Routes to highly substituted thiophenol derivatives

Syntheses of highly substituted thiophenol derivatives that incorporate steric bulk into the ligand framework via ortho and para tert-butyl substituents are reported. S-Benzyl and trityl protection were investigated and the effects of substituents on the Newman-Kwart rearrangement of the thiocarbamate discussed. Single crystal X-ray structures are reported for three compounds and demonstrate the role of hydrogen bonding in stabilising the thiophenol to oxidation.     

Enantioselective bromolactonization using an S-alkyl thiocarbamate catalyst

The apple never falls far from the tree: S-alkyl thiocarbamate 1 (see scheme, NBP = N-bromophthalimide) was prepared in high yield through a synthetic sequence involving a Newman-Kwart rearrangement of the corresponding O-alkyl thiocarbamates. Compound 1 was used to catalyze bromolactonization, thus providing enantioenriched δ-lactones in excellent yield and enantioselectivity.     

Sulfur-incorporating cyclotriveratrylene analogues: the synthesis of cyclotrithioguaiacylene

Cyclotriguaiacylene 1 is the universal precursor of cryptophanes, and represents an important intermediate for the preparation of functionalized cavitands of the cyclotriveratrylene family. Its thio analogue (cyclotrithioguaiacylene 3) was synthesized by two different routes, involving either the Newman-Kwart or the Pummerer rearrangement. The latter, performed starting from a trisulfoxide precursor, produced a purer compound in higher overall yield.     

2,4-Bis(fluorocarbon)-substituted phenols for high yield Newman-Kwart rearrangement reactions

The Newman-Kwart thermal rearrangement of two 2,4-disubstituted O-arylthiocarbamates, prepared from the corresponding phenols, is reported. Clean conversion to the S-arylthiocarbamates in high yields was observed. The rearrangement appears to be facilitated by the presence of electron-withdrawing substituents in the 2- and 4-positions of the aromatic ring.     

Unique monoterpenoid indole alkaloids from Alstonia scholaris

[structure: see text] A pair of geometrically isomeric monoterpenoid indole alkaloids with a skeleton rearrangement and two additional carbons, named (19,20) E-alstoscholarine (1) and (19,20) Z-alstoscholarine (2), were obtained from the leaf extract of Alstonia scholaris. Their structures were elucidated on the basis of spectroscopic methods and then confirmed by X-ray crystal diffraction. The biogenesis of these compounds was also proposed.     

5,6-二甲氧基-N-[(R)-4-甲氧基-2-(丙烯-2-基)-2,3-二氢苯并呋喃-5-基]-1,1a,2,7b-四氢环丙并[c]苯并吡喃-7b-基甲酰胺的合成与表征

鱼藤酮与氧硫叶立德反应得到关键中间体(5,6-二甲氧基-1,1a,2,7b-四氢环丙并[c]苯并吡喃-7b-基)[(R)-4-羟基-2-(丙烯-2-基)-2,3-二氢苯并呋喃-5-基]甲酮(2),2再通过醚化、肟化、贝克曼重排得到5,6-二甲氧基-N-[(R)-4-甲氧基-2-(丙烯-2-基)-2,3-二氢苯并呋喃-5-基]-1,1a,2,7b-四氢环丙并[c]苯并吡喃-7b-基甲酰胺(5),化合物的结构经1H NMR,MS和元素分析确认,采用单晶X射线衍射法确定化合物5的晶体结构.化合物5属于三斜晶系,P1空间群,晶胞参数:a=0.95772(5)nm,b=1.06591(6)nm,c=1.30112(7)nm,α=111.8460(10)°,β=109.8870(10)°,γ=93.0870°,V=1.13429(11)nm3,Z=2,Dc=1.281 g/cm3,μ(Mo Kα)=0.092 mm-1,F(000)=464.     

二苯美仑的合成工艺改进及其同类物的合成

以苯甲醇、苯酚为起始原料,在活性A l2O3催化作用下,通过C laisen重排反应得到关键中间体2-苄基苯酚,再经过醚化、胺化、酸化反应得到一种新型结构的二苯美仑类化合物.反应过程经优化使中间体2-苄基苯酚产率较文献提高8%.合成的新化合物经IR,1H NMR及元素分析表征.     

含dmpzm配体的锌和镉配合物的合成、结构及性质研究

通过M(NO₃)₂(M=Zn，Cd)和二(3，5-二甲基吡唑)甲烷(dmpzm)的反应，合成了2个锌和镉配合物[M(dmpzm)₂(NO₃)][NO₃](1：M=Zn；2：M=Cd)。配合物1和2经元素分析,红外光谱表征，并经X射线单晶衍射法证实。配合物1属于正交晶系，空间群为Pca2₁，晶体学参数：a=1.625 9(3) nm，b=0.832 10(17) nm，c=2.031 1(4) nm，V=2.747 9(10) nm³，Z=4。配合物2属于正交晶系，空间群为Pca2₁，晶体学参数：a=1.674 36(15) nm，b=0.821 29(7) nm，c=2.048 01(19) nm，V=2.816 3(4) nm³，Z=4。在这2个配合物的阳离子中，金属原子分别与2个dmpzm中的4个N原子及1个NO₃^-中的2个O原子配位，形成略为畸变的八面体构型。配合物1和2的晶体中，NO₃^-的O原子与配体dmpzm中的甲基及亚甲基间存在的C-H…O氢键作用，从而形成了有趣的三维网状结构。此外，还研究了配合物1和2的荧光性质。     

1-(取代硅基甲硫基)甲基-2,8,9-三氧杂-5-氮杂-1-硅杂双环[3.3.3]十一烷的合成与生物活性

2,8,9一三氧杂一5一氮杂司一硅杂双环［3．3．3」十一烷（Silatrane）衍生物是一类具有广泛生物活性的五配位有机硅化合物,自6O年代发现以来一直引起人们浓厚的兴趣,随着其1位硅原子上所连基团的变化,该类化合物可表现出通然不同的生物活性［’j．为寻找新的生物活性物质,本文在Silatranel位引入一类含硅甲硫醚基团,合成了11种新的Silatrane衍生物,并初步测定了其在农药、医药方面的生物活性;同时,在其质谱中发现存在罕见的重排裂解过程．合成方法如下：回实验部分1．l仪器与试剂BrukerAC－PZOO型NMR仪,CDCI。为溶剂,TM…     

Synthesis of New 3‐(Furan‐2‐yl)‐Substituted Dibenzo‐Diazepin‐1‐one Derivatives

A new series of 3‐(furan‐2‐yl) dibenzo‐diazepin‐1‐one derivatives were synthesized by condensation of 5‐(furan‐2‐yl)‐1,3‐cyclohexanedione, o‐phenylenediamine, and aromatic aldehydes, in which in some of them existed two very close isomer compounds. All the compounds were characterized by IR, MS, ¹H NMR, and elemental analysis. Also presented were the crystal structures of 3a , 3b and 3e , which were obtained and determined by X‐ray single‐crystal diffraction.     

Structurally characterized hetero-oligopolyphenylenes: synthetic advances toward next-generation heterosuperbenzenes

The successful Diels-Alder [2+4] cycloaddition of dipyrimidyl acetylene and suitably substituted 2,3,4,5-tetraarylcyclopenta-2,4-dien-1-ones (3-7) generates a series of selectively functionalized hexaarylbenzenes. Each has two pairs of peripheral functