Synthesis and properties of nitrogenous heterocycles containing a spiro-fused cyclopropane fragment

Tomilov, Yurii V.; Kostyuchenko, I. V.; Нефедов, О. М.

doi:10.1070/rc2000v069n06abeh000571

Cited by 18 publications

(9 citation statements)

References 118 publications

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“…According to the 1 H NMR spectrum, the reaction mixture contained the starting oxaspiropentanes 8a and 8b and their isomerization products, cyclobutanones (1S,4S,5R) 9a and (1S,4R,5R) 9b in a ratio ~1 : 2.2 (conversion ~30%). 1 H and 13 C NMR spectra are represented in Tables 1 and 2. B. A solution of spiro[6,8 dioxabicyclo[3.2.1]oct 2 ene 4,2´ cyclobutan] 1 one (10) (332 mg, 2 mmol) in EtOH (10 mL) and 190 mg of 10% Pd/C were placed into an autoclave (30 mL), which was filled with hydrogen (3 bar) and shaken for 11 h at room temperature.…”

Section: Resultsmentioning

confidence: 99%

“…oxirane 3´,1″ cyclopropane] (3a) according to1 H and13 C NMR spectra(Tables 1 and 2). Column chromatography on SiO 2 (eluent -benzene-AcOEt, gradient from 1 : 0 to 1 : 3) afforded cyclobutanone 4a as the main component resulting from the isomerization of oxaspiropentane 3a as well as com pounds 4b, 5, and 6 initially present in the reaction mixture.Spiro[7,9 dioxatricyclo[4.2.1.0 2,4 ]nonane 5,2´ cyclobutan] 1 one.…”

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confidence: 99%

“…The temperature was increased to 0 °C, a drop of water (0.2 mL) was added and the mixture was passed through a small layer of silica gel mixed with anhydrous MgSO 4 . After removal of the solvents in vacuo, yellow oily liquid (120 mg) was obtained containing mainly a mixture of the stereoisomeric oxaspiropentanes (1S,4S,5R) 8a and (1S,4R,5R) 8b in a ratiõ 2.8 : 1 according to1 H and 13 C NMR spectra. An analytically pure sample of the mixture of stereoisomeric oxaspiropentanes 8 in the form of colorless oil was obtained by preparative TLC on SiO 2 (CH 2 Cl 2 -AcOEt, 1 : 1, R f 0.75).…”

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Reactions of diazocyclopropane with hydrogenated and cyclopropanated levoglucosenone analogs

et al. 2009

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Diazocyclopropane attacks the carbonyl group of 6,8 dioxabicyclo[3.2.1]octan 4 one or 7,9 dioxatricyclo[4.2.1.0 2,4 ]nonan 5 one, saturated derivatives of levoglucosenone, to form the corresponding stereoisomeric oxaspiropentanes. In the case of the strained tricyclononane, 5R isomer isomerizes under the reaction conditions into spiro fused cyclobutanone. For this ketone, the formation of homologation products, i.e., the respective regioisomeric spiro [8,10 dioxatricyclo[5.2.1.0 2,4 ]decane 6(5),1´ cyclopropan] 5(6) ones, is also observed.It is known 1-4 that diazocyclopropane generated by decomposition of N cyclopropyl N nitrosourea under the action of different bases reacts with unsaturated compounds containing an activated C=C bond, which allows introduction of spirocyclopropane fragments into molecules of heterocyclic compounds. Due to high reac tivity, diazocyclopropane reacts, like other diazoalkanes, with carbonyl compounds as well to form the respective oxaspiropentanes and homologation products of the ke tones. 5-8 Also the reactions of diazocyclopropane with unsaturated carbonyl compounds were described, but the known examples are limited to 3 acetoxypregna 5,16 dien 20 one and pregna 4,16 diene 3,20 dione 9,10 where the reactions with the carbonyl groups were ob served along with 1,3 dipolar addition to the C=C bond of ring D. Recently, we have shown 11 that diazocyclo propane generated in situ from N cyclopropyl N nitroso urea under the action of bases reacts selectively with either the C=C double bond of levoglucosenone to form 1 pyrazoline (K 2 CO 3 , CH 2 Cl 2 , 5 °C) or the carbonyl group with selective formation of the respective oxaspiropentane (MeONa/MeOH, -30 °C) depending on the reaction conditions.In continuation of the investigations into the reac tions of diazocyclopropane with ketones and aiming at synthesis of new optically active derivatives of 6,8 dioxabicyclo[3.2.1]octan 4 one with cyclopropane fragments in the molecule, we studied the reaction of diazocyclopropane with 6,8 dioxabicyclo[3.2.1]octan 4 one 12 and with a cyclopropane analog of levoglucos enone, 7,9 dioxatricyclo[4.2.1.0 2,4 ]nonan 5 one, ob tained by us earlier in three steps from levoglucosenone. 13 Results and DiscussionThe reaction of diazocyclopropane with 7,9 dioxa tricyclo[4.2.1.0 2,4 ]nonan 5 one (1) was carried out under the conditions analogous to those used in its reaction with levoglucosenone, 11 the decomposition of N cyclopropyl N nitrosourea (2) under the action of MeONa/MeOH at -30 °C in dichloromethane at a molar ratio of 1 and 2 equal to 1 : 2 was used for the generation of diazo cyclopropane. 1 H and 13 C NMR spectroscopic analysis of the reaction mixture revealed the presence of several compounds the main of which were oxaspiropentane derivative of 7,9 dioxatricyclo[4.2.1.0 2,4 ]nonane (3a) and spiro fused cyclobutanone 4b in the ratio ~2 : 1. Together with these compounds, the "cyclopropane homologation" products of ketone 1, regioisomeric spiro[8,10 dioxa tricyclo[5.2.1.0 2,4 ]decane 5(6),1´ cyclopro...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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Reactions of diazocyclopropane with hydrogenated and cyclopropanated levoglucosenone analogs

