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Electron impact mass spectra of eight of the title compounds are discussed. Based on our data a mechanism for the formation of the m/e 91 ion is proposed. Fragmentation pathways have been confirmed by measurement of the metastable peaks. 相似文献
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We report the first synthetic route to prepare 3-methyl-4-nitro-5-(2-alkylethenyl)isoxazoles in high yields and exclusively as E-diastereoisomers. 相似文献
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3-Methyl-1-(6-methyl-2-methylsulfanylpyrimidin-4-yl)-1H-pyrazol-5-ol available via cyclocondensation of 6-methyl-2-methylsulfanylpyrimidin-4-ylhydrazine with ethyl acetoacetate reacted with aromatic aldehydes to give two kinds of products, 4-arylmethylidene-5-oxo-4,5-dihydropyrazole and arylbis(5-hydroxypyrazol-4-yl)methane derivatives, depending on the substituent in the aromatic aldehyde. 相似文献
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The electron impact mass spectrometric fragmentation pathways for several 2-methylindazoles, II, were investigated. Our investigation of the mass spectra of these compounds revealed interesting relationships between the 2-N-methyl-substituent in the framework of II and the fragmentation patterns. 相似文献
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Yurii S. Nekrasov Svetlana Yu. Sil'vestrova Aleksandr I. Grigo'ev Lyudmila N. Reshetova Viktor A. Sipachev 《Journal of mass spectrometry : JMS》1978,13(9):491-494
The electron impact mass spectra of eight polynuclear beryllium complexes Be4O(RCO2)6 (R?H, CH3, C2H5) and Be4O(RCO2)5OR′ (R?CH3, R′?H, CH3, C2H5, C3H7; R?C2H5, R′?C2H5) are reported. The major fragmentations involve the elimination of (RCO)2O (RCOOR′) or Be(RCO2)2 (Be(RCO2)OR′) from the ions [M? L]+ and of {(R? H)CO}, (R′? H), H2O and BeO from the lighter ions. The fragmentation patterns are practically independent of the organic groups present and can be rationalized by stereochemical considerations. 相似文献
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以乙醇为溶剂,冰醋酸为催化剂,4-氨基-5-(1-苯基-3-甲基-5-氯吡唑)-1,2,4-三唑-3-硫酮(1)与芳醛经缩合反应合成了7个新型的4-取代苯次甲亚胺-5-(1-苯基-3-甲基-5-氯吡唑)-4H-1,2,4-三唑-3-硫酮(3a~3g),收率66%~74%,其结构经1H NMR,IR及元素分析表征。合成4-(苯次甲亚胺)-5-(1-苯基-3-甲基-5-氯吡唑)-2H-1,2,4-三唑-3-硫酮(3a)的最佳反应条件为:以乙醇为溶剂,乙酸为催化剂,1 10 mmol,n(苯甲醛)∶n(1)=1.2,于75℃反应3 h,产率74%。 相似文献
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Salvatore Occhipinti Gaetano Alberghina Salvatore Fisichella Orazio Puglisi Leopoldo Ceraulo 《Journal of mass spectrometry : JMS》1980,15(12):632-636
The 70 eV electron impact mass spectra of twelve 5- and 3-substituted thiophene-2-carboxamides are discussed with the aid of exact mass measurements and labelling experiments. All mass spectra exhibit pronounced molecular ions. Some isomeric 5- and 3-substituted title compounds can be differentiated by mass spectrometry. The fragmentation is influenced by a strong ‘ortho-effect’ which activates the NH3 elimination. In the other cases the most important fragmentation is NH2˙ loss, followed by CO elimination. 相似文献
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The title compound 3 was obtained during the rearrangement of isoxazol-5-yl hydrazine 1 to 1-aminopyrazolone 2 at 115°. X-ray analysis of the corresponding benzylidene derivative allowed us to achieve the structure assignment. 相似文献
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Six side chain analogs of the highly active antimalarial agent 8-(4-amino-1-methylbutylamino)-6-methoxy-4-methyl-5-(3-trifluoromethylphenoxy)quinoline (I) were prepared and evaluated for blood and tissue schizonticidal activity. Although most examples were markedly superior to primaquine none was superior to the parent compound I. 相似文献
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The title compound,(E)-ethyl 2-(5-(3-methyl-2-butenyloxy)-2-(3-(4-(3-methyl-2-butenyloxy)phenyl) acryloyl) phenoxy)acetate(1),has been synthesized and characterized by FT-IR and 1H-NMR spectroscopy,ESI-MS,and X-ray single-crystal diffraction.FT-IR,1H-NMR and ESI-MS confirm the functional groups,particularly the ethyl groups in the ester moiety,of the compound.The single-crystal X-ray diffraction has revealed a monoclinic structure,space group P21/n with a = 14.6832(14),b = 7.7581(7),c = 23.075(2),β = 101.670(2)o,V = 2574.2(4) ?3,Z = 4,Dc = 1.235 g/cm,μ = 0.085 mm-1,and F(000) = 1024.The skeleton of chalcone in the molecular structure is coplanar. 相似文献
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Roberto Pepino Alfredo Ricci Maurizio Taddei Piero Tedeschi 《Journal of organometallic chemistry》1982,231(2):91-94
Silylation of activated heterocyclic systems via treatment with organolithium reagents followed by coupling with Me3SiCl, leads to the expected product in the case of 3,5-dimethyl-1,2,4-oxadiazole, whereas for 3,5-dimethyl-4-nitroiso-xazole the predominant reaction is addition of the lithiating agent, to give after work-up 3,5-dimethyl-5-butyl-4-nitro-4,5-isoxazoline. 相似文献
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A detailed study of the products of elimination of some 4-aryl-3-methyl-4-piperidinols has been made and the PMR spectra of derived 1-alkyl (and aralkyl)-4-aryl-5-methyl-1,2,5,6-tetrahydropyridines and the corresponding hydrochloric salts reported and discussed. The 5-methyltetrahydropyridine hydrochlorides are shown to exist in epimeric forms in deuterochloroform and their PMR spectra have been interperted in terms of probable conformations. 相似文献