scholarly journals A modular phosphate tether-mediated divergent strategy to complex polyols

2014 ◽  
Vol 10 ◽  
pp. 2332-2337 ◽  
Author(s):  
Paul R Hanson ◽  
Susanthi Jayasinghe ◽  
Soma Maitra ◽  
Cornelius N Ndi ◽  
Rambabu Chegondi
Keyword(s):  
Reduction Process ◽  
Phosphoryl Chloride ◽  
One Pot ◽  
Simple Order ◽  
Coupling Strategy ◽  
Phosphate Tether

An efficient and divergent synthesis of polyol subunits utilizing a phosphate tether-mediated, one-pot, sequential RCM/CM/reduction process is reported. A modular, 3-component coupling strategy has been developed, in which, simple “order of addition” of a pair of olefinic-alcohol components to a pseudo-C 2-symmetric phosphoryl chloride, coupled with the RCM/CM/reduction protocol, yields five polyol fragments. Each of the product polyols bears a central 1,3-anti-diol subunit with differential olefinic geometries at the periphery.

scholarly journals Facile preparation and excellent microwave absorption properties of an RGO/Co0.33Ni0.67 lightweight absorber

RSC Advances ◽  
2017 ◽  
Vol 7 (69) ◽  
pp. 43831-43838 ◽  
Author(s):  
Hai Pan ◽  
Mingzhen Xu ◽  
Qing Qi ◽  
Xiaobo Liu
Keyword(s):  
Microwave Absorption ◽  
Reduction Process ◽  
Thermal Reduction ◽  
Thermal Method ◽  
Absorption Properties ◽  
One Pot ◽  
Microwave Absorption Properties ◽  
Facile Preparation

A lightweight absorber with an ordered sandwich-like structure was fabricated using a simple one-pot solvent-thermal method and thermal reduction process.

A Comprehensive One-Pot Synthesis of Protected Cysteine and Selenocysteine SPPS Derivatives

2014 ◽  
Vol 21 (12) ◽  
pp. 1257-1264
Author(s):  
Stevenson Flemer
Keyword(s):  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Reduction Process ◽  
Building Blocks ◽  
High Yield ◽  
One Pot ◽  
Peptide Models ◽  
Direct Use ◽  
Proof Of Principle ◽  
Subsequent Incorporation

A proof-of-principle methodology is presented in which all commercially-available cysteine (Cys) and selenocysteine (Sec) solid phase peptide synthesis (SPPS) derivatives are synthesized in high yield from easily prepared protected dichalcogenide precursors. A Zn-mediated biphasic reduction process applied to a series of four bis-Nα-protected dichalcogenide compounds allows facile conversion to their corresponding thiol and selenol intermediates followed by insitu S- or Se-alkylation with various electrophiles to directly access twenty one known Cys and Sec SPPS derivatives. Most of these derivatives were able to be precipitated in crude form out of petroleum ether in sufficient purity for direct use as peptide building blocks. Subsequent incorporation of these derivatives into peptide models nicely illustrates their viability and applicability toward SPPS.

The synthesis of arylcyanamides: a copper-catalyzed consecutive desulfurization and C–N cross-coupling strategy

2018 ◽  
Vol 42 (2) ◽  
pp. 918-922 ◽  
Author(s):  
S. N. Murthy Boddapati ◽  
Naresh Polam ◽  
Baby Ramana Mutchu ◽  
Hari Babu Bollikolla
Keyword(s):  
Cross Coupling ◽  
One Pot ◽  
Highly Efficient ◽  
Simple Protocol ◽  
Coupling Strategy

A one pot highly efficient and simple protocol for the construction of aromatic cyanamides from thioureaviadesulphurization/C–N cross coupling using a cheap, readily available and air stable copper source as a catalyst has been described.

scholarly journals Ni-catalyzed deaminative cross-electrophile coupling of Katritzky salts with halides via C─N bond activation

2019 ◽  
Vol 5 (6) ◽  
pp. eaaw9516 ◽  
Author(s):  
Shengyang Ni ◽  
Chun-Xiao Li ◽  
Yu Mao ◽  
Jianlin Han ◽  
Yi Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Primary Amines ◽  
One Pot ◽  
Carbon Centers ◽  
Alkyl Bromides ◽  
Wide Range ◽  
Coupling Strategy ◽  
The One

The reductive cross-coupling of sp3-hybridized carbon centers represents great synthetic values and insurmountable challenges. In this work, we report a nickel-catalyzed deaminative cross-electrophile coupling reaction to construct C(sp)─C(sp3), C(sp2)─C(sp3), and C(sp3)─C(sp3) bonds. A wide range of coupling partners including aryl iodides, bromoalkynes, or alkyl bromides are stitched with alkylpyridinium salts that derived from the corresponding primary amines. The advantages of this methodology are showcased in the two-step synthesis of the key lactonic moiety of (+)-compactin and (+)-mevinolin. The one-pot procedure without isolation of alkylpyridinium tetrafluoroborate salt is also proven to be successful. This cross-coupling strategy of two electrophiles provides a highly valuable vista for the convenient installation of alkyl substituents and late functionalizations of sp3 carbons.

‘Green' Synthesis of 2-Substituted 6-Hydroxy-[3H]-pyrimidin-4-ones and 4,6-Dichloropyrimidines: Improved Strategies and Mechanistic Study

2015 ◽  
Vol 68 (5) ◽  
pp. 814 ◽  
Author(s):  
Andreas Opitz ◽  
Werner Sulger ◽  
Ewald Daltrozzo ◽  
Rainer Koch
Keyword(s):  
Strong Acid ◽  
Nitrogen Heterocycle ◽  
Mechanistic Study ◽  
Salt Formation ◽  
Phosphoryl Chloride ◽  
One Pot ◽  
General Applicability ◽  
Aqueous Sodium Carbonate ◽  
Weak Complexes ◽  
First Time

An improved route to 2-substituted 6-hydroxy-[3H]-pyrimidin-4-ones 4 and to 2-substituted 4,6-dichloropyrimidines 5 is reported. Without using highly toxic reactants, compounds 4 can be prepared conveniently in a one pot synthesis on a one mol scale with average yields up to 80 %. 4,6-Dichloropyrimidines 5, which are usually prepared in small quantities, are synthesized with average yields of 80 %, using up to 80 g of starting material. The mechanism of the chlorination of 4 is investigated computationally for the first time. The results suggest that the chlorination with phosphoryl chloride occurs in an alternating phosphorylation–chlorination manner (pathway 1) which is preferred over a sequence which starts with two phosphorylations. The investigated 4,6-dichloropyrimidines described herein form strong complexes with dichlorophosphoric acid but weak complexes with hydrochloric acid (generated during workup). These latter complexes explain the necessity of using aqueous sodium carbonate during the working up. In order to prevent possible formation of pyrimidinium salts between intermediates or the final dichloropyrimidines and unreacted hydroxypyrimidone, the latter could be deactivated with a strong acid such as dichlorophosphoric acid, thus allowing chlorination but prohibiting salt formation. Because of its general applicability to all nitrogen heterocycle chlorinations with phosphoryl chloride, the proposed route to dichloropyrimidines without solvent or side products, using less toxic reactants, is of general synthetic interest.

scholarly journals Comparative Studies on Thermal, Mechanical, and Flame Retardant Properties of PBT Nanocomposites via Different Oxidation State Phosphorus-Containing Agents Modified Amino-CNTs

Nanomaterials ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 70 ◽  
Author(s):  
San-E Zhu ◽  
Li-Li Wang ◽  
Hao Chen ◽  
Wei Yang ◽  
Anthony Yuen ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Oxidation State ◽  
High Performance ◽  
Melt Blending ◽  
Phosphoryl Chloride ◽  
One Pot ◽  
Blending Method ◽  
Phosphorus Containing ◽  
Flame Retardant Properties ◽  
Thermal Stability Of

High-performance poly(1,4-butylene terephthalate) (PBT) nanocomposites have been developed via the consideration of phosphorus-containing agents and amino-carbon nanotube (A-CNT). One-pot functionalization method has been adopted to prepare functionalized CNTs via the reaction between A-CNT and different oxidation state phosphorus-containing agents, including chlorodiphenylphosphine (DPP-Cl), diphenylphosphinic chloride (DPP(O)-Cl), and diphenyl phosphoryl chloride (DPP(O3)-Cl). These functionalized CNTs, DPP(Ox)-A-CNTs (x = 0, 1, 3), were, respectively, mixed with PBT to obtain the CNT-based polymer nanocomposites through a melt blending method. Scanning electron microscope observations demonstrated that DPP(Ox)-A-CNT nanoadditives were homogeneously distributed within PBT matrix compared to A-CNT. The incorporation of DPP(Ox)-A-CNT improved the thermal stability of PBT. Moreover, PBT/DPP(O3)-A-CNT showed the highest crystallization temperature and tensile strength, due to the superior dispersion and interfacial interactions between DPP(O3)-A-CNT and PBT. PBT/DPP(O)-A-CNT exhibited the best flame retardancy resulting from the excellent carbonization effect. The radicals generated from decomposed polymer were effectively trapped by DPP(O)-A-CNT, leading to the reduction of heat release rate, smoke production rate, carbon dioxide and carbon monoxide release during cone calorimeter tests.

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