Single & Two-photon Excited Fluorescence of Two New Compounds with 2-Benzothiazolyl as Electron Acceptor

When certain lasers are used as pump source, some organic molecules can simultaneously absorb two photons to reach one of their excited states and subsequently frequency up-converted fluorescence emission may follow1,2. Compared with common single-photon excited fluorescence (SPEF), this two-photon excited fluorescence (TPEF) is characterized by its excitation process of two-photon absorption (TPA) that presents several advantages including high three-dimensional resolution as well as low…     

Thermal decomposition of s-2-benzothiazole thiocarbonates

Thermal decompositions of S-2-benzothiazole thiocarbonates have been investigated. The results are best rationalized by an Sni ion-pair return mechanism from which S-substituted benzothiazoles are the major products obtained. The ready ionization of the carbon-oxygen bond of thiocarbonates at elevated temperature renders a concerted Sni mechanism (internal substitution with allylic rearrangement) inoperative. Of particular interest is the mixed benzo-thiazole-2-thiol and 2-thione compound isolated from the decomposition of 2 (or 3)-halogen-substituted ethyl (or propyl) thiocarbonates. Evidence is presented that the thione 14 results from the nucleophilic opening of the cyclic intermediate, 2,3-dihydrothiazolo[2,3-b]benzothi-azolium chloride ( 20 ). The latter is readily formed under the experimental condition by intramolecular cyclization of the corresponding 2-(2-chloroethyl)benzothiazole ( 23 ), a primary product from the decomposition of S-2-benzothiazole 2-chloroethylthiocarbonate ( 7 ).     

上转换荧光化合物DMSSB与CSSB的合成、结构与光物理性质

以苯并噻唑为电子受体,以双苯乙烯基为共轭桥链,分别以二甲基胺和咔唑为电子给体合成了2个新的有机化合物DMSSB(反式,反式-2-{4-[(4-N,N-二甲基胺)苯乙烯基]苯乙烯基}-1,3-苯并噻唑)和CSSB(反式,反式-2-{4-[(4-N-咔唑)苯乙烯基]苯乙烯基}-1,3-苯并噻唑).用X射线衍射方法测定了CSSB的晶体结构.用波长为800nm的激光激发时,DMSSB与CSSB在THF中分别发出强的上转换橙色(λ_max=589nm)和蓝绿色荧光(λ_max=488nm).2个化合物在不同溶剂中的光物理数据和理论计算结果表明,苯并噻唑基是一个很好的电子受体.     

Synthesis of 2-benzylimidazo[2,1-b][1,3]benzothiazoles through palladium-catalyzed heteroannulation of acetylenic compounds

The reaction of 2-imino-3-(2-propynyl)-1,3-benzothiazole with various iodobenzenes in the presence of a palladium catalyst leads to the production of 2-benzylimidazo[2,1-b][1,3]benzothiazoles.     

Synthièse de nouveaux systèmes hétérocycliques renfermant le benzothiazole,le 1,3,4-thiadiazole et le furane

The 2-(4-methylphenyl)acyl-l,3-benzothiazole 3b reacts with the N-bromosuccinimide to give the dimerised compound 4. This product leads to the furane 5 by refluxing in triethylphosphite. The 2-phenylacyl1,3-benzothiazole 3a leads to 1,3,4-thiadiazoles 9 and 10 by sulfurisation and condensation with nitrilimines 7 and 8.     

Preparation of benzoheterocycles containing a chlorofluoromethyl group using the ‘Yarovenko reagent’

ortho-Bifunctional benzenes such as 2-aminophenol o-phenylenediamine, 2-aminothiophenol, 2-aminobenzamide and catechol reacted very easily with 2-chloro-1,1,2-trifluoroethyldiethlylamine, the ‘Yarovenko reagent,’ affording 2-(chlorofluoromethyl)benzoxazole, -benzoimidazole, -benzothiazole, 2-(chlorofluoromethyl)-4-quinazolone and 2-diethylamino-2-(chlorofluoromethyl)dioxole respectively.     

Substituted (pyridinyl)benzoazole palladium complexes: Synthesis and application as Heck coupling catalysts

The synthesis of 2-(4-tert-butylpyridin-2-yl)-benzooxazole (L3), 2-(4-tert-butyl-pyridin-2-yl)-benzothiazole (L4) and 6-tert-Butyl-2-(4-tert-butyl-pyridin-2-yl)-benzothiazole (L5) by intramolecular cyclization under basic conditions is described. Reactions of 2-pyridin-2-yl-1H-benzoimidazole (L1), 2-pyridin-2-yl-benzothiazole (L2) and L3–L5 with either [Pd(NCMe)₂Cl₂] or [Pd(COD)MeCl] afforded the corresponding mononuclear palladium complexes [Pd(L1)MeCl] (1), [Pd(L2)MeCl] (2), [Pd(L3)Cl₂] (3), [Pd(L3)MeCl] (4), [Pd(L4)Cl₂] (5), [Pd(L4)MeCl] (6) and [Pd(L4)MeCl] (7) as confirmed by mass spectrometry and elemental analyses. The palladium complexes are efficient Heck coupling catalysts for the reaction of iodobenzene with butylacrylate under mild conditions. Benzothiazole and benzooxazole containing complexes show faster induction periods compared to the benzoimidazole analogues.     

A convenient one-step synthesis of fluoroethylidene derivatives

A convenient one-step synthesis of gem-monofluoroalkylolefins starting from aldehydes or ketones was developed. This method comprises the utilisation of 2-(1-fluoroethyl)sulfonyl-1,3-benzothiazole according to Julia's procedure and opens a new opportunity for the synthesis of fluoroalkylidene derivatives.     

Chemistry of the hetero analogs of isoflavones. 22. Mannich reaction in the benzimidazole and benzothiazole analogs of isoflavones

New 3-(2-benzothiazolyl)chromones were obtained by the reaction of 2-(2,4-dihydroxy-5-ethylphenacyl)-benzothiazole with triethyl orthoformate or carboxylic acid anhydrides. Aminomethylation of the chromones and also of familiar 3-(2-benzimidazolyl)chromones by substituted 1,1-diaminomethanes gave Mannich bases.For Communication 21, see [1].Taras Shevchenko Kiev University, Kiev, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1072–1078, August, 1998.     

The reaction of 2,2,4,4-tetramethyl-1,3-cyclobutanedione with o-aminophenols,o-aminothiophenol and with aliphatic 2- and 3-hydroxy- and -mercaptoamines

Studies of the reaction of the dione dimer of dimethylketene ( 1 ) with a series of o-aminophenols and with o-aminothiophenol have been carried out. These reactions give 2-[2-(2,4-dimethyl-3-oxopentyl)]benzoxazoles and -benzothiazole, respectively. Aliphatic 2- and 3-hydroxy- and 2- and 3-mercaptoamines yield 2-substituted 2-oxazolines, 5,6-dihydro-4H-1,3-oxazines, 2-thiazolines and 5,6-dihydro-4H-1,3-thiazines.     

Heterocyclization of 2-(Propargylsulfanyl)-1,3-thiazole Derivatives by the Action of Halogens

Reactions of 2-(propargylsulfanyl)-5-methyl-1,3,4-thiadiazole, N-[5-(propargylsulfanyl)-1,3,4-thiadiazol- 2-yl]benzamide, 2-(propargylsulfanyl)-1,3-benzothiazole, and 2-(propargylsulfanyl)-4,5-dihydro-1,3- thiazole with iodine involved annulation of the unsaturated substituent with formation of fused thiazole ring. 2(5)-(Propargylsulfanyl)-1,3,4-thiadiazole derivatives reacted with bromine to give mixtures of heterocyclization products and bromine adducts to the triple bond. The bromination of 2-(propargylsulfanyl)-4,5-dihydro- 1,3-thiazole afforded only the bromine addition product to the triple bond.     

偶氮基杯芳烃化合物的合成及其偶氮-醌腙互变异构性质

通过芳胺的重氮化-偶合反应合成了8个偶氮基杯芳烃化合物, 其结构经IR, 1H NMR, ESI-MS和元素分析表征. 通过UV-Vis, 1H NMR和IR考察了溶液pH值对所合成化合物5,11,17,23-四[(2-苯并噻唑基)偶氮基]-25,26,27,28-四羟基杯芳烃(3)和5,17-二[(1-萘基)偶氮基]-25,26,27,28-四羟基杯芳烃(4)的偶氮-醌腙互变异构的影响. 结果表明, 随着溶液pH值增加, 醌腙体在偶氮-醌腙互变异构平衡中的比例增加, 当pH≥10时, 几乎全部转变为醌腙体. 特别当溶液pH=-1时, 化合物4可以形成一种大的共轭体系, 使其λmax由477 nm红移至545 nm.     

超高效液相色谱法测定橡胶中6种橡胶助剂的含量

取条状橡胶样品(厚约2mm,宽约1mm)1.000g,加入体积比为6∶1的乙腈-二氯甲烷混合溶液50mL,超声提取60min,所得溶液经0.45μm滤膜过滤,滤液用于超高效液相色谱法分析。用ZORBAX Eclipse XDB-C18色谱柱(4.6mm×100mm,1.8μm)为固定相,以体积比为40∶60的乙腈-pH 4.0的12.5mmol·L^-1磷酸二氢钠混合溶液为流动相进行等度洗脱,使所测定的6种橡胶助剂得以分离,对6种橡胶助剂在不同波长处进行紫外检测,防老剂6PPD[N-(1,3-二甲基)丁基-N′-苯基对苯二胺]的检测波长为290nm,防焦剂CTP(N-环己基硫代邻苯二甲酰亚胺)和其他4种硫化促进剂[TBBS(N-叔丁基-2-苯并噻唑次磺酰胺)、MBTS(2,2-二硫化二苯并噻唑)、CBS(N-环己基-2-苯并噻唑次磺酰胺)、DCBS(N,N-二环己基-2-苯并噻唑次磺酰胺)]的检测波长均为226nm。6种橡胶助剂的标准曲线的线性范围均为5.0~500.0mg·L^-1,其检出限(3S/N)为0.3~2.5mg·L^-1。按标准加入法进行回收试验,测得回收率为82.8%~107%,测定值的相对标准偏差(n=5)均小于5.0%。     

Syntheses and Crystal Structures of Pyrazoline Derivants

SNNHNH2 OSSNNHNH2 OS1 INTRODUCTION Pyrazoline derivatives, used as carrier transporting as well as emitting materials[1], have been widely investigated in many areas due to their blue light emission with high quantum yield[2～5], ready acces- sibility and easy processability. 1,3,5-Triaryl-2-pyrazo- lines are reported as the hole transporting or emitting Scheme 1N NN SEtOHmaterials in organic EL devices[6～8]. However, ben- zothiazoyl pyrazolinederivatives containing aro…     

New Quinoline Derivatives on the Basis of (4-Hydroxy-2-methylquinolin-3-yl)acetic Acid

A procedure was developed for the synthesis of (4-hydroxy-2-methylquinolin-3-yl)acetic acid and the corresponding acyl chloride. Reactions of the latter with o-aminobenzenethiol, o-phenylenediamine, o-aminophenol, anthranilic acid, and thiosemicarbazide gave, respectively, 2-(4-hydroxy-2-methylquinolin-3-ylmethyl)-1,3-benzothiazole, -benzoxazole, -benzimidazole, 2-(4-hydroxy-2-methylquinolin-3-ylmethyl)-4H-3,1-benzoxazin-4-one, and 4-hydroxy-2-methyl-3-(5-sulfanyl-1H-1,2,4-triazol-3-ylmethyl)quinoline.     

ZnO nanoparticles: a green efficient catalyst for the room temperature synthesis of biologically active 2-aryl-1,3-benzothiazole and 1,3-benzoxazole derivatives

A facile synthetic protocol for the synthesis of 2-aryl-1,3-benzothiazoles and 1,3-benzoxazoles has been demonstrated using ZnO nanoparticles as a mild and efficient heterogeneous catalyst. The reactions using ZnO nanoparticles were very fast (<8 min) and provided excellent yields (>90%) of the products. The catalyst was recycled and reused up to eight times without significant loss of catalytic activity. The potential application of 2-(4-hydroxyphenyl)-1,3-benzothiazole as new acid–base indicator has also been demonstrated in this Letter.     

N-叔丁基-2-苯并噻唑次磺酰胺的合成工艺研究进展

N-叔丁基-2-苯并噻唑次磺酰胺(TBBS)是一种重要的橡胶硫化促进剂,生产量和应用范围不断扩大.综述了近年来TBBS的合成工艺,包括次氯酸钠氧化法、催化氧化法、双氧水氧化法、电解氧化法和氯气氧化法等,对其工艺路线的优缺点进行了总结比较,并简要介绍了TBBS的国内外生产及市场开发情况.     

Photochemistry of 5-nitro-1,2-benzisothiazole derivatives: effects of substituents, solvents and excitation wavelength

3-R-5-Nitro-1,2-benzisothiazole derivatives (1, R = substituents) in solution, undergo photochemical isomerization to produce 2-R-5-nitro-1,2-benzothiazole derivatives. Here, generalizations and limitations by the substituent, solvent, and excitation wavelength for the photoisomerization reaction of 5-nitro-1,2-benzisothiazoles are reported.     

Syntheses and reactivities of non-symmetrical "active ester" bi-dentate cross-linking reagents having a phthalimidoyl and acid chloride, 2-benzothiazole, or 1-benzotriazole group

We have newly synthesized the non-symmetrical "phthalimidoyl active ester" bi-dentate cross-linking reagents having an acid chloride, 2-benzothiazole, or 1-benzotriazole group (i.e., 9, 15, and 16) on the basis of the reactivity study of the "active ester" model compounds, 11-14, toward the various nucleophiles and examined their reaction selectivity towards the same nucleophiles. Then, we applied for the modification of cholesterol at the more reactive site of the bi-dentate linkers to give 3β-cholesteryl 4-(phthalimidoyloxycarbonyl)butyrate (39), and the subsequent reaction of 39 with several amines, such as benzylamine, 4-chlorobenzylamine, 2-phenylethylamine, L-phenylalanine methyl ester, or diphenylalanine benzyl ester as a protein model of the cholesterol antigen.     

Intramolecular aromatic substitution (SRN1) reactions; use of entrainment for the preparation of benzothiazoles

The process of entrainment (catalytic chain initiation) with the enolate-anion of acetone has been used in intramolecular aromatic S_RN1 subsitution for the preparation of 2-phenyl- and 2-methyl-1,3-benzothiazole in high yield from o-iodothiobenzanilide and o-iodothioacetanilide.