Domino Reactions of Chromones with Heterocyclic Enamines

Synlett ◽  
2021 ◽  
Author(s):  
Peter Langer
Keyword(s):  
Carbon Atom ◽  
Carbonyl Group ◽  
Functional Groups ◽  
Conjugate Addition ◽  
Heterocyclic Ring ◽  
Ring Cleavage ◽  
Domino Reactions ◽  
Chromone Derivatives ◽  
Convenient Synthesis ◽  
Heterocyclic Enamines

AbstractDomino reactions of heterocyclic enamines with chromone derivatives provides a convenient synthesis of a great variety of annulated heterocyclic ring systems. The course of the reaction depends on the type of substituent located at position 3 of the chromone. Reactions of 3-unsubstituted chromones, 3-nitrochromones, and 3-halochromones proceed by conjugate addition of the carbon atom of the enamine to carbon C-2 of the chromone, ring cleavage, and recyclization via the chromone carbonyl group. In the case of 3-formylchromes, 3-dichloroacetylchromone, 3-perfluoroalkanoylthiochromones, 3-(2-fluorobenzoyl)chromones, and 3-methoxalylchromones the final cyclization proceeds via the carbonyl group located outside the chromone moiety. The functional groups located at the carbonyl group at position 3 of the chromone allow for further synthetic transformations including additional ring closures.Contents1 Introduction2 3-Unsubstituted Chromones3 3-Nitrochromones4 3-Formylchromes5 3-Dichloroacetylchromone6 3-Perfluoroalkanoylthiochromones7 3-Methoxalylchromones8 3-(2-Fluorobenzoyl)chromones9 3-Halochromones10 Chromone-3-carboxylic Acids11 Conclusions

Dative behavior of N-heterocyclic carbenes (NHCs) with selenium in Se-NHC compounds

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Munazzah Yaqoob ◽  
Mahvish Abbasi ◽  
Hira Anwar ◽  
Javed Iqbal ◽  
Mohammad Asad ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Carbon Atom ◽  
Lone Pair ◽  
Heterocyclic Ring ◽  
Heterocyclic Carbenes ◽  
The Other ◽  
Donor Ligands ◽  
Important Research ◽  
Dative Bond ◽  
Back Bonding

Abstract N-heterocyclic carbenes (NHCs) are an eminent class of carbenes having a heterocyclic ring in which a divalent carbon atom is attached directly to a nitrogen atom. In the NHCs, the donation of lone pair is another important research in the dative bonding and not only in NHCs the dative bond plays a functionalized role in the other classes of complex formation like ylidones L → E ← L and carbones L → C ← L. M–NHC bond is L-M sigma-dative bond and NHCs are considered as strong sigma-donor ligands. The clear picture of the M–NHC bond can be better understood by M–NHC pi-interaction. M-L pi interaction is comprised of two steps. One is L → M sigma-donation and M → L π* back bonding. This dative donor nature of NHC and also its behavior in organoselenium is studied through DFT in which it’s optimized structure, bond lengths, molecular vibrations are calculated.

Convenient Synthesis of Oxazolo[5,4-h]pyrrolo[4,3,2-de]quino­lones via Hypervalent Iodine Mediated Intramolecular Oxidative Cyclization

Synthesis ◽  
2017 ◽  
Vol 28 (19) ◽  
pp. 4517-4522
Author(s):  
Li-Ping Sun ◽  
Chun-Meng Wang ◽  
Sheng-Wei Yang ◽  
Kai-Xiang Tang ◽  
Tian-Hong Gao ◽  
...  
Keyword(s):  
Functional Groups ◽  
Practical Method ◽  
Oxidative Cyclization ◽  
Hypervalent Iodine ◽  
Air Atmosphere ◽  
Convenient Synthesis ◽  
Reaction Proceeds ◽  
Intramolecular Oxidative Cyclization

A convenient and practical method has been developed for the synthesis of substituted oxazolo[5,4-h]pyrrolo[4,3,2-de]quinolones via the intramolecular oxidative cyclization by using PIFA as oxidant and TMSOTf as additive in DCE under an air atmosphere. The reaction proceeds in good yields and has good functional groups tolerance.

