Search results for "Nitrogen"

ChemInform Abstract: α-Cyanation of Aromatic Tertiary Amines Using Ferricyanide as a Non-Toxic Cyanide Source.

2016

Aromatic tertiary amines, mostly isoquinoline derivatives and analogous N-heterocycles, are treated with the non-toxic agent (II) under conditions A) or B) to produce the desired N-aminonitrile compounds as amino acid precursors and as building blocks of complex nitrogen heterocycles.

Base-Dependent Stereodivergent Intramolecular Aza-Michael Reaction: Asymmetric Synthesis of 1,3-Disubstituted Isoindolines

2013

The nucleophilic addition (A(N)) / intramolecular aza-Michael reaction (IMAMR) process on Ellman's tert-butylsulfinyl imines, bearing a Michael acceptor in the ortho position, is studied. This reaction affords 1,3-disubstituted isoindolines with a wide range of substituents in good yields and diastereoselectivities. Interestingly, careful choice of the base for the aza-Michael step allows either the cis or the trans diastereoisomers to be exclusively obtained. This stereodivergent cyclization has enabled the synthesis of C2-symmetric bisacetate-substituted isoindolines. In addition, bisacetate isoindolines bearing two well-differentiated ester moieties are also noteworthy because they may a…

TAURINE SUPPLEMENTATION PREVENTS HYPERAMINOACIDEMIA IN GROWING TERM INFANTS FED HIGH PROTEIN COW'S MILK FORMULA. † 1891

1996

Blood urea nitrogen (BUN) and plasma and urine amino acid concentrations were compared between three cohorts of healthy term infants who were breast-fed (BF) or randomly assigned to one of two formulas either taurine non-supplemented (FF) or taurine supplemented (FF+T). The formulas had a protein concentration of 2 g/dl (2.9 g/100 kcal) and a whey/casein ratio of 20/80. The infants were studied from 2 to 12 weeks of age. Weight gain and growth in length was normal and similar in all three feeding groups during the study interval. At 12 weeks BUN was significantly higher in the FF group than in the BF and FF+T groups of infants, 16.5 mg/dl vs 7.0 and 7.3 mg/dl respectively. Total plasma amin…

Polycondensed nitrogen heterocycles. Part19. Pyrrolo[1,2-f]phenanthridines by pschorr-type cyclization brought about by hypophosphorous acid

1986

Pyrrolo[1,2-f]phenanthridines were prepared in good yields by the diazotization in acetic acid of the amines la,b and subsequent treatment with hypophosphorous acid. The necessity for hypophosphorous acid in the reaction was demonstrated.

ChemInform Abstract: Differential Reactivity of Fluorinated Homopropargylic Amino Esters vs Gold(I) Salts. The Role of the Nitrogen Protecting Group.

2015

The gold(I)-catalyzed hydroarylation/isomerization reaction of N-protected homopropargyl amino esters (III) gives quinoline derivatives of type (IV).

The orientational glass state of argon:Nitrogen and cyanide mixed crystals

1990

Abstract Solid solutions of Ar:N 2 and ( KBr ) 1− x ( KCN ) x mixed crystals show a so-called orientational glass state where the orientations of the aspherical species, N 2 respectively CN - , are frozen in random patterns. The main experimental characteristics of this state and the pertinent theoretical concepts are discussed.

1981

New nitrogen mustard analogues in which bis(2-chloroethyl)-amino groups are separated by oxyethylene groups, 1,14-dichloro-3,12-bis(2-chloroethyl)-3,12-diaza-6,9-dioxatetradecan (3c) and 1,17-dichloro-3,15-bis(2-chloroethyl)-3,15-diaza-6,9,12-trioxaheptadecane (3d), were synthesized by reaction of bis(2-hydroxyethyl)amine (2) with bis(2-chloroethyoxy)ethylene (1a) and with 1,11-dichloro-3,6,9-trioxaundecane (1b), respectively, followed by treatment with thionyl chloride. The analogues were then complexed with heparin. The resulting heparin-complexes show inhibiting activity against transplanted Sarcoma-180 A in mice.

Linking food webs to ecosystem processes: Piecewise linear models of soil microcosms

2008

Abstract A piecewise linear approach to link decomposer biomass and soil nitrogen dynamics is proposed. Dynamics of a detritus–fungus–nematode food chain were studied in a microcosm experiment and modelled to evaluate the role of fungal-feeding nematodes in N mineralization. The nematode dynamics switched from exponential growth to a resource-limited phase. At the same time the amount of ammonium nitrogen in soil started to increase, following an initial immobilization phase. Both nematode and ammonium dynamics could be described by two-phase linear equations. Two nitrogen models were compared. A model in which the nematode accounted for all mineralization could be fitted to the ammonium da…

Synthesis of a new bridgehead nitrogen heterocyclic system. Pyrrolo [2,1-f]-1,2,4-triazine derivatives

1979

1-Ureidopyrroles of type 6a,b prepared by the general method previously described (2), readily cyclized under basic conditions giving pyrrolo [2,1-f]-1,2,4-triazine-2,4(1H, 3H)dione derivatives.

ChemInform Abstract: Polycondensed Nitrogen Heterocycles. Part 25. Aminopyrrolo(1,2-f) phenanthridines by Decomposition of 2-(3-Azidophenyl)-1-arylpy…

2010

Acid catalyzed decomposition of the azido derivatives 4a-c gave rise to amino-hydroxy-phenylpyrroles of type 7 and 8 upon hydrolysis of the intermediate aryl nitrenium ions, together with the hydrogen abstraction compounds of type 3. The aminopyrrolo[1,2-f]phenanthridines 10, 11, and 12 were obtained by treatment with TFMSA of the azide 4d in which the ring being attacked was made more nucleophilic by the introduction of the methoxy group.