Kinetics and mechanism of formation of isomeric 1-methyl- and 2-methyl-5-vinyltetrazoles

Островский, В. А.; Podkameneva, M. E.; Poplavskii, V. S.; Trifonov, R. E.

doi:10.1007/s11172-009-0293-y

Cited by 9 publications

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References 3 publications

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“…High resolution mass spectra were measured on an instrument Bruker MicroTOF (ESI) in the resource center «Methods of analysis of substances composition» of the Saint-Petersburg State University. 2-Methyl-5-vinyl-2H-tetrazole 1 was obtained following recommendations of [8], the compound properties were consistent with the published data.…”

Section: -Methyl-5-styryl-2h-tetrazoles (3a-3d) Genesupporting

confidence: 80%

Heck reaction of 2-methyl-5-vinyl-2H-tetrazole with iodoarenes

et al. 2015

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SHORT COMMUNICATIONSVinyltetrazoles and their derivatives are promising substrates in the synthesis of various tetrazolecontaining polymers with valuable properties utilized in medicine and engineering [1]. Synthesis of some derivatives of vinyltetrazoles, in particular, of styryltetrazoles, is poorly understood.In a series of publications [2, 3] the synthesis of styryltetrazoles, containing substituents with strong electron-acceptor properties (F, NO 2 , CN, CO 2 H) in the aryl fragment based on cross-coupling of С-, Nvinyltetrazole with halobenzenes by Heck reaction is described. However no information exists on the synthesis of similar compounds containing electrondonor substituents. The electronic effect of the substituent in the aromatic fragment may significantly affect the efficiency of this reaction. The nature of the halogen present in the haloarene and the composition of the catalytic system are also of fundamental importance [4][5][6][7].In this study we synthesized styryltetrazoles 3a-3d, containing in the para-position of the aromatic fragment donor (Me, t-Bu, MeO) and weakly acceptor (Cl) substituents. In the reaction with 2-methyl-5-vinyl-2Н-tetrazole iodoarenes 2a-2d were used applying as a catalyst Pd(OAc) 2 . The reaction was carried out in the presence of K 2 CO 3 in DMF at heating.In all cases the reaction proceeded with high yields (73-80%). The cross-coupling occurs stereoselectively affording exclusively Е-2-methyl-5-styryltetrazoles 3a-3d, as show the large values of the spin-spin coupling constants ( 3 J 16.5 Hz).Hence, 2-methyl-5-vinyl-2H-tetrazole enters in Heck reaction with iodoarenes containing not only electron-acceptor (as has been shown in [2,3]), but also electron-donor substituents at the use as a catalytic system Pd(OAc) 2 in the presence of K 2 CO 3 in DMF. (3a-3d). General procedure. Pd(OAc) 2 (4 mol %) was added to a solution of 45 mmol of iodoarene 2a-2d in 5 mL of DMF under an argon atmosphere. The reaction mixture 2-Methyl-5-styryl-2H-tetrazoles

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Section: -Methyl-5-styryl-2h-tetrazoles (3a-3d) Genesupporting

confidence: 80%

Heck reaction of 2-methyl-5-vinyl-2H-tetrazole with iodoarenes

et al. 2015

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“…Interestingly in this case, as show the HPLC data, fi rst appears the chromatographic peak corresponding to 1-methyl-5-vinyltetrazole (II), and only after some time of the reaction, the peak corresponding to 2-methyl-5-vinyltetrazole (III). This fact does not contradict the mechanism discussed in [13]: According to the latter, the rate of the formation of tetrazole II from the 1-methyl-5-(β-trimethylammoniumethyl)tetrazole is signifi cantly (21-fold) faster than the formation of tetrazole III. Finally, in keeping the suggestions of [13], for the elimination of the proton from the α-methylene group of the bipolar ion VI (see the scheme) in the reaction solution the pH ≥ 13 should be maintained.…”

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confidence: 57%

“…The later attempts at "simplifying" the dehydrochlorination of the 5-(2-chloroethyl)tetrazole by varying the temperature, solvent, adding the polymerization inhibitor [12] did not fundamentally improved the version reported in [6]. Another approach to the sysnthesis of derivatives of 5-vinyltetrazole (I) was developed in [13]. Here the results were presented on the study of the kinetics and mechanism of Hofmann deamination of isomeric N-methyl-5-(β-trimethylammoniumethyl) tetrazoles methylsulfates leading to the formation of the corresponding N-methyl-5-vinyltetrazoles II and III.…”

