Cross-coupling of highly pyramidalized alkenes: A straightforward access to functionalized tetrasecododecahedradienes

The synthesis and chemical trapping of a highly pyramidalized pentacyclo[6.4.0.0(2,10).0(3,7).0(4,9)]dodec-8-ene containing ketal functions is reported. Its cross-coupling reaction with 3, 7-dimethyltricyclo[3.3.0.0(3,7)]oct-1(5)-ene followed by a [2 + 2] retrocycloaddition reaction gives a straightforward access to functionalized tetrasecododecahedradienes.     

Synthesis and structure of new 3,7-diazabicyclo[3.3.1]nonane derivatives

Aminomethylation of triethylammonium 4-aryl-3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridin-2-olates and their sulfur and selenium analogs, as well as the structure of formed products, were studied in details. The reaction is of general character and leads to the formation of 7-substituted 9-aryl-2,4-dioxo-, 9-aryl-4-oxo-2-thioxo-, 9-aryl-4-oxo-2-selenoxo-3,7-diazabicyclo[3.3.1]nonane derivatives or their salts. The structures of ethyl 9-(2-chlorophenyl)-5-cyano-7-(4-methylphenyl)-2-oxo-4-thioxo-3,7-diazabicyclo[3.3.1]nonane-1-carboxylate (as a complex with N-methylmorpholine) and triethylammonium salt of 7-benzyl-4-oxo-2-selenoxo-9-(2-thienyl)-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarbonitrile were studied by X-ray crystallography.     

Synthesis and molecular structure of 7<Emphasis Type="Italic">H</Emphasis>-12-oxa-3,7-diazapleiadene-substituted 1,3-tropolones

An acid-catalyzed reaction of substituted 2-methyl-7H-12-oxa-3,7-diazapleiadenes with 1,2-benzoquinones leads to 7H-12-oxa-3,7-diazapleiadene-substituted 1,3-tropolones. Molecular structure of 5,7-di(tert-butyl)-2-[9,11-di(tert-butyl)-4-methyl-7H-12-oxa-3,7-diazapleiaden-2-yl]-4-nitro-1,3-tropolone was established by X-ray crystallography. Energy and structural characteristics of isomeric 5,7-di(tert-butyl)-2-[9,11-di(tert-butyl)-4-methyl-7H-12-oxa-3,7-diazapleiaden-2-yl]-4-nitro-1,3-tropolones in the gaseous phase and a polar solution were studied by the PBE0/6-31G** method.     

Cucurbit[7]uril mediates the stereoselective [4+4] photodimerization of 2-aminopyridine hydrochloride in aqueous solution

The 2:1 guest-host complex of 2-aminopyridine hydrochloride with cucurbit[7]uril (CB[7]) undergoes a stereoselective [4+4] photodimerization reaction in aqueous solution to yield exclusively the anti-trans isomer of 4,8-diamino-3,7-diazatricyclo[4.2.2.2(2,5)]dodeca-3,7,9,11-tetraene, and in the absence of CB[7], the photochemical reaction produces the anti-trans and syn-trans photodimers in a 4:1 ratio. In addition, encapsulation of the photodimer product in the CB[7] cavity stabilizes it with respect to the otherwise observed rearomatization to the 2-aminopyridine monomer at room temperature.     

Intramolecular 1,5- versus 1,6-hydrogen abstraction reaction promoted by alkoxy radicals in carbohydrate models

[reaction: see text] The alkoxy radical generated by reaction of 3,7-anhydro-2-deoxyoctitols with (diacetoxyiodo)benzene (DIB) and iodine abstracts regioselectively either the proton at C7 or that at C4 depending on the electronegativity of the substituent at C4. The correct election of this substituent can switch the reaction to give 2,9-dioxabicyclo[3.3.1]nonane or hexahydro-2H-furo[3,2-b]pyran ring systems.     

Synthesis of macrolides containing an azine or hydrazide fragment via successive tishchenko disproportionation and [1 + 1]-condensation

Eight potentially useful 15-, 17-, 20-, and 22–25-membered macrolides having an azine or hydrazide fragment were synthesized starting from L-menthol, tetrahydropyran, and 4-methyltetrahydropyran via [1 + 1]-condensation of hydrazine hydrate and some dicarboxylic dihydrazides with 7-oxooctyl 7-oxooctanoate, 3-methyl-7-oxooctyl 3-methyl-7-oxooctanoate, and (3R)-3,7-dimethyl-6-oxooctyl (3R)-3,7-dimethyl-6-oxooctanoate obtained by the Tishchenko reaction from 7-oxo-, 3-methyl-7-oxo, and (3R)-3,7-dimethyl-6-oxooctanals, respectively.     

