4‐(2‐Hydroxyphenyl)‐2‐phenyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepine and the 2‐(2,3‐dimethoxyphenyl)‐, 2‐(3,4‐dimethoxyphenyl)‐ and 2‐(2,5‐dimethoxyphenyl)‐substituted derivatives

The 1,5‐benzodiazepine ring system exhibits a puckered boat‐like conformation for all four title compounds [4‐(2‐hydroxyphenyl)‐2‐phenyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₁H₁₈N₂O, (I), 2‐(2,3‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (II), 2‐(3,4‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (III), and 2‐(2,5‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (IV)]. The stereochemical correlation of the two C₆ aromatic groups with respect to the benzodiazepine ring system is pseudo‐equatorial–equatorial for compounds (I) (the phenyl group), (II) (the 2,3‐dimethoxyphenyl group) and (III) (the 3,4‐dimethoxyphenyl group), while for (IV) (the 2,5‐dimethoxyphenyl group) the system is pseudo‐axial–equatorial. An intramolecular hydrogen bond between the hydroxyl OH group and a benzodiazepine N atom is present for all four compounds and defines a six‐membered ring, whose geometry is constant across the series. Although the molecular structures are similar, the supramolecular packing is different; compounds (I) and (IV) form chains, while (II) forms dimeric units and (III) displays a layered structure. The packing seems to depend on at least two factors: (i) the nature of the atoms defining the hydrogen bond and (ii) the number of intermolecular interactions of the types O—H...O, N—H...O, N—H...π(arene) or C—H...π(arene).     

Synthesis and Spectral Properties of 4‐(2,5‐Dimethoxyphenylmethelene)‐2‐phenyl‐5‐oxazolone (DMPO)

An interesting flourophore, 4‐(2,5‐dimethoxyphenylmethelene)‐2‐phenyl‐5‐oxazolone (DMPO) was synthesized by mixing an equivalent molar quantity of hippuric acid and 2,5‐dimethoxybenzaldehyde in acetic anhydride in the presence of anhydrous sodium acetate. The absorption and fluorescence characteristics of 4‐(2,5‐dimethoxy‐phenylmethelene)‐2‐phenyl‐5‐oxazolone (DMPO) were investigated in different solvents. DMPO dye exhibits red shift in both absorption and emission spectra as solvent polarity increases, indicating change in the dipole moment of molecules upon excitation due to an intramolecular charge transfer interaction. The fluorescence quantum yield depends strongly on the properties of the solvents, which was attributed to positive and negative solvatokinetic effects. A crystalline solid of DMPO gave strong excimer like emission at 630 nm due to the excitation of molecular aggregates. This is expected from the idealized crystal structure of the dye that belongs to the B‐type class of Steven's Classification. DMPO displayed fluorescence quenching by triethylamine via nonemissive exciplex formation.     

2-(对烷氧基苯甲酸酯基或对烷氧基苯丙烯酸酯基)-5-氧-2,5-二氢呋喃化合物的合成与液晶性质研究

Two series of p-alkoxybenzoates Ia-If and p-alkoxycinnamates IIa-IIf, each species beating one terminal furanone, have been synthesized and characterized by IR, ^13C NMR, ^1H NMR, MS spectra and elemental analysis. The mesogenic properties of both series of furanones have been studied by polarizing optical microscopy and differential scanning calorimetry （DSC）. The relationship between structures and mesogenic properties was discussed. The results show that the increased alkoxy chain length （C7-C12） and the bridging groups between the benzene ring and the furanone ring affected the mesomorphic properties greatly, and the two series of furanones might display monotropic or enantiotropic nematic （N） or semetic C （SmC） mesophases and different mesomorpic phase temperature ranges corresponding to different carbon chain length.     

Synthesis of 4‐(5‐aryl‐1,3,4‐oxadiazol‐2‐yl)phenyl‐hydrazine derivatives from 3‐(4‐hydrazinocarbonyl‐phenyl)sydnones

The synthesis of potential fluorescent active 4‐(5‐aryl‐1,3,4‐oxadiazol‐2‐yl)phenylhydrazine derivatives was accomplished in three steps. The key step was the dehydration cyclization of 1,2‐diacylhydrazines to form the 1,3,4‐oxadiazole ring by use of acetic anhydride/perchloric acid mixture as the dehydrating agent. The sydnone moiety served as the masked hydrazines, which could be demasked by HCl for further application. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:438–442, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20318     

Potassium 3‐cyano‐4‐(dicyanomethylene)‐5‐oxo‐4,5‐dihydro‐1H‐pyrrol‐2‐olate

The crystal structure of the title potassium salt, K⁺·C₈HN₄O₂⁻, of the organic anion 3‐cyano‐4‐(di­cyano­methyl­ene)‐5‐oxo‐4,5‐di­hydro‐1H‐pyrrol‐2‐olate shows that the di­cyano­methyl­ene moiety is able to accept an electron in the same way as does tetra­cyano­ethyl­ene, to yield the novel product. The organic anion is nearly planar, with deviations caused by steric crowding among the exocyclic cyano groups. The K⁺ cations lie within tricapped trigonal prisms that stack to form channels. The three‐dimensional structure is completed by the formation of hydrogen‐bonded chains by the anions.     

Synthesis of 3‐phenyl‐5‐(trifluoromethyl)isoxazole and 5‐phenyl‐3‐(trifluoromethyl)isoxazole

Reaction of 4,4,4‐trifluoro‐1‐phenyl‐1,3‐butanedione with hydroxylamine led to the formation of 5‐hydroxy‐3‐phenyl‐5‐(trifluoromethyl)‐4,5‐dihydroisoxazole which was dehydrated to 3‐phenyl‐5‐(trifluoro‐methyl)isoxazole. This isomer can also be synthesized by reaction of 4‐chloro‐4‐phenyl‐1,1,1‐trifluoro‐3‐buten‐2‐one with sodium azide. The regioisomer, 5‐phenyl‐3‐(trifluoromethyl)isoxazole was synthesized by reaction of 1,1,1‐trifluoro‐4‐phenylbut‐3‐yn‐2‐one with hydroxylamine and by the reaction of 3‐chloro‐1‐phenyl‐4,4,4‐trifluorobut‐2‐en‐1‐one with sodium azide. Both isomers were characterized by mass and NMR spectroscopy.     

FeCI3‐promoted [3+3] cycloaddition: Efficient preparation of 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylate and 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxamide derivatives

A facile approach was developed on assembly of the 2‐pyridone nucleus by ferric chloride promoted [3+3] cycloaddition in propionic acid. The tandem process involves cyclization of Michael adduct followed by aromatization. Thus, different substituted 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylate and 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxamide derivatives were prepared in good yields from various enones with malonamic ester and malonamide, respectively     

A new synthesis of 4‐cyano‐1,3‐dihydro‐2‐oxo‐2H‐imidazole‐5‐(N1‐tosy1)carboxamide : reactive precursor for thiopurine analogues

N‐[(5‐Cyano‐2‐oxoimidazolidin‐4‐yl)‐iminomethyl]‐p‐toluensulfonamide 3 was prepared in fairly good yield by the base catalyzed cyclisation of N‐[(Z)‐2‐amino‐1,2‐dicycanovinylcarbamoyl]‐p‐toluenesulfon‐amide 2 . The N‐[(Z)‐2‐amino‐1,2‐dicycanovinyl carbamoyl]‐p‐toluenesulfonamide 2 was reacted readily with two molar amount of p‐nitrobenzaldehyde at room temperature in the presence of base to give 7,8‐dihy‐dro‐2‐(4‐nitrophenyl)‐8‐oxo‐9‐tosylpurine‐6‐carboxamide 8 . Thiation of compounds 3 and 8 using Lawesson's reagent in tetrahydrofuran gave novel thioimidazoles 4, 5 , and 6 and thiopurines 9, 10 , and 11 , which have been characterized spectroscopically.     

Synthesis of 4‐(2‐hydroxyphenyl)‐1‐phenyl‐1,2,4‐triazolidine‐3,5‐dione derivatives through cyclic transformations of 3‐(2‐phenylcarbazoyl)‐2(3H)‐benzoxazolone derivatives

Four 3‐(3‐benzylidene‐2‐phenylcarbazoyl)‐2(3H)‐benzoxazolone derivatives 3 have been synthesized from benzoxazolone derivatives 1 and benzaldehyde N‐chloroformylphenylhydrazone 2. By acid hydrolysis, these compounds yielded 3‐(2‐phenylcarbazoyl)‐2(3H)benzoxazolone derivatives 4 which were not isolated and were transformed via an intramolecular reaction into 4‐(2‐hydroxyphenyl)‐1‐phenyl‐1,2,4‐triazolidine‐3,5‐dione derivatives 5 in a good yield. Attempts to cyclize these compounds by intramolecular elimination of water into tricyclic compounds 6 with various dehydrating agents were unsuccessful.     

