New N-(Arylsulfonyl)-5-aminomethylbicyclo[2.2.1]hept-2-enes. Synthesis, 1H and 13C NMR Spectra,and Chemical Reactions

A synthesis of new N-(arylsulfonyl)-5-aminomethylbicyclo[2.2.1]hept-2-enes obtained by reaction of stereoisomeric exo- and endo-5-aminomethylbicyclo[2.2.1]hept-2-enes with arylsulfonyl chlorides is described. With the use of the data of ¹H and ¹³C NMR spectra, including those of two-dimensional spectra recorded in COSY and NOESY mode, the contribution of stereochemical features of sulfonamides into the spectra structure of endo- and exo-isomers was evaluated. Applying various methods of the phase-transfer catalysis alkylation and acylation of the stereoisomeric arylsulfonamides containing a norbornene fragment was carried out. The reactions of alkylated stereoisomeric sulfonamides, N-(benzyl)-N-(3,4-dichlorophenylsulfonyl)-5-aminomethylbicyclo[2.2.1]hept-2-enes, with peroxyphthalic acid provide epoxides; the orientation of substituents in the cage norbornene fragment does not affect the direction of the process. The structure of the products obtained by sulfonamides transformations was confirmed by IR, ¹H and ¹³C NMR spectra.     

Structure determination of diacholestanes by means of 13C-NMR and 1H-NMR spectroscopy

A full analysis of the ¹³C-NMR spectra of five C6-functionalized diacholestenes is reported using SFORD, PRS and LIS techniques. Good agreement was obtained between spectral results and data calculated for a theoretical model.The structure of the two C20 epimeric diacholest-13(17)-enes, as well as of their epoxidation products, was established by means of ¹³C and ¹H-NMR analysis.     

Simple NMR method for assigning relative stereochemistry of bridged bicyclo[3.n.1]-2-enes and tricyclo[7.n.1.0]-2-enes

The stereochemistry of syn and anti-forms of bridged bicyclo[3.n.1]-2-ene, tricyclo[7.n.1.0]-2-ene (n=1-3) and bicyclo[4.3.1]dec-7-ene derivatives can be assigned from the ¹³C chemical shift difference of the double bond. Both syn-9-R-bicyclo[3.3.1]non-2-enes and syn-13-R-tricyclo[7.3.1.0^2,7]tridec-2(7)-enes have a large shielding difference between sp² carbons, while the corresponding anti-forms have a smaller one. In contrast, 8-R-bicyclo[3.2.1]oct-2-enes and 12-R-tricyclo[7.2.1.0^2,7]dodec-2(7)-enes have an inverse correlation. The reason of this specificity is the influence of the γ-gauche effect on the chemical shift of C(2) atom. The GIAO theory has been applied to investigate the ¹³C chemical shifts. The conformational equilibrium in the formamide group of 13-formylamino-tricyclo[7.3.1.0^2,7]tridec-2(7)-enes has been studied.     

Ene Synthesis of Bicyclic Arylmethylenedihydropyrazoles Using 4-Phenyl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione

8-Acetyl-7-aryl-2-arylmethylene-8,9-diaza- and 4,8,9-triazabicyclo[4.3.0]non-9-enes react with4-phenyl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione, following the ene addition pattern. Under similar conditons 7-aryl-2-arylmethylene-8-methyl-8,9-diazabicyclo[4.3.0]non-9-enes give rise to both mono- and polyadditionproducts. The product structures were studied by ¹H and ¹³C NMR, IR, and UV spectroscopy and singlecrystal X-ray diffraction.     

13C nuclear magnetic resonance spectroscopy of atisine and veatchine-type C20-diterpenoid alkaloids from aconitum and garrya species

¹³C NMR spectra of the atisine- and veatchine-type alkaloids, as well as certain of their derivatives, have been obtained by the Fourier transform technique at 25.03 MHz. With the help of single-frequency off-resonance proton decoupling techniques, additivity relationships, and the effects induced by certain structural changes, self-consistent assignments of nearly all the resonances have been made. The ¹³C NMR spectra are also analyzed to identify skeletal features of the atisine and veatchine-type alkaloids of use in the structure determination of new C₂₀-diterpenoid alkaloids. On the basis of the ¹³C NMR analysis of atisine and veatchine as well as a temperature-dependence study of atisine, the existence of C-20 epimers in these alkaloids is demonstrated. A ¹³C NMR study of the behavior of the oxazolidine ring of atisine in non-ionic and ionic solvents indicates that the C-20 epimers of atisine do not exist in an equilibrium mixture in solution and are not interconvertible via a zwitterion as reported earlier.     

