Reaction of 1, 1-dichloro-1-nitrosobutane with N,N-dimethylamidodichlorophosphite

Conclusions 1,1-Dichloro-1-nitrosobutane reacts exothermally with N, N-dimethylamidodichlorophosphite to give N,N-dimethylamidotetrachlorophosphorane and a nitrile oxide. In the presence of SO₂,this reaction gives O-propylchloroformimino-N, N-dimethylamidochlorophosphate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1416–1418, June, 1989.     

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.     

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.     

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.     

Crystal structure and thermal expansion of N,N,N′,N′-tetrakis-[(1H,2,4-triazol-1-yl)methyl]-ethane-1,2-diamine

Structural Chemistry - The crystal structure of N,N,N′,N′-tetrakis-[(1H,2,4-triazol-1-yl)methyl]-ethane-1,2-diamine has been fully determined at six different temperatures by X-ray...     

Magnesium and Calcium Complexation with 2-Hydroxypropylene-1, 3-Diamine-N,N,N′,N′-Tetraacetic Acid

Stability constants and heats of formation of magnesium and calcium hydroxypropylenediaminetetraacetates are determined, and the standard thermodynamic characteristics of the complexation equilibria are estimated.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 3, 2005, pp. 375–378.Original Russian Text Copyright © 2005 by Gridchin, Kochergina, Vasil’ev, Pyreu.     

Crystal Structure of a Supramolecular Complex Formed between 1-bromo-2-iodo-tetrafluoroethane and N,N,N′,N′-tetramethyl-ethylenediamine

X-ray analysis has revealed that N,N,N′,N′-tetramethyl-ethylenediamine 1 form donor–acceptor complex 3 with 1-bromo-2-iodo-tetrafluoroethane 2, in which the N X (X = Br, I) distances are longer than the average covalent bond length between X and N, but are also definitively shorter than the sum of the corresponding van der Waals radii of X and N, thus that indicating weak interactions between the nitrogen and bromine or iodine atoms. In our experimental section, a valuable method for recrystallization and collect X-ray data from crystals that easily exhibit decay and can be cracked is reported.