Synthesis of Bacterial Metabolites of Polycyclic Aromatic Hydrocarbons: Benzochromenones,o‐Carboxyvinylnaphthoates,and o‐Substituted Aryl‐α‐Oxobutenoates

Bacterial metabolites of phenanthrene and anthracene include benzochromenones, o‐carboxyvinylnaphthoates, and o‐substituted aryl α‐oxobutenoates, which were synthesized with the Wittig reaction, the Heck reaction, and coupling of aromatic aldehyde with pyruvate.     

Synthesis of N‐Aryl‐2‐substituted Tetrahydrobenzimidazoles via Direct N‐Arylation

A series of novel N‐aryl‐2‐substituted tetrahydrobenzimidazoles has been synthesized via direct N‐arylation of 2‐substituted tetrahydrobenzimidazoles, which was accomplished by a medium aryl electrophile, 4‐methylsulfonylfluorobenze, in the presence of 37% KF/Al₂O₃ and 18‐crown‐6 in fair yields under mild reaction conditions. Meanwhile, the hydrogenation of 2‐phenylbenzimidazole was studied.     

Adsorption and Micellization Properties of Novel Heterodouble‐Chained N‐Acyltaurate Surfactants

A set of heterodouble‐chained N‐acyltaurate surfactants (abbreviated as m+nP‐T, where m and n were carbon numbers of alkyl chain; P was phenyl; T was taurate) were synthesized. The novel amphiphiles contained sodium taurine as hydrophilic moiety and two different hydrocarbon chains as hydrophobic moiety. One was a long alkyl chain, and the other had an aromatic residue. Their surface properties were determined by Wilhelmy‐plate method, and micellization properties were investigated by fluorescence spectra of extrinsic probe and intrinsic probe. It was found that these surfactants showed some aberrant properties. It was difficult to obtain the equilibrium surface tension and critical micelle concentration (cmc) for the surfactants with two long chains. Pyrene was solubilized in micelle at concentration above cmc, and the fluorescent intensity ratio of the first vibronic peak (373 nm) to the third vibronic peak (383 nm) of pyrene decreased gradually. The aggregation number N, characterized by quenching the phenoxyl residue with methyl viologen (MV²⁺) as the extrinsic quencher, gradually increased with increasing surfactant concentration. These indicated that more and more molecules packed in a micelle with increasing concentration.     

Copper‐ and Amine‐Free Sonogashira Reaction of N,N‐Disubstituted Propargylamine: Synthesis of Substituted Aryl Propargylamine

A copper‐ and amine‐free Sonogashira reaction of N,N‐disubstituted propargylamine (DEP) is reported. The procedure was mild and tolerated a series of aryl bromides, affording the substituted aryl propargylic amines in good to excellent yield.     

Synthesis and Properties of Surfactants derived from N‐Acetyl‐D‐Glucosamine

The synthesis of 2‐acetamido‐2‐deoxy‐6‐O‐octanoyl‐D‐glucono‐1,5‐lactone 9 and 2‐acetamido‐2‐deoxy‐6‐O‐octanoyl‐α‐D‐glucopyranose 7 from 2‐acetamido‐2‐deoxy‐α‐D‐glucopyranose is reported. For both targets, the key intermediate was allyl 2‐acetamido‐3,4‐di‐O‐benzyl‐2‐deoxy‐6‐O‐octanoyl‐α‐D‐glucopyranoside 5. Surface tension measurements (critical micellar concentration of 22.3 mM and 5 mM for 9 and 7, respectively) showed up the surface activity of both compounds, while enzyme inhibition assays indicated that 9 could inhibit bovine β‐N‐acetylglucosaminidase (K_i=6.5 µM) but not Serratia marcescens chitobiase nor hen egg‐white lysozyme. Moreover, 7 was shown to induce chitinase production of S. marcescens and to be readily metabolized by these bacteria.      

Straightforward Synthesis of 2‐Aryl‐1‐alkynylphosphonates and Arylpropiolates

A protocol for the direct cross coupling of trialkylsilyl‐alkynes bearing electron‐withdrawing groups and aryl halides using a Pd/Ag catalytic system is described. The procedure allows the straightforward synthesis of a variety of alkynylphosphonates and aryl propiolates derivatives in good yields.     