Type 2 intramolecular N-acylnitroso diels-alder reaction: stereoselective synthesis of bridged bicyclic oxazinolactams

[reaction: see text] The type 2 intramolecular N-acylnitroso Diels-Alder reaction has been employed for the synthesis of substituted bridged bicyclic oxazinolactams. Upon oxidation of hydroxamic acid 6, a 3-benzylated oxazinolactam (7) was synthesized with complete diastereoselectivity. Elaboration of cycloadduct 7 liberated a cis-3,7-disubstituted azocin-2-one (9).     

Structural characterization of flavonol 3,7-di-O-glycosides and determination of the glycosylation position by using negative ion electrospray ionization tandem mass spectrometry

Flavonol 3,7-di-O-glycosides were investigated by negative ion electrospray ionization tandem mass spectrometry using a quadrupole linear ion trap (LIT) mass spectrometer. The results indicate that the fragmentation behavior of flavonol 3,7-di-O-glycosides is substantially different from that of their isomeric mono-O-diglycosides. In order to characterize a flavonoid as a flavonol 3,7-di-O-glycoside, both [Y3(0) - H]-* and [Y(0) - 2H]- ions should be present in [M - H]- product ion spectrum. The MS(3) product ion spectra of Y3(0)-, [Y3(0) - H]-* and Y7(0)- ions generated from the [M - H]- ion provide sufficient structural information for the determination of glycosylation position. Furthermore, the glycosylation positions are determined by comparing the relative abundances of Y3(0)- and Y7(0)- ions and their specific fragmentation patterns with those of flavonol mono-O-glycosides. In addition, a [Y3(0) - H]-* ion formed by the homolytic cleavage of 3-O glycosidic bond with high abundance points to 3-O glycosylation, while a [Y(0) - 2H]- ion formed by the elimination of the two sugar residues is consistent with glycosylation at both the 3-O and 7-O positions. Investigation of negative ion ESI-MS(2) and MS(3) spectra of flavonol O-glycosides allows their rapid characterization as flavonol 3,7-di-O-glycoside and their differentiation from isomeric mono-O-diglycosides, and also enables their direct analysis in crude plant extracts.     

Heterotricyclodecane XXVII. Ein weiterer Zugang zu 2,6-Dioxatricyclo [3.3.2.03,7]decan

A Further Approach to 2,6-Dioxatricyclo[3.3.2.0^3,7]decane A further synthesis of 2,6-dioxatricyclo[3.3.2.0^3,7]decane ( 10 ) is described by bridging the 9-oxabicyclo[4.2.1]non-7-en-3endo-ol ( 9 ). The latter compound was prepared by ring expansion starting from the known 8-oxabicyclo[3.2.1]oct-6-en-3-on ( 1 ).     

Novel Complexes of 3-[3-(1H-Imidazol-1-yl)propyl]-3,7-diaza-bispidines and β-Cyclodextrin as Coatings to Protect and Stimulate Sprouting Wheat Seeds

We report the syntheses and characterization of novel 3,7-bicycl[3.3.1]bispidines possessing an imidazolpropyl group attached to N-3, and at N-7 a Boc group, as well as a benzoylated-oximated group at C-9. These compounds were complexed with β-cyclodextrin [β-CD] and evaluated as seed protectors of selected wheat seedlings. Using strong acid, condensations of N-substituted piperidones with the appropriate imidazolpropyl groups at N-3 and N-7 led to bispidinones 6 and 7. These intermediates were reduced to the corresponding 3,7-diazabicyclo[3.3.1]nonane targets. The oxime at C-9 was benzoylated to yield 13. Heating these 3,7-diazabicyclo[3.3.1]nonanes in ethanol with β-CD generated the complexes required. We investigated the ability of such complexes as coatings on seedlings to protect and stimulate growth of three varieties of wheat, namely Kazakhstanskaya-10, Severyanka, and Miras. The complex of 3-[3-(1H-imidazol-1-yl)propyl]-7-(3-methoxypropyl)-3,7-diazabicyclo[3.3.1]nonane (2) promoted growth in the root systems of all three wheat varieties by more than 30% in Kazakhstanskaya-10, 30% in Severyanka and 8.5% in Miras. A complex of 3-Boc-7-[3-(1H-imidazol-1-yl)propyl]-3,7-diazabicyclo[3.3.1]nonane (9) increased both shoot and root length in only the Severyanka variety. The complex of 3-(3-butoxypropyl)-7-[3-(1H-imidazol-1-yl)propyl]-3,7-diazabicyclo[3.3.1]nonane (11) stimulated both shoot growth (0.8%, 12.3%, 13.5%) and root growth (12.3%, 9.4%, 21.7%) in all three varieties of wheat, respectively. The nature of substituents on the bispidine affect the activity. Solid complexes (1:1) were generated as powders which melted above 240 °C (dec) and were characterized via elemental analyses as 1:1 complexes.     