et al. 2009

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“…[17] It is interesting to note analogously with diazocyclopropane (3) generated in situ, giving stable 2-(difluoromethyl) that under the same conditions cyclopropyldiazonium 2 and diazocyclopropane 3 or both can be intermediates in reactions with appropriate substrates, such as 4 and 5, to afford the products of 1,3-dipolar cycloaddition 6 in the case of unsaturated compounds [19] and the azo coupling products 7 in the case of CϪH acids. [17] It is also known [20Ϫ23] that diazocyclopropane generated in situ reacts with some ketones to form oxaspiropentane derivatives or the products of their rearrangement.…”

Section: Introductionmentioning

confidence: 97%

Fluorinated β‐Diketones in Reactions with Diazocyclopropane Generated in situ

et al. 2004

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Treatment of 1,1‐di‐ and 1,1,1‐trifluoroalkane‐2,4‐diones 10−13 with cyclopropyldiazonium intermediates 2 and 3, generated in situ through the decomposition of N‐cyclopropyl‐N‐nitrosourea 1 by treatment with moist K2CO3, did not result in the expected azo coupling of the cyclopropyldiazonium ion, but afforded the corresponding oxaspiropentanes 14−17 as products of the addition of diazocyclopropane (3) onto one of the carbonyl groups. In addition, the reaction proceeded selectively on the carbonyl groups adjacent to the di‐ or trifluoromethyl substituents. 1,1‐Difluoroacetone reacted analogously with diazocyclopropane (3) generated in situ, giving stable 2‐(difluoromethyl)‐2‐methyloxaspiropentane in approximately 50% yield. The resulting oxaspiropentanes 14−17, on heating or in the presence of lithium iodide, rearranged selectively into cyclobutanones 20−23, while in the presence of Al2O3 they formed mixtures of approximately equal amounts of the corresponding cyclobutanones and the 1‐vinylcyclopropanols 24−27. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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“…Chemical transformations of N cyclopropyl N nitrosourea (1) have been investigated for more than 70 years; 1 at the moment, this compound is the most suitable source for generation of a number of highly reac tive intermediates such as, e.g., diazocyclopropane (2) and the cyclopropyldiazonium ion (3). Although these intermediates cannot yet be detected by direct physico chemical methods, their formation from compound 1 in the presence of bases is confirmed by chemical methods involving various trapping species (Scheme 1).…”

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Decomposition of N-cyclopropyl-N-nitrosourea in the presence of reducing agents as a new way of generating the cyclopropyl radical

et al. 2006

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A new way of generating cyclopropyl radicals in the base catalyzed decomposition of N cyclopropyl N nitrosourea in the presence of organic reducing agents (1 phenylpyrazolidin 3 one and 4 methoxyphenol) was developed. The cyclopropyl radical generated under these conditions can not only abstract a proton from the substrate to give cyclopropane but also form C-C or C-Br bonds in reactions with aromatic substrates or polybromomethanes.

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Synthesis and properties of nitrogenous heterocycles containing a spiro-fused cyclopropane fragment

Cited by 18 publications

References 118 publications

Reactions of diazocyclopropane with hydrogenated and cyclopropanated levoglucosenone analogs

Reactions of diazocyclopropane with hydrogenated and cyclopropanated levoglucosenone analogs

Fluorinated β‐Diketones in Reactions with Diazocyclopropane Generated in situ

Decomposition of N-cyclopropyl-N-nitrosourea in the presence of reducing agents as a new way of generating the cyclopropyl radical

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