Water Mediated Construction of Trisubstituted Pyrazoles/Isoxazoles Library Using Ketene Dithioacetals
摘要:
A small molecule library of alkyl, sulfone, and carboxamide functionalized pyrazoles and isoxazoles has been developed via a rapid sequential condensation of various alpha-acylketene dithioacetals (1a-o) with hydrazine hydrate or hydroxylamine hydrochloride, followed by oxidation of sulfide to sulfone using water as the reaction medium. An efficient and safe oxidation of sulfides (4/5a-o) to the corresponding sulfones (6/7a-o) using sodium per borate system in aqueous medium is reported. The concise and two step synthesis of trisubstituted pyrazoles and isoxazoles was investigated under variety of reaction condition. The newly developed methodology has the advantage of excellent yield and chemical purity with short reaction time using water as a solvent.
[5 + 1] Annulation: A Synthetic Strategy for Highly Substituted Phenols and Cyclohexenones
摘要:
A novel [5 + 1] annulation strategy is developed for the synthesis of highly substituted phenols and cyclohexenones from alpha-alkenoyl ketenedithioacetals and nitroalkanes.
Thermal Cyclization of Ketene Dithioacetals: A Convenient Synthetic Route to Substituted 2(1<i>H</i>)-Quinolinones and 2(1<i>H</i>)-Pyridones
作者:Chwang Siek Pak、Eun Bok Choi
DOI:10.1055/s-1992-26361
日期:——
Acyl(arylcarbamoyl)ketene dithioacetals 2 and acyl(1-alkenylcarbamoyl)ketene dithioacetals 5 obtained from the corresponding ß-oxo amides 1, 4 were thermally cyclized to give various 3-acyl-4-alkylthio-2(1H)-quinolinones 3, and 3-acyl-4-alkylthio-5-aryl-2(1H)-pyridones 6, respectively, depending on the substituent of the amide group.
Synthesis of β-Lactam from Acyl(Arylcarbamoyl)-<i>S,S</i>-bis(alkylketene) Dithioacetal: Revised Structure of the Product from Thermal Cyclization of Acyl(Arylcarbamoyl)-<i>S,S</i>-bis(alkylketene) Dithioacetal
The structure of the quinolinone obtained from thermal cyclization of ketene dithioacetal has been revised by X-ray crystallographic analysis as 4-quinolinone instead of the previously reported 2-quinolinone. In the course of study on the mechanistic feature of the thermal cyclization, highly substituted β-lactams were obtained by alkylating β-lactam anion with MEMCl, MOMCl, or MeI in the presence of NaH.
作者:Anilkumar S. Patel、Naval P. Kapuriya、Yogesh T. Naliapara
DOI:10.1002/jhet.2860
日期:2017.9
A concise and effective approach to dicarboxamide functionalized novel pyrazolo[1,5‐a]pyrimidine has been developed. The method involves [3 + 3] hetroaromatization of oxoketene dithioacetals (16a–x) with 5‐amino‐N‐cyclohexyl‐3‐(methylthio)‐1H‐pyrazole‐4‐carboxamide (12) in the presence of K2CO3. This method has advantages of excellent yields, operational simplicity, and avoidance of hazardous base
已经开发出一种简洁有效的方法将二甲酰胺官能化的新型吡唑并[1,5- a ]嘧啶。该方法涉及在存在K 2 CO的情况下,用5-氨基-N-环己基-3-(甲硫基)-1H-吡唑-4-羧酰胺[ 12 +3]氧化氧杂环丁二硫缩醛(16a–x)的芳香化。3。该方法的优点是产率高,操作简单并且避免了诸如哌啶的有害碱。
Facile synthesis of highly functionalized novel pyrazolopyridones using oxoketene dithioacetal and their anti-HIV activity
作者:Mahesh M. Savant、Kartik D. Ladva、Archna B. Pandit
DOI:10.1080/00397911.2018.1458239
日期:2018.7.3
synthesized starting from various oxoketene dithioacetals. The cyclocondensation reaction of 2-(bis(methylthio)methylene)-3-oxo-N-arylbutanamide 2a–w with cyanoacetamide using NaOiPr as base under reflux condition afforded novel highly functionalized pyridone 3a–w derivatives. Further, [3 + 2] cyclocondensation reaction of pyridones with hydrazine in the presence of alcohol was yielded pyrazolopyridones
A facile and efficient synthesis of substituted pyridine-2,6(1H,3H)-diones via an intramolecular [5 + 1] annulation of readily available α-alkenoyl-α-carbamoyl ketene-S,S-acetals mediated by phosphorus bromide (PBr3) under very mild conditions is described.