نتایج جستجو برای: copolyamide imides
تعداد نتایج: 737 فیلتر نتایج به سال:
The C-C coupling of N,N'-bis(5-norbornene-2,3-dicarboximide) (3) and N,N'-bis(7-oxa-5-norbornene-2,3-dicarboximide) (6) with aryl and heteroaryl iodides gave under reductive Heck conditions the C-aryl(hetaryl), substituted N,N'-bistricyclic imides 7a-f and 8a,b. The fused spiro-1,3-indandionolylpyrrolidine compounds, 9, 10 and 11 were also obtained from ninhydrine, sarcosine and 3 or 6 via [3+2...
A general procedure for the synthesis of enantiopure â-substituted, â-amino acids is presented. Alkylation of the sodium enolates derived from chiral N-acyloxazolidinone imides 2 (R ) Me, i-Pr, t-Bu, Ph, Bn) with tert-butyl bromoacetate afforded the 2-substituted succinate derivatives 3 in good yields (82-89%) and with high selectivity (g93:7). Following hydrolysis, Curtius rearrangement of the...
Cyclic imides such as succinimides, maleimides, glutarimides, phthalimides and their derivatives contain an imide ring and a general structure -CO-N(R)-CO- that confers hydrophobicity and neutral characteristic. A diversity of biological activities and pharmaceutical uses have been attributed to them, such as antibacterial, antifungal, antinociceptive, anticonvulsant, antitumor. In spite of the...
Thermodynamic and kinetic considerations of nitrogen carriers for chemical looping ammonia synthesis
Abstract Ammonia (NH 3 ) is a promising clean energy carrier, provided that its production driven by renewable rather than fossil fuel-based Haber–Bosch (H–B) process. Chemical looping ammonia synthesis (denoted as CLAS) can intervene in the ubiquitous scaling relations catalytic separately feeding reactants to nitrogen carrier achieve atmospheric operation, which provides an alternative synthe...
Z. Naturforsch. 51 b, 409-416 (1996); eingegangen am 28. Juni 1995 Reduction, Narthigenine, Butyrolactones, Butyrolactams, Tetramic Acids A series of potentially cytotoxic a,/?-unsaturated 7 -hydroxy-butyrolactones, -lactams and -thiolactones has been synthesized via regioselective hydride reduction of the appropriate maleic acid anhydrides, imides and thioanhydrides. By this means a straightfo...
A catalytic, asymmetric process for the synthesis of 1,4-benzoxazinones from o-benzoquinone imides and ketene enolates is reported. Addition of Lewis acids (Zn(OTf)2, In(OTf)3, and in particular Sc(OTf)3) creates a bifunctional catalytic system that dramatically increases the reaction rate and the yield of these non-natural amino acid precursors while preserving the remarkable enantioselectivit...
Intramolecular [2+2] photocycloaddition of aromatic chain imides possessing bis-phenanthrene moieties afforded straight and cross ring closure products. The ratio of cycloadducts was dependent on reaction time and temperature, which resulted in a reversal of regioselectivity. The reaction was proved to involve a retro cycloaddition. The cross ring closure products were formed predominantly in t...
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