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1.
Islam Md Rafiqul 《Tetrahedron letters》2004,45(32):6187-6190
A series of 1,2,4-dichalcogenazoles were synthesized by the reaction of 6H-1,3,5-oxachalcogenazines with elemental chalcogen through the plausible pathway involving in situ generation of 1,3-chalcogenaza-1,3-butadienes and the subsequent reaction with chalcogen species. Synthetic utilities of 1,2,4-dichalcogenazoles were also explored. 相似文献
2.
[reaction: see text] A novel three-component annulation reaction involving N-alkylimidazoles, dimethyl acetylenedicarboxylate, and in situ generated aryl methyl ketenes leading to the synthesis of 6-vinyl-1,3a-diazapentalene derivatives is reported. 相似文献
3.
G. A. Mironova E. N. Kirillova V. N. Kuklin N. A. Smorygo B. A. Ivin 《Chemistry of Heterocyclic Compounds》1984,20(10):1088-1094
The reaction of 2-aryl-4-hydroxy-6-oxo-1,3-thiazines with Vilsmeier's reagent results in the formation of a mixture of 2-aryl-6-oxo-4-chloro-1,3-thiazines and their 5-formyl analogs. Reactions involving the nucleophilic replacement of the halogen and nucleophilic addition to an aldehydic group have been studied. The intramolecular cyclization of the oxime and phenylhydrazone of 6-oxo-2-phenyl-5-formyl-4-chloro-1,3-thiazine gives new heteroaromatic systems, viz., isoxazolo-[4,5-d]-1,3-thiazine and pyrazolo]4,5-d]-1,3-thiazine, respectively.For report 54 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1328–1334, October, 1984. 相似文献
4.
Chaudhary Ankita Khanna Garima Chopra Haritma Gaba Ritu 《Research on Chemical Intermediates》2022,48(5):2267-2278
A simple, efficient, and eco-friendly protocol for the synthesis of 1,3-oxazine derivatives, viz. 7-aryl-7,8-dihydro-6H-[1,3]dioxolo[4′,5′:4,5]benzo[1,2-e][1,3]oxazines and 3-aryl-3,4-dihydro-2H- naphtho[2,3-e][1,3]oxazine-5,10-diones, involving one-pot multicomponent condensation reaction of various amines and formaldehyde with sesamol/2-hydroxy-1,4-naphthoquinone, respectively, catalyzed by a choline chloride–oxalic acid deep eutectic solvent has been developed. The method offers several advantages, including mild reaction conditions, simple operating procedure, recyclable and biodegradable catalyst, short reaction times, and excellent yields of the target products.
相似文献5.
Irradiation of 8-oxabicyclo[3.2.1]oct-6-en-2-ones results in a 1,3-acyl rearrangement. The initial photoproduct undergoes a subsequent reaction involving hydrogen transfer followed by intramolecular cycloaddition of a ketene intermediate. 相似文献
6.
Kenji Naganuma Takayuki Kawashima Renji Okazaki 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):513-516
Treatment of a bis(β-hydroxyalkyl)diphenylstannane with potassium hydride in THF in the presence of 18-crown-6 gave the corresponding pentacoordinate t-alkoxy-l,2-oxastannetanide as stable crystals instead of a hexacoordinate stannate with two oxetane rings. This compound is considered to be formed by novel tin-1,3-migration reaction from carbon to oxygen reaction involving the formation of an oxetane ring and the subsequent tin-carbon bond cleavage. 相似文献
7.
Non-stereospecific ring expansion reactions of 5-membered heterocyclic sulfoxides, 1,3-benzoxathiole sulfoxides, 1,3-benzodithiole sulfoxides, and 1,3-dithiolane sulfoxides having a heteroatom at β-position to the sulfinyl group with acetic anhydride or p-toluenesulfonic acid are described together with thier reaction mechanism involving a sulfonium ion intermediate. 相似文献
8.
9.
