[EN] PROCESS FOR THE PREPARATION OF INTERMEDIATES USEFUL FOR MAKING (2S,5R)-7-OXO-N-PIPERIDIN-4-YL-6-(SULFOXY)-1,6-DIAZABICYCLO[3.2.1]OCTANE-2-CARBOXAMIDE<br/>[FR] PROCÉDÉ DE PRÉPARATION D'INTERMÉDIAIRES UTILES POUR LA FABRICATION DE (2S,5R)-7-OXO-N-PIPÉRIDIN-4-YL-6-(SULFOXY)-1,6-DIAZABICYCLO[3.2.1]OCTANE-2-CARBOXAMIDE
申请人:MERCK SHARP & DOHME
公开号:WO2020219405A1
公开(公告)日:2020-10-29
The invention is related to the preparation of protected piperidine carboxylates suitable for use as intermediates that lead, via a series of additional process steps, including a sulfation of a hydroxy urea compound, to the preparation of the beta lactamase inhibitor (2S,5R)-7-oxo-N-piperidin-4-yl-6-(sulfoxy)-1,6-diazabicyclo[3.2.1]octane-2-carboxamide.
High relative reactivities of aromatic cation radicals compared to related carbocations. Observation of an unexpected deuterium kinetic isotope effect
作者:Bjorn Reitstoen、Fredrik Norrsell、Vernon D. Parker
DOI:10.1021/ja00204a019
日期:1989.10
The reaction between 9-phenylanthracene (PAH) cation radical and acetate ion was studied to probe for an electron-transfer pathway. The decomposition of acetoxy radical to methyl radical and carbon dioxide, accompanied by the regeneration of PAH, is the expected result of an initial electron transfer. Rate-determining attack of acetate ion on PAHsup sm bullet}+} followed by rapid product-forming
研究了 9-苯基蒽 (PAH) 阳离子自由基与乙酸根离子之间的反应,以探索电子转移途径。乙酰氧基分解为甲基自由基和二氧化碳,伴随着多环芳烃的再生,是初始电子转移的预期结果。乙酸根离子对 PAH sup sm bullet}+} 的定速攻击,然后是快速的产物形成反应,可能导致二次 alpha} 氘动力学同位素效应。这些结果均未观察到。观察到醋酸离子在 293 K 的乙腈中对 PAH sup sm bullet}+} 的攻击几乎是在扩散控制下发生的。
Eberson, Lennart; Joensson, Lennart, Acta chemica Scandinavica. Series B: Organic chemistry and biochemistry, 1986, vol. 40, # 2, p. 79 - 91
作者:Eberson, Lennart、Joensson, Lennart
DOI:——
日期:——
Eberson, Lennart; Larsson, Berit, Acta chemica Scandinavica. Series B: Organic chemistry and biochemistry, 1986, vol. 40, # 3, p. 210 - 225
作者:Eberson, Lennart、Larsson, Berit
DOI:——
日期:——
Rapid Formation and Slow Collapse of a Carbocation−Anion Pair to a Neutral Molecule
作者:Weifang Hao、Vernon D. Parker
DOI:10.1021/jo702492r
日期:2008.1.1
The 4,4',4"-trimethoxytrityl cation (TMT+) was observed to react with acetate ion in acetic acid reversibly to give the corresponding ester (TMT-OAc). The rate of the reaction was found to be independent of [NaOAc] over a 25000-fold range. Similar results were observed in the presence of BU4N+ in acetic acid as well as in HOAc/AN (1/1). It was concluded that TMT+ (HOAc/AcO-)} is an ion pair that forms essentially completely from free TMT+ and HOAc/AcO- during the time of mixing under stopped-flow conditions. The process which was studied kinetically is the intramolecular collapse of the ion pair to TMT-OAc which takes place in two steps involving a kinetically significant intermediate. The remarkably close resemblance of this reaction to the Winstein scheme for solvolysis reactions is noted. In analogy to the Winstein scheme, it was proposed that the intermediate could be an intimate ion pair formed upon extrusion of solvent from the solvent separated ion pair. The product-forming step could then correspond to the intimate ion pair reacting further to form a covalent bond between the two moieties within the complex. The values of the thermodynamic and the activation parameters as well as the apparent rate constants for the reaction in the presence of either sodium or tetrabutylammonium ions suggest that these counterions play insignificant roles in the reactions. However, the equilibrium constant for the intramolecular step (K-4) was observed to be two times greater in the presence of Bu4N+ than in the presence of Na+. The rate of the reaction in HOAc was observed to be about four times as great as that in HOAc/AN (1/1).