排序方式: 共有36条查询结果,搜索用时 31 毫秒
11.
A new one-pot, three-component reaction of phenacyl pyridinium bromides, various primary aromatic amines, and phenyl glyoxal or ethyl glyoxalate for the stereoselective synthesis of acylic enaminones in good chemical yields is described. 相似文献
12.
A simple, efficient, and environmentally friendly one‐pot, three‐component synthesis of β‐enaminones via Sonogashira coupling–Michael addition sequences under solvent‐free conditions has been reported. Also the synthesis of β‐enaminones has been achieved in high yields by the direct reaction of amines with ynones under solvent‐free conditions. 相似文献
13.
A detailed study on the cycloaddition reactions of cross-conjugated enaminones 1 and 9 with dimethyl acetylenedicarboxylate (DMAD) and ketenes is described. The reactions provide a variety of pyran (4, 11), pyran-2-one 14 and pyrrol-3-ylidene 8 derivatives having great pharmacological and medicinal significance. Moreover, the preferred formation of product 8 over 7 has been explained on the basis of molecular dynamics (MD) simulations performed on the intermediate 5 in the gas phase. The synthetic potential of enaminones 9 has further been explored by treating them with Lawesson's reagent (LR) and trapping the in situ generated enaminothiones 16 with some acrylates 17 leading to the formation of thiopyran derivatives 19. To the best of our knowledge, this is the first report in which cross-conjugated enaminothiones 16 have been utilized in cycloaddition reactions. 相似文献
14.
15.
Synthesis of β‐enaminones from β‐dicarbonyl compounds has been achieved in high yields within a minute using primary and aromatic amines and catalytic amounts of iodine under solvent‐free conditions at room temperature. 相似文献
16.
Ren-Lin Zheng Xiu-Xiu Zeng Hai-Yun He Jun He Sheng-Yong Yang Luo-Ting Yu 《合成通讯》2013,43(10):1521-1531
An improved synthesis of 6-aryl-3-cyanopyridine-2-(1H)-thiones utilizing enaminones as starting materials catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) was described. Moreover, a convenient one-pot conversion of aryl ketones to 6-aryl-3-cyanopyridine-2-(1H)-thiones was also developed in moderate to good yields (up to 80%). 相似文献
17.
The title compound 5-cyclopropyl-10-(4-fluorophenyl)-7,7-dimethyl-7,8-dihydro- 5H-indeno[1,2-b]quinolne-9,11(6H,10H)-dione was obtained by the reaction of 4-fluorobenzal- dehyde, 2H-indene-1,3-dione and 3-(cyclopropylamino)-5,5-dimethylcyclohex-2-enone in the presence of acetic acid under microwave irradiation. Its structure was confirmed by IR and 1H- NMR spectra. The crystal is of monoclinic, space group P21/c with a = 14.138(3), b = 8.952(2), c = 17.140(3) , β = 102.253(3)o, C27H24FNO2, Mr = 413.47, Z = 4, V = 2119.9(8) 3, Dc = 1.296 g/cm3, μ(MoKα) = 0.087 mm-1, F(000) = 872, the final R = 0.0425 and wR = 0.0905 for 2336 observed reflections (I > 2σ(I)). X-ray analysis revealed that the pyridine ring adopts a boat conformation and the six-membered ring fused with it assumes a twist boat conformation. 相似文献
18.
Padmakar A. Suryavanshi Dr. Vellaisamy Sridharan Prof. J. Carlos Menéndez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(39):13207-13215
The cerium(IV) ammonium nitrate (CAN)‐catalyzed sequential multicomponent reaction between tryptamine, α,β‐unsaturated aldehydes, and β‐dicarbonyl compounds affords highly substituted indolo[2,3‐a]quinolizines in a single synthetic operation. Two rings are generated through the creation of two C? C and two C? N bonds by a domino process comprising initial β‐enaminone formation, followed by individual Michael addition, 6‐exo‐trig cyclization, iminium formation, and Pictet–Spengler steps. Furthermore, the reaction is diastereoselective and affords exclusively compounds with a trans relationship between the H‐2 and H‐12b protons. The use of amines bearing a less nucleophilic side chain aromatic ring (5‐bromotryptamine, 3,4‐dimethoxyphenylethylamine) prevents the Pictet–Spengler final step and leads to N‐indolylethyl or N‐phenylethyl‐1,4‐dihydropyridines, which are cyclized to the corresponding indolo[2,3‐a]quinolizines or benzo[a]quinolizines in the presence of HCl in methanol/water. Treatment of the fused quinolizine derivatives with sodium triacetoxyborohydride led to the corresponding indolo[2,3‐a]quinolizidines or benzo[a]quinolizidines, possessing four stereogenic centers, as mixtures of two diastereomers. 相似文献
19.
Ze‐Hun Cao Yu‐Hao Wang Subarna Jyoti Kalita Uwe Schneider Yi‐Yong Huang 《Angewandte Chemie (International ed. in English)》2020,59(5):1884-1890
Unprecedented phosphine‐catalyzed [4+1] cycloadditions of allenyl imides have been discovered using various N‐based substrates including methyl ketimines, enamines, and a primary amine. These transformations provide a one‐pot access to cyclopentenoyl enamines and imines, or (chiral) γ‐lactams through two geminal C?C bond or two C?N bond formations, respectively. Several P‐based key intermediates including a 1,4‐(bis)electrophilic α,β‐unsaturated ketenyl phosphonium species have been detected by 31P NMR and HRMS analyses, which shed light on the postulated catalytic cycle. The synthetic utility of this new chemistry has been demonstrated through a gram‐scaling up of the catalytic reaction as well as regioselective hydrogenation and double condensation to form cyclopentanoyl enamines and fused pyrazole building blocks, respectively. 相似文献
20.
I. V. Nagorichna A. A. Tkachuk M. M. Garazd Ya. L. Garazd V. P. Khilya 《Chemistry of Natural Compounds》2009,45(2):164-168
Heteroarylcoumarins containing 2-indole, 3-pyrazole, and 4-pyrimidine substituents in the 6-position of the coumarin ring
were synthesized.
Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 145-148, March-April, 2009. 相似文献