Reactions of phenyldimethylsilyllithium with β-N,N-dimethylaminoenones: A convenient synthesis of β-dimethyl(phenyl)silylacrylic acid and its derivatives

2004 ◽  
Vol 82 (2) ◽  
pp. 325-332 ◽  
Author(s):  
Ian Fleming ◽  
Elena Marangon ◽  
Chiara Roni ◽  
Matthew G Russell ◽  
Sandra Taliansky Chamudis
Keyword(s):  
Key Words ◽  
Methyl Iodide ◽  
Carbonyl Compounds ◽  
Conjugate Addition ◽  
Brief Treatment ◽  
Dimethylamino Group ◽  
Convenient Synthesis ◽  
Work Up

Phenyldimethylsilyllithium reacted with 5,5-dimethyl-3-(N,N-dimethylamino)cyclohex-2-enone (7), 3-(E)-N,N-dimethylaminopropenal (11), and 4-N,N-dimethylaminobut-3-en-2-one (13) to give the corresponding β-silyl-α,β-unsaturated carbonyl compounds 8, 12, and 14, in which the dimethylamino group has been displaced by the phenyldimethylsilyl group. Phenyldimethylsilyllithium reacted with ethyl β-N,N-dimethylaminopropenoate (15) by conjugate addition, but, in contrast to the ketones 7 and 13 and the aldehyde 11, the intermediate enolate 16 was C-protonated in the aqueous work-up to give ethyl 3-N,N-dimethylamino-3-dimethyl(phenyl)silylpropanoate (17). When the enolate 16 was instead given a mysteriously brief treatment with methyl iodide before work-up, the product was ethyl 3-(E)-dimethy(phenyl)silylpropenoate (18). Phenyllithium and methyllithium also added conjugatively to ethyl β-N,N-dimethylaminoacrylate (15) but, in contrast to the silyl case, the intermediate enolate 22 reacted unexceptionally with methyl iodide to give the products 25 and 26 of stereoselective C-methylation. This synthesis of the ester 18 was used to synthesize the Oppolzer sultam derivative 30.Key words: conjugate addition, elimination, substitution, silyllithium, silylenone.

Reaction of picrate with creatinine and cepha antibiotics.

1984 ◽  
Vol 30 (10) ◽  
pp. 1664-1666 ◽  
Author(s):  
M H Kroll ◽  
C Hagengruber ◽  
R J Elin
Keyword(s):  
Glomerular Filtration Rate ◽  
Carbon Atom ◽  
Glomerular Filtration ◽  
Carbonyl Group ◽  
Filtration Rate ◽  
Carbon And Nitrogen ◽  
Estimate Glomerular Filtration Rate ◽  
Cephalosporin Antibiotics

Abstract The concentration of creatinine in serum, which is used to estimate glomerular filtration rate, is measured by reaction with alkaline picrate, but this reaction is not specific for creatinine. Although several other cephalosporin antibiotics have been reported not to react with picrate, we reacted picrate with creatinine, cefoxitin, penicillin, and eight different cephalosporins, and found that all compounds reacted with picrate and showed superimposable spectrophotograms with absorption maxima at 485 nm. From these results we conclude that the color-absorbing moiety of the product is the picrate molecule. Further, the structure common to creatinine and the cephalosporins, cefoxitin, or penicillin is the carbonyl group attached to a nitrogen and a carbon atom. We postulate that the carbonyl group with the adjacent carbon and nitrogen atoms is probably the chemical moiety that reacts with picrate to absorb energy at 485 nm.

