Nucleophilic Aromatic Substitution of Nitrobenzenes with Nitrite Ion

It is experimentally found that different renction courses exist when mtrite ion reacts with nitrobenzenes with different electron withdrawing groups. when it is substituted with strong electron withdrawing groups. self-condensation in aprotic polar solvent occurs to give symmnetrical disubstituted diphenyl ethers. However. when it is substituted with moderate electron withdrawing groups, no diphenyl ethers are obtained under the same conditions, instead, corresponding carboxylates are yielded. As a result. the applicability of this reaction is distinctly clarified

Single-crystal Cultivation and Structure Analysis of Unstable 1-Azido-2-chloro-4-nitrobenzene

The 1-azido-2-chloro-4-nitrobenzene was prepared by nucleophilic substitution between 2-chloro-4-nitro-1-(trifluoromethylsulfinyl)benzene and sodium azide, and its structure was characterized by NMR spectrum and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group P21/n, Z = 8 and Mr = 198.57. A cultivation process of the single crystal of unstable aryl azide was provided. The group of trifluoromethyl sulfinyl was found for the first time to be a new excellent leaving group of aromatic nucleophilic substitution reactions.

A Facile Route to Unsymmetrical Sulfide

Unsymmetrical sulfides can be generated by the reaction of chlorine substituted aromatic compounds in sulfoxide in the presence of fluorine anion in fair yield. A likely mechanism was proposed.

2,4-Dinitrophenyl Ether of Polyvinyl Alcohol and Polymer Bound Anionic SIGMA Complexes

A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP polymer was characterized by NMR, IR, and UV-visible spectroscopy. The reaction of PVA-DNP with sodium methoxide was followed by NMR and UV-visible spectroscopy. Evidence of polymer bound spirocyclic SIGMA complex, C-1 and C-3 polymer bound DNP-methoxy SIGMA complexes and the formation and C-1 methoxy complex of 2,4-dinitroanisole was observed.

Efficient synthesis of unsymmetrical diaryl thioethers via TBAF-mediated denitrative substitution of nitroarenes with PhSTMS under mild and neutral conditions

Tetrabutylammonium fluoride （TBAF） effectively facilitated a denitrative substitution reaction of electron-deficient nitroarenes with phenylthiotrimethylsilane （PhSTMS） under mild and base-free neutral conditions at room temperature, providing a practical and efficient synthesis of useful unsymmetrical diaryl thioethers. Nitroarenes bearing ortho- and para-positioned electron-withdrawing groups are the most reactive substrates, indicating that this reaction most possibly proceeded via the nucleophilic aromatic substitution （SNAr） mechanism.

Highly stable dioxin-linked metallophthalocyanine covalent organic frameworks

We report a series of highly stable metallophthalocyanine-based covalent organic frameworks(MPc-dxCOFs) linked by robust 1,4-dioxin bonds constructed through nucleophilic aromatic substitution(SNAr)reaction. The chemical structures and crystallinity of the COFs largely remain unchanged even after treating with boiling water(90°C), concentrated acids(12 mol/L HCl) or bases(12 mol/L Na OH), oxidizing(30% H_(2)O_(2)) or reducing agents(1 mol/L NaBH;) for three days due to their stable M-Pc building blocks and resilient dioxin linkers. With metallated phthalocyanine active sites regularly arranged in the stable framework structures, MPc-dx-COFs can be directly used as efficient electrocatalysts for the oxygen reduction reaction(ORR) without pyrolysis treatment that has commonly been used in previous studies.

C-S coupling with nitro group as leaving group via simple inorganic salt catalysis

An efficient and practical synthetic protocol to synthesize nonsymmetrical aryl thioethers by nucleophilic aromatic substitution(S_NAr)reaction of nitroarenes by thiols with potassium phosphate as the catalyst is described.Various moderate to strong electron-withdrawing functional groups are tolerated by the system to provide thioethers in a good to excellent yields.We also showed that the present method allows access to 3 drug examples in a short reaction time.Finally,mechanistic studies suggest that the reaction may form the classic Meisenheimer complex through a two-step additionelimination mechanism.