A one-pot protocol for the synthesis of triazole-annulated polyheterocycles via metal-catalyzed coupling of internal 1,4-disubstituted 1,3-diynes and organic azides has been described. The mechanistic rationale for the reaction suggests tandem cyclizations involving copper-catalyzed cycloaddition and 6-endo carbocyclization reactions. The cascade cyclization leads to an increase in molecular complexity to furnish naphtho[1,2-d]triazoles in satisfactory yields. The generality of the method has been demonstrated by using a series of aromatic/aliphatic azides and symmetrical internal 1,3-diynes. 相似文献
10.
[reaction: see text]. We have discovered a Ni(II)-catalyzed Conia-ene reaction of 1,3-dicarbonyl compounds with alkynes. In the presence of Ni(acac)2 and Yb(OTf)3, various acetylenic 1,3-dicarbonyl compounds underwent Conia-ene reaction to give mono- and bicyclic olefinic cyclopentanes. A mechanism involving the enol-yne-Ni complex formation is proposed and supported by deuterium-labeling experiments. 相似文献
11.
Goncalves S Santoro S Nicolas M Wagner A Maillos P Himo F Baati R 《The Journal of organic chemistry》2011,76(9):3274-3285
An unprecedented and highly diastereoselective 6-endo-trig cyclization of 2-alkenyl-1,3-dithiolanes has been developed yielding trans-decalins, an important scaffold present in numerous di- and triterpenes. The novelty of this 6-endo-trig cyclization stands in the stepwise mechanism involving 2-alkenyl-1,3-dithiolane, acting as a novel latent initiator. It is suggested that the thioketal opens temporarily under the influence of TMSOTf, triggering the cationic 6-endo-trig cyclization, and closes after C-C bond formation and diastereoselective protonation to terminate the process. DFT calculations confirm this mechanistic proposal and provide a rationale for the observed diastereoselectivity. The reaction tolerates a wide range of functionalities and nucleophilic partners within the substrate. We have also shown that the one-pot 6-endo-trig cyclization followed by in situ 1,3-dithiolane deprotection afford directly the corresponding ketone. This improvement allowed the achievement of the shortest total synthesis of triptophenolide and the shortest formal synthesis of triptolide. 相似文献
12.
Kaiser RI Parker DS Zhang F Landera A Kislov VV Mebel AM 《The journal of physical chemistry. A》2012,116(17):4248-4258
The crossed beam reactions of the phenyl radical (C(6)H(5), X(2)A(1)) with 1,3-butadiene (C(4)H(6), X(1)A(g)) and D6-1,3-butadiene (C(4)D(6), X(1)A(g)) as well as of the D5-phenyl radical (C(6)D(5), X(2)A(1)) with 2,3-D2-1,3-butadiene and 1,1,4,4-D4-1,3-butadiene were carried out under single collision conditions at collision energies of about 55 kJ mol(-1). Experimentally, the bicyclic 1,4-dihydronaphthalene molecule was identified as a major product of this reaction (58 ± 15%) with the 1-phenyl-1,3-butadiene contributing 34 ± 10%. The reaction is initiated by a barrierless addition of the phenyl radical to the terminal carbon atom of the 1,3-butadiene (C1/C4) to form a bound intermediate; the latter underwent hydrogen elimination from the terminal CH(2) group of the 1,3-butadiene molecule leading to 1-phenyl-trans-1,3-butadiene through a submerged barrier. The dominant product, 1,4-dihydronaphthalene, is formed via an isomerization of the adduct by ring closure and emission of the hydrogen atom from the phenyl moiety at the bridging carbon atom through a tight exit transition state located about 31 kJ mol(-1) above the separated products. The hydrogen atom was found to leave the decomposing complex almost parallel to the total angular momentum vector and perpendicularly to the rotation plane of the decomposing intermediate. The defacto barrierless formation of the 1,4-dihydronaphthalene molecule involving a single collision between a phenyl radical and 1,3-butadiene represents an important step in the formation of polycyclic aromatic hydrocarbons (PAHs) and their partially hydrogenated counterparts in combustion and interstellar chemistry. 相似文献
13.
