Catalyzed double Michael addition of anilines to vinyl sulfone

Substituted anilines and vinyl sulfone undergo a facile double Michael addition to form substituted phenylthiomorpholine dioxide, catalyzed with AlCl₃ or H₃PO₄. Scope and conditions were explored.     

Trifluoromethanesulfonyl azide: an efficient reagent for the preparation of α-cyano-α-diazo carbonyls and an α-sulfonyl-α-diazo carbonyl

The reaction scope of trifluoromethanesulfonyl azide in diazo transfer reactions was extended to include the preparation of α-cyano-α-diazo-carbonyls, phenyl sulfonyl diazoacetophenone and diethyl diazomalonate in high yields. The effect of the bases used in the diazo transfer reactions were found to have a dramatic influence on the success of the reaction with pyridine being the base of choice.     

Effects of the structure on the properties of new poly(arylene ether sulfone)s containing naphthalene units

A series of new poly(arylene ether sulfone)s has been obtained by solution condensation polymerisation starting from 1,5- and 2,6-bis-(4-fluorosulfonyl)naphthalene with various aromatic dihydroxy compounds. The polymers, obtained in quantitative yields, possessed inherent viscosities in the range 0.28-0.68 dl g⁻¹, had good thermal stability (10% weight loss temperatures were above 405 and 420 °C respectively in nitrogen and air) and high glass transition temperatures (in the range 217-258 °C). They have been characterised by elemental and infrared analyses, GPC and wide-angle X-ray diffraction. The properties of these poly(arylene ether sulfone)s have been compared with those of the corresponding poly(arylene ether ketone)s.     

Solvent effects on catalytic activity of manganese porphyrins with cationic,anionic and uncharged meso substituents: Indirect evidence on the nature of active oxidant species

Oxidation of cyclohexene and styrene with sodium periodate and tetra‐n‐butylammonium periodate (TBAP) catalyzed by MnT(3‐MePy)P(OAc), MnT(4‐SO₃)PP(OAc) and MnTPP(OAc) has been studied in water, methanol, acetonitrile and dichloromethane as solvents. The results show significant dependence of the product distribution on the type of solvent and the electronic nature of the aryl substituents introduced at the porphyrin periphery. While the oxidation of cyclohexene and styrene in the presence of MnT(3‐MePy)P(OAc) and MnTPP(OAc) in water (also in methanol) gave the corresponding epoxides as nearly the sole product, performing the reactions in the presence of MnT(4‐SO₃)PP(OAc) yielded the products of allylic oxidation, cyclohexene‐2‐ol and cyclohexene‐2‐one and acetophenone as the major products. In the case of styrene, performing the reaction in the presence of MnT(4‐SO₃)PP(OAc), MnT(3‐MePy)P(OAc) and MnTPP(OAc) in acetonitrile gave a mixture of styrene oxide and acetophenone as the products. Under the same conditions, the oxidation of cyclohexene afforded cyclohexene oxide as approximately the exclusive product. Furthermore, the oxidation of olefins in dichloromethane gave the corresponding epoxide as the exclusive products. The product distributions observed in the protic and aprotic solvents were used to provide indirect evidence on the relative contribution and reactivity of high valent manganese oxo and periodato Mn(III) porphyrin species to the oxidation reactions.     

Self-cleaning Anti-fouling TiO2/Poly(aryl ether sulfone) Composite Ultrafiltration Membranes

A series of novel TiO2/poly(aryl ether sulfone) ultrafiltration membranes with anti-fouling and self-cleaning properties was designed and prepared. First, anti-photocatalytic degraded fluorine contained polv(aryl ether sulfone) matrix(PAES-F) was synthesized. Then the composite membranes were prepared via TiO2 nanopartides and PAES-F polymer matrix by solution blending and non-solvent induced phase inversion methods. Further, separation efficiency, fouling behavior and self-cleaning property of the composite ultrafiltration(UF) membranes were investigated by dead-end filtration experiments using a polyacn lamide solution. The composite UF membranes exhibited outstanding self-cleaning efficiency and anti-photocatalytic degraded property after exposure to simulated sunliglit irradiation.The water flux recovery ratios(FRR)of the optimal composite UF membranes could reach 74.24%, which was attributable to photocatalytic degradation of the organic contaminant by TiO2. And the retention rates of the composite UF membranes could maintain over 97%, which indicated the excellent photocatalytic degradation resistance of the fluorine contained PAES-F matrix. The novel high perfomiance composite UF membranes have a broad application prospect in water treatment.     

茶螺烷酮合成的新工艺

以α-紫罗兰酮为原料,经间氯过氧苯甲酸环氧化、甲醇钠开环、超声波辐射Pd/C催化甲酸铵选择性碳碳双键加H、硼氢化钠还原、脱水环化及乙酰丙酮亚钴催化烯丙位氧气氧化等6步反应,以总收率52.6％合成了食用香料2,6,10,10-四甲基-1-氧杂-螺[4.5]-6-癸烯-8-酮(茶螺烷酮)。 用IR、1H NMR、MS谱及元素分析等测试技术表征了产物的结构和组成。     

Catalytic activity of chiral chelating N-heterocyclic carbene palladium complexes towards asymmetric allylic alkylation

Abstract

The catalytic activity of a series of chiral heteroaryl coordinated chelating N-heterocyclic carbene (NHC) palladium complexes towards asymmetric allylic alkylation (AAA) were presented here. The effects of different N-substituents, NHC backbones and chelate rings on the catalytic activity and the enantioselectivity of the alkylation of (E)-1,3-diarylallyl acetates with dialkyl malonate were investigated. The results showed that, under the optimized conditions, complexes 3a, 3b, and 3i carrying the pyridinyl-coordinated five-membered chelate ring showed high catalytic activity and chiral induction efficiency. The corresponding alkylated products were obtained in high yields with moderate ee. Furthermore, it was found that the substituents of (E)-1,3-diarylallyl acetates and the type of the nucleophile affect the results as well.     

Sulfonated Condensed Polynuclear Aromatic (S-Copna) Resin Catalyzed Selective Oxidation of Sulfides to Sulfoxides or Sulfones Using Hydrogen Peroxide

Abstract

Sulfonated condensed polynuclear aromatic (S-COPNA) resin was found to be a highly efficient, environmentally friendly, recyclable heterogeneous catalyst for the oxidation of alkyl and aryl sulfides to the corresponding sulfoxides or sulfones, in good yields under mild reaction conditions using 30% hydrogen peroxide as an oxidant.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Synthesis of the S-COPNA resin catalyst. Spectroscopic data for compounds.     

Addition of Organometallic Reagents to Chiral N‐Methoxylactams: Enantioselective Syntheses of Pyrrolidines and Piperidines

Enantioselective iridium‐catalyzed allylic substitutions were used to prepare N‐allyl hydroxamic acid derivatives that were suitable for ring‐closing metathesis, giving N‐methoxylactams. Reactions of these derivatives with Grignard or organolithium compounds gave hemiaminals, which could be reduced diastereoselectively via acyliminium intermediates to give cis‐piperidines or cis‐pyrrolidines with substituents in the 2,6‐ or 2,5‐positions, respectively. In addition, compounds with a quaternary carbon center could be synthesized by corresponding reactions with potassium cyanide/AcOH. The procedures were applied in the syntheses of alkaloids (?)‐209D and (+)‐prosophylline.