Synthesis of 2,6-dioxatricyclo[3.3.1.0]nonanes by intramolecular haloetherification and/or transannular hydroxycyclization of alkenes in [4+3]-cycloadducts

The synthesis of new difunctionalized 2,6-dioxatricyclo[3.3.1.0^3,7]nonanes is described. This type of structure is an interesting synthetic building block for potential bioactive molecules and it was prepared from 8-oxabicyclo[3.2.1]oct-6-en-3-one having a NHBoc function on C-1. This precursor was obtained by a [4+3] cycloaddition reaction of 2-tert-butoxycarbonylaminofuran and the oxyallyl cation generated in situ from 2,4-dibromo-3-pentanone. Reduction of the carbonyl group at C-3 was accomplished in high yield and stereoselective manner to afford the corresponding axial alcohol at C-3 as a major product. Further intramolecular haloetherification of this type of alcohols with NBS and I(py)2BF₄ led to the corresponding bromo and iodo-derivatives at C-8 of the 2,6-dioxatricyclo[3.3.1.0^3,7]nonane framework, in high yield. Epoxidation of 8-oxabicyclo[3.2.1]oct-6-en-3-ol followed by treatment with NaCN, NaN₃, and/or NaOH in MeOH afforded 8-hydroxy-2,6-dioxatricyclo[3.3.1.0^3,7]nonanes in high yield via a transannular hydroxycyclization mediated by a base and through an alkoxide intermediate. The new 2,6-dioxatricyclo[3.3.1.0^3,7]nonanes were tested for biological activity against HIV-1 virus and MT-4 lymphoid cell line, showing a low anti-HIV activity and a high degree of cytotoxicity.     

Reaction of C3 and C4 ketoses with alkenals and alkenones in water

Treatment of 1,3-dihydroxyacetone and acrolein with aqueous KOH gave a tetrahydrofuran derivative, 1,4-dihydroxy-3,7-dioxabicyclo[3.3.0]octane, in 80% yield. Similarly, 6-alkyl substituted 1,4-dihydroxy-3,7-dioxabicyclo[3.3.0]octanes were obtained by reaction of 1,3-dihydroxyacetone with various α,β-unsaturated aldehydes. In the cases of long chain alkenals, the reaction was effectively accelerated in the presence of organic co-solvent. On the other hand, the corresponding tricyclic products were synthesized by reaction of 1,3-dihydroxyacetone with cyclic enones, such as 2-cyclopentenone and 2-cyclohexenone. This method was successfully applied to the reaction of a tetrulose in the absence of any protecting groups.     

Synthesis and study on 2,4,6,8-tetraaryl- 3,7-diazabicyclo[3.3.1]nonanes and their derivatives

1-Carbethoxy-2,4,6,8-tetraaryl-3,7-diazabicyclo[3.3.1] nonan-9-ones (1, 2) were synthesized and their 1H and 13C NMR data are reported. Chemical shifts and spectral assignments for 2,4,6,8-tetrakis(4-chlorophenyl)-3,7-diazabicyclo[3.3.1]nonan-9-one (3), 2,4,6,8-tetraphenyl-3-thia-7-azabicyclo[3.3.1]nonan-9-one (4) and 2,4,6,8-tetraaryl-3,7-diazabicyclo[3.3.1]nonanes (5-7) are also included.     

Three-dimensional structures and spectra of 2,6- and 2,8-diethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones

Isomeric 2,6- and 2,8-diethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones were obtained by the reaction of glyoxal with ethylurea, and their crystal structures and IR, Raman, and PMR spectra were studied.Translated from Khimiya Geterotsikiicheskikh Soedinenii, No. 7, pp. 937–941, July, 1991.     

New stereoselective intramolecular redox reaction in the system of 3,7-diazabicyclo[3.3.1]nonan-9-one

The ring opening in the 1-benzyl-5,7-dimethyl-6-oxo-1-azonia-3-azaadamantane chloride under the treatment with excess aqueous alkali led to a stereoselective formation of anti-1,5-dimethyl-7-benzyl-3-formyl-3,7-diazabicyclo[3.3.1]nonan-9-ol whose structure was established by means of X-ray diffraction analysis and NMR spectroscopy. A reaction mechanism was suggested involving an intramolecular redox hydride transfer.     

Dehalogenation of 1,3-diiodotricyclo[3.3.0.0(3,7)]octane: generation of 1,3-dehydrotricyclo[3.3.0.0(3,7)]octane, a 2,5-methano-bridged [2.2.1]propellane

Compounds isolated from the reaction of (+/-)-1,3-diiodotricyclo[3.3.0.0(3,7)]octane with molten sodium or tBuLi suggest the intermediate formation of (+/-)-1,3-dehydrotricyclo[3.3.0.0(3,7)]octane. Worthy of note is the formation of stereoisomeric bi(5-methylenebicyclo[2.2.1]hept-2-ylidene) derivatives, probably by coupling of two units of (+/-)-1,3-dehydrotricyclo[3.3.0.0(3,7)]octane of the same or different absolute configuration followed by fragmentation, processes that have been studied by theoretical calculations.     

Bis(1-Benzyl-3,5,7-Triaza-1-Azoniatricyclo[3.3.1.13,7] Decane) Peroxodisulfate: A Mild and Efficient Oxidation of Organic Compounds Under Anhydrous and Aprotic Conditions

Bis (1-benzyl-3, 5, 7-triaza-1-azoniatricyclo[3.3.1.1^3,7] decane) perox-odisulfate was readily prepared as an white solid from commercically available hexam-ethylenetetramine and potassium peroxodisulfate. This reagent could be used as a stable, mild and efficient oxidizer to produce the corresponding carbonyl compounds from hydroxyl compounds or hydrazones or oximes and disulfides from thiols under anhydrous and aprotic conditions. The yields were almost quantitative, and the reaction time was very short.     

Synthesis of new functionalized 3,7-diazabicyclo[3.3.1]nonanes by aminomethylation of the Guareschi imides

The aminomethylation of 4,4-dialkyl-2,6-dioxopiperidine-3,5-dicarbonitriles (Guareschi imides) was studied for the first time. When the Guareschi imides were treated with primary aliphatic amines and an excess of formaldehyde, 2,4-dioxo-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarbonitriles were obtained in varying yields (15–67%). The structure of 9,9-dimethyl-7-(2-methylpropyl)-2,4-dioxo-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarbonitrile was studied by X-ray diffraction analysis.     

One-step synthesis of substituted 3,5-dinitropiperidines and 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonanes from 1,3-dinitropropanes

1,5-Dinitro-3,7-diazabicyclo[3.3.1]nonane derivatives were synthesized in up to 83%yields by the Mannich reaction of 1,3-dinitropropanes with excess formaldehyde and primary amines. In some cases, for instance, when 2,2-dimethyl-1,3-dinitropropane and benzylamine or monoethanolamine are used, the reaction occurs with low yields or stops at the step of formation of 3,5-dinitropiperidines. The influence of the structure of the starting compounds and reaction conditions on the yields of 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonanes and 3,5-dinitropiperidines was studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 405–411, February, 2005.     

Facile Preparation of 3,7-Diazabicyclo[3.3.0]octane and 3,7,10-Triheterocyclic [3.3.3]Propellane Ring Systems from 1,5-Diazacyclooctane 3,7-Derivatives(1)

The cyclodimerization of p-toluenesulfonamide and 3-chloro-2-(chloromethyl)-1-propene to prepare N,N'-bis(p-toluenesulfonyl)-3,7-bis(methylene)-1,5-diazacyclooctane (1a) and its ozonation to the corresponding 3,7-dione 2a are reported. Unusual transannular cyclizations initiated by lithium aluminum hydride treatment or bromination of 1a and oxidative coupling of the dioxime derived from 2a are described. These reactions lead, respectively, to the following derivatives of the little-studied 3,7-diazabicyclo[3.3.0]octane ring system: 1,5-dimethyl-3,7-diazabicyclo[3.3.0]octane (5), N,N'-bis(p-toluenesulfonyl)-1,5-bis(bromomethyl)-3,7-diazabicyclo[3.3.0]octane (8), and N,N'-bis(p-toluenesulfonyl)-1,5-dinitro-3,7-diazabicyclo[3.3.0]octane, (12). Acid-catalyzed hydration of 1a, in contrast, gives the expected 5-methyl-3,7-diazabicyclo[3.3.1]nonan-1-ol (10). Reaction of the dibromide 8 with the nucleophiles, sodium sulfide, sodium oxide, and sodium p-toluenesulfonamide conveniently delivers the corresponding novel 3,7,10-triheterocyclic [3.3.3]propellanes.