A Novel and Expedient Approach to New Thiazoles, Thiazolo[3,2-a]pyridines, Dihydrothiophenes, and Hydrazones Incorporating Thieno[2,3-b]thiophene Moiety

This paper reports details about the synthesis of a series of novel functionalized symmetrical bis-heterocyclic compounds containing a thieno[2,3-b]thiophene motif. Bis-thiazole derivatives 2, 3a-c and thiazolo[3,2-a]pyridine derivatives 4a-c are achieved. The hitherto unknown dihydrothiophene derivatives 6a-dvia bis-pyridimium salt 5 are obtained. Additionally, the novel hydrazonothieno[2,3-b]thiophene derivatives 10a-c are obtained via bis-tosylacetylthieno[2,3-b]thiophene derivative 9. All compounds are characterized by (1)H-, (13)C-NMR, GCMS, IR, and UV-vis spectrometry. These compounds represent a new class of sulfur and nitrogen containing heterocycles that should also be of interest as new materials.     

Comprehensive and Facile Synthesis of Some Functionalized Bis-Heterocyclic Compounds Containing a Thieno[2,3-b]thiophene Motif

A comprehensive and facile method for the synthesis of new functionalized bis-heterocyclic compounds containing a thieno[2,3-b]thiophene motif is described. The hitherto unknown bis-pyrazolothieno[2,3-b]thiophene derivatives 2a-c, bis-pyridazin othieno[2,3-b]thiophene derivatives 4, bis-pyridinothieno[2,3-b]thiophene derivatives 6a,b, and to an analogous bis-pyridinothieno[2,3-b]thiophene nitrile derivatives 7 are obtained. Additionally, the novel bis-pyradazinonothieno[2,3-b]thiophene derivatives 9, and nicotinic acid derivatives 10, 11 are obtained via bis-dienamide 8. The structures of all newly synthesized compounds have been elucidated by (1)H, (13)C NMR, GCMS, and IR spectrometry. These compounds represent a new class of sulfur and Nitrogen containing heterocycles that should also be of interest as new materials.     

Synthesis and Antimicrobial Studies of Some Novel Bis-[,,]thiadiazole and Bis-thiazole Pendant to Thieno[2,3-b]thiophene Moiety

The synthetic utility of 3,3'-(3,4-dimethylthieno[2,3-b]thiophene-2,5-diyl)bis (3-oxopropanenitrile) (1) in the synthesis of some novel bis-[1,3,4-thiadiazole] 6a-g and bis-thiazole 10 and 13 derivatives with thieno[2,3-b]thiophene moiety is reported. Antimicrobial evaluation of some selected examples from the synthesized products was carried out and showed promising results.     

含噻二唑环噻吩并[2,3-d]嘧啶类含氟衍生物的合成及抗肿瘤活性

通过2-氨基-3-氰基噻吩与三氟乙酸、三氯氧磷反应"一锅法"制得2-三氟甲基-4-氯噻吩并[2,3-d]嘧啶,收率为60%,再与2-氨基-5-(取代苄硫基)-1,3,4-噻二唑发生芳香族亲核取代反应合成10个含噻二唑环噻吩并[2,3-d]嘧啶类含氟衍生物,收率为64%~75%。目标化合物的结构经红外光谱、核磁共振氢谱、质谱与元素分析表征,并采用MTT法对其进行初步的体外抗肿瘤活性筛选。结果表明,化合物Ⅳc和Ⅳf对Hep G2和BGC-823细胞的抑制活性高于对照样吉非替尼。     