Configurational assignment by NMR spectroscopy of stereoisomeric 2,6-dimethyl-tricyclo[5.2.1.02,6]dec-3-enes and decanes: Albene and isoalbene

By means of ¹³C NMR spectroscopy a distinction is made between the two stereoisomeric 2,6-dimethyl-tricyclo [5.2.1.0^2,6]dec-3-enes 1 and 5. This corrects the previously proposed structure of the natural hydrocarbon “albene”.     

The chemistry of the tetracyclic diterpenoids—XII: The labelling and functionalization of the kauranoid 6β-position

The stereochemistry of hydroboronation, osmylation and epoxidation of kaur-6,7-enes are described. The routes yield substances suitably functionalized for study as intermediates in gibberellin biosynthesis.     

13C NMR spectra of polycyclic compounds. Bicyclo[2.2.1]heptadiene tetramers

Comparison of experimental and calculated chemical shifts of carbon atoms in¹³C NMR spectra of two isomeric dodecacyclo[14.9.1.1^4,13.1^7,10.0^2,15.0^3,14.0^5,12.0^6,11.0^17,25.0^18,24.0^19,21. 0^20,24]-octacos-8-enes, bicyclo[2.2.1]heptadiene tetramers, confirmed theirexo-trans-exo-trans-exo-endo-andexo-trans-exo-trans-exo-exo-configurations. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2545–2547, December, 1998.     

Transformed steroids. 128. Synthesis of the isomeric 16α- and 16β-lactones of 3β,16-dihydroxy-24-nor-5α-cholan-23-oic acid

The paper is devoted to the synthesis of steroids with an additional ring E consisting of a saturated lactone ring in forms isomeric at the 16-center. The basic intermediates for yielding such compounds were the products of the Reformatskii reaction with 3,16α-diacetoxypregn-5-en-20 one. The Δ²⁰⁽²²⁾-lactone was hydrogenated to the compound with a saturated lactone ring and a Δ⁵ bond and to the fully saturated product. Its epimer at the 16-center was obtained from the ethoxycarbonyl triol forming the second product of the Reformatskii reaction. The dehydration of the latter gave a mixture of 20(21)- and 20(22)-enes, the hydrogenation of which led to the 3,16-diacetate of ethyl 24-norcholanoate. Subsequent saponification, methylation, oxidation, reduction, and cyclization led to the 6-deoxy analog of chiogralactone. The absolute configurations at C(16) of the three lactones obtained were determined by the Hudson-Klyne rule and were confirmed by analysis of the CD spectra. The unambiguity of the hydrogenation of the Δ²⁰⁽²²⁾ bonds of the intermediate compounds was confirmed by the PMR spectra.     

13C and proton NMR spectra of 2(1H)pyrazinones

¹³C and proton NMR spectra data are given for eleven 2(1H)pyraziones. Assignments of chemical shifts were made by methods which included: deuterium exchange with certain protons of 3-alkyl substituents; change of chemical shifts of certain carbon atoms with change in pH; the use of long-range coupling constants for ¹³C to protons; and various correlations among assigned spectra.     

Conversion of trans,trans-1-methoxy-3,5-diaryl-2-oxabicyclo[4.4.0]dec-3-enes into hemidithioacetals and 4H-thiopyrans. Structure of trans,trans-1-mercapto-3-phenyl-5-(4-methoxyphenyl)-2-thiabicyclo[4.4.0] dec-3-ene

The conversion of trans,trans-1-methoxy-3,5-diaryl-2-oxabicyclo[4.4.0]dec-3-enes into trans,trans-1-mercapto-3,5-diaryl-thiabicyclo[4.4,0]dec-3-enes or 2,4-diaryl-5,6-tetramethylene-4H-thiopyrans, which takes place when hydrogen Sulfide is reacted with the acetals in acetic acid with the use of gaseous hydrogen chloride as a catalyst, has been described. A mechanism for the reaction has been proposed. The structure and confirmations of the molecules have been determined by x-ray diffraction analysis and ¹³C NMR.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 28–33, January, 1986.     

Ozonides of perfluorooct-1-ene and perfluorooct-2-ene

Ozonides of higher perfluoroalkenes were prepared for the first time by ozonation of perfluorooct-1-and-2-enes in Freon-113. The structures of the resulting compounds were confirmed by¹³C NMR spectroscopy and GLC-mass spectrometry.     

Vinylierung und 91Zr-NMR-Spektren von Substituierten Zirconocendichloriden

Vinylation and ⁹¹Zr N.M.R. Spectra of substituted Zirconocene Dichlorides Substituted zirconocene dichlorides react with vinyl lithium with formation of zirconacyclopent-2-enes, Cp₂ZrCH = CHCH₂CH₂, or zirconocene butadiene complexes, Cp₂Zr(C₄H₆). The compounds obtained were characterized by their ¹H and ¹³C n.m.r. spectra. The ⁹¹Zr n.m.r. chemical shifts of substituted zirconocene dichlorides correlate with the bond angles Cp′? Zr? Cp′ and Cl? Zr? Cl respectively. They can be used to estimate the reaction behaviour of zirconocene dichlorides.     

