Simple,Efficient, and Catalyst‐Free Synthesis of (2‐Amino‐4H‐1‐benzopyran‐4‐yl)phosphonates in Polyethylene Glycol

Several (2‐amino‐4H‐1‐benzopyran‐4‐yl)phosphonates were efficiently synthesized by employing a multicomponent protocol involving a salicylaldehyde, malononitrile or ethyl cyanoacetate, and a trialkyl phosphite in polyethylene glycol. The latter could be recovered and re‐used. No additional solvent or catalyst was required. To the best of our knowledge, this is the first report of the one‐pot preparation of (2‐amino‐4H‐1‐benzopyran‐4‐yl)phosphonic acid dimethyl esters.     

A Novel and Efficient Synthesis of 3‐[(4,5‐Dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐chromen‐2‐ones (=3‐[(4,5‐Dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐1‐benzopyran‐2‐ones)

An efficient one‐pot synthesis of 3‐[(4,5‐dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐chromen‐2‐one (=3‐[(4,5‐dihydro‐1H‐pyrrol‐3yl)carbonyl]‐2H‐1‐benzopyran‐2‐one) derivatives 4 by a four‐component reaction of a salicylaldehyde 1 , 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one, a benzylamine 2 , and a diaroylacetylene (=1,4‐diarylbut‐2‐yne‐1,4‐dione) 3 in EtOH is reported. This new protocol has the advantages of high yields (Table), and convenient operation. The structures of these coumarin (=2H‐1‐benzopyran‐2‐one) derivatives, which are important compounds in organic chemistry, were confirmed spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2).     

Photocycloaddition of Six‐Membered Cyclic Enones to Propen‐2‐yl Isocyanate

On irradiation in the presence of propen‐2‐yl isocyanate ( 4 ), six‐membered cyclic enones 3 are converted into regio‐ and stereoisomeric mixtures of [2+2] cycloadducts 5 – 10 ; the preferentially formed HT products, 5 – 8 , can be converted into the corresponding bicyclic amines by acid hydrolysis, whereas, under these conditions, the regioisomeric HH‐isocyanato derivatives undergo a retro‐Mannich reaction.     

三氯化铟高效催化3-(1-吡咯基)吲哚-2-酮类化合物的合成方法

使用三氯化铟在乙醇中回流的条件下催化不同的靛红衍生物与4-羟基脯氨酸反应,以较高的产率(83-99%)和纯度合成得到了相应的产物3-(1-吡咯基)吲哚-2-酮化合物,并对这个反应做了一个比较全面系统的研究.     

One‐Step Synthesis of 1‐(4,5‐Diphenylpyrimidin‐2‐yl)thiourea

A simple and straightforward methodology toward the synthesis of novel 1‐(4,5‐diphenylpyrimidin‐2‐yl)thiourea has been developed by a one‐step reaction of isoflavones with amidinothiourea. A series of 16 new compounds was synthesized. All compounds were characterized by FT‐IR, NMR, and elemental analysis. The structure of a typical compound was established by X‐ray diffraction. A variety of substrates can participate in the process with good yields and high purities, making this methodology suitable for library synthesis in drug discovery.     

A 2D Metal‐Organic Framework Based on 9‐(Pyridin‐4‐yl)‐9H‐carbazole‐3,6‐dicarboxylic Acid: Synthesis,Structure and Properties

A metal‐organic framework (MOF ) formulated as [Cd₂(μ₃‐L)₂(DMF )₄]•H₂O ( CdL ) [H₂L =9‐(pyridin‐4‐yl)‐ 9H ‐carbazole‐3,6‐dicarboxylic acid, DMF =N ,N ‐dimethylformamide] was synthesized under solvothermal condition. Crystal structural analysis reveals that CdL features the layered 2D framework with L^{2 −} ligands as 3‐connected nodes. The compound CdL emits blue‐violet light with the narrow emission peak and the emission maximum at 414 nm upon excitation at the maximum excitation wavelength of 340 nm. The compound CdL has a similar emission spectrum curve to the free H₂L ligand that indicates the emission of compound CdL should be originated from the coordinated L^{2 −} ligands.     

Synthesis and Transformation of Methyl 2‐(6‐Hydroxy‐2‐phenylpyrimidin‐4‐yl)acetate: Simple Preparation of Pyrimidines with Heterocyclic Substituents

A simple and efficient synthesis of four new substituted pyrimidines, compounds 9a – d , from the title compound 3 is described. Conversion of 3 to methyl (E)‐3‐(dimethylamino)‐2‐(6‐methoxy‐2‐phenylpyrimidin‐4‐yl)prop‐2‐enoate ( 4 ), followed by condensation with various dinucleophiles according to the ‘enaminone methodology’, afforded the target compounds 9 in medium‐to‐good yields.     

A Gadolinium Complex of the 5‐(1H‐Tetrazol‐5‐yl)isophthalic Acid Ligand: [Gd(C9H3N4O4)(H2O)3·2H2O]n

The reaction of Gd(ClO₄)₃·6H₂O with 5‐(1H‐tetrazol‐5‐yl)isophthalic acid affords a 3D framework gadolinium coordination polymer, [Gd(C₉H₃N₄O₄)(H₂O)₃·2H₂O]_n ( 1 ). Its crystal structure belongs to a triclinic system, space group , with a = 7.909(2) Å; b = 8.448(2) Å; c = 10.994(2) Å; α = 102.65(3)°; β = 124.32(2)°; γ = 96.28(3)°; V = 704.5(2) ų; Z = 2; R₁ = 0.0245 for 3225 reflections with I >2σ(I), wR₂ = 0.0556. Fluorescent analyses show that compound 1 exhibits purple fluorescence in the solid state at room temperature.     

Synthesis and Reactions of 2‐[1‐Methyl‐1‐(pyrrolidin‐2‐yl)ethyl]‐1H‐pyrrole and Some Derivatives with Aldehydes: Chiral Structures Combining a Secondary‐Amine Group with an 1H‐Pyrrole Moiety as Excellent H‐Bond Donor

The synthesis of compound 2 and its derivatives 6 and 8 combining a pyrrolidine ring with an 1H‐pyrrole unit is described (Scheme 2). Their attempted usability as organocatalysts was not successful. Reacting these simple pyrrolidine derivatives with cinnamaldehyde led to the tricyclic products 3b, 9b , and 10b first (Scheme 1, Fig. 2). The final, major products were the pyrrolo‐indolizidine tricycles 3a, 9a , and 10a obtained via the iminium ion reacting intramolecularly with the nucleophilic β‐position of the 1H‐pyrrole moiety (cf. Scheme 1).     

2‐(1H‐Benzotriazole‐1‐yl)‐1,1,3,3‐Tetramethyluronium Tetrafluoro Borate (TBTU) as an Efficient Coupling Reagent for the Esterification of Carboxylic acids with Alcohols and Phenols at Room Temperature

Esterification of carboxylic acids with alcohols and phenols by using 2‐(1H‐benzotriazole‐1‐yl)‐1,1,3,3‐tetramethyluronium tetrafluoroborate (TBTU) in the presence of triethylamine as a base proceeded smoothly under mild conditions to afford the corresponding esters in good to high yields in acetonitrile at room temperature.     

Synthesis of 3‐(ω‐Hydroxyalkoxy)isobenzofuran‐1(3H)‐ones by Trifluoroacetic Acid‐Mediated Lactonization of tert‐Butyl 2‐(1,3‐Dioxol‐2‐yl)‐ or 2‐(1,3‐Dioxan‐2‐yl)benzoates

An efficient two‐step method for the preparation of 3‐(2‐hydroxyethoxy)‐ or 3‐(3‐hydroxypropoxy)isobenzofuran‐1(3H)‐ones 3 has been developed. Thus, the reaction of 1‐(1,3‐dioxol‐2‐yl)‐ or 1‐(1,3‐dioxan‐2‐yl)‐2‐lithiobenzenes, generated in situ by the treatment of 1‐bromo‐2‐(1,3‐dioxol‐2‐yl)‐ or 1‐bromo‐2‐(1,3‐dioxan‐2‐yl)benzenes 1 with BuLi in THF at ?78°, with (Boc)₂O afforded tert‐butyl 2‐(1,3‐dioxol‐2‐yl)‐ or 2‐(1,3‐dioxan‐2‐yl)benzoates 2 , which can subsequently undergo facile lactonization on treatment with CF₃COOH (TFA) in CH₂Cl₂ at 0° to give the desired products in reasonable yields.     

Two different one‐dimensional supramolecular chains formed from the reaction of 2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline with two different precursors,Co(NO3)2 and CoCl2

Two different one‐dimensional supramolecular chains with Co^II cations have been synthesized based on the semi‐rigid ligand 2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline (L), obtained by condensation of 2‐(1H‐benzimidazol‐2‐yl)quinoline and 4‐(chloromethyl)pyridine hydrochloride. Starting from different Co^II salts, two new compounds have been obtained, viz. catena‐poly[[[dinitratocobalt(II)]‐μ‐2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline] dichloromethane monosolvate acetonitrile monosolvate], {[Co(NO₃)₂(C₂₂H₁₆N₄)]·CH₂Cl₂·CH₃CN}_n, (I) and catena‐poly[[[dichloridocobalt(II)]‐μ‐2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline] methanol disolvate], {[CoCl₂(C₂₂H₁₆N₄)]·2CH₃OH}_n, (II). In (I), the Co^II centres lie in a distorted octahedral [CoN₃O₃] coordination environment. {Co(NO₃)₂L}_n units form one‐dimensional helical chains, where the L ligand has different directions of twist. The helical chains stack together via interchain π–π interactions to form a two‐dimensional sheet, and another type of π–π interaction further connects neighbouring sheets into a three‐dimensional framework with hexagonal channels, in which the acetonitrile molecules and disordered dichloromethane molecules are located. In (II), the Co^II centres lie in a distorted trigonal–bipyramidal [CoCl₂N₃] coordination environment. {CoCl₂L}_n units form one‐dimensional chains. The chains interact via C—H...π and C—H...Cl interactions. The result is that two‐dimensional sheets are generated, which are further linked into a three‐dimensional framework via interlayer C—H...Cl interactions. When viewed down the crystallographic b axis, the methanol solvent molecules are located in an orderly manner in wave‐like channels.     

A Convenient Synthesis of 2‐Sulfanylbenzoselenazole Derivatives via the Reaction of 2‐Lithiophenyl Isothiocyanates with Selenium

The title compounds have been prepared from 2‐bromophenyl isothiocyanates 1 . Thus, 2‐lithiophenyl isothiocyanates 2 , obtained from 1 and BuLi through Br/Li exchange, reacted with Se at ?78° to form lithium benzoselenazole‐2‐thiolates 3 , which, upon aqueous workup, afforded benzoselenazole‐2(3H)‐thiones 4 . The thiolates 3 were alkylated with reactive alkyl halides and acylated with carboxylic acid chlorides to give 2‐(alkylsulfanyl)benzoselenazoles 5 and S‐(benzoselenazol‐2‐yl) thiocarboxylates 6 , respectively.     

Synthesis of N,N‐Dialkyl‐9‐oxoacridine‐10(9H)‐carbothioamides via the Reaction of (2‐Halophenyl)(2‐isothiocyanatophenyl)methanones with Secondary Amines,Followed by Cyclization with NaH

The first preparation of acridin‐9(10H)‐ones carrying a tertiary thiocarbamoyl group at C(10), i.e., N,N‐dialkyl‐9‐oxoacridine‐10(9H)‐carbothioamides 9 , is described. The method is based on the reaction of (2‐halophenyl)(2‐isothiocyanatophenyl)methanones 7 , prepared from (2‐aminophenyl)(2‐halophenyl)methanones 5 by a convenient three‐step sequence, with secondary amines in DMF at room temperature to generate the corresponding thiourea derivatives 8 in situ, which are treated with NaH at 100–120° to provide the desired products in one‐pot reactions in generally good yields.     

Incorporating two different chromophores onto a silicon atom: the crystal structure and photophysical properties of 9‐{4‐[(9,9‐dimethyl‐9H‐fluoren‐2‐yl)dimethylsilyl]phenyl}‐9H‐carbazole

The crystal structure of the title bifunctional silicon‐bridged compound, C₃₅H₃₁NSi, (I), has been determined. The compound crystallizes in the centrosymmetric space group P2₁/c. In the crystal structure, the pairs of aryl rings in the two different chromophores, i.e. 9‐phenyl‐9H‐carbazole and 9,9‐dimethyl‐9H‐fluorene, are positioned orthogonally. In the crystal packing, no classical hydrogen bonding is observed. UV–Vis absorption and fluorescence emission spectra show that the central Si atom successfully breaks the electronic conjugation between the two different chromophores, and this was further analysed by density functional theory (DFT) calculations.     

Dimerization of Dimethyl 2‐(Naphthalen‐1‐yl)cyclopropane‐1,1‐dicarboxylate in the Presence of GaCl3 to [3+2], [3+3], [3+4], and Spiroannulation Products

In the presence of a catalytic amount of GaCl₃, dimethyl 2‐(naphthalen‐1‐yl)cyclopropane‐1,1‐dicarboxylate 5 undergoes selective [3+2]‐annulation‐type dimerization to give a polysubstituted cyclopentane containing two naphthalenyl substituents in the vicinal position (Scheme 2). Treatment of the same cyclopropane with an equimolar amount of GaCl₃?THF results in dimerization with electrophilic attack on each of the benzene rings to give [3+3] and [3+4] annulation products. The latter represent a new type of dimerization of donor? acceptor cyclopropanes. Finally, under conditions of double catalysis with GaCl₃, 3,3,5,5‐tetrasubstituted 4,5‐dihydropyrazole, this cyclopropane‐dicarboxylate undergoes stereospecific dimerization as a result of electrophilic ipso‐attack to give a tetracyclic pentaleno[6a,1‐a]naphthalene derivative (Scheme 5). Possible reaction mechanisms are proposed.     

1H and 13C chemical shifts for acridines: Part XVII. (1,3‐Benzothiazol‐2‐yl)amino‐9(10H)‐acridinone derivatives

The ¹H and ¹³C NMR resonances for 16 acridin‐9(10H)‐ones substituted with amino or (1,3‐benzothiazol‐2‐yl)amino groups were completely and unequivocally assigned by the concerted application of gs‐COSY, gs‐HMQC and gs‐HMBC experiments. Evidence for hydrogen bond and amino–imino tautomerism is presented for 1‐ and 4‐substituted acridin‐9(10H)‐ones. Copyright © 2002 John Wiley & Sons, Ltd.     

Syntheses,Crystal Structures,and Photocatalytic Activities of Three Copper Coordination Polymers Based on Bis(1H‐imidazol‐4‐yl)benzene/3‐(2‐Pyridyl)pyrazole

Three copper(II) coordination polymers (CuCPs), namely, [Cu_0.5(1,4‐bib)(SO₄)_0.5]_n ( 1 ), {[Cu(1,3‐bib)₂(H₂O)] · SO₄ · H₂O}_n ( 2 ), and [Cu(bpz)(SO₄)_0.5]_n ( 3 ), were assembled from the reaction of three N‐donors [1,4‐bib = 1,4‐bis(1H‐imidazol‐4‐yl)benzene, 1,3‐bib = 1,3‐bis(1H‐imidazol‐4‐yl)benzene, and Hbpz = 3‐(2‐pyridyl)pyrazole] with copper sulfate under hydrothermal conditions. Their structures were determined by single‐crystal X‐ray diffraction analyses and further characterized by elemental analyses (EA), IR spectroscopy, powder X‐ray diffraction (PXRD), and thermogravimetric analyses (TGA). Structure analyses reveal that complex 1 is a 3D 6‐connected {4¹² · 6³}‐ pcu net, complex 2 is a fourfold 3D 4‐connected 6⁶‐ dia net, whereas complex 3 is a 1D snake‐like chain, which further expanded into 3D supramolecular architectures with the help of C–H ··· O hydrogen bonds. Moreover, the photocatalytic tests demonstrate that the obtained CuCPs are photocatalysts in the degradation of MB with the efficiency is 86.4 % for 1 , 75.3 % for 2 , and 91.3 % for 3 after 2 h, respectively.     

Synthesis of 10‐Aryl‐ and 10‐(Arylmethyl)acridin‐9(10H)‐ones via the Reaction of (2‐Fluorophenyl)(2‐halophenyl)methanones with Benzenamines and Arylmethanamines

The reaction of 1‐fluoro‐2‐lithiobenzenes, generated from 1‐bromo‐2‐fluorobenzenes 1 and BuLi, with 2‐halobenzaldehydes and subsequent oxidation of the resulting alcohols 2 afforded (2‐fluorophenyl)(2‐halophenyl)methanones 3 , which, on treatment with benzenamines or arylmethanamines, followed by NaH, gave rise efficiently to 10‐aryl‐ or 10‐(arylmethyl)acridin‐9(10H)‐ones ( 5 or 7 ), respectively.