四氢苯并[4,5]噻吩并[2,3-d]嘧啶含氟衍生物的合成、晶体结构及抗肿瘤活性

以环己酮、丙二腈和单质硫为起始原料,通过改良的Gewald反应合成2-氨基-3-氰基-4,5,6,7-四氢苯并[b]噻吩(Ⅰ),再与三氟乙酸、三氯氧磷反应"一锅法"直接制得4-氯-2-三氟甲基-5,6,7,8-四氢苯并[4,5]噻吩并[2,3-d]嘧啶,然后与取代苄胺反应合成13个噻吩并[2,3-d]嘧啶类含氟衍生物,收率为69%~83%。目标化合物的结构经1HNMR、IR、MS和元素分析方法进行表征。并采用X射线单晶衍射测定化合物Ⅲa的晶体结构,结果表明,该化合物晶体属单斜晶系,空间群为C2/c,a=2.695 9(4)nm,b=0.772 45(13)nm,c=1.688 5(3)nm,α=90°,β=109.320(2)°,γ=90°,V=3.318 2(9)nm3,Z=8,Dc=1.455×106g·m-3,μ=0.23 mm-1,F(000)=1 504,R1=0.057 9,wR2=0.160 4。初步的生物活性实验表明,部分化合物表现出良好的抗肿瘤活性,其中化合物Ⅲc、Ⅲf和Ⅲj对Hep G2和MCF-7细胞的抑制活性高于阳性对照样吉非替尼。     

Development of new dyeing photoinitiators based on 6H-indolo[2,3-b]quinoxaline skeleton

The series of new dyes, which structures are based on 6H-indolo[2,3-b]quinoxaline skeleton that possess characteristic electronic absorption band at a boundary of UV and visible light were tested as potential light absorbing chromophores for photoinitiated polymerization.The studied dyes can be classified into two different groups. The first is the group, so called ‘the branched dyes’, which structures possess the part of molecule that can rotate without restraints and are characterized by low photoinitiation ability. The second, planar and rigid group of molecules provides another chromophores, which possess quite different properties in comparison to that observed for the branched dyes. Their photoinitiation ability is comparable to that observed for many commercially available photoinitiating systems.The location of electronic absorption spectra at a boundary of UV and visible light makes the tested dyes the good candidates for the photoinitiating system applied in dental restorative materials. Their high molar absorption coefficient allows to decrease the dyes concentration in dental formulation in comparison to commonly used camphorquinone.     

Synthesis of some new fused thiopyrano[2,3-d]thiazoles and their derivatives

A series of some new fused thiopyrano[2,3-d]thiazole derivatives have been synthesized by a stereo-selective hetero-Diels-Alder reaction of 5-(2,4-dihydroxy-benzylidene)-4-thioxo-thiazolidine derivatives 3a,b with acrylonitrile, ethyl acrylate, N-phenylmale-imide, ω-nitrostyrene and N-phenyl-1, 3, 4-triazole-2,5-dione. 5-Amino-9-hydroxy-dihydro-benzopyrano[3′,4′:4,5]thiopyrano[2,3-d]thiazol-6-one derivatives 14a,b have been synthesized by Michael addition of 3a,b with malononitrile. Structures and conceivable mechanisms are discussed.     

Novel red-emitting thieno-[3,4-b]-pyrazine derivatives suitable for vacuum evaporation and solution method to fabricate non-doped OLEDs

Two novel red-emitting thieno-[3,4-b]-pyrazine-cored molecules with phenyls (TP) or polyphenyls (Müllen type dendron, DTP) as peripheral groups were designed and synthesized. They have large Stokes shifts over 100 nm. DTP is thermally stable with decomposition temperature up to 458 °C. More importantly, it is amorphous with a remarkably high glass transition temperature of 262 °C. DTP can be made into thin films either by solution method or vacuum evaporation. Red OLEDs were fabricated using either spin coated or vacuum evaporated DTP film as emitting layer. The evaporated device exhibited a maximum brightness of 1753 cd m⁻² and a luminous efficiency of 0.74 cd A⁻¹, which are among the best data ever reported for thieno-[3,4-b]-pyrazine derivatives so far. In contrary, TP failed to produce satisfied red emission in its evaporated OLEDs.     

Synthesis of highly fluorescent coumarinyl chalcones derived from 8-acetyl-1,4-diethyl-1,2,3,4-tetrahydro-7H-pyrano[2,3-g]quinoxalin-7-one and their spectral characteristics

A series of novel coumarin based chalcones were synthesized by the classical crossed aldol condensation reaction of 8-acetyl-1,4-diethyl-1,2,3,4-tetrahydro-7H-pyrano[2,3-g]quinoxalin-7-one and various substituted benzaldehydes. These novel ketocoumarin derivatives having a 1,4-diethyl-1,2,3,4-tetrahydroquinoxaline framework exhibited brilliant fluorescence. The novel chalcones absorbed in the range of 458-523 nm in various solvents. The wavelength of maximum absorption of these chalcones was found to be significantly longer than their simple acyl derivative known in the literature. The dyes displayed longer wavelength of absorption in the high polarity solvents compared to non-polar solvents. Thermogravimetric analysis of the chalcones revealed that the chalcones possess good thermal stability.     