1-Oxa-4-azabutadienes proved to be prone to react with some heterocumulenes after 1,3-cycloaddition patterns yielding various 5,5-disubstituted derivatives of 1,3-diaryl-hydanotoins as it was shown by the chemical and spectroscopic analysis. Relatively high yields, mild reaction conditions and a very weak effect of solvent polarity on the reaction rate suggested a synchroneous mechanism involving 1,2-migration of a substituent. 相似文献
14.
Stereodefined monocyclic, spirobicyclic, and bis-spirotricyclic pyrazolidin-3-ones can be prepared efficiently by a three-component reaction involving a 1,3-dipolar cycloaddition of azomethine imines obtained from hydrazones with α-oxo-ketene dipolarophiles generated in situ. The reaction allows the creation of four covalent bonds and two contiguous chiral quaternary centers with excellent diastereoselectivity in a single catalyst/additive-free, highly atom-economical transformation. From a fundamental point of view, the reaction introduces α-oxo-ketenes as effective dipolarophiles in 1,3-dipolar cycloadditions. 相似文献
15.
[reaction: see text] The reactions of aryl aldehydes with styrene derivatives, mediated by various boron Lewis acids, were investigated. 1,3-Dihalo-1,3-diarylpropanes were obtained in high yields with boron trihalides, while 3-chloro-1,3-diarylpropanols were obtained in good to excellent yields with phenylboron dichloride. Reactions involving nonenolizable aliphatic aldehydes, trans-cinnamaldehyde, and beta-substituted styrenes were also investigated for the first time. 相似文献
16.
Multicomponent synthesis of 1,3-diaryl-hexahydropyrimidines by a one-pot reaction of 1,3-dicarbonyl compounds, amines and formaldehyde catalysed by FeCl3 in dichloromethane at room temperature (25-30 °C) has been reported. Double amino methylation occurs at the α-position of the 1,3-dicabonyl compounds/β-keto esters. The same methodology leads to spiro compounds with indane-1,3-dione. In this reaction, six molecules condense in one pot to form six new covalent bonds, thus, creating high atom economy. This is the first report of the synthesis of the substituted hexahydropyrimidines involving β-keto esters and its spiro analogues with indane-1,3-dione. 相似文献
17.
A copper-catalyzed oxidative coupling of benzylic C-H bonds with 1,3-dicarbonyl compounds is described. The reaction utilizes an inexpensive copper catalyst-oxidant system that is suitable for the coupling of a range of benzylic C-H bonds with various 1,3-dicarbonyl compounds. Kinetic isotope studies support a mechanism involving a benzylic hydrogen abstraction. 相似文献
18.
Alaa A. Hassan Ahmed M. Nour El-Din Fathy F. Abdel-Latif Sara M. Mostafa Stefan Bräse 《Chemical Papers》2012,66(4):295-303
The reaction of (substituted) alkenylidene-hydrazinecarbothioamides with 2-(1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile led to the formation of 1,3-dioxospiroindene[1,3]-thiazine and thioxoindeno[2,1-d]imidazolone derivatives in modest yields. In addition, 1,3-dihydroxyindan-2-ylidenepropanedinitrile was found. Explanations
of these conversions involving nucleophilic reactions and condensations are presented. 相似文献
19.
Synthesis of some novel isoxazolidine/dihydroisoxazole annulated thiopyrano[2,3-b]indole derivatives from simple oxindole via 1,3-dipolar cycloaddition reaction involving nitrone and nitrile oxide as 1,3-dipole is reported. 相似文献
20.
A tandem one-pot method for the construction of a pyridine moiety with selective control of substitution patterns has been developed through the sequential reactions of nitrile with a Reformatsky reagent and 1,3-enyne involving regio- and chemoselective addition of the Blaise reaction intermediate to 1,3-enyne, followed by isomerization, cyclization, and an aromatization cascade. 相似文献