Synthesis and Properties of Aromatic Side Chained N‐Acyltaurate Surfactants

A series of anionic N‐acyltaurate surfactants, side chain containing aromatic nucleus (abbreviated as SAATT), were synthesized via Williamson reaction, hydrolyzation, and acylation. Krafft temperatures and surface properties of these surfactants at 30°C, that is, critical micelle concentration, cmc, surface excess concentration, Γ_max, surface area demand per molecule, A _min, efficiency in surface tension reduction, pC₂₀, effectiveness in surface tension reduction, π_cmc, and cmc/C₂₀ parameter were determined. It was shown that these surfactants exhibit good solubility which was confirmed by measuring Krafft temperature. The cmc of SAATT was much smaller than that of conventional surfactants with similar effective carbon numbers, and shifted to lower concentration with increasing hydrocarbon chain length. In addition, the γ_cmc decreased with decrease in Γ_max. The pC₂₀ and the cmc/C₂₀ got larger with the increase in hydrocarbon chain length. From the fluorescence intensity ratios of I ₁ (373 nm) and I ₃ (384 nm) using pyrene as a probe, it was indicated that the molecules of SAATT formed loose micelles with a broad size distribution.     

Synthesis and Properties of A Novel Triphenylamine Derivative

A novel triphenylamine derivative of 4, 4‘-bis-[2-[4-[N,N-bis-(4-methoxyphenyl-amino)] phenyl-l-yl]-viny1-1-y1]-1, 1‘-biphenyl (DMPAVBI) was synthesized. The chemical structure was confirmed by IR, ^1H NMR spectroscopy and elemental analysis. Its properties were studied by UV-Vis spectroscopy, photoluminescence spectroscopy and cyclic voltammetry methods.     

Synthesis and Properties of a Novel Photochromic Compound

A new photochromic compound containing pyrazolone-ring was synthesized, and its crystal structure was determined on X-ray singlecrystal diffraction, which belongs to monoclinic crystal system, space group P21/c. The UV spectrum of the compound is studied.     

Synthesis and Antioxidant Properties of Novel Silybin Analogues

Eight novel silybin analogues (7a-h) were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were determined. Several synthetic compounds showed comparable antioxidative effect to that of quercetin.     

Synthesis of Novel N‐Morpholinoacetyl‐2,6‐diarylpiperidin‐4‐ones

A series of N‐chloroacetyl‐2,6‐diarylpiperidin‐4‐ones (10–18) obtained from the corresponding 2,6‐diarylpiperidin‐4‐ones upon base‐catalyzed condensation with morpholine afforded N‐morpholinoacetyl‐2,6‐diarylpiperidin‐4‐ones (19–27). The synthesized compounds have been characterized by their elemental, analytical, and spectral data.     

Synthesis of Methyl N‐Aryl Oxamate Using Soluble Polymer Support

A variety of methyl N‐aryl oxamates were synthesized using poly(ethylene glycol) (PEG) as a soluble polymer support and a monoproctection group with excellent yields.     

Convenient Synthesis of 5‐Aryl Uracils

A convenient one‐step synthesis of 5‐aryl uracils has been developed. The procedure involves heating ethyl 3‐hydroxy‐2‐arylpropenate with urea at 130°C, followed by base‐catalyzed cyclization. The method is simple and high yielding.     

Novel Synthesis and Characterization of N‐Substituted‐calix[4]azacrown Derivatives

Novel calix[4]azacrown derivatives from the reaction between calix[4]amidocrown and the different N‐(4‐bromoacetamidephthalimido)alkanes derivatives, which may be useful intemediate compounds of pseudorotaxane, have been synthesized and structurally characterized by IR, ¹H NMR, ¹³C NMR, MS, and elemental analyses. From their analysis data, it was found that compounds 6a–d adopted a cone conformation.     

Synthesis and Novel Properties of Alkyl Thiphosporamidate Derivatives of Nucleosides

Novel alkyl thiophosphoramidate derivatives of nucleosde analogues(5) have been prepared by phosphochloridothioate chemistry.O-Isopropyl 2‘,3‘-O-isopropylidene uridine-5‘-yl N-thiophosphoryl threonine and serine methyl esters(5a and 5b )underwent the intramolecular catalyzed hydrolysis reaction.     

