Synthesis and self-assembly of novel calix[4]arenocrowns: formation of calix[4]areno[2]catenanes

A series of novel calix[4]arenocrowns 1a-c were efficiently synthesized by a one-pot reaction of calix[4]monohydroquinone diacetate 5 with ditosylate 6 and its analogues in the presence of sodium hydroxide. It was found that the calix[4]arenocrowns could form stable pseudorotaxane-type complexes 2a-c with paraquat, and further self-assemble into calix[4]areno[2]catenanes 3a-c with dicationic salt 8 and p-bis(bromomethyl)benzene.     

First Asymmetric Total Synthesis of (R,E)-1-[4-(3-Hydroxyprop-1-enyl)phenoxyl]-3-methylbutane-2,3-diol

A new anti-inflammatory active phenylpropenoid, (R,E)-1-[4-(3-hydroxyprop-1-enyl) phenoxyl]-3-methylbutane-2,3-diol (1), isolated from the stem wood of Zanthoxylum integrifoliolum, has been synthesized for the first time using commercially available 4-hydroxy benzaldehyde (2). The key step involves the Sharpless asymmetric dihydroxylation of olefin (3).

Synthesis and reactions of 2-hydroxy-4-oxo-4-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-but-2-enoic acid methyl ester

2-Hydroxy-4-oxo-4-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-but-2-enoic acid methyl ester (1) was synthesized by the reaction of pentafluoroacetophenone with dimethyl oxalate in the presence of sodium methylate. Subsequently, reactions of compound 1 with aniline, o-phenylenediamine, and o-aminophenol were investigated. In addition, the thermal cyclization of ester 1 was studied and led to the formation of 5,6,8-trifluoro-7-methoxy-4-oxo-4H-chromene-2-carboxylic acid methyl ester (6) due to nucleophilic substitution of the 3-fluoro group. Hydrolysis of compound 1 and subsequent cyclization by treatment with SOCl₂ gave 5-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-furan-2,3-dione (3). Thermal decarbonylation of compound 3 under mild conditions resulted in the formation of 3-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-propene-1,3-dione (4) which dimerized to pyranone 5.     

1-(2-Quinoxalyl)-, 1-[3,5-Di(trifluoromethyl)phenyl]-, 1-(2-Carboxyphenyl)-, and 1-Ethoxycarbonyl-4-oxo-4,5,6,7-tetrahydroindazoles

The corresponding 1-(2-quinoxalyl)-, 1-[3,5-di(trifluoromethyl)phenyl]-, and 1-ethoxycarbonyl-3-methyl-4-oxo-4,5,6,7-tetrahydroindazoles have been obtained from reactions of 2-acetyl-1,3-cyclohexanedione, its 5,5-dimethyl and 5-(2-furyl) derivatives, with 2-hydrazinoquinoxaline, 3,5-di(trifluoromethyl)phenylhydrazine, and ethoxycarbonylhydrazine. On interaction with ethoxycarbonylhydrazine the intermediate 2-[1-(-ethoxycarbonyl)hydrazino]ethylidene-1,3-cyclohexanediones were also isolated. From the potassium salt of 2-formyldimedone and 2-carboxyphenylhydrazine hydrochloride, 2-(2-carboxyphenyl)hydrazinomethylene-5,5-dimethyl-1,3-cyclohexanedione was obtained, the cyclization of which in ethanol in the presence of HCl led to 1-(2-carboxyphenyl)- and 1-(2-ethoxycarbonylphenyl)-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazole.     

Synthesen von 4-Amino-thieno[2,3—b]pyridinen

The Cyclization of 2-(1,1-dicyanovinylamino)-thiophenes2 by treatment with AlCl₃ yield 4-amino-5-cyano-thieno[2,3-b]pyridines3. 2-(1-acylvinyl-amino)-3-cyano-thiophenes7, obtainable from 2-amino-3-cyano-thiophenes and -diketones, react in the presence of AlCl₃ to form 4-acylamino-thieno[2,3-b] pyridines8. This reaction is connected with the transfer of the acyl group from C- to the N-atom. 4-Amino-5-cyano-thieno[2,3-b]pyridones-(6)11 are synthesized from 2-amino-3-cyano-thiophenes and ethyl cyano acetate in the presence of sodium ethoxide.

