The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Bruce H Lipshutz - One of the best experts on this subject based on the ideXlab platform.
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Synthetic chemistry in water: applications to peptide synthesis and Nitro-Group reductions
Nature Protocols, 2019Co-Authors: Margery Cortes-clerget, Nicholas R. Lee, Bruce H LipshutzAbstract:Amide bond formation and aromatic/heteroaromatic Nitro-Group reductions represent two of the most commonly used transformations in organic synthesis. Unfortunately, such processes can be especially wasteful and hence environmentally harmful, and may present safety hazards as well, given the reaction conditions involved. The two protocols herein describe alternative technologies that offer solutions to these issues. Polypeptides can now be made in water at ambient temperatures using small amounts of the designer surfactant TPGS-750-M, thereby eliminating the use of organic solvents as the reaction medium. Likewise, a safe, inexpensive and efficient procedure is outlined for Nitro-Group reductions, using industrial iron in the form of carbonyl iron powder (CIP), an inexpensive item of commerce. The peptide synthesis will typically take, overall, 3–4 h for a simple coupling and 8 h for a two-step deprotection/coupling process. The workup usually consists of a simple extraction and acidic/basic aqueous washings. The Nitro reduction procedure will typically take 6–8 h to complete, including setup, reaction time and workup.Amide bond formation and aromatic Nitro-Group reductions are common reactions that are environmentally harmful. An alternative approach is to perform the reactions in water at ambient temperatures using small amounts of a designer surfactant.
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carbonyl iron powder a reagent for Nitro Group reductions under aqueous micellar catalysis conditions
Organic Letters, 2017Co-Authors: Agata A Bikovtseva, Margery Cortesclerget, Fabrice Gallou, Bruce H LipshutzAbstract:An especially mild, safe, efficient, and environmentally responsible reduction of aromatic and heteroaromatic Nitro-Group-containing educts is reported that utilizes very inexpensive carbonyl iron powder (CIP), a highly active commercial grade of iron powder. These reductions are conducted in the presence of nanomicelles composed of TPGS-750-M in water, a recyclable aqueous micellar reaction medium. This new technology also shows broad scope and scalability and presents opportunities for multistep one-pot sequences involving this reducing agent.
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sustainable and scalable fe ppm pd nanoparticle Nitro Group reductions in water at room temperature
Organic Process Research & Development, 2017Co-Authors: Christopher M Gabriel, Bruce H Lipshutz, Michael Parmentier, Christian Riegert, Marian Lanz, Sachin Handa, Fabrice GallouAbstract:An operationally simple and general process for the safe and selective reduction of Nitro Groups utilizing ppm Pd supported on Fe nanomaterials in aqueous solution of designer surfactant TPGS-750-M has been developed and successfully carried out at a 100 mmol scale. Preferred use of KBH4 as the hydride source, at ambient temperature and pressure, lends this process suitable for a standard reaction vessel alleviating the need for specialized hydrogenation equipment. Calorimetry data parallel those expected for a classical Nitro Group reduction when measuring the heat of reaction (−896 to −850 kJ/mol).
Benson M Kariuki - One of the best experts on this subject based on the ideXlab platform.
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Weak interactions in crystal engineering—understanding the recognition properties of the Nitro Group
New Journal of Chemistry, 2000Co-Authors: James M A Robinson, Douglas Philp, Kenneth D M Harris, Benson M KariukiAbstract:1,3,5-TriNitrobenzene and 1,3,5-triethynylbenzene cocrystallise to form a solid state structure in which the two components assemble to form segregated hydrogen-bonded tapes. This behaviour is rationalised, through the use of the Cambridge Structural Database and ab initio electronic structure calculations, in terms of the fundamental recognition properties of the Nitro Group. The recognition behaviour of the Nitro Group is a function of both the intrinsic electronic properties of the Nitro Group itself and the nature of the hydrogen bond donor with which it interacts.
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weak interactions in crystal engineering understanding the recognition properties of the Nitro Group
New Journal of Chemistry, 2000Co-Authors: James M A Robinson, Douglas Philp, Kenneth D M Harris, Benson M KariukiAbstract:1,3,5-TriNitrobenzene and 1,3,5-triethynylbenzene cocrystallise to form a solid state structure in which the two components assemble to form segregated hydrogen-bonded tapes. This behaviour is rationalised, through the use of the Cambridge Structural Database and ab initio electronic structure calculations, in terms of the fundamental recognition properties of the Nitro Group. The recognition behaviour of the Nitro Group is a function of both the intrinsic electronic properties of the Nitro Group itself and the nature of the hydrogen bond donor with which it interacts.
Fabrice Gallou - One of the best experts on this subject based on the ideXlab platform.
