Synthesis and reactivity of 2-(2-furyl)-1,7-dimethyl-1<Emphasis Type="Italic">H</Emphasis>,7<Emphasis Type="Italic">H</Emphasis>-benzo[1,2-<Emphasis Type="Italic">d</Emphasis>: 3,4-<Emphasis Type="Italic">d</Emphasis>′]diimidazole

2-(2-Furyl)-1,7-dimethyl-1H,7H-benzo[1,2-d: 3,4-d′]diimidazole was synthesized by the Weidenhagen reaction followed by N-methylation. Electrophilic substitution reactions of the title compound (nitration, bromination, sulfonation, formylation, and acylation) involved both the furan ring and central benzene fragment.     

Formation and cyclization of <Emphasis Type="Italic">N</Emphasis>′-(benzoyloxy)benzenecarboximidamides

The formation of N′-(benzoyloxy)benzenecarboximidamides and their subsequent cyclization to 3,5-disubstituted 1,2,4-oxadiazoles in different solvents were studied. A probable reaction mechanism was proposed on the basis of the obtained results.     

Synthesis of 2-aryl-4-(4-<Emphasis Type="Italic">β</Emphasis>-D-allopyranosyloxyphenyl)4,6,7,8-tetrahydroquinolin-5(1<Emphasis Type="Italic">H</Emphasis>)-one derivatives under solvent-free conditions and study of sedative activity

Under solvent-free conditions, syntheses of 2-aryl-4-(4-β-D-allopyranosyloxyphenyl)-4,6,7,8tetrahydroquinolin-5(1H)-one derivatives were carried out from chalcone (2a–2e), cyclohexane-1,3-dione (3), and NH₄OAc in excellent yield without using any catalysts. The structure of the new compounds were characterized by ¹H NMR, IR, and HR-MS spectroscopy. The preliminary bioassay tests of 4a–4j indicated that compounds 4b, 4e, and 4f exhibited potent sedative and hypnotic activity.     

Structure and stabilization factors of the 2-aminobenzimidazolium–3,3′-(phenylmethylene)- bis(4-hydroxy-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-one) anion associate in the system 4-hydroxy-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-one–benzimidazol-2-amine–benzaldehyde

The molecular and crystal structures of the ionic associate formed by 2-aminobenzimidazolium cation solvated by one dimethyl sulfoxide molecule and 3,3′-(phenylmethylene)bis(4-hydroxy-2H-chromen-2- one) anion were determined by X-ray analysis. This associate was isolated in the acid-catalyzed three-component reaction of 4-hydroxy-2H-chromen-2-one with benzimidazol-2-amine and benzaldehyde together with regioisomeric dihydrochromenopyrimidobenzimidazolones resulting from the classical Biginelli condensation. The steric and electronic structures of the cation and anion were calculated at the B3LYP/6-311++G(d,p) level of theory in combination with NBO analysis. Factors stabilizing the ion pair and crystal field effects on the stability of the associate and its constituents were considered. The formation of 3-[(2,4-dioxo-3H-chromen-3-yl)(phenyl)methyl]-2-oxo-2H-chromen-4-olate anion in the one-pot reaction was shown to be irreversible.     

First example of the synthesis of <Emphasis Type="Italic">S</Emphasis>,<Emphasis Type="Italic">O</Emphasis>-macroheterocycle based on 2(5<Emphasis Type="Italic">H</Emphasis>)-furanone and 2,2´-oxydiethanethiol

A base-catalyzed reaction of 3,4-dichloro-5-methoxy- and 3,4-dichloro-5-ethoxy-2(5H)-furanones with 2,2´-oxydiethanethiol gave thiols and bis-thioethers of 2(5H)-furanone series. A new S,O-macroheterocyclic compound containing a 18-membered oxathiamacrocycle and two 2(5H)-furanone fragments was synthesized based on the thiols in an aqueous solution of potassium hydroxide, which was characterized by X-ray diffraction.     

Synthesis and calming activity of 6<Emphasis Type="Italic">H</Emphasis>-2-Amino-4-Aryl-6-(4-<Emphasis Type="Italic">β</Emphasis>-D-Allopyranosyloxyphenyl)-1,3-Thiazine

E-(4-β-D-Allopyranosyloxyphenyl)-1-(4-substituted phenyl)propenone derivatives (1a–g) have been synthesized by the Claisen-Schmidt condensation of helicid with 4-substituted acetophenone using 10% NaOH aqueous solution as a catalyst. 6H-2-Amino-4-aryl-6-(4-β-D-allopyranosyloxyphenyl)-1,3-thiazine (2a–g) were synthesized by the 1,4-Michael reaction of 1a–g with thiourea. The structures of all the new products were established by ¹H NMR, IR, and MS spectroscopy. Compound 2b (200 mg·kg^–1) showed better sedative-hypnotic activity, so further modification of helicid should be worthwhile.     

Synthesis and characteristics of <Emphasis Type="Italic">N</Emphasis>-(glyoxyldioxime)-<Emphasis Type="Italic">N</Emphasis>′-(2-hydroxybenzylidene)-1,4-diaminonaphthalene and its metal complexes

A new vic-dioxime, N-(glyoxyldioxime)-N′-(2-hydroxybenzylidene)-1,4-diaminonaphthalene, was synthesized proceeding from naphthalene. Its complexes of nickel, copper and cobalt were prepared. The vicdioxime and its complexes were charecterized by FT-IR, UV, ¹H NMR, mass spectrometry, elemental analysis, DTA/TG analysis techniques and conductometric measurements. Published in Russian in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 5, pp. 797–802. The text was submitted by authors in English.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-nitro-<Emphasis Type="Italic">N</Emphasis>′-(trimethylsilyl)carbodiimide

Nitration of N,N′-bis(trimethylsilyl)carbodiimide with N₂O₅ or (NO₂)₂SiF₆ afforded N-nitro-N´-(trimethylsilyl)carbodiimide, the first representative of N-nitro carbodiimides. Its further nitration led to the release of CO₂, which is presumably formed in the course of N,N´-dinitrocarbodiimide decomposition. The reactions of N-nitro-N´-(trimethylsilyl)carbodiimide with nucleophiles take place both at the tri methylsilyl group (for example, with NH₃) to give nitrocyanamide salts and at the carbodiimide C atom (for example, with Et₂NH) to give the corresponding nitroguan idines.     

Versatile three-component synthesis of 2′-amino-1,2-dihydrospiro[(3<Emphasis Type="Italic">H</Emphasis>)-indole-3,4′-(4′<Emphasis Type="Italic">H</Emphasis>)-pyran]-2-ones

A versatile method for the synthesis of 2′-amino-1,2-dihydrospiro[(3H)-indole-3,4′-(4′H)-pyran]-2-ones has been suggested consisting in the three-component reaction of isatins, cyanoacetic acid derivatives, and α-methylenecarbonyl compounds (β-dicarbonyl compounds, activated phenols, and OH-substituted heterocycles) in ethanol in the presence of triethylamine as a catalyst. The reaction proceeds selectively to form spiro[(3H)-indole-3,4′-(4′H)-pyrans].     

2-Nitroguanidine derivatives: XI. Reactions of <Emphasis Type="Italic">N</Emphasis>′-nitrohydrazinecarboximidamide and 2-methylidene-<Emphasis Type="Italic">N</Emphasis>′-nitrohydrazinecarboximidamide with glyoxal

The reaction of glyoxal with N′-nitrohydrazinecarboximidamide (1-amino-2-nitroguanidine) in the presence of sodium hydroxide at a molar ratio of 1 : 1 : 1 gave N′-nitro-2-(2-oxoethylidene)hydrazinecarboximidamide as a mixture of syn and anti isomers, whereas at a reactant ratio of 1:2:2 N′-nitro-2-[(5-nitroamino-2H-1,2,4-triazol-3-yl)methyl]hydrazinecarboximidamide and 3-nitroamino-4,5-dihydro-1,2,4-triazin-5-ol were formed. N′-Nitro-2-(2-oxoethylidene)hydrazinecarboximidamide reacted with N′-nitrohydrazinecarboximidamide in boiling ethanol to give N′-nitro-2-[(5-nitroamino-2H-1,2,4-triazol-3-yl)methyl]hydrazinecarboximidamide, while in glacial acetic acid 2,2′-(ethane-1,2-diylidene)bis(N′-nitrohydrazinecarboximidamide) was obtained. The latter was also formed in the reaction of glyoxal with N′-nitrohydrazinecarboximidamide in acetic acid at room temperature. The reaction of 2-methylidene-N′-nitrohydrazinecarboximidamide with glyoxal led to the formation of 3-nitroimino-2,3,4-5-tetrahydro-1,2,4-triazine-5-carbaldehyde or 1-(methylideneamino)-2-(nitroimino)imidazolidine-4,5-diol, depending on the conditions.     

