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1.
The reaction of dimethyl acetylenedicarboxylate with 1-methyl-2-vinylpyrrole is temperature dependent. At 80° the predominant reaction is the [4π + 2π] cycloaddition to give dimethyl 1-methyl-6,7-dihydroindole-4, 5-dicarboxylate, whereas at room temperature Michael addition of the acetylenic ester at the 5-position of the pyrrole ring to give fumaric and maleic ester derivatives also occurs. Unequivocal assignment of the configurations of the Michael adducts have been made on the basis of their 3JCO,h coupling constants. 1-Phenyl-2-vinylpyrrole reacts with dimethyl acetylenedicarboxylate to give only the [4π + 2π] cycloadduct at room temperature and at elevated temperatures. 相似文献
2.
A. Corsico Coda G. Desimoni M. Pappalardo P.P. Righetti P.F. Seneci G. Tacconi R. Obberti 《Tetrahedron》1985,41(12):2545-2555
The copper(II) acetate complex of isatin-3-phenylhy-drazone (2a) reacted with dimethyl acetylenedicarboxylate (DMAD) by two competitive pathways: a Cu++ oxidation of the ligand and a [2+2] cycloaddition. The former reaction gave 3-car- benindolin-2-one (13) which reacted with DMAD in a l,3-dipolar cycloaddition, to give 3a. This was synthesized by an independent route. The phenyl radical, generated in the same process, was trapped by three DMAD and gave . The [2+2] cycloaddition gave a spiro adduct 10 which, by electrocyclic ring opening and intramolecular cyclization, allowed isolation of a pyridazino [3,4-b] indole (|5a). The reaction was performed on -chlorophe-nylhydrazone 1b and the structure of 5b was demonstrated by X-ray analysis. A rationalization of the reactivity was attempted in terms of MO interactions of the reactants. 相似文献
3.
Kaspar Bott 《Tetrahedron letters》1985,26(27):3199-3202
On treating with potassium methoxide at room temperature the donor-substituted ethylenediazonium ion equilibrates with the stable α-diazoolefin . At the same temperature the reaction of with dilute methanesulfonic acid leads to a quantitative elimination of diazo nitrogen. Finally the 1,3-dipolar cycloaddition of to dimethyl acetylenedicarboxylate affords the pyrazole derivative in high yield. 相似文献
4.
Aminonitrenes are produced on reaction of -aminopyrroles with dimethyl acetylenedicarboxylate; a new reaction of dialkyl aminonitrenes is described. 相似文献
5.
Enamino-thiones 1 prepared from the corresponding enaminones by thiation with Lawesson's Reagent, were allowed to react with 2-chloroacrylonitrile and dimethyl acetylenedicarboxylate giving dihydro-2-thiopyrans, 2, and 4-thipyrans, 3, respectively. The reaction of 1a with ethyl propiolate at room temperature afforded 4-thipyrans, 4a, which on standing rearranged to 2-thiopyran, 5a(1, 3 amide shift). The reaction of 1b with ethyl propiolate produced 4b and 5b. Some of the 13C NMR data are reported. 相似文献
6.
α-Diazo phosphonates with a conjugated 1,3-diene unit are synthesised by the Bamford-Stevens reaction ( →→). They undergo [4+2]-cycloadditions with the dienophile to form the tetrahydrotriazolopyridazines , which possess an unchanged diazo group. In contrast, dimethyl acetylenedicarboxylate () reacts exclusively with the diazo dipole of to yield the 3H-pyrazoles , which rearrange to by sigmatropic PO-shifts and hydrolyse to form . The diazo compound isomerises to the pyrazole when heated in benzene. 相似文献
7.
The [4π?+?2π] cycloaddition of methyl 3-(1,3-butadien-1/2-yl)pyropheophorbides-a with tetracyanoethylene, dimethyl acetylenedicarboxylate, and naphthoquinone gave the corresponding Diels–Alder reaction adducts. The trans-1-substituted 1,3-butadiene was more reactive than its regioisomeric 2-substituent. The oxidation of some cycloadducts gave C3-arylated chlorophyll derivatives, whose ortho-substitution blue-shifted the corresponding Qy absorption maxima in dichloromethane because of the steric repulsion between the aryl and chlorin π-planes. 相似文献
8.
The condensation of p-diazooxide with dimethyl acetylenedicarboxylate at 90°–100°C yields two C26H32O9 products, corresponding to addition of two molecules of ester to one of the carbene . The major product is the novel spirodecatetraenone , and the minor product is the remarkable, nonenolizable naphthalenone . Spirodecatetraenone is not a precursor of , since the former is stable to acids and rearranges only above 200° to give the blocked azulenone . A mechanism for the concomitant formation of product and is proposed. 相似文献
9.
Kiyoshi Matsumoto Hiroyuki Taketsuna Jong Chul Kim Akikazu Kakehi 《Journal of heterocyclic chemistry》2001,38(5):1233-1236
A first example of an inverse‐electron demand [π2 + σ2 + σ2] cycloaddition reaction of dimethyl oxaquadricyclane‐2,3‐dicarboxylate was reported: cyclooctyne underwent cycloaddition with dimethyl oxaquadricyclane‐2,3‐dicarboxylate to afford the corresponding adducts one of whose structure was confirmed by a single crystal X‐ray analysis. 相似文献
10.
