and Characterization of Mono-Aroyl Squarimides
作者:Elena Sanna、Carlos López、Pablo Ballester、Carmen Rotger、Antoni Costa
DOI:10.1002/ejoc.201501235
日期:2015.12
We report the reaction of 4,4′-substituted benzils with squaramides (SQ) affording mono-squarimides (SQIs). The 1H NMR and X-ray structures of the SQIs (R = H) revealed the existence of a strong C=O···HN intramolecular hydrogen-bond motif. The unprecedented reaction between SQs and benzils highlights the difference in reactivity between urea and squaramide units.