Direct13C-13C spin-spin coupling constants of olefinic carbons in vinyl ethers

Conclusions In alkyl vinyl ethers, the values of¹J (¹³C=¹³C) SSCC increase with increasing effective volume of the alkyl group, opposite to the change in the corresponding constants in the series of alkyl phenyl ethers.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2249–2252, October, 1982.     

13C-13C spin-spin coupling constants in 3-carene

Novosibirsk Institute of Organic Chemistry, Siberian Branch, USSR Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, Vol. 6, pp. 853–854, November–December, 1989.     

13C-13C spin-spin coupling constants in six-membered ring azaaromatic compounds

The ¹³C-{¹H} NMR spectra of monomethyl substituted diazines, protonated at the picoline and 2-methylopyrimidine nitrogen atoms, have been analyzed, along with that of pyridine N-oxide and its 2-methyl derivatives protonated at the oxygen atom. Direct and vicinal ¹³C-¹³C spin-spin coupling constants (SSCC) have been measured. It was found that the ¹³C-¹³C SSCC in diazines follow additivity rules which are based on consideration of the number and mutual orientation or distribution of nitrogen atoms in the ring. It has also been demonstrated that increased direct ¹J_CC values involving methyl group carbon atoms in -positions to nitrogen atoms in the aromatic ring are due to effects associated with unshared electron pairs.Translated from Khimiya Geterotsiklieheskikh Soedinenii, No. 9, pp. 1243–1250, September, 1988.     

13C-13C spin-spin coupling constants in the spectra of monosubstituted pyridines

The ¹³C- {¹H} NMR spectra of pyridine and a number of monosubstituted pyridines for compounds with the natural percentage of the ¹³C isotope were analyzed. The direct, geminal, and vicinal ¹³C-¹³C spin-spin coupling constants (SSCC) were determined. Linear relationships that link the ¹³C-¹³C SSCC in the spectra of monosubstituted pyridines and benzenes were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1383–1385, October, 1985.     

NMR study of conjugation effects 15.13C-13C spin-spin coupling constants in phenyl alkyl ether

Conclusions ¹³C-¹³C SSCC were measured for a series of phenyl alkyl ethers. The values through the bond between C² and C³ in mono substituted benzenes most clearly reflect the -electron interaction of the aromatic ring with the substituent, provided the latter contains no atoms from a period of the periodic table higher than the second.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya.No. 1, pp. 113–119, January, 1982.The authors thank N. M. Sergeev for useful discussions while the work was in progress, and V. N. Khlopkov for technical assistance in setting up the experiments.     

13C-13C spin-spin coupling constants in structural studies: XLIII. Stereochemical study on functionalized 3-iminopyrrolizines

Three 1-ethylsulfanyl-3-imino-3H-pyrrolizine-2-carboxamides were synthesized by intramolecular cyclization of substituted (2Z)-2-cyano-3-ethylsulfanyl-3-(1H-pyrrol-2-yl)prop-2-enamides. The products were assigned syn configuration at the C=N bond and preferential s-cis orientation of the carbamoyl group on the basis of the experimental ¹³C-¹³C coupling constants and high-level nonempirical quantum-chemical calculations.     

Direct 13C-13C spin-spin coupling constants in the vinyl group of N-vinylazoles

The unshared electron pair of the dicoordinated nitrogen atom introduces a stereospecific contribution to the ¹³C-¹³C spin-spin coupling constant (SSCC) in the vinyl group of a series of N-vinylazoles, the value of which depends on the energetics of the unshared pair.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 197–200, February, 1989.     

Direct13C-13C spin-spin coupling constants for the triple bond in activated acetylenes

Conclusions ¹³C-¹³C SSCC values across the triple bond in activated acetylenes are determined primarily by the -electronic properties of substituents. The enhanced sensitivity of¹J_cc in acetylene derivatives to substituent effects also asserts their possible utility in estimating the electronegative properties of substituents.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1287–1292, June, 1988.     

Use of13C-13C spin-spin coupling constants for establishing the configuration of 1-alkoxy-1-aminoxyethanes

Conclusions Direct¹³C-¹³C coupling constants were used to establish the configuration of 1-alkoxy-1-aminoxyethanes. The compounds are mixtures of Z and E isomers, of which the E isomers are more stable.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2137–2138, September, 1985.     

13C-15N spin-spin coupling constants of amides: H-bonding effects in a cyclohexapeptide

The effect of intramolecular H-bonding and solvent acidity on the magnitude of one-bond ¹³C-¹⁵N spin-spin coupling constants has been examined using specifically ¹⁵N-labeled $\text{cyclo}$-(Gly-L-Pro-Gly)₂ and related linear peptides.     

1H and 13C NMR chemical shifts and spin-spin coupling constants in trans- and cis-decalins

The NMR parameters characterizing the spectra of trans- and cis-decalins were determined from theoretical calculations and experimental spectra. The calculated values of the shielding constants are in good agreement with the measured chemical shifts, with a small but noticeable difference in accuracy for the bridgehead atoms. Of all the spin-spin coupling constants, only most of (1)J(C,C) and (1)J(C,H) values could be extracted from the spectra, and the corresponding computed values are in good agreement with experiment. It appears that the applied density functional theory (DFT) approach overestimates slightly the J(C,C) coupling and underestimates the differences between one-bond (1)J(C,H) coupling constants. For all these constants [J(C,C), J(C,H) and J(H,H)] through one to three bonds, which could not be obtained experimentally, the predicted values are in good agreement with the general rules relating spin-spin coupling to the number and spatial arrangement of the intervening bonds.