Copper-Catalyzed Cascade Synthesis of [1,2,4]-Triazoloquinazolinones

Synlett ◽  
2018 ◽  
Vol 29 (10) ◽  
pp. 1395-1399 ◽  
Author(s):  
Zhenbang Lou ◽  
Ningning Man ◽  
Haijun Yang ◽  
Changjin Zhu ◽  
Hua Fu
Keyword(s):  
Functional Groups ◽  
Practical Method ◽  
Domino Reactions

An efficient and practical method for the synthesis of 1,2,4-triazolo[5,1-b]quinazolin-9(3H)-ones has been developed via the copper-catalyzed domino reactions of readily available substituted N′-acetyl-2-bromobenzohydrazides with cyanamide. The protocol uses inexpensive CuI as the catalyst, and no other ligand or additive was required. The target products were prepared in good to excellent yields with tolerance of various functional groups.

Infrared Study of Benzaldehyde and 4-Substituted Benzaldehydes in Carbon Tetrachloride and/or Chloroform Solutions: The Carbonyl Group

1991 ◽  
Vol 45 (10) ◽  
pp. 1641-1648 ◽  
Author(s):  
Richard A. Nyquist ◽  
Sam E. Settineri ◽  
Davin A. Luoma
Keyword(s):  
Carbon Tetrachloride ◽  
Carbonyl Group ◽  
Functional Groups ◽  
Functional Group ◽  
Solvent System ◽  
Infrared Study ◽  
Solvent Systems ◽  
Substituted Benzaldehydes ◽  
Uniform Manner ◽  
Acceptor Numbers

The carbonyl stretching mode of 4- x-benzaldehydes increases in frequency as the mole % CHCl3/CCl4 decreases and as the value of σP− or σRO for the 4- x atom or group increases. Other functional groups such as OH, NO2 and CN are also affected by interaction with the CHCl3 and/or CCl4 solvent system. Other solvents may interact differently with each functional group so that, say, vC=O vs. σP−, σRO, or solvent acceptor numbers (AN) may not correlate in a uniform manner in all solute/solvent systems.

ChemInform Abstract: A Convenient Synthesis of Imidazolidin-4-ones via Domino Reactions.

ChemInform ◽  
2010 ◽  
Vol 41 (2) ◽  
Author(s):  
Xueming Chen ◽  
Hui Wei ◽  
Yunyun Chen ◽  
Xingshu Li
Keyword(s):  
Domino Reactions ◽  
Convenient Synthesis

Research on FTIR Analysis of Populus nigra L. Lignin Structure Changes in Different Bleaching Processes

2011 ◽  
Vol 236-238 ◽  
pp. 1283-1287
Author(s):  
Qiang Zhao ◽  
De Zhi Sun ◽  
Jun Wen Pu ◽  
Xiao Juan Jin ◽  
Mian Xing
Keyword(s):  
Carbonyl Group ◽  
Functional Groups ◽  
Populus Nigra ◽  
Side Chain ◽  
Ftir Analysis ◽  
Bleaching Process ◽  
Ether Bond ◽  
Bleaching Efficiency ◽  
Structure Changes ◽  
Alcoholic Hydroxyl

To study the bleaching mechanisms of H2O2 bleaching, H2O2 displacement bleaching and H2O2 /TAED bleaching, three kinds of lignin bleached with above processes were obtained. Three types of treated Populus nigra L lignins structure were identified and the functional groups were quantitied by FTIR. In contrast, the deacetylation and the breakage of ester bonds in H2O2/TAED bleaching system was much more significant. The total carbonyl group of H2O2 bleached lignin decreased 6.6% while displacement bleached lignin and H2O2/TAED bleached lignin decreased 9.2% and 15.8% respectively. The PT bleaching process had stronger oxidability to destroy the syringyl units in lignin. The breakage of ether bonds and alcoholic hydroxyl dehydration in side chain increased after bleaching. In contrast, the stronger destroyed effection on guaiacyl dialkyl ether bond with PT bleaching processes. The conclusions obtained may interpret H2O2 displacementbleaching and H2O2/TAED bleaching systems have better bleaching efficiency than H2O2 bleachingsystem.

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