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carbonyl iron powder a reagent for Nitro Group reductions under aqueous micellar catalysis conditions
Organic Letters, 2017Co-Authors: Agata A Bikovtseva, Margery Cortesclerget, Fabrice Gallou, Bruce H LipshutzAbstract:An especially mild, safe, efficient, and environmentally responsible reduction of aromatic and heteroaromatic Nitro-Group-containing educts is reported that utilizes very inexpensive carbonyl iron powder (CIP), a highly active commercial grade of iron powder. These reductions are conducted in the presence of nanomicelles composed of TPGS-750-M in water, a recyclable aqueous micellar reaction medium. This new technology also shows broad scope and scalability and presents opportunities for multistep one-pot sequences involving this reducing agent.
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sustainable and scalable fe ppm pd nanoparticle Nitro Group reductions in water at room temperature
Organic Process Research & Development, 2017Co-Authors: Christopher M Gabriel, Bruce H Lipshutz, Michael Parmentier, Christian Riegert, Marian Lanz, Sachin Handa, Fabrice GallouAbstract:An operationally simple and general process for the safe and selective reduction of Nitro Groups utilizing ppm Pd supported on Fe nanomaterials in aqueous solution of designer surfactant TPGS-750-M has been developed and successfully carried out at a 100 mmol scale. Preferred use of KBH4 as the hydride source, at ambient temperature and pressure, lends this process suitable for a standard reaction vessel alleviating the need for specialized hydrogenation equipment. Calorimetry data parallel those expected for a classical Nitro Group reduction when measuring the heat of reaction (−896 to −850 kJ/mol).
Margery Cortes-clerget - One of the best experts on this subject based on the ideXlab platform.
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Synthetic chemistry in water: applications to peptide synthesis and Nitro-Group reductions
Nature Protocols, 2019Co-Authors: Margery Cortes-clerget, Nicholas R. Lee, Bruce H LipshutzAbstract:Amide bond formation and aromatic/heteroaromatic Nitro-Group reductions represent two of the most commonly used transformations in organic synthesis. Unfortunately, such processes can be especially wasteful and hence environmentally harmful, and may present safety hazards as well, given the reaction conditions involved. The two protocols herein describe alternative technologies that offer solutions to these issues. Polypeptides can now be made in water at ambient temperatures using small amounts of the designer surfactant TPGS-750-M, thereby eliminating the use of organic solvents as the reaction medium. Likewise, a safe, inexpensive and efficient procedure is outlined for Nitro-Group reductions, using industrial iron in the form of carbonyl iron powder (CIP), an inexpensive item of commerce. The peptide synthesis will typically take, overall, 3–4 h for a simple coupling and 8 h for a two-step deprotection/coupling process. The workup usually consists of a simple extraction and acidic/basic aqueous washings. The Nitro reduction procedure will typically take 6–8 h to complete, including setup, reaction time and workup.Amide bond formation and aromatic Nitro-Group reductions are common reactions that are environmentally harmful. An alternative approach is to perform the reactions in water at ambient temperatures using small amounts of a designer surfactant.
Chaoyang Zhang - One of the best experts on this subject based on the ideXlab platform.
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review of the establishment of Nitro Group charge method and its applications
Journal of Hazardous Materials, 2009Co-Authors: Chaoyang ZhangAbstract:Abstract On the basis of our previous work, a new approach, Nitro Group charge method (NGCM) is established and applied to understand, evaluate and predict the properties of Nitro compounds or explosives, including molecular stability, impact sensitivity and nitrating reaction. At first, the more negative Nitro charges ( Q Nitro ) correspond to the more stable Nitro compounds. Secondly, for all Nitro explosives in which the R Nitro bond is the weakest, Q Nitro can be regarded as a structural parameter to assess and predict the impact sensitivity. The more negative Q Nitro means the higher H 50 . Thirdly, the conditions, the velocities and the products’ occurrence ratios of some nitrating reactions can be approximately evaluated and compared using NGCM: the more negative Q Nitro corresponds to the easier and the faster reaction, and the higher occurrence ratio. Meanwhile, this idea of using charges on common atoms or Groups to investigate related properties can be generalized to some other systems such as azide explosives.
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investigation of correlation between impact sensitivities and Nitro Group charges in Nitro compounds
Journal of Physical Chemistry B, 2005Co-Authors: Chaoyang Zhang, Yigang Huang, Xiaodong Zhao, Haishan DongAbstract:A new method of calculating the Mulliken net charges of the Nitro Group, QNO2, to assess impact sensitivities for Nitro compounds is established. All calculations including optimizations and Mulliken population and frequency analyses are performed by density functional theory (DFT) and the general gradient approximation (GGA) method in Acceryls' code Dmol3 with the Beck-LYP hybrid functional and the DNP basis set. As a result, the charges on Nitro Group can be regarded as a structural parameter to estimate the impact sensitivity on the bond strength, oxygen balance, and molecular electrostatic potential. The compound with more −QNO2 will be insensitive and gives a large value of impact sensitivity H50. This method considering the molecular structure is applicable for almost all Nitro compounds when the C−NO2, N−NO2, or O−NO2 bond is the weakest in the molecule. According to the results in this paper, the compounds with −QNO2 >0.23e show H50 ≤ 0.4 m.