A Rapid and Highly Efficient Microwave-Promoted Four-Component Domino Reaction for the Synthesis of Novel Spiro[benzo[a]chromeno[2,3-c]phenazine] Derivatives Under Solvent-Free Conditions

p-Toluenesulfonic acid was applied as an efficient, non-toxic and solid acid catalyst for the one-pot, four-component condensation between 2-hydroxy-1,4-naphthoquinone, benzene-1,2-diamine, cyclic 1,3-dicarbonyl compounds and isatin or ninhydrin to afford the corresponding novel spiro[benzo[a]chromeno[2,3-c]phenazine] derivatives via a new two-step domino protocol under conventional heating and microwave irradiation. This solvent-free process produces biologically considerable heterocycles with the formation of five new bonds (two C–C, two C?N, and one C–O) and two new rings in a single operation and this effective green process provides considerable advantages such as: operational simplicity, very short reaction time, high yields, absence of any tedious process or purification, and it avoids hazardous reagents/solvents.     

Synthesis, X-ray crystal structure and optical properties of novel 2,5-diaryl-1,3,4-oxadiazole derivatives containing substituted pyrazolo[1,5-a]pyridine units

A series of pyrazolo[1,5-a]pyridine-containing 2,5-diaryl-1,3,4-oxadiazole derivatives were synthesized and their structures were characterized by IR, ¹H NMR and HRMS spectra. The crystal structure of 3a was determined using single crystal X-ray crystallography. Its spatial structure was found to be monoclinic, and all aromatic rings were approximately coplanar, which allowed conjugation. The absorption results showed that compounds 1a-f presented their absorption peaks ranging from 264 nm to 290 nm, while compounds 3a-f with a larger conjugation system exhibited red-shifted absorption character (absorption maxima between 283 nm and 303 nm) compared to the corresponding absorption of 1a-f. Fluorescence spectra revealed that these compounds exhibited blue fluorescence (421-444 nm) in dilute solutions and showed quantum yields of fluorescence between 0.32 and 0.83 in dichloromethane.     

Synthesis of light-emitting π-conjugated poly(pyrimido[5,4-d]-pyrimidine-2,6-diyl) with bulky side chains and high molecular weight

New poly(pyrimido[5,4-d]pyrimidine-2,6-diyl) (PPympym) with bulky dialkylamino substituents (-NR₂, R=hexyl, decyl) was prepared by organometallic dehalogenative polycondensation using a zerovalent Ni complex. The obtained PPympym was soluble in common organic solvents such as CHCl₃ and THF, and GPC analysis (in CHCl₃; vs. polystyrene standards) indicated that new Ppympyms had high number-average molecular weights M_n of 19,100-34,000; they also gave a high [η] value of about 2.1 dl g⁻¹. PPympym showed strong photoluminescence both in CHCl₃ and in film, and greenish-blue electroluminescence from PPympym-based double-layer light-emitting devices (ITO/PEDOTh/PPympym/Ca-Al; PEDOTh, poly(ethylenedioxythiophene)) was observed.     

Novel aminated benzimidazo[1,2-a]quinolines as potential fluorescent probes for DNA detection: Microwave-assisted synthesis, spectroscopic characterization and crystal structure determination

A synthesis of novel benzimidazo[1,2-a]quinolines, substituted with piperidine, pyrrolidine and piperazine nuclei has been accomplished using an uncatalyzed amination protocol under microwave heating. All compounds were characterized by means of ¹H, ¹³C NMR, IR, UV/Vis and fluorescence spectroscopy. Crystal and molecular structures of 2-chloro- and 2-piperidinyl-benzimidazo[1,2-a]quinoline-6-carbonitrile were determined by X-ray diffractometry. These molecules are essentially planar. Their molecular assembly is characterized by the existence of weak intermolecular hydrogen bonds of C-H⋅⋅⋅N type and π-π aromatic interactions. The π-π aromatic stacking observed in the solid state structures of the 2-chloro- and 2-piperidinyl- derivatives are not analogous. The spectroscopic properties of these amino substituted benzimidazo[1,2-a]quinolines as their hydrochloride salts in the presence of ct-DNA were studied by means of fluorescence spectroscopy. Comparison of binding properties of amino substituted benzimidazo[1,2-a]quinoline hydrochloride salts to ct-DNA revealed significantly enhanced fluorescence emission intensity and thus offer the potential applications as a DNA-specific fluorescent probes.     