The reaction of pyrroles with diisopropyl azodicarboxylate yields 2- and 2,5-substituted derivatives. 3- and 1,3-substituted indolizines and are formed by the same route. Cycl[3.2.2]azines have been obtained from and with dimethyl acetylenedicarboxylate. 相似文献
11.
Yoshinori Tominaga Noriko Yoshioka Raymond N. Castle Jiann-Kuan Luo Tadashi Hata 《Journal of heterocyclic chemistry》1997,34(2):613-620
The reaction of 5-amino-1-phenylpyrazole-4-carbonitriles 1a-c with dimethyl acetylenedicarboxylate in the presence of potassium carbonate in dimethyl sulfoxide gave trimethyl 4,5,5a,8-tetrahydro-1-phenyl-4,8-dioxo-1H-pyrazolo[3,4-e]indolizine-5,5a,6-tricarboxylate derivatives 3a-c from the basic solution. The products were formed by a double Michael reaction of 1 with dimethyl acetylenedicarboxylate followed by cyclization to the cyano group. The structure of product 3a was established by X-ray crystallography. 相似文献
12.
The reaction of 4-azidoquinoline N-oxide with dimethyl acetylenedicarboxylate occurs via a 1,3-dipolar cycloaddition mechanism at the N-oxide and not at the azide group. 相似文献
13.
1-Phenyl-2-(benzenesulphonyl)-ethylene and 1-phenyl-2-(benzenesulphonyl)-prop-1-ene have been shown to undergo ,-photoisomerisation, whereas 2-benzenesulphonylindene readily forms [π2 + π2] photoadducts with 2,3-dimethylbut-2-ene, cyclopentene, and cyclohexene. 相似文献
14.
Kenichi Somekawa Yasuo Okumura Kunitomi Uchida Tetsuro Shimo 《Journal of heterocyclic chemistry》1988,25(3):731-734
The low temperature photoaddition of 2-pyridone with dimethyl acetylenedicarboxylate gave a [4 + 2]-cycloadduct and a [2 + 2]-cycloadduct across the 5,6-position of 2-pyridone. Their formations were competing with a Michael reaction of the two substrates at the room temperature reaction. The reactions of other pyridones with dimethyl acetylenedicarboxylate gave [2 + 2]- and/or [4 + 2]-cycloadducts. The [2 + 2]-cycloadducts underwent an intriguing rearrangement to fused β-lactams. 相似文献
15.
Horst Prinzbach Klaus Weidmann Stephan Trah Lothar Knothe 《Tetrahedron letters》1981,22(27):2541-2544
The stereoelectronic prerequisites for unusual “zipper-type” [π 2+σ 2+σ 2]- and [π 2+π 2]-reaction sequences, e.g. in the still unknown C7H6-pentamers (1)/(2), are being studied using model compounds with systematically varied geometrical parameters. In line with expectations based on model considerations, in the [3]-series ((6), (7)) , in the [5]-series ((10), (11)) cyclic processes clearly predominate. 相似文献
16.
Z. G. Aliev V. G. Kartsev L. O. Atovmyan G. N. Voronina 《Chemistry of Heterocyclic Compounds》1982,18(1):77-79
1,3-Dipolar cycloaddition to the diazomethine grouping takes place in the reaction of 2-diazoacetylfuran with dimethyl acetylenedicarboxylate. The structure of the crystalline reaction product, viz., dimethyl 3-(2-furoyl)pyrazole-4,5-dicarboxylate, was investigated by x-ray diffraction analysis. The entire molecule, except for one of the two CO2CH3 groups, forms a planar conjugated system. The spectral characteristics of the synthesized compounds are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 91–94, January, 1982. 相似文献
17.
A.M. Moiseenkov V.V. Veselovsky Z.G. Makarova V.M. Zhulin W.A. Smit 《Tetrahedron letters》1984,25(51):5929-5932
Lewis acid initiated reaction of isoprene with PhSOCl proceeds in a ene fashion with the formation of 2-phenylsulphinylmethyl-1,3-butadiene. High pressure promoted addition produces Z-1-phenylsulphinyl-4-chloroadduct presumably [4+2]cycloaddition. 相似文献
18.
The anodic reactions of the halide ions in dimethyl sulfoxide at the pyrolytic graphite electrode have been studied. The iodide ion demonstrates a 3-step oxidation; the bromide, a 2-step oxidation and chloride, a 1-step oxidation. The electrode reaction (X-→ X2 + e-) is complicated by a catalytic reaction occurring after the electrode reaction. The catalytic reaction is important for only bromide and chloride causing a considerable diffusion current enhancement. The αna value for all 3 primary reactions is of the order of 0.5. 相似文献
19.
N-Arylmethylene and N-benzhydrylideneamines react with fluorocarbene yielding fluoro-substituted azomethine ylides that undergo 1,3-π-cyclization into aziridines. Generation of fluoroylides in the presence of dipolarophiles (dimethyl maleate or dimethyl acetylenedicarboxylate) led to the reaction of 1,3-dipolar cycloaddition resulting in substituted 2-pyrrolines or pyrroles. 2-Fluoroaziridines, products of N-alkyl-N-benzhydrylideneamines 1,3-π-cyclization, in the presence of acid catalysts suffer isomerization into α-fluoroimines and 1,3-disubstituted indoles. 相似文献