One-pot synthesis of polyfunctional pyrazoles: an easy access to α-diazoketones from arylglyoxal monohydrates and tosylhydrazine
摘要:
A new and efficient method for the generation of alpha-diazoketones has been developed from arylglyoxal monohydrates and tosylhydrazine at room temperature. 1,3-Dipolar cycloaddition reactions were used to constructing polyfunctional pyrazole derivatives by the reaction of generated alpha-diazoketones in situ with electron-deficient alkenes, quinones and coumarins in one pot. The one-dimensional molecular packing of 1H-benzo[f]indazole-4,9-dione derivatives along the c direction demonstrated a helical chain formation via N-H center dot center dot center dot O hydrogen-bonding. (C) 2014 Elsevier Ltd. All rights reserved.
Metal-Free Insertion Reactions of Diazo Carbonyls to Azlactones
作者:Amanda C. de Mello、Patrícia B. Momo、Antonio C. B. Burtoloso、Giovanni W. Amarante
DOI:10.1021/acs.joc.8b01683
日期:2018.9.21
Insertionreactions of diazo carbonyls to azlactones in basic conditions have been performed. The developed method allows the preparation of a wide range of oxazole derivatives in yields ranging from 74 to 98%. Different substituents on both azlactone rings and diazo carbonyls do not compromise the methodology, even those containing stereogenic centers. Isotopic labeling experiments revealed the mechanism
A two-step synthesis of the bioprotective agent JP4-039 from N-Boc-l-leucinal
作者:Barbara Bernardim、Antonio C.B. Burtoloso
DOI:10.1016/j.tet.2013.10.059
日期:2014.5
An expedited synthesis of the bioprotective agent JP4-039 is described from N-Boc-l-leucinal in 50% overall yield. The synthesisinvolves the use of an α,β-unsaturated diazoketone as the key intermediate, followed by a photochemical Wolff rearrangement in the presence of 4-amino-TEMPO (4-AT).
Ketene Reactions with the Aminoxyl Radical TEMPO: Preparative, Kinetic, and Theoretical Studies
作者:Annette D. Allen、Bernice Cheng、Michael H. Fenwick、Babak Givehchi、Huda Henry-Riyad、Valerij A. Nikolaev、Elena Aleksadrovna Shikhova、Daryoush Tahmassebi、Thomas T. Tidwell、Silas Wang
DOI:10.1021/jo0011336
日期:2001.4.1
reactive ketenes were generated as rather long-lived species by photochemical Wolff rearrangement in isooctane solution, characterized by IR and UV, and used for kinetic studies. The rate constants of TEMPO addition to eight different ketenes have been measured and give a qualitative correlation of log k(2)(TEMPO) = 1.10 log k(H(2)O) -3.79 with the rate constants for hydration of the same ketenes. Calculations
四甲基哌啶基氧基(TEMPO,TO *)与通过Wolff重排或酰基氯的脱氯化氢反应生成的烯酮RR(1)C = C = O反应,得到的产物是将一个TEMPO自由基加到羰基碳上,再将第二个TEMPO自由基加成激进。苯基乙烯基乙烯酮4b和4f,苯基炔基乙烯酮4c和二烯基乙烯酮AcOCMe = CHCH = CHCMe = C = O的反应发生烯丙基或炔丙基重排。通过在异辛烷溶液中进行光化学Wolff重排,甚至以相当长的寿命生成了相当活泼的烯酮,其特征在于IR和UV,并用于动力学研究。已测量了TEMPO除八种不同烯酮外的速率常数,并给出了log k(2)(TEMPO)= 1.10 log k(H(2)O)-3.79与相同烯酮水合的速率常数的定性相关性。
Preparation of <i>Z</i>-α,β-Unsaturated Diazoketones from Aldehydes. Application in the Construction of Substituted Dihydropyridin-3-ones
作者:Isac G. Rosset、Antonio C. B. Burtoloso
DOI:10.1021/jo401191s
日期:2013.9.20
The stereoselective preparation of α,β-unsaturateddiazoketones with Z geometry is described from aldehydes and a new olefination reagent. When prepared from amino aldehydes, these diazoketones could be converted to substituted dihydropyridin-3-ones in just one step, after an intramolecular N–H insertion reaction. The straightforward synthesis of a natural trihydroxylated piperidine demonstrates the