Facile synthesis and characterization of novel bis(2-S-alkylpyridines) and bis(3-aminothieno[2,3-b]pyridines) incorporating 1,3-diarylpyrazole moiety

3-(4-Hydroxyphenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde (1) is condensed with acetophenone to afford the corresponding unsaturated carbonyl compound 4 whose potassium salt is reacted with 1,4-dibromobutane to afford the bis-unsaturated carbonyl compound 3. Both carbonyl compounds 3 and 4 are reacted with 2-cyanoethanethioamide, through Michael addition reaction followed by cyclocondensation, to prepare the starting materials bis(pyridine-2(1H)-thione) derivative 5 and pyridine-2(1H)-thione derivative 8. Two synthetic routes to synthesize the target materials 7 and 14 are described to get the most efficient method for preparation and maximum yield%. The first route came from the direct alkylation of the bis(pyridine-2(1H)-thione) derivative 5 using iodomethane (6a) and benzyl chloride (6b) to afford the corresponding bis(2-S-alkylpyridine) derivatives 7a,b. The reaction of 5 with halo-containing compounds 10a–d to synthesize the target materials bis(3-aminothieno[2,3-b]pyridine) derivatives 14a–d failed under various reaction conditions. The second route involves the reaction of pyridine-2(1H)-thione derivative 8 with 6a,b and 10a–d to afford the corresponding 2-S-alkylpyridine derivatives 9a,b and 3-aminothieno[2,3-b]pyridine derivatives 13a–d, through the formation of 2-S-alkylpyridine derivatives 12a–d followed by a Thrope-Ziegler reaction, whose potassium salts reacted with 1,4-dibromobutane to afford the corresponding target materials 7a,b and 14a–d, respectively. The structures of target molecules were elucidated using elemental analyses and spectral data.     

Nickel complexes bearing 2-(1H-benzo[d]imidazol-2-yl)-N-benzylidenequinolin-8-amines: Synthesis,structure and catalytic ethylene oligomerization

A series of 2-(1H-benzo[d]imidazol-2-yl)-N-benzylidenequinolin-8-amines was synthesized and characterized. They are stable as solids while displaying a tendency to decompose in solution. On reaction with NiCl₂, different coordination pattern sets of L·NiCl₂ or [L₂Ni]²⁺·2Cl⁻ are obtainable in THF or ethanol. When activated by Et₂AlCl, the complexes L·NiCl₂ exhibit good to high catalytic activities and selectivities for 1-C₄ in ethylene oligomerization, while the complexes [L2Ni]²⁺·2Cl⁻ hardly showed any activity, which is attributable to nickel coordination by two ligands barring interaction of ethylene with the metal center.     

Pyridine-2(1H)-thione in heterocyclic synthesis: synthesis and antimicrobial activity of some new thio-substituted ethyl nicotinate,thieno[2,3-b]pyridine and pyridothienopyrimidine derivatives

3-(4-Bromophenyl)-2-cyanoprop-2-enethioamide (1) reacted with ethyl 3-oxo-3-phenylpropanoate (2) to give ethyl 4-(4-bromophenyl)-5-cyano-2-phenyl-6-thioxo-1,6-dihydropyridine-3-carboxylate (3). Compound 3 was taken as a starting material for the synthesis of thio-substituted ethyl nicotinate derivatives 5a–d, which underwent cyclization to the corresponding thieno[2,3-b]pyridines 6a–d. Also 3 reacted with hydrazine hydrate to give the pyrazolo[3,4-b]pyridine derivative 7, which upon diazotization gave the diazonium derivative 8. Compound 6a condensed with dimethylformamide–dimethylacetal to afford thieno[2,3-b]pyridine derivative 9, which reacted with different amines 10a–e to afford the pyridothienopyrimidine derivatives 12a–e through the Dimroth rearrangement. Moreover, compound 6a reacted with different reagents to give pyridothienopyrimidine derivatives 14a and b, 17 and pyrazolothienopyridine derivative 18. In addition, acetylating compound 6c with chloroacetylchloride afforded the 3-[(2)-chloroacetylamino]thieno[2,3-b]pyridine derivative 20, which upon cyclization yielded the corresponding 2-chloromethylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine derivative 21. Some of the newly synthesized compounds were screened in vitro for their antimicrobial activities.