Synthesis and Novel Properties of Alkyl Thiophosphoramidate Derivatives of Nucleosides

Ｉｎｔｒｕｄｕｃｔｉｏｎ　　Ｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｎｕｃｌｅｏｓｉｄｅｐｒｏｄｒｕｇｓｃａｐａｂｌｅｏｆｕｎｄｅｒｇｏｉｎｇｉｎｔｒａｃｅｌｌｕｌａｒａｃｔｉｖａｔｉｏｎｔｏｔｈｅｃｏｒｒｅｓｐｏｎｄｉｎｇｎｕｃｌｅｏｔｉｄｅｈａｓｂｅｃｏｍｅａｎａｒｅａｏｆｉｎｔｅｎｓｅｉｎｔｅｒｅｓｔ.1Ｓｅｖｅｒ ａｌｐｕｒｉｎｅａｎｄｐｙｒｉｍｉｄｉｎｅｂａｓｅｓａｎｄｎｕｃｌｅｏｓｉｄｅａｎａｌｏｇｓａｒｅｉｍｐｏｒｔａｎｔｗｅａｐｏｎｓｉｎｔｈｅａｎｔｉｃａｎｃｅｒａｎｄａｎｔｉｖｉｒａｌｃ…     

Solid‐Phase Synthesis of N‐Aryl‐N′‐Carboalkoxy Guanidines by the Mitsunobu Reaction of Fmoc‐Guanidines

Abstract

A new method for the solid‐phase synthesis of N‐aryl‐N′‐carboalkoxy guanidines is described. Aromatic amines were reacted with Fmoc‐isothiocyanate to provide Fmoc‐thioureas, which were coupled with Rink amide resin to provide the corresponding resin‐bound Fmoc‐guanidines. Subsequent Mitsunobu alkylation with a variety of alcohols delivered N‐aryl‐N′ carboalkoxy guanidines in good to high purity after resin cleavage.     

A Facile and Efficient Synthesis of N,N—Dimethylarylamines from Aryl Bromides

Catalytie amination of aryl bromides with in situ generated dimethylamines from N,N-dimethylacetamide(DMA)has been suceessfully carried out using Ni(phen)Cl2 as catalyst,Both electron-rich and electron-poor aromatie system reaeted smoothly under the conditions to give N,N-dimethylarylamines in good yields.     

Synthesis,Structures and Properties of Polyimide Based on 2,2′‐Bis(4‐aminophenoxy phenyl) Propane

2,2‐Bis[4‐(4‐aminophenoxy)phenyl] propane (BAPP), as a monomer to prepare polyimide, was synthesized from Bisphenol A and p‐chloronitrobenzene via the nucleophilic substitution reaction. The structures of the diamine monomer BAPP and an intermediate dinitrocompound 2,2′‐bis(4‐nitrophenoxy phenyl) propane (BNPP) were confirmed by FTIR and NMR. A novel polyimide was derived from BAPP and 3,3′,4,4′‐oxydiphthalic dianhydride (ODPA) in DMAc by a two‐step method. FTIR, DSC, TGA, and DMA were employed to characterize the precursor and the polyimide. The glass transition temperature of the polyimide was about 225–230°C. The measurement of mechanical properties indicated that the polyimide exhibited a typical yield behavior of thermoplastic polymers, which is very different from other polyimides. The elongation at break of the polyamic acid and polyimide was 6% and 29%, respectively.     

Synthesis and Properties of Novel Hemicyanine Dye-β-Cyclodextrin

A series of novel hemicyanine dye-β-cyclodextrin compounds： mono-6-deoxy-β-cyclodextrin-6-[p-（p-substituted styryl）pyridium] p-totylfulfonates were synthesized by the condensation of mono-6-deoxy-β- cyclodextrin-6-（p-methyl pyridinium） p-toluenesulfonate with （un）substituted benzaldehydes. Their structures were established by 1^H NMR, IR, UV-Vis and elemental analysis. The absorption and fluorescence properties of the novel compounds were measured in solution and the photostability of a selected hemicyanine dye-β-cyclodextrin compound was also investigated.