13C NMR spectra of biologically active compounds.

The¹³C spectra of 25 new substituted cyclopropanes of the pyrethoid series have been investigated and a stereochemical assignment has been made of the stereoisomers formed. As the criterion for stereochemical assignment it is proposed to use the values of the chemical shifts for the -carbon atoms of the substituents in the cyclopropane ring.Institute of Chemistry, Bashkir Branch, USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 266–272, March–April, 1989.     

13C NMR spectra of biologically active compounds

The diastereomeric effects on the¹³C NMR chemical shifts of thirteen epimeric pairs of 16-aryloxy-11-deoxyprostaglandins of the E₁ and F₁ series caused by the change in the configuration of the 15-hydroxy group, which are differential parameters for assigning epimers to the 15- and 15-stereochemical series, have been determined.For Communication (VIII), see [1].Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 123–128, January–February, 1991.     

13C NMR spectra of biologically active compounds XI. Diastereomeric effects in C-glycosides

The¹³C NMR spectra of epimeric C-D-glucopyranosides with alkyl, aryl, and alkynyl substituents have been studied. The diastereomeric effects of the chemical shifts have been determined and assignments have been made to the 1-and 1- stereochemical series on the basis of HH COSY and CH HET CORR two-dimensional NMR spectra. The diastereomeric effects observed for the C-3 and C-5 carbon atoms are proposed as characteristic parameters for establishing the stereochemistry at the C-1 carbon atom.Institute of Chemistry, Bashir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 368–373, May–June, 1991.     

13C NMR spectra of biologically active compounds. I. α-Homologs of 11-deoxyprostaglandin E1

The¹³C NMR spectra of a number of -homologs of 11-deoxyprostaglandin E₁ have been investigated and a stereochemical assignment has been made of the diasteromeric pairs of isomers with lengths of the -chain from seven to twelve carbon atoms. The most informative characteristics for the separation of the classes of epimers have been determined; these are differences in the chemical shifts of the C₁₃ and C₁₅ carbon atoms.Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 315–319, May–June, 1985.     

1H and13C NMR spectra of biologically active compounds. III. Diastereomers of (±)-7-thia- and 13-thia-16-aryloxy analogs of 11-deoxyprostaglandins of the E1 series

The structure has been established and stereochemical assignments have been made of two complete sets of diastereomers of the 7-thia and 13-thia analogs of 11-deoxy-prostaglandins of the E₁ series by the¹³C NMR method. It is proposed to determine the diastereomeric effects of the¹³C NMR chemical shifts, which are differential parameters bearing information on the stereochemistry of the molecules. Diagnostic diastereomeric effects have been found for assigning stereoisomers with respect to the C-15-hydroxy group and also with respect to the C-8 and C-12 chiral centers of the cyclopentane ring.Institute of Chemistry of the Bashkir Branch of the USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 282–287, March–April, 1988.     

1H and13C NMR spectra of polycyclic compounds

Using 2D¹H and¹³C correlation NMR spectroscopy, all signals in the¹H and¹³C NMR spectra of five stereoisomeric bicyclo[2.2.1]heptadiene trimers, decacyclo[9.9.1.0^2.10.0^3.8.0^4.6.0^5.9.0^12.20.0^13.18.0^14.16.0^15.19]heneicosanes, obtained by Pd-catalyzed codimerization of norbornadiene dimer with quadricyclane followed by homocyclotrimerization of the latter were assigned unambiguously. Independent stereochemical identification of the trimers was performed using data on the nuclear Overhauser effect.     

1H and 13C NMR spectra of benzyl compounds

Proton and carbon-13 spectra of benzyl compounds of the general formula (C₆H₅CH₂)_nX with a large variety of X substituents have been measured. While a linear relationship between the CH₂ chemical shift and the substituent electronegativity was found both for ¹H and ¹³C, large deviations from linearity were observed for transition metals such as titanium and zirconium. These later results are correlated with the X-ray studies of the latter compounds.     

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.     

1H and13C NMR spectra of biologically active compounds

The¹H and¹³C NMR spectra of diols of the hexachlorobicycloheptene and-heptadiene series, and also of the diacetates and sulfites corresponding to them, have been investigated. Criteria for the stereochemical assignment of the compounds mentioned on the basis of chemical shifts and spin-spin coupling constants have been determined.Institute of Chemistry, Bashkir Branch, USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 439–443, May–June, 1988.     

Detailed 1H and 13C NMR structural assignment of three biologically active lignan lactones

In this paper we present a complete 1H and 13C NMR spectral analysis of three lignan lactones (methylpluviatolide, dimethylmatairesinol and hinokinin) by the use of techniques such as COSY, HMQC, HMBC and J-resolved. Complete assignment and all homonuclear hydrogen coupling constant measurements were performed, providing enough data also to the confirmation of the relative stereochemistry.     

1H and 13C NMR spectra of N-vinylpyrroles

The position of the substituants in 2, 3-dialkyl-1-vinylpyrroles and 7-methyl-1 vinyl-4,5,6,7-tetrahydroindole was established on the basis of the ¹H and ¹³C NMR spectra. It was found that the S-trans conformation of the N-vinyl group is preferred. It is shown that the condensation of ketoximes with acetylene proceeds through the formation of free pyrroles and that vinyl oximes are not intermediates in the condensation.     

