Neue N1-substituierte Sulfonamide1

Es wird die Herstellung des N₁-(n)-Butyrylsulfanilamid (III) und des N-(n)-Butyrylglycyltoluolsulfonamid (IV) beschrieben. Keineder Verbindungen zeigte eine blutzuckersenkende Wirkung.

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IV. Mitt., Mh. Chem.87, 313 (1956).     

Synthesis of N1-methyldesthiobiotin

Conclusions N₁-Methyldesthiobiotin was synthesized by starting with the ethyl ester of-ketodehydrodesthiobiotin.We express our gratitude to prof. V. V. Filippov for testing (III) for biotin activity.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1416–1418, June, 1973.     

Traceless solid-phase synthesis of N1,N7-disubstituted purines

A highly regioselective and traceless solid-phase route to N1,N7-disubstituted purines has been developed. Key steps in the reaction strategy involves (i) coupling of 6-chloropurine to the REM resin (Michael addition), (ii) oxidation, (iii) N1-alkylation, (iv) quaternization, and (v) product release through Hofmann elimination. A library of 15 N1,N7-disubstituted purines was synthesized.     

Bis-(N2-hydroxyhexafluoroisopropyl-N1,N1-substituted)terephthalamidines and their reaction with perfluorohexanecarbonitrile

Bis(N²-hydroxyhexafluoroisopropyl-N¹,N¹-substituted) terephthalamidines, which are stable up to their melting points, were obtained by reacting substituted tetraphthalamidines with hexafluoroacetone. The reaction of bis(N²-hydroxyhexafluoroisopropyl-N¹N¹-substituted)terephthalamidines with perfluorohexanecarbonitrile results in the formation of 1,4-bis(2,4-per-fluorohexyltriazinyl) benzene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1613–1616, July, 1990.     

N1,N1-Diethyl-N2-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)acet­amidine

The solid-state conformation of the title compound, C₂₀H₃₂N₂O₉, has been determined at 150 K. The pyran­ose ring has a distorted chair conformation. Among the possible conformations of the C—N glycosidic bond, that of the E rotamer is observed and a short intramolecular C_methyl⋯O contact may partly stabilize this conformation. Crystal cohesion is stabilized by an extensive network of weak C—H⋯O hydrogen bonds and close contacts.     

1H, 1 3C,and 1 5N Chemical shifts and 1H-1 5N and 1 3C-1 5N heteronuclear spin-spin coupling constants in the NMR spectra of 5-substituted furfural oximes

The ¹H, ¹³C, and ¹⁵N NMR spectra of ¹⁵N-enriched 5-substituted furfural oximes were investigated. It was shown that the chemical shifts of the ring atoms and the oxime group correlate satisfactorily with the F and R substituent constants, whereas their sensitivity to the effect of the substituents is lower than in monosubstituted furan derivatives. The constants of spin-spin coupling between the ring protons and the oxime group were determined. An analysis of the ¹H-¹H spin-spin coupling constants (SSCC) on the basis of their stereospecificity indicates that the E isomers have primarily an s-trans conformation in polar dimethyl sulfoxide, whereas the Z isomers, on the other hand, have an s-cis conformation. The signs of the direct and geminal ¹³C-¹⁵N SSCC were determined for 5-trimethylsilylfurfural oxime.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1172–1177, September, 1985.The authors thank N. O. Saldabol, L. M. Ignatovich, and N. P. Erchak for providing us with the investigated compounds.     

Theoretical study of bifurcated hydrogen bonding effects on the 1J(N,H), 1hJ(N,H), 2hJ(N,N) couplings and 1H, 15N shieldings in model pyrroles

According to the density functional theory calculations, the X···H···N (X?N, O) intramolecular bifurcated (three‐centered) hydrogen bond with one hydrogen donor and two hydrogen acceptors causes a significant decrease of the ^1hJ(N,H) and ^2hJ(N,N) coupling constants across the N? H···N hydrogen bond and an increase of the ¹J(N,H) coupling constant across the N? H covalent bond in the 2,5‐disubsituted pyrroles. This occurs due to a weakening of the N? H···N hydrogen bridge resulting in a lengthening of the N···H distance and a decrease of the hydrogen bond angle at the bifurcated hydrogen bond formation. The gauge‐independent atomic orbital calculations of the shielding constants suggest that a weakening of the N? H···N hydrogen bridge in case of the three‐centered hydrogen bond yields a shielding of the bridge proton and deshielding of the acceptor nitrogen atom. The atoms‐in‐molecules analysis shows that an attenuation of the ^1hJ(N,H) and ^2hJ(N,N) couplings in the compounds with bifurcated hydrogen bond is connected with a decrease of the electron density ρ_H···N at the hydrogen bond critical point and Laplacian of this electron density ?²ρ_H···N. The natural bond orbital analysis suggests that the additional N? H···X interaction partly inhibits the charge transfer from the nitrogen lone pair to the σ*_{N? H} antibonding orbital across hydrogen bond weakening of the ^1hJ(N,H) and ^2hJ(N,N) trans‐hydrogen bond couplings through Fermi‐contact mechanism. An increase of the nitrogen s‐character percentage of the N? H bond in consequence of the bifurcated hydrogen bonding leads to an increase of the ¹J(N,H) coupling constant across the N? H covalent bond and deshielding of the hydrogen donor nitrogen atom. Copyright © 2010 John Wiley & Sons, Ltd.     

X-ray structural investigation of N,N′-dibenzoyl-N,N′-diisobutyl-1,2-diamino-1-chloroethylene

N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 2, pp. 166–168, March–April, 1991.