     

长春西汀中间体-1-(2',2'-二羧乙酯乙基)-1-乙基-1,2,3,4,6,7,12,12b-八氢吲哚(2,3-a)喹嗪的合成

提出了一条以Wenkert's烯胺和二甲羧乙酯基乙烯为原料合成长春西汀的关键中间体-1-(2',2'-二羧乙酯乙基)-1-乙基-1,2,3,4,6,7,12,12b-八氢吲(2,3-a)喹嗪的新路线。对新工艺条件进行了优化,反应温度85℃,反应时间7h、催化剂用量5.1%,此优化条件下中间体收率达到85.5%。利用红外光谱、质谱和核磁共振确定了中间体的结构。     

2-烷氨基-3-对氟苯基-5-甲基-6-(1H-1,2,4-三唑-1-基)-噻吩并[2,3-d]嘧啶-4(3H)-酮衍生物的合成及其杀菌活性

已见含氟类有机物具有杀菌能力的报道,将氟元素引入到噻吩并嘧啶酮的衍生物之中,考查其杀菌活性。通过Gewald反应生成噻吩,产物同PPh3、C2Cl6、Et3N作用得到膦亚胺,再用对氟苯基异氰酸酯与之作用得到碳二亚胺,之后与伯胺反应得到10种新的标题化合物,其结构经1HNMR、MS和元素分析表征。生物活性测试表明,此类衍生物对常见农作物部分菌体均表现出较大的抑制作用,其中以2-正庚氨基-3-对氟苯基-5-甲基-6-(1H-1,2,4-三唑-1-基)-噻吩并[2,3-d]嘧啶-4(3H)-酮活性最好,它对棉花枯萎菌的抑制率达90%。该系列物质相对不含氟元素的同种取代基的噻吩并嘧啶酮衍生物的杀菌活性有一定程度的提高。     

3-苯基-2-（4-叔丁基苯氧基）-3＇-氧环己烷并噻吩并[2，3-d]嘧啶-4（3H）-酮的合成及其与BSA的相互作用

通过Aza-Wittig反应。碳二亚胺与酚类化合物在碱性催化条件下成环,合成了3-苯基-2-（4-叔丁基苯氧基）-3’-氧环己烷并噻吩并[2,3-胡嘧啶-4（3H）-酮（PTP）。在生理条件下。采用紫外吸收光谱法及荧光光谱法研究了PTP与牛血清白蛋白（BSA）的相互作用。并采用同步荧光法考察了PTP的加入对BSA构象的影响。结果表明,PTP对BSA的荧光猝灭机理为静态猝灭过程。PTP与BSA的结合反应为自发进行,反应中主要作用力是氢键和范德华力,两者的结合位点数为1、结合距离为1．78nm．PTP的加入对BSA构象没有明显影响。     

The electrocatalytic cascade assembling of isatins, malononitrile and N-alkyl barbiturates: An efficient multicomponent approach to the spiro[indole-3,5′-pyrano[2,3-d]pyrimidine] framework

Electrochemically induced catalytic multicomponent transformation of isatins, barbituric acid or N-alkyl barbiturates and malononitrile in alcohols in an undivided cell results in the formation of substituted 7′-amino-2,2′,4′-trioxo-1,1′,2,2′,3′,4′-hexahydrospiro[indole-3,5′-pyrano[2,3-d]pyrimidine]-6′-carbonitriles in 80–95% yields. The developed efficient electrocatalytic approach to corresponding spiro[indole-3,5′-pyrano[2,3-d]pyrimidine] system is beneficial from the viewpoint of diversity-oriented large-scale processes and represents a new example of the ecologically pure synthetic concept for electrocatalytic multicomponent reactions strategy.