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Gavrilov, A. S.; Golod, E. L.; Качала, В. В.; Уграк, Б. И.

doi:10.1023/a:1013930219704

Cited by 14 publications

(5 citation statements)

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“…These observations correspond well with previous studies on the reactivity of azoles and adamantyl cations in acidic media [22,23,24,25,26], where it was determined that adamantylation with 1-adamantanol is possible with fairly acidic pyrazoles, the approximate limit to the pK BH + being 0.8 [26]. Acidities of both unsubstituted pyrazole and imidazole are much lower (0.47 and 0.39) than that value [27].…”

Section: Resultssupporting

confidence: 90%

“…This reaction went smoothly for both unsubstituted and 3,5-substituted 1,2,4-triazoles, as well as tetrazoles—much to our surprise, because usually, adamantylation of azoles can be achieved by substitution reaction of bromo- or hydroxy- groups [22,23,24,25,26]. Despite the fact that the carboxylic moiety destabilizes adamantyl cations to a significant extent, the reaction between azoles and 1-adamantanecarboxylic acid proceeded smoothly and gave new bifunctional adamantane derivatives in good yields.…”

Section: Resultsmentioning

confidence: 96%

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Facile Synthesis of 3-(Azol-1-yl)-1-adamantanecarboxylic Acids—New Bifunctional Angle-Shaped Building Blocks for Coordination Polymers

et al. 2019

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For the first time, orthogonally substituted azole-carboxylate adamantane ligands were synthesized and used for preparation of coordination polymers. The angle-shaped ligands were prepared by the reaction of 1-adamantanecarboxylic acid and azoles (1H-1,2,4-triazole, 3-methyl-1H-1,2,4-triazole, 3,5-dimethyl-1H-1,2,4-triazole, 1H-tetrazole, 5-methyl-1H-tetrazole) in concentrated sulfuric acid. Variation of the solvent and substituents in azole rings allowed to prepare both 1D and 2D copper(II) and nickel(II) coordination polymers, [Cu2(trzadc)4(H2O)0.7]∙DMF∙0.3H2O, [Cu(trzadc)2(MeOH)]∙MeOH, [Ni(trzadc)2(MeOH)2] and [Cu2(mtrzadc)3(MeOH)]+NO3– (trzadc-3-(1,2,4-triazol-1-yl)-adamantane-1-carboxylic acid; mtrzadc-3-(3-methyl-1,2,4-triazol-1-yl)-adamantane-1-carboxylic acid) which were structurally characterized by single crystal X-ray diffraction. Complex [Cu(trzadc)2(MeOH)]∙MeOH was shown to act as a catalyst in the Chan-Evans-Lam arylation reaction.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 96%

Facile Synthesis of 3-(Azol-1-yl)-1-adamantanecarboxylic Acids—New Bifunctional Angle-Shaped Building Blocks for Coordination Polymers

et al. 2019

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“…The unambiguous determination of N-adamantylation site(s) in heterocycles 5 and 6 using well-established 1 H and 13 C NMR methods (such as 1D, 2D COSY, HMQC, HMBC, and INADEQUATE spectra) was difficult because the heterocyclic moiety was covalently attached to the adamantane tertiary carbon that had no bound hydrogen atoms. Nuclear Overhauser effect spectroscopy (NOESY or ROESY) also did not provide unequivocal structures of the N-adamantylated derivatives [ 13 – 14 ]. For example, the attachment of an adamantyl group to the N1 or N3 atom in the azole ring of compounds 5 and 6 could not be distinguished by NOE data.…”

Section: Introductionmentioning

confidence: 99%

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

Деев¹,

Paramonov²,

Шестакова³

et al. 2017

Beilstein J. Org. Chem.

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Determining the accurate chemical structures of synthesized compounds is essential for biomedical studies and computer-assisted drug design. The unequivocal determination of N-adamantylation or N-arylation site(s) in nitrogen-rich heterocycles, characterized by a low density of hydrogen atoms, using NMR methods at natural isotopic abundance is difficult. In these compounds, the heterocyclic moiety is covalently attached to the carbon atom of the substituent group that has no bound hydrogen atoms, and the connection between the two moieties of the compound cannot always be established via conventional 1H-1H and 1H-13C NMR correlation experiments (COSY and HMBC, respectively) or nuclear Overhauser effect spectroscopy (NOESY or ROESY). The selective incorporation of 15N-labelled atoms in different positions of the heterocyclic core allowed for the use of 1H-15N (J HN) and 13C-15N (J CN) coupling constants for the structure determinations of N-alkylated nitrogen-containing heterocycles in solution. This method was tested on the N-adamantylated products in a series of azolo-1,2,4-triazines and 1,2,4-triazolo[1,5-a]pyrimidine. The syntheses of adamantylated azolo-azines were based on the interactions of azolo-azines and 1-adamatanol in TFA solution. For azolo-1,2,4-triazinones, the formation of mixtures of N-adamantyl derivatives was observed. The J HN and J CN values were measured using amplitude-modulated 1D 1H spin-echo experiments with the selective inversion of the 15N nuclei and line-shape analysis in the 1D 13С spectra acquired with selective 15N decoupling, respectively. Additional spin–spin interactions were detected in the 15N-HMBC spectra. NMR data and DFT (density functional theory) calculations permitted to suggest a possible mechanism of isomerization for the adamantylated products of the azolo-1,2,4-triazines. The combined analysis of the J HN and J CN couplings in 15N-labelled compounds provides an efficient method for the structure determination of N-alkylated azolo-azines even in the case of isomer formation. The isomerization of adamantylated tetrazolo[1,5-b][1,2,4]triazin-7-ones in acidic conditions occurs through the formation of the adamantyl cation.

