scholarly journals Selective rearrangement of terminal epoxides into methylketones catalysed by a nucleophilic rhodium–NHC–pincer complex

2015 ◽  
Vol 51 (10) ◽  
pp. 1897-1900 ◽  
Author(s):  
Eva Jürgens ◽  
Barbara Wucher ◽  
Frank Rominger ◽  
Karl W. Törnroos ◽  
Doris Kunz
Keyword(s):  
High Yield ◽  
Mild Conditions ◽  
Pincer Complex ◽  
Very High

The highly nucleophilic complex 1 isomerises terminal epoxides exclusively to the respective methylketones in very high yield under mild conditions.

DURIMPHY

Alloy Digest ◽  
2007 ◽  
Vol 56 (2) ◽  
Keyword(s):  
Tensile Strength ◽  
Corrosion Resistance ◽  
Yield Strength ◽  
Physical Properties ◽  
Precipitation Hardening ◽  
Heat Treating ◽  
High Yield ◽  
High Yield Strength ◽  
Precision Alloys ◽  
Very High

Abstract Durimphy is a maraging steel with 1724 MPa (250 ksi) tensile strength and a very high yield strength due to precipitation hardening. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: FE-140. Producer or source: Metalimphy Precision Alloys.

Radioactive Fall-Out Hazards From Surface Bursts of Very High Yield Nuclear Weapons, Sanitized Version

1954 ◽  
Author(s):  
D. C. Borg ◽  
L. D. Gates ◽  
T. A. Gibson ◽  
Pain Jr. ◽  
Jr R. W.
Keyword(s):  
Nuclear Weapons ◽  
High Yield ◽  
Very High

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

Eco-Friendly Synthesis of Sulphonic Acid Oxime Esters Catalyzed by 2-(1H-Benzotriazole-1-yl)-1,1,3,3-Tetramethyluronium Tetrafluoroborate

2014 ◽  
Vol 525 ◽  
pp. 93-96
Author(s):  
Wei Shi ◽  
Ji Ming Zhang ◽  
Jian Hua Zhou ◽  
Jian Hua Zhou ◽  
Song Song Ding
Keyword(s):  
High Selectivity ◽  
Sulphonic Acid ◽  
Present Approach ◽  
High Yield ◽  
Facile Synthesis ◽  
Reaction Duration ◽  
Mild Conditions ◽  
Environmental Friendly

Herein we describle a facile synthesis of sulphonic acid oxime esters in acetonitrile from the corresponding sulphonic acids and oximes catalyzed by the environmental friendly 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) in the presence of triethylamine (TEA) under mild conditions. The present approach offers the advantages of a clean reaction, simple methodology, employing readily available catalyst, short reaction duration, high selectivity and high yield.

Nuclear Recoil Reactions in Organo-Manganese Compounds. V. —Mn(CO)5 Target Compounds

1971 ◽  
Vol 49 (12) ◽  
pp. 2175-2178 ◽  
Author(s):  
H. Jakubinek ◽  
S. C. Srinivasan ◽  
D. R. Wiles
Keyword(s):  
Thermal Dissociation ◽  
Nuclear Recoil ◽  
Radical Reactions ◽  
High Yield ◽  
Target Molecule ◽  
Product Spectrum ◽  
Rapid Exchange ◽  
Manganese Compounds ◽  
Very High

HMn(CO)5, DMn(CO)5, CH3Mn(CO)5, and C6H5Mn(CO)5 have been irradiated with neutrons and the product spectrum of 56Mn-containing molecules determined. The results show that H56Mn(CO)5 is formed in all cases: 21.0%, 23.6% from HMn(CO)5 and DMn(CO)5 targets, respectively, and 6.9% and 2.1% from CH3Mn(CO)5 and C6H5Mn(CO)5, respectively. Thus the yields are not in accord with the number of H atoms per target molecule. Preliminary experiments show that •*Mn(CO)5 exchanges rapidly with HMn(CO)5 and DMn(CO)5 and very slowly with CH3Mn(CO)5 and C6H5Mn(CO)5. It is deduced that the very high yield of H56Mn(CO)5 in HMn(CO)5 and DMn(CO)5 targets could arise from the rapid exchange, while the lower yields of H56Mn(CO)5 in other targets must likely come from radical reactions following thermal dissociation of the target molecule.

scholarly journals Multi-curie production of gallium-68 on a biomedical cyclotron and automated radiolabelling of PSMA-11 and DOTATATE

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Helge Thisgaard ◽  
Joel Kumlin ◽  
Niels Langkjær ◽  
Jansen Chua ◽  
Brian Hook ◽  
...  
Keyword(s):  
Radiochemical Purity ◽  
High Yield ◽  
Clinical Use ◽  
Automated Production ◽  
Automated Method ◽  
Gallium 68 ◽  
High Yields ◽  
High Level ◽  
Mev Protons ◽  
Very High

Abstract Background With increasing clinical demand for gallium-68, commercial germanium-68/gallium-68 ([68Ge]Ge/[68Ga]Ga) generators are incapable of supplying sufficient amounts of the short-lived daughter isotope. In this study, we demonstrate a high-yield, automated method for producing multi-Curie levels of [68Ga]GaCl3 from solid zinc-68 targets and subsequent labelling to produce clinical-grade [68Ga]Ga-PSMA-11 and [68Ga]Ga-DOTATATE. Results Enriched zinc-68 targets were irradiated at up to 80 µA with 13 MeV protons for 120 min; repeatedly producing up to 194 GBq (5.24 Ci) of purified gallium-68 in the form of [68Ga]GaCl3 at the end of purification (EOP) from an expected > 370 GBq (> 10 Ci) at end of bombardment. A fully automated dissolution/separation process was completed in 35 min. Isolated product was analysed according to the Ph. Eur. monograph for accelerator produced [68Ga]GaCl3 and found to comply with all specifications. In every instance, the radiochemical purity exceeded 99.9% and importantly, the radionuclidic purity was sufficient to allow for a shelf-life of up to 7 h based on this metric alone. Fully automated production of up to 72.2 GBq [68Ga]Ga-PSMA-11 was performed, providing a product with high radiochemical purity (> 98.2%) and very high apparent molar activities of up to 722 MBq/nmol. Further, manual radiolabelling of up to 3.2 GBq DOTATATE was performed in high yields (> 95%) and with apparent molar activities (9–25 MBq/nmol) sufficient for clinical use. Conclusions We have developed a high-yielding, automated method for the production of very high amounts of [68Ga]GaCl3, sufficient to supply proximal radiopharmacies. The reported method led to record-high purified gallium-68 activities (194 GBq at end of purification) and subsequent labelling of PSMA-11 and DOTATATE. The process was highly automated from irradiation through to formulation of the product, and as such comprised a high level of radiation protection. The quality control results obtained for both [68Ga]GaCl3 for radiolabelling and [68Ga]Ga-PSMA-11 are promising for clinical use.

Regioselective 1,4-conjugate aza-Michael addition of dienones with benzotriazole

2017 ◽  
Vol 23 (4) ◽  
Author(s):  
Zheng Li ◽  
Tianpeng Li ◽  
Rugang Fu ◽  
Jingya Yang
Keyword(s):  
Transition Metal ◽  
Michael Addition ◽  
Potassium Acetate ◽  
High Yield ◽  
Metal Free ◽  
Mild Conditions

AbstractThe regioselective 1,4-conjugate aza-Michael addition of dienones with benzotriazole catalyzed by potassium acetate is described. A series of 3-(benzotriazol-1-yl)-1,5-diarylpent-4-en-1-ones were efficiently synthesized under mild conditions. This protocol has advantages of transition-metal free catalyst, high yield and high regioselectivity.

scholarly journals High yield accelerated reactions in nonvolatile microthin films: chemical derivatization for analysis of single-cell intracellular fluid

2018 ◽  
Vol 9 (40) ◽  
pp. 7779-7786 ◽  
Author(s):  
Zhenwei Wei ◽  
Xiaochao Zhang ◽  
Jinyu Wang ◽  
Sichun Zhang ◽  
Xinrong Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Single Cell ◽  
Individual Cell ◽  
High Yield ◽  
Chemical Derivatization ◽  
Intracellular Fluid ◽  
Mild Conditions ◽  
Successful Analysis ◽  
Trace Components

The identification of trace components from an individual cell can require derivatization under mild conditions for successful analysis by mass spectrometry (MS).

Sign in / Sign up

Export Citation Format

Share Document