Silylation of gamma-nitro ketones of the general formula (RCOCH)-C-1(R-2)CH(R-3)CH(R-4)NO2 proceeded stereoselectively to give 2-[N,N-bis(trimethylsilyloxy)amino]-2,3-dihydrofurans, conjugated enoximes, silylation products of the carbonyl group or both functional groups, or N, N-bis(trimethylsilyloxy)enamine depending on the nature and positions of the substituents in the carbon skeleton. Dihydrofuran derivatives are formed for R-1 = Ar or cyclo-C3H5. Enoximes are generated as the silylation products of the starting ketones with enhanced P-proton mobility (R-3 CO2Me or 4-NO2C6H4). The presence of an alkyl group at the carbonyl function (R-1 = Alk) is favorable for the formation of enoximes. Finally, the introduction of a substituent at the a position with respect to the nitro group (R-4 = Me, CO2Me, or Ph) leads to the formation of silyl enolates. Under the action of NH4F in MeOH, dihydrofurans can be transformed into substituted furans in moderate yields.
Sequential Michael addition/retro-Claisen condensation of 1,3-diarylpropan-1,3-diones with nitrostyrenes: one-step synthesis of 4-nitro-1,3-diarylbutan-1-ones
作者:ZHENG LI、HAO LU、ZHENRONG LIU、XIAOLONG MA
DOI:10.1007/s12039-019-1603-z
日期:2019.4
Abstract The sequential Michael addition/retro-Claisencondensation of 1,3-diarylpropan-1,3-diones with nitrostyrenes is described. 4-Nitro-1,3-diarylbutan-1-ones were efficiently synthesized in good to high yield under mild, transition-metal-free condition. This one-step method involving sequential carbon-carbon bond formation and cleavage provides a good alternative to the synthesis of various \(\gamma
Reaction between 4-Nitro-1,3-diarylbutan-1-ones and Ammonium Acetate in the Presence of Morpholine and Sulfur: An Efficient Synthesis of 2,4-Diarylpyrroles
An efficient synthesis of 2,4-diarylpyrroles is described. Heating a mixture of a 4-nitro-1,3-diarylbutan-1-one and ammoniumacetate in the presence of morpholine and sulfur afforded the corresponding 2,4-diarylpyrroles in excellent yields.
Triton B Catalyzed Rapid and Mild Synthetic Protocol for both Henry Reaction of Isatin and Michael Reaction of Chalcone with Nitroalkane
作者:Eeshwaraiah Begari、Mrinal Talukdar、Nasreen Islam、Akanksha Mishra、Alpa Y Dave
DOI:10.1055/s-0043-1774862
日期:2025.1
hydroxide) and isatins and chalcones, respectively. This methodology is inexpensive, the reagents are easy to handle, and the approach offers wide functional group tolerance of isatins and chalcones. The base catalyst Triton B is less toxic, recyclable, and reusable. This efficient method reduces reaction times, minimizes reagent excess, avoids chromatography, and is aligned with sustainable chemistry principles
分别使用无金属催化剂 Triton B(氢氧化苄基三甲基铵)以及靛红和查耳酮,开发了亨利反应和迈克尔反应的高效通用合成方案。该方法价格低廉,试剂易于处理,并且该方法对靛红和查耳酮具有广泛的官能团耐受性。碱性催化剂 Triton B 毒性较小、可回收、可重复使用。这种高效的方法减少了反应时间,最大限度地减少了试剂过量,避免了色谱法,并且符合可持续化学原理,为不同行业提供了环保应用。
460. Chalcones and related compounds. Part V. Addition of nitro-compounds to chalcones