Oxygen-18 isotope shifts on the 13C nuclear magnetic resonance of metal carbonyl derivatives

The oxygen-18 isotope shifts on the natural abundance ¹³C spectra of oxygen-18 enriched samples of W(CO)₈ and W(CO)₅PPh₃ have been observed to be 0.040 ppm (0.61 Hz at 15.03 MHz) upfield from that of a ¹³C nucleus bearing an oxygen-16 atom.     

13C NMR spectra of biologically active compounds. II. 11-Deoxy-16- and 17-aryloxyprostaglandins

The¹³C NMR spectra of the initial ω-aryloxy chains and the final 16-and 17-aryloxyprostaglandins of the 11-deoxy series have been investigated, and stereochemical assignments have been made for the diastereomeric pairs. A weakening of the diastereotopic effects in the spectra of the 15- and 16-methyl-substituted 16- and 17-phenoxypropstaglandins to 0.1 ppm has been shown.     

Application de la RMN du 13C a la determination de la configuration de centres quaternaires en serie alicyclique et hydrate de carbone a chaine ramifiee

Configurational assignments to quaternary centres of 2-(l,3-dithianyl) branched-chain carbohydrates, important intermediates for the synthesis of carbohydrate-containing antibiotics, have been made through natural abundance ¹³C NMR spectroscopy. Configurations of quaternary carbons in 21, 24 and 26 were assigned by comparison with ¹³C spectra of structurally-related alicyclic derivatives 1–16.     

Etude RMN 13C d'un Dérivé Uniformément Enrichi en 13C. Signe des Valeurs des Constantes de Couplage Observées

The ¹³C NMR parameters of 3-O-acetyl-1,2:5,6-di-O-isopropylidène-α-D-[U-¹³C] glucofuranose, used as a sample for analysis in double labelling biosynthetic experiments, have been measured. Homonuclear double resonance experiments ¹³C? {¹³C} at 62.8 MHz have permitted the determination of all the ¹³C? ¹³C coupling constants. By theoretical computation of spectra, in connection with the second order effects existing at 25.2 MHz and 15.08 MHz, the sign of the coupling constants has been determined. The theoretical computation of spectra took into account all the isotopomers and was calculated with the help of a program (adapted from the LAOCOON program) allowing for the weighted addition of the spectra.     

3-Azabicyclo[3.3.1]nonane Derivatives: IX. Synthesis and Molecular Structure of 3-Azabicyclo[3.3.1]nonane-1,5-diamines in Solution and in Solid State

During catalytic reduction with hydrogen on nickel of a series of 3-substituted 1,5-dinitro-3-azabicyclo-[3.3.1]non-6-enes alongside nitro groups reduction occurred also hydrogenation of the double bond. New diamines of the 3-azabicyclo[3.3.1]nonane series were synthesized, and their structure was established by means of IR, ¹H and ¹³C NMR spectroscopy and X-ray diffraction study.     

Regioselective Enzyme-Mediated Glycosylation of Natural Polyhydroxy Compounds. Part 1. Galactosylation of stevioside and steviolbioside

Bovine β-1,4-galactosyltransierase is an efficient catalyst for the regioselective transfer of galactose from UPD-galactose, generated in situ with the UDP-glucose/UDP-glucose-4-epimerase system, to the kaurane glycosides stevioside ( 1 ) and Steviolbioside ( 2 ), affording the corresponding galactosyl derivatives 3 and 4 in high yields. By a combination of 2D NMR techniques (COSY, TOCSY, ROESY, HMQC, and HMBC), the structure of the products is established as 13-[(β -D -galactopyranosyl-(1 → 4)-β-D -glucopyranosyl-(1 → 2)- β -D -glucopyranosyl)oxy]kaur-16-en-19-oic acid β -D -glucopyranosyl ester ( 3 ) and 13-[(β-D -galactopyranosyl-(1 → 4)- β-D -glu-copyranosyl-(1 → 2)- β-D -glucopyranosyl)oxy]kaur-16-en-19-oic acid ( 4 ).     

On the assignment of the carbon-13 NMR spectrum of bilirubin

An individual assignment of certain peaks in the proton and ¹³C NMR spectra of bilirubin and of bilirubin dimethyl ester is described. The assignment was achieved through the spectra of vinylneoxanthobilirubinic acid and by off-resonance decoupled ¹³C spectra of bilirubin dimethyl ester. The signals due to the endo and exo vinyl groups were separately assigned. This assignment allows a rational interpretation of previously obtained spin-lattice relaxation times of the vinyl carbon peaks. The two vinyl groups are found to differ considerably in their motional correlation time.