     

Synthesis and Characterization of Some Novel Multisubstituted 6,7-Dihydro-5H-cyclopenta[b]pyridine Derivatives

In this study, we describe systematic preparation of a series of aryl-substituted pyridine derivatives. The 1,5-dicarbonyls (3a–i) were prepared in the solvent-free conditions starting from chalcone derivatives (1a–i). The target compounds, 4-aryl-2-(thiophen-3-yl)-6,7-dihydro-5H-cyclopenta[b]-pyridine derivatives (5a–i), were synthesized by a cyclization reaction of the 1,5-dicarbonyls (3a–i) with ammonium acetate (NH₄OAc) in acetic acid. The characterization of synthesized compounds was proved by elemental analyses, infrared, mass spectrometry, and ¹H and ¹³C NMR spectroscopy.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis and Properties of Substituted Isoxazolo[3',4':4,5]thieno[2,3-b]pyridines

We synthesized derivatives of a novel heterocyclic system, isoxazolo[3',4':4,5]thieno[2,3-b]pyridine by sequential conversions in three steps: isomerization of 2-(2-R-ethylthio-2-oxo)-3-pyridyl cyanides obtained by alkylation from substituted 3-cyano-2(1H)-pyridinethiones by -halomethyl ketones in alkaline medium, to form 3-aminothieno[2,3-b]pyridines; diazotization of the amino group followed by nucleophilic substitution of the diazonium group by an azido group, bypassing the step of isolating the diazonium salts; and thermolysis of the azides formed.     

Synthesis and Crystal Structure of (Z)-Ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate

The compound (Z)-ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate 3 has been synthesized by the reaction of ethylacetoacetate 1 and phenylisothiocyanate 2. Its structure has been established by ¹H NMR, ¹³C NMR, infrared, mass spectra, and x-ray crystallography.      

First synthesis of 2-[alkylamino(diethoxyphosphoryl)methyl]acrylic ethyl esters

The ethyl α-bromomethyl-β-(diethoxyphosphoryl)acrylic acid ester 9 has been prepared by addition of bromine to allylphosphonate 7 then dehydrobromination with DBU in acetonitrile. Reaction of allylic bromide 9 with primary amines in a bimolecular S_N2′-type mecanism in methanol at low temperature, gives rise to the 2-[alkylamino(diethoxyphosphoryl)methyl]acrylic acid ethyl esters 6.     

EPR studies on H-abstraction from methylbenzenes by “magic blue” reagent

After mixing a methylbenzene 4 with “magic blue” solution in F113 (CClF₂CCl₂F) containing bis{perfluoro[1-(2-fluorosulfonyl)ethoxy]ethyl}nitroxide 2 and perfluoro-1-nitroso-1-[1-(2-fluorosulfonyl)ethoxy]ethane 3 at room temperature, benzylic H-atom of 4 could be selectively abstracted by 2, and benzyl radical 5 thus generated was immediately trapped by 3. Based on hyper-fine splitting constants (hfsc), the structure of the spin adducts perfluoro[1-(2-fluorosulfonyl)ethoxy]ethyl benzyl nitroxides 6 derived from seven methylbenzenes have been identified. The mechanism of the H-abstraction/spin trapping process is also discussed.     

Efficient,Stereoselective Approach to the Synthesis of 3-(1-Phenyl-2-(Z-styrylsulfonyl)-1H-imidazol-4-yl)-2H-chromen-2-ones

Reaction of phenyl acetylene with 3-(1-aryl-2-mercapto-4-imidazolyl)-2H-1-benzopyran-2-ones (4) in the presence of sodium hydroxide in absolute ethanol led to the formation of 3-(1-phenyl-2-(Z-styrylthio)-1H-imidazol-4-yl)-2H-chromen-2-ones (6) in excellent yields. These, on further oxidation with H₂O₂/AcOH, gave the corresponding sulfones (7) with retention of stereochemistry.

由MOPIP配体构筑的两种金属配合物的合成、表征及晶体结构(英文)

采用水热法由2种不同金属盐和MOPIP(MOPIP=2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)配体合成了2种新型零维配合物[Cd(MOPIP)3(H2O)9]4n(1)和[Mn(MOPIP)3(H2O)6]2n(2),并对其进行了元素分析、红外光谱表征、热失重和X射线单晶衍射测定。结果表明,每个金属中心离子与来自3个不同MOPIP分子上的6个氮原子进行配位,形成畸变的八面体构型。     

2-[2-(6-Methylbenzothiazolyl)azo]-5-Diethylaminobenzoic acid as a new analytical reagent for the spectrophotometric determination of nickel

A new thiazolylazo chromogenic reagent, 2-[2-(6-methylbenzo-thiazoly)azo]-5-diethylaminobenzoic acid (6-Me-BTAEB), has been synthesized. Its chromogenic reaction with microamounts of nickel in the presence of sodium dodecylsulfate (SDS) has been thoroughly studied. 6-Me-BTAEB reacts with nickel(II) in weak acid medium containing appropriate amounts of SDS to form a blue-violet complex with high sensitivity, good selectivity and high stability. The composition is found to be 1:2 (nickel to 6-Me-BTAEB) and its absorption maximum is at 650 nm with an apparent molar absorptivity of 1.67 × 10⁵l mole^–1 cm^–1. Beer's law is obeyed over the range 0-0.4 g of nickel per ml. The proposed method has been applied to the direct determination of nickel in aluminium alloys, pure magnesium and low alloy steels at the 0.2–0.3% (w:w) level with satisfactory results.     

Reaction of 2-(4-Arylthiazol-2-yl)-4-chloro-3-oxobutyronitriles with Secondary Aliphatic Amines

We have obtained 2-(4-arylthiazol-2-yl)-4-chloro-3-oxobutyronitriles by acylation of 4-aryl-2-cyanomethylthiazoles with -chloroacetyl chloride. We have studied their reaction with secondary aliphatic amines, leading to formation of 4-dialkylamino-2-(4-arylthiazol-2-yl)-3-oxobutyronitriles, and also intramolecular alkylation with formation of 3-aryl-7-cyano-6(5H)-oxopyrrolo[2,1-b]thiazoles. We have determined some aspects of the tautomerism of the synthesized compounds.     

Synthesis and hydrolytic cleavage of tetrazolo[1,5-c]quinazolines

A series of tetrazolo[1,5-c]quinazolines were synthesized by [4 + 1]-cyclocondensation of 4-hydrazinoquinazolines with sodium nitrite with good yields. Peculiarities of this reaction were discussed, namely, the influence of halogen on the reaction yield. Hydrolytic cleavage of tetrazolo[1,5-c]quinozoline cycle was studied in order to obtain 2-(1H-tetrazolo-5-yl)anilines. The structures of the compounds were elucidated by ¹H NMR, ¹³C NMR, infrared, mass spectrometry, and elemental analysis.     

Über Reaktionen von Arylbiguaniden mit Benzoin beimpH der Biguanidbasen

Summary Arylbiguanides2 a–e react with benzoin (1) at thepH of the base to two different products.1 undergoes in presence of the base2 a–e oxidation to benzil and benzoic acid, which reacts fast with the arylbiguanides2 a–e to yield N-[4-(arylamino)-6-phenyl-1,3,5-triazine-2-yl]benzamides3 a–d. After lowering thepH of the reaction mixture, the bases2 b–e react with benzil to yield 2-[1-aryl-5-oxo-4,4-diphenyl-2-imidazoline-2-yl]guanidine4 b–e. The mechanism of the formation is discussed. The structure of4b was established from a single crystal x-ray structure analysis. The analysis was carried out at 100K: C₂₃H₂₁N₅O,M _r=383.5, monoclinic, C 2/c,a=15.842(6),b=8.419(3),c=30.223(10) Å, =98.44(3)°,V=3 987.3(9) ų,Z=8,d _x=1.277 g/cm³, =0.81 cm^–1,R=5.89%R _w=4.97% (1 537 observations, 233 parameters).

     

Synthesis and study of some properties of 1-aryl-2-oxo-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole 4-oxides

A number of 1-aryl-2-oxo-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole 4-oxides were synthesized based on 3-[N-aryl-N-(chloroacetyl)amino]-2-formylindoles. The nature of the substituent in the 1-aryl fragment has a pronounced influence on the course of reactions throughout the whole sequence of transformations during the synthesis of diazepinoindoles. The reduction of 4-oxides by formamidinosulfinic acid, hydrogen in the presence of Pd/C, and sodium bisulfite was studied. The structures of the reaction products were confirmed using IR and ¹H NMR spectroscopy and mass spectrometry.     

Complexation of Porphyrin-Appended Guests by Calix[4]arene-Appended Cyclodextrins

A calix[4]arene based -cyclodextrin dimerand tetramer (1 and2, Figure 1) were synthesized by covalentattachment of amono(2-O-xylylamino)--cyclodextrinderivative to calix[4]areneplatforms, bi- or tetrafunctionalized withcarboxylic acid groups at their upperrims. The complexation of porphyrin-basedguest molecules by these hosts inwater was studied using microcalorimetry.Tetrakis(4-phenylsulfonato)porphyrin(TsPP) binds to 2 in a 1 : 2 (host : guest)fashion with enhanced bindingstrength (K₁ = 6.6 × 10⁶ M ^-1) ascompared to the monomeric TsPP–CDinteraction (K = 8.8 × 10⁵ M ^-1). Thisenhancement is attributed tothe involvement of two cyclodextrin units in theaccommodation of one TsPP guest.Increase of the number of 4-sulfonatophenyl siteson the guest by generating the-oxo-dimer of the iron(III) complex of TsPPled to further increase of thebinding strength owing to participation of three-cyclodextrin cavities of2 (K = 1.5 × 10⁷ M ^-1). The geometricincompatibility betweenhost and guest, stemming from the fact that both TsPPand its -oxo-dimer arefairly small compared to the multi-cyclodextrin hosts,probably explains why theenhancement is still moderate. A much more pronouncedincrease in complexationstrength was achieved with p- and m-pyridylporphyrinextended withp-tert-butylbenzyl guest sites. Theseguests are large enough to accommodatethree to four -cyclodextrin units. The bettermatch in size between host and guestgave association constants up 10⁸ and 10⁹ M ^-1for the -cyclodextrindimer and tetramer, respectively. In fact, the 1 : 1complex betweentetrakis(p-tert-butylbenzyl)-p-pyridylporphyrinand 2(K = 5 × 10⁹ M ^-1) is the strongestreported for cyclodextrin–porphyrininteractions.