Synthesis and light-emitting properties of 2-(<Emphasis Type="Italic">N</Emphasis>-phenyl-α-naphthylamino) and 2-dimesitylboron-7-(<Emphasis Type="Italic">N</Emphasis>-phenyl-α-naphthylamino)-9,9-diethylfluorene

A fluorescent organic triarylamine with a symmetric structure, 2,7-bis(N-α-naphthyl-phenylamino)-9,9-diethylfluorene (NPAEF) was synthesized using two methods, modified Ullmann coupling and modified palladium-catalyzed amination. An activated copper and a combination of Pd(OAc)₂/P(t-Bu)₃ and Pd(dba)₂/P(t-Bu)₃ were selected as catalysts to improve yields of reactions. These synthetic procedures were also successfully applied to an asymmetric 2-dimesitylboron-7-(N-phenyl-α-naphthylamino)-9,9-diethylfluorene (BNPEF). Photoluminescent emission peaks in solid film and in diluted solution of NPAEF were both observed at 461 nm, while the main emission peaks of BNPEF appeared at 422 nm in hexane, and at 480 nm in methanol. The double emission peaks of BNPEF in hexane reflected fine structure in the vibrational state. With an increasing polarity of solvent, the main PL emission peaks were red-shifted and vibrational fine structure disappeared. Additionally, energy levels of NPAEF were investigated and an electroluminescence (EL) device of ITO/PVK:NPAEF/Al was fabricated, which showed a turn-on voltage of 9 V and peaked at 462 nm. The EL spectrum was in good agreement with PL spectrum, which indicated that they were from the same emitting center in the device. Supported by the National Natural Science Foundation of China (Grant Nos. 20674004, 60776039, 60825407 & 10434030), Beijing Commission of Education (Grant No. KM200710015009), Beijing Sustentation Fund for Elitist (Grant No. 20041D0500410), Laboratory of Printing and Packaging Material and Technology and Beijing Area Major Laboratory Project (Grant No. KF200811) and BJTU Fund (Grant No. 2006XM043).     

Synthesis of lupane and 19<Emphasis Type="Italic">β</Emphasis>,28-epoxy-18<Emphasis Type="Italic">α</Emphasis>-oleanane 2,3-<Emphasis Type="Italic">seco</Emphasis>-derivatives based on betulin

The α-hydroxyoximes of methyl betulonate and allobetulone were synthesized. Beckmann fragmentation of them produced the lupane and 19β,28-epoxy-18α-oleanane 2,3-seco-derivatives. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 491–494, September-October, 2008. Original article submitted July 4, 2008.     

Two crystalline polymorphic forms of α-(<Emphasis Type="Italic">N</Emphasis>-benzoxazolin-2-one)acetic acid

Two crystalline polymorphic forms of α-(N-benzoxazolin-2-one)acetic acid (BAA) are prepared by changing the temperature of its crystallization from solution in ethanol. Crystallographic data of the α-form are determined: a = 12.7769(17) Å, b = 8.2574(9) Å, c = 16.7390(19) Å, β = 105.087(13)°, space group C2/c, V = 1705.2(4) ų, and Z = 8, while those of β form are a = 5.2854(4) Å, b = 5.9880(4) Å, c = 13.4509(5) Å, β = 94.666(4)°, space group P2₁, V = 424.30(4) ų, and Z = 2. It is found that BAA molecules of the α form combine into infinite one-dimensional chains arranged along axis b by means of O?H···O and C?H···O hydrogen bonds, and these chains are crosslinked via C?H···O hydrogen bonds to form a threedimensional structure. The β form has another system of hydrogen bonds, one of which is bifurcated (O4···O2, O4···O3), and the π–π-interactions between the benzoxazolinone fragments of BAA molecules combined into a chain also arranged along axis b are observed. Calorimetric analysis shows that the polymorphic transition from the α form to the β form occurs at 129°C.     

Reactions of <Emphasis Type="Italic">N</Emphasis>-(2,2-dichloro-1-cyanoethenyl)-<Emphasis Type="Italic">N</Emphasis>′-methyl(phenyl)ureas with aliphatic amines

Novel derivatives of 3,3-dichloroprop-2-enenitrile containing methylurea or phenylurea fragments have been synthesized. The obtained N-(2,2-dichloro-1-cyanoethenyl)-N′-methyl(phenyl)ureas undergo intramolecular cyclization in the presence of triethylamine to form 4-(dichloromethylidene)-5-imino-1-methyl (phenyl)imidazolidin-2-ones. Reactions of N-(2,2-dichloro-1-cyanoethenyl)-N′-methylurea with aliphatic amines have afforded 4-(alkylamino)-4-(dichloromethyl)-5-imino-1-methylimidazolidin-2-ones.     

Synthesis and transformations of 3-allyl-7,10-dimethyl-2-sulfanylidene-2,3,5,6-tetrahydrospiro[benzo[<Emphasis Type="Italic">h</Emphasis>]quinazoline-5,1′-cyclopentan]-4(1<Emphasis Type="Italic">H</Emphasis>)-one

Ethyl 4′-amino-5′,8′-dimethyl-1′H-spiro[cyclopentane-1,2′-naphthalene]-3′-carboxylate reacted with allyl isothiocyanate to give 3-allyl-7,10-dimethyl-2-sulfanylidene-2,3,5,6-tetrahydrospiro[benzo[h]quinazoline- 5,1′-cyclopentan]-4(1H)-one. Reactions of the latter with alkyl halides and hydrazine hydrate and subsequent transformations of the products afforded a series of new benzo[h]quinazoline derivatives containing an allyl group in the 3-position.     

Preparation of surfactant-free nanoparticles of methoxy poly(ethylene glycol)-<Emphasis Type="Italic">b</Emphasis>-poly(D,L-lactide-<Emphasis Type="Italic">co</Emphasis>-glycolide-<Emphasis Type="Italic">co</Emphasis>-ɛ-caprolactone)

Surfactant-free nanoparticles of methoxy poly(ethylene glycol)-b-poly(D,L-lactide-co-glycolide-co-ɛ-caprolactone) diblock copolymers (MPEG-b-PDLLGCL) with different DLL:G:CL ratios were prepared by modified-spontaneous emulsification solvent diffusion method. Sizes of resulted colloidal nanoparticles obtained from light-scattering analysis were in the range of 121–132 nm with narrow size distribution. The nanoparticle sizes depended on the composition of the PDLLGCL block. Scanning electron microscopy demonstrated that the nanoparticles were aggregated after drying process, suggested they were soft nanoparticles. However, their initial aggregates can be observed and it was shown that the nanoparticles have spherical shape with smooth surface. The text was submitted by the authors in English.     

Synthesis of (7<Emphasis Type="Italic">S</Emphasis>)-(−)-7-aryl-5-methyl-7-trifluoromethyl-1,3,6,7-tetrahydro-2<Emphasis Type="Italic">H</Emphasis>-1,4-diazepin-2-ones

Acylation of (S)-(−)-4-amino-4-aryl-5,5,5-trifluoropentan-2-ones with chloroacetyl chloride gave the corresponding chloroacetamides which were treated with sodium azide and then with triphenylphosphine to obtain triphenyl-λ⁵-phosphanylideneaminoacetic acid amides. The latter underwent thermal (boiling toluene) or base-catalyzed (NaOH/MeOH) intramolecular cyclization with elimination of triphenylphosphine oxide and formation of (7S)-(−)-7-aryl-5-methyl-7-trifluoromethyl-1,3,6,7-tetrahydro-2H-1,4-diazepin-2-ones.     

Cyclization of the substituted <Emphasis Type="Italic">N</Emphasis>-(<Emphasis Type="Italic">Ortho</Emphasis>-cyclopropylphenyl)-<Emphasis Type="Italic">N′</Emphasis>-aryl ureas and thioureas in the gas phase and solution

Electron ionization (EI), chemical ionization (CI), tandem mass spectrometry, high-resolution measurements, and labeling studies as well as quantum chemical calculations were used to understand the behavior of the molecular radical cations (EI) and protonated molecules (CI) of substituted N-(ortho-cyclopropylphenyl)-N'-aryl ureas and N-(ortho-cyclopropylphenyl)-N'-aryl thioureas in a mass spectrometer. Fragmentation schemes and possible mechanisms of primary isomerization were proposed. According to the fragmentation pattern, formation of the corresponding benzoxazines and benzothiazines was considered as the major process of isomerization of the original M(+.) and MH(+), although some portions of these ions definitely transformed into other structures. The treatment of N-(ortho-cyclopropylphenyl)-N'-phenyl urea and N-(ortho-cyclopropylphenyl)-N'-phenylthiourea in solution with strong acids formed predicted 4-ethyl-N-phenyl-4H-3,1-benzoxazin-2-amin and 4-ethyl-N-phenyl-4H-3,1-benzothiazin-2-amine as principal products.     

Synthesis and photoluminescence properties of poly(2-methoxy-5-(2’-ethylhexyloxy)-<Emphasis Type="Italic">p</Emphasis>-phenylene vinylene-<Emphasis Type="Italic">co</Emphasis>-styrene) copolymers

A series of conjugated and non-conjugated copolymers of poly(2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene-co-styrene) were synthesized via a typical chlorine precursor route. The obtained copolymers were characterized by FTIR spectra, UV-Vis spectra, ¹H NMR and GPC. The results obtained indicated that the introduction of non-conjugated PS segments in MEH-PPV led to the interruption of conjugation structure and shortened the effective conjugated length, by which the optical properties of the conjugated polymer can be adjusted.