13C and1H NMR spectra of porphyrin dianions and their charge distribution

The¹H and¹³C NMR spectra of a number of zinc complexes of meso-substituted porphyrins and their dianions have been investigated. The upfield shifts of the signals of all the protons in the spectra of the dianions are caused by the effects of the paramagnetic ring current. A linear relationship of the calculated electron density with both the experimental chemical shifts of the¹³C nuclei in the original porphyrins and the shifts calculated in the framework of the mean excitation energy has been revealed. Differences in the behavior of the signals of the -, -, and meso-carbon atoms have been discovered upon the formation of the dianions, and they have been attributed to the influence of the electronic charge, the change in the mean excitation energy, and the paramagentic ring currents.Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 24, No. 1, pp. 41–49, January–February, 1988.     

13C NMR spectra of biologically active compounds. VIII. Stereochemistry of a triterpeneglycoside — Glycyrrhizic acid — And its derivatives

Details of the¹³C NMR spectra of glycyrrhizic acid and four of its derivatives are given, and on their basis the configurations of the anomeric centers of the carbohydrate chain have been redetermined and the β-configuration of the C-1′ carbon atom has been suggested. Institute of Chemistry, Bashkir Scientific Center, Urals Branch, USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 500–505, July–August, 1989.     

Diels-alder adducts of a spirocyclopentenotriazoloazodienophile. Assignment of their 1H and 13C NMR spectra

1-Phenyl-cyclopenteno[1,2-d]-1,2,3-rriazolo-5-spiro-4′-[perhydropyrazolino-3′,5′-dione] (5) afforded in situ, by oxidation with lead tetraacetate, the corresponding cyclopentenotriazolo-spiropyrazolodione 6 , which was trapped with dienes giving the hetero-Diels-Alder adducts 10–12 in good yields. The Diels-Alder reactions were examined on the basis of AM1 MO calculations. Total assignment of the ¹H- and ¹³C-nmr chemical shifts as well as the relative configuration of these adducts was accomplished with the help of 2D (¹H-¹H COSY, ¹H -¹ H NOESY, ¹H-¹³C XHCORR, ¹H-¹³C COLOC) and NOE difference spectroscopy. The structures of compounds 11a and 11b were also examined by molecular modeling.     

1H and 13C NMR spectra of N-substituted morpholines

(1)H and (13)C NMR data for N-substituted morpholines 1-20 were measured using 1D (DEPT, 1D NOE difference) and 2D NMR spectroscopic methods including (1)H-(1)H COSY, long-range (1)H-(1)H COSY, NOESY, gHMBC and gHMQC experiments. At room temperature the (1)H NMR spectra of protonated compounds 2 and 9 show the chair conformation for the morpholine ring. Spin-spin coupling constants were deduced from the resolution-enhanced proton spectra.     

13C and 119Sn NMR spectra of Di-n-butyltin(IV) compounds

The ¹³C and ¹¹⁹Sn NMR spectra of a set of di-n-butyltin(IV) compounds and their complexes in coordinating and non-coordinating solvents have been studied. The results have shown that it is possible to describe semiquantitatively the shape of coordination polyhedra of these compounds from analysis of their δ(¹¹⁹Sn) and ¹J(¹¹⁹Sn-¹³C) parameters. The values of δ(¹¹⁹Sn) define the regions with different coordination numbers of the central tin atom, so that four-coordinate compounds have δ(¹¹⁹Sn) ranging from about + 200 to −60 ppm, five-coordinate compounds, −90 to −190 ppm, and six-coordinate compounds, −210 to −400 ppm. The values of ¹J(¹¹⁹Sn-¹³C) were used for the calculation of the CSnC angle in the coordination polyhedron of individual compounds.     

13C and 119Sn NMR spectra of some tribenzyltin(IV) compounds

The ¹³C and ¹¹⁹Sn NMR spectra of some tribenzyltin(IV) compounds and their complexes in coordinating and non-coordinating solvents have been studied. The δ(¹¹⁹Sn) chemical shifts and coupling constants ¹J(¹¹⁹Sn, ¹³C) clearly depend on the coordination number of the central tin atom and the geometry of its coordination polyhedra. Approximate ranges of the characteristic values of both the NMR parameters were determined for various configurational types of tribenzyltin compound. The ¹³C and ¹¹⁹Sn NMR parameters found are indicative of a distinct interaction between the polarized σ(SnC) bond and adjacent π-electron system of the aromatic ring(s).     

Detailed 1H and 13C NMR structural assignment of ent-polyalthic acid,a biologically active labdane diterpene

In this paper, a complete ¹H and ¹³C NMR data assignment of ent-polyalthic acid, a biologically active labdane-type diterpene, is presented. The assignments were carried on the basis of spectroscopic data from ¹H NMR, ¹³C{¹H} NMR, gCOSY, gHMQC, and gHMBC experiments. Furthermore, a software-assisted methodology, using FOMSC3_rm_NB and NMR_MultSim programs, supported the detailed and unequivocal assignment of ¹H and ¹³C signals, allowing all hydrogen coupling constants to be determined and thus clarifying all hydrogen signal multiplicities.