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confidence: 99%

“…Here the results were presented on the study of the kinetics and mechanism of Hofmann deamination of isomeric N-methyl-5-(β-trimethylammoniumethyl) tetrazoles methylsulfates leading to the formation of the corresponding N-methyl-5-vinyltetrazoles II and III. Partially applying the method described in [13] we developed a new procedure of the synthesis of NHunsubstituted 5-vinyltetrazole (I). This method is based on the synthesis of 5-(β-dimethyl-aminoethyl)tetrazole (IV) and its subsequent methylation at the terminal dimethylamino group.…”

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confidence: 99%

“…13 C NMR spectra were registered on a spectrometer Bruker DPX-300 at operating frequencies 300.1 and 75.5 MHz respectively from solutions in…”

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Vinyltetrazoles: I. Synthesis of NH-unsubstituted 5-vinyltetrazole

et al. 2010

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The NH-unsubstituted 5-vinyltetrazole was obtained in 55% yield by exhaustive methylation of 5-(β-dimethylaminoethyl)tetrazole with dimethyl sulfate at the terminal dimethylamino group with the subsequent elimination of a proton from the α-CH 2 group and Hofmann β-cleavage of the intermediate 5-(β-trimethylammoniumethyl)tetrazolide methyl sulfate. The microwave irradiation was shown to reduce 5-fold the time of the synthesis of the initial substrate, 5-(β-dimethylaminoethyl)tetrazole.NH-Unsubstituted 5-vinyltetrazole (I) and its alkyl derivatives, e.g., II and III, have a considerable practical interest as substrates for preparation of polymers with a high nitrogen content, poly(vinyl-5-yltetrazoles) [1]. These polymers and materials based thereon are required by to-day medicine and engineering [2]. The poly(vinyl-5-yltetrazoles) can underlie the fi lter materials for the purifi cation of the biological fl uids from heavy metal ions and radionuclides [3], superabsorbents of moisture [4], effi cient energy-rich materials [5].Up till now only few chemical reactions of NHunsubstituted 5-vinyltetrazole (I) are known at the endocyclic nitrogen atoms. Arnold and Thatcher showed that the acylation of 5-vinyltetrazole (I) with acetic anhydride followed by the thermolysis of the intermediate N-acyl derivative occurring with elimination of a nitrogen molecule led to the formation of 2-methyl-5-vinyl-1,3,4-oxadiazole [6]. The reaction of 5-vinyltetrazoles I-III with PdCl 2 resulted in the formation of coordination compounds of the general formula PdL 2 Cl 2 [7]. On replacing in these processes palladium chloride with CuCl 2 or NiCl 2 the arising coordination compounds do not contain chlorine in their composition. Therefore Kizhnyaev and Kruglova [7] suggest that here the ligand is the corresponding anionic form 5-vinyltetrazolide. In [8] the rate constants were measured of tetrazole I alkylation with methyl iodide in acetonitrile in the presence of triethylamine, and the ratio was established of isomeric reaction products, 1-(II) and 2-methyl-5-vinyltetrazoles (III). The reactions involving the vinyl group of tetrazole I save the polymerization processes [1] are virtually unknown notwithstanding the obvious possibility to obtain in this way new promising compounds. The development of research in this fi eld of the tetrazole chemistry is hampered by the limited availability of the initial compound, NH-unsubstituted 5-vinyltetrazole (I). Evidently the development of an effi cient procedure of the synthesis of NH-unsubstituted 5-vinyltetrazole (I) is an urgent task.The most wide-spread preparation method for NHunsubstituted 5-R-tetrazoles is the 1,3-dipolar cycloaddition of azides to nitriles. Recently versatile versions of this process were developed permitting the preparation of various 5-R-tetrazoles (R = Alk, Ar, Ht) in good yield and under relatively mild conditions [3]. However the only example of the synthesis of NH-unsubstituted 5-vinyltetrazole (I) directly from acrylonitrile was reported

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