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Adamantylation of azoles with 1,3-dehydroadamantane. Selective N-adamantylation of pyrazoles

et al. 2011

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The main procedure for the synthesis of N-and C-adamantyl-containing pyrazoles is based on acidcatalyzed adamantylation of pyrazoles with various functional derivatives of adamantane [1][2][3][4][5][6]. However, this method ensures fairly poor yields of the target products and requires strongly acidic medium. A promising method for the preparation of N-adamantylsubstituted pyrazoles involves as initial compound strained [3.3.1]propellane, 1,3-dehydroadamantane (I), which is characterized by a high proton affinity (pyrazoles are weak NH acids; pK a of unsubstituted pyrazole is 14.0 [7])We previously synthesized a series of N-adamantylsubstituted imidazoles by reaction of 1,3-dehydroadamantane with the corresponding imidazoles [8]. In the present communication we report for the first time on the N-adamantylation of pyrazole (IIa), 4-bromopyrazole (IIb), and 3,5-dimethylpyrazole (IIc) with 1,3-dehydroadamantane (I). The reactions were carried by heating equimolar amounts of compound I and pyrazoles IIa-IIc at 65-101°C over a period of 2-6 h, and the corresponding 1-adamantylpyrazoles IIIa-IIIc were obtained in 71-80% yield.Analysis of the products by gas chromatographymass spectrometry showed that the main reaction direction is adamantylation at the NH nitrogen atom of the pyrazole ring and that the contribution of C-adamantylation does not exceed 10%. The described procedure ensures preparation of N-adamantyl-substituted pyrazoles in good yields under relatively mild conditions. 1-(1-Adamantyl)-1H-pyrazole (IIIa).A solution of 2.92 g (0.041 mol) of pyrazole IIa in 20 ml of dioxane was added to a solution of 5 g (0.037 mol) of 1,3-dehydroadamantane (I) in 30 ml of dioxane. The mixture was heated for 2 h under reflux, the solvent was distilled off, and the residue was washed with water, dried under reduced pressure, and recrystallized from propan-2-ol. Yield 6.57 g (71%), colorless crystals, mp 52-54°C; published data [7]: mp 51-53°C. 1 H NMR spectrum, δ, ppm: 1.70 s (6H, CH 2 , Ad), 2.08 s (6H CH 2 , Ad), 2.15 s (3H, CH, Ad), 6.20 s (1H), 7.40 s (1H), 7.80 s (1H). Mass spectrum, m/z (I rel , %): 202 (100) [M] + , 145 (61) [M -C 4 H 9 ] + , 135 (26) [Ad] + , 119 (67) [Ad -C 3 H 6 ] + , 79 (25) [Ad -C 4 H 8 ] + . 1-(1-Adamantyl)-4-bromo-1H-pyrazole (IIIb).A solution of 5.44 g (0.037 mol) of pyrazole IIb in 15 ml of tetrahydrofuran was added to a solution of 5 g (0.037 mol) of 1,3-dehydroadamantane (I) in 20 ml of tetrahydrofuran. The mixture was heated for 4 h under R 1 = R 2 = R 3 = H (a); R 1 = R 3 = H, R 2 = Br (b); R 1 = R 3 = Me, R 2 = H (c).

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Cited by 14 publications

References 3 publications

Facile Synthesis of 3-(Azol-1-yl)-1-adamantanecarboxylic Acids—New Bifunctional Angle-Shaped Building Blocks for Coordination Polymers

Facile Synthesis of 3-(Azol-1-yl)-1-adamantanecarboxylic Acids—New Bifunctional Angle-Shaped Building Blocks for Coordination Polymers

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

Adamantylation of azoles with 1,3-dehydroadamantane. Selective N-adamantylation of pyrazoles

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Untitled

Cited by 14 publications

References 3 publications

Facile Synthesis of 3-(Azol-1-yl)-1-adamantanecarboxylic Acids—New Bifunctional Angle-Shaped Building Blocks for Coordination Polymers

Facile Synthesis of 3-(Azol-1-yl)-1-adamantanecarboxylic Acids—New Bifunctional Angle-Shaped Building Blocks for Coordination Polymers

15N-Labelling and structure determination of adamantylated azolo-azines in solution

Adamantylation of azoles with 1,3-dehydroadamantane. Selective N-adamantylation of pyrazoles

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¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution