Neutronenbeugung an der Tieftemperaturmodifikation von Rubidiumdeuteroamid

Neutron Diffraction of the Low Temperature Modification of Rubidium Deutero Amide A polycrystalline sample of RbND₂ was prepared by reaction of liquid ND₃ and Rb (320 K, 4 d). Rietveld refinement of neutron powder diffraction data collected on the E2 (HMI-BENSC, Berlin) yielded the deuterium positions and allowed the temperature factors of all atoms to be refined anisotropically: space group P2₁/m, Z = 2, a = 4.846(1) Å, b = 4.136(1) Å, c = 6.396(2) Å, β = 98.051(7)°, N(I/σ_(I) > 1) = 179, N(Var.) = 25, R_P = 0.025, wR_P = 0.032, R_B(I/σ_(I) > 1) = 0.095. In a monoclinic distorted rock salt structure the amide ions are oriented antiferroelectrically in almost planar zick-zack chains.     

Modified polyisophthalamides bearing pendent benzoylamino and/or (phenylamino)carbonyl groups

A series of modified polyisophthalamides were prepared from 5-(phenylamino)carbonyl-1,3-phenylenediamine and 5-benzoylamino-isophthalic acid. The polymers were characterized by FT-IR, ¹H-NMR, inherent viscosity, water absorption measurements, x-ray, DTA, TGA, and isothermal gravimetric analysis. The modified polyamides were amorphous and softened at 210–245°C. They showed higher hydrophilicity and better solubility in certain solvents such as DMF, DMSO, CCl₃COOH, cyclohexanone, and m-cresol than the corresponding unmodified polyamide. They started to lose weight at 329–344°C in N₂ or air, whereas the degradation of unmodified polyamide started at 320°C in N₂ and 308°C in air. © 1996 John Wiley & Sons, Inc.     

Recent Advances in Visible-Light-Mediated Amide Synthesis

Visible-light photoredox catalysis has attracted tremendous interest within the synthetic community. As such, the activation mode potentially provides a more sustainable and efficient platform for the activation of organic molecules, enabling the invention of many controlled radical-involved reactions under mild conditions. In this context, amide synthesis via the strategy of photoredox catalysis has received growing interest due to the ubiquitous presence of this structural motif in numerous natural products, pharmaceuticals and functionalized materials. Employing this strategy, a wide variety of amides can be prepared effectively from halides, arenes and even alkanes under irradiation of visible light. These methods provide a robust alternative to well-established strategies for amide synthesis that involve condensation between a carboxylic acid and amine mediated by a stoichiometric activating agent. In this review, the representative progresses made on the synthesis of amides through visible light-mediated radical reactions are summarized.     

Configuration effects of ortho,meta, and para linkages on liquid crystallinity during thin‐film polymerization of poly(ester‐amide)s

By in situ thin‐film polymerization conducted on a heating stage of a polarizing microscope, we have investigated the effects of monomer structures on the formation of liquid crystallinity. Three polymerization systems studied are 2,6‐acetoxynaphthoic acid (ANA)/acetoxy acetanilide (AAA)/phthalic acid (PA), ANA/AAA/isophthalic acid (IA) and ANA/AAA/terephthalic acid (TA). In the three systems, PA, IA, and TA may create an ortho, a meta, and a para linkage, respectively. The formation of liquid crystallinity was found strongly dependent on the straightness and configuration of monomeric units. For ANA/AAA/PA and ANA/AAA/IA systems, there exists the critical ANA content to yield the liquid crystalline phase. Below this critical content, either amorphous phase forms or crystallization occurs during polymerization. Experimental data also indicate that defect density in the polymerization product reduces with increasing ANA content. Surprisingly, for the first time, we have observed that the ANA/AAA/PA system has a higher tendency to yield liquid crystallinity than the ANA/AAA/IA system. For the ANA/AAA/TA system, the polycondensation reaction is incomplete if the TA content is too high because of the low reactivity and the high melting point of TA. Polymerization of the ANA/AAA/TA system does not yield totally random copolymers because the liquid crystal phase appears before all TA crystals disappear during the polymerization. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2221–2231, 2000     

Poly(ester amide)s derived from L‐tartaric acid and amino alcohols. II. Aregic polymers

A series of aregic poly(ester amide)s (a‐PEAT6) with ester/amide ratios (a : b) varying from 1 : 19 to 1 : 2 were prepared with L ‐tartaric acid, 6‐aminohexanol, and 1,6 hexanediamine as the starting materials. Polycondensation in a solution of the diamine with mixtures of pentachlorophenyl‐activated di‐O‐methyl‐L ‐tartaric and 6‐aminohexyl‐di‐O‐methyl‐L ‐tartaric acids led to a‐PEAT6(a : b), with the a : b ratio determined by the composition of the feed. The newly synthesized poly(ester amide)s were characterized by elemental analysis, size exclusion chromatography, and IR and NMR spectroscopy. They had number‐average molecular weights between 25,000 and 45,000 and were highly crystalline, showing melting temperatures ranging from 100 to 230 °C and glass‐transition temperatures oscillating between 50 and 100 °C. The thermal degradation of a‐PEAT6(a : b) began above 200 °C and concluded with a final weight loss between 60 and 90% of the initial mass. The process evolved with the formation of cyclic tartarimide units and extensive main‐chain scissions. The degradation mechanism is discussed in relation to the chemical composition and microstructure of the polymers. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2687–2696, 2000     

The Synthesis of (4E)‐N‐(4‐chlorophenyl)‐5‐substituted‐2‐diazo‐3‐oxopent‐4‐enoic Acid Amides

The (4E)‐N‐(4‐chlorophenyl)‐5‐(3‐chlorophenyl)‐2‐diazo‐3‐oxopent‐4‐enoic acid amides 5a˜j were synthesized with N‐(4‐chlorophenyl)‐2‐diazo‐3‐oxobutyramide 4 from p‐chloroaniline and various arylaldehydes. The yielded products 5a˜j were investigated with NMR, MS, IR, and X‐ray crystallographic techniques.     

Target-based design,synthesis and biological activity of new pyrazole amide derivatives

Based on the similarities in the conformation of VS008 (N-(4-methylphenyl)-3-(tert-butyl)-1-(phenylmethyl)-1H-pyrazole-5-carboxamide) and BYIO6830 (N'-(3,5-dimethylbenzoyl)-N'-tert-butyl-5-methyl-2,3-dihydro-1,4-benzodioxine-6-carbohydrazide) bound to the active site of the EcR subunit of the ecdysone receptor (EcR)-ultraspiracle protein (USP) heterodimeric receptor, a series of new pyrazole amide derivatives were designed and synthesized. Their structures were confirmed by IR, ¹H NMR, ¹³C NMR and elemental analysis. Results from a preliminary bioassay revealed that two of the pyrazole derivatives exhibited promising insecticidal activity. Specifically, compounds 6e and 6i exhibited good activity against Helicoverpa armigera (cotton bollworm) at low concentration. Symptoms displayed by tebufenozide-treated H. armigera were identical with those displayed by its treated counterpart. 6i showed the same poisoning symptoms as those of tebufenozide. In addition, results from molecular docking result indicated that the binding modes of 6e and 6i at the active site of the EcR subunit of the heterodimeric receptor were similar to that of the bound tebufenozide.