Reactivity of (2‐methylsulfanyl‐4‐oxo‐6‐phenyl‐4h‐pyrimidin‐3‐yl)‐acetic acid methyl ester towards hydrazine hydrate and benzylamine

The title ester 1 reacted with hydrazine hydrate to give hydrazide 2 , which underwent intramolecular cyclization to yield 1‐amino‐7‐phenyl‐1H‐imidazo[1,2‐a]pyrimidine‐2,5‐dione ( 3 ) or took place in a substitution reaction with benzylamine to form N‐benzyl‐2‐(2‐benzylamino‐4‐oxo‐6‐phenyl‐4H‐pyrimidin‐3‐yl)‐acetamide ( 4 ). The reaction of ester 1 with benzylamine gave corresponding amide 7 , disubstituted derivative 4 or 1‐benzyl‐7‐phenyl‐1H‐imidazo[1,2‐a]pyrimidine‐2,5‐dione ( 8 ) depending on the reaction conditions.     

Efficient synthesis of 1‐substituted‐4‐phenyl‐1, 4‐dihydro‐5H‐tetrazole‐5‐thione and (1‐phenyl‐1H‐tetrazol‐5‐yl)thioacetyl derivatives

A new and convenient synthesis of a variety of N‐ and S‐substituted tetrazoles has been developed via azide and Mannich reaction methods. Compounds were characterized by elemental analysis, MALDI MS, and ¹H NMR data. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:637–643, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20353     

Thiol–thione tautomeric forms recognition on the example of 4‐[3‐(2‐methyl‐furan‐3‐yl)‐5‐thioxo‐1,2,4‐triazolin‐4‐yl]acetic acid

The synthesis of 4‐[3‐(2‐methyl‐furan‐3‐yl)‐5‐thioxo‐1,2,4‐triazolin‐4‐yl]acetic acid, its structural study in the solid state, and the thiol–thione tautomeric recognition on the basis of spectroscopic data and theoretical calculations are presented. It is shown that NMR spectra, especially ¹³C and ¹⁵N, are indicative of the actual tautomeric form whereas vibrational data can be ambiguous. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:337–344, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20433     

2‐(Benzoylsulfanyl)acetic acid and 2,5‐dioxopyrrolidin‐1‐yl 2‐(benzoylsulfanyl)acetate by powder X‐ray diffraction studies

The structures of the title compounds, C₉H₈O₃S, (I), and C₁₃H₁₁NO₅S, (II), were determined by X‐ray powder diffraction. Both were solved using the direct‐space parallel tempering algorithm and refined using the Rietveld method. In (I), the C—S—C bond angle is slightly smaller than normal, indicating more p character in the bonding orbitals of the S atom. The carboxylic acid group joins across an inversion centre to form a dimer. The crystal packing includes a weak C—H...O hydrogen bond between an aromatic C—H group and a carboxylic acid O atom to form a two‐dimensional network parallel to (10). The C—S—C bond angle in (II) is larger than its counterpart in (I), indicating that the S atom of (II) has less p character in its bonding orbitals than that of (I), according to Bent's rule. The crystal structure of (II) includes weak C—H...O hydrogen bonds between the H atoms of the methylene groups and carbonyl O atoms, forming a three‐dimensional network.     

Ammonium 3‐cyano‐4‐(dicyano­methyl­ene)‐5‐oxo‐4,5‐dihydro‐1H‐pyrrol‐2‐olate monohydrate

Each anion of the title salt, NH₄⁺·C₈HN₄O₂⁻·H₂O, is linked by two N—H⋯O hydrogen bonds to another anion, thus forming an essentially planar centrosymmetric dimer. The dimers are considered to be mol­ecular building blocks of an anionic wall. The building blocks form infinite ribbons via–C—N⋯N—C– dipole–dipole and π–π inter­actions. Adjacent ribbons are stacked by means of π–π inter­actions, thus forming an anionic wall. Neighbouring walls are connected by (NH₄⁺…H₂O)_n chains running along the b axis.     

Efficient synthesis and dehydration reaction of trichloromethylated 2‐(3‐phenyl‐5‐hydroxy‐4,5‐dihydro‐1H‐pyrazol‐1‐yl)‐4‐aryl‐5‐alkylthiazoles

A convenient method for the synthesis of a novel series of 11, specifically substituted, noncondensed 5,5‐bicycles 2‐[3‐phenyl‐5‐hydroxy‐5‐trichloromethyl‐4,5‐dihydro‐1H‐pyrazol‐1‐yl]‐4‐aryl‐5‐alkylthiazoles ( 3a–k ; 65–94% yield) from the reactions of 3‐phenyl‐5‐hydroxy‐5‐trichloromethyl‐4,5‐dihydro‐1H‐1‐pyrazolethiocarboxyamide ( 1 ) with substituted 2‐bromo‐4′‐acetophenones ( 2a–f ) and 2‐bromo‐4′‐propiophenones ( 2g–k ) is reported. Dehydration of compounds 3a–k with a mixture of concentrated sulfuric acid/chloroform furnished the corresponding 2‐[3‐phenyl‐5‐trichloromethyl‐1H‐pyrazol‐1‐yl]‐4‐aryl‐5‐alkylthiazoles ( 4a–k ) in good yields (61–93%). © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:132–137, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10113     

3‐(phenylhydrazono)‐indan‐1‐one and 2‐dimethylaminomethylene‐3‐(phenylhydrazono)‐indan‐1‐one as useful synthons for the construction of new heterocyclic systems

The hydrazone 1 reacts with DMFDMA to give 2‐dimethylaminomethylene‐3‐(phenylhydrazono)‐indan‐1‐one (2) which reacts with hydrazine hydrate and the pyrazole derivative 4 to afford the indenopyrazole derivatives 3 and the indenofluorene 5 respectively. The reaction of 2 with the active methylene compounds, mainly malononitrile, cyanoacetamide and malononitrile dimer was investigated and found to proceed successfully to yield the indenopyran 7 , indenpyridine 8b and trinitrile 9 respectively. Compound 2 reacted with lH‐benzimidazole‐2‐acetonitrile 10 to give to the diazaindenofluorene derivative 11 . Also, 2 reacted with ω‐cyano compounds 12a,b to afford the indenopyran 14 . On the other hand the hydrazone 1 was allowed to react with the enaminones 15, 18 and 21 affording the diazabenzoazulene derivatives 17, 20 and the indeno[1,2‐b]pyridin 23 , respectively.     

Synthesis and Antimicrobial Studies of New Bis[4,5‐dihydro‐1‐phenyl‐5‐thienyl‐3‐(phenyl‐4‐alkoxy)‐1H‐pyrazole] Derivatives

Syntheses and antimicrobial behavior of the alkyl linked new bispyrazolines 4a , 4b , 4c , 4d , 4e , 4f , 4g have been investigated. These compounds exhibited better antimicrobial activities as compared with their corresponding bischalcones. The structures of the prepared compounds ( 3a , 3b , 3c , 3d , 3e , 3f , 3g and 4a , 4b , 4c , 4d , 4e , 4f , 4g ) were determined from the rigorous analysis of their IR, ¹H NMR, ¹³C NMR, and mass spectral parameters.     

The Synthesis of 2‐(Chromon‐2/3‐yl)‐3‐(5‐thione‐4‐hydro‐1,3,4‐thiadiazol‐2‐yl)‐4‐oxo‐thiazolidine

2‐Formylchromones and 3‐formylchromones as the first materials singly reacted with 2‐amino‐5‐mercapto‐1,3,4‐thiadiazole to give the corresponding Schiff bases, which on cyclocondensation with mercapto‐acetic acid in 1,4‐dioxane yielded target compounds named 4‐oxo‐thiazolidines. The structures of all the synthetic compounds were confirmed by elemental analysis and IR, ¹H NMR, LC‐MS (ESI) spectral data.     

Preparation of 2‐phenyl‐2‐hydroxymethyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline and 2‐methyl‐4‐oxo‐3,4‐dihydroquinazoline derivatives formation

The cyclization of phenacyl anthranilate has been studied with the aim to develop the synthesis of 2‐(2′‐aminophenyl)‐4‐phenyloxazole. However, a different course of the reaction than expected was observed. 2‐Phenyl‐2‐hydroxymethyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 3a ) was formed by the reaction of phenacyl anthranilate ( 2 ) with ammonium acetate under various conditions. 3‐Hydroxy‐2‐phenyl‐4(1H)‐quinolinone ( 4 ) arose by heating compound 3a in acetic acid. The same compound was obtained by melting compound 3a , but the yield was lower. Different types of products resulted in the reaction of compound 3a with acetic anhydride. Under mild conditions acetylated products 2‐acetoxymethyl‐2‐phenyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 7a ) and 2‐acetoxymethyl‐3‐acetyl‐2‐phenyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 8 ) were prepared. If the reaction was carried out under reflux of the reaction mixture, molecular rearrangement took place to give cis and trans 2‐methyl‐4‐oxo‐3‐(1‐phenyl‐2‐acetoxy)vinyl‐3,4‐dihydroquinazolines ( 9a and 9b ). All prepared compounds have been characterised by their ¹H, ¹³C and ¹⁵N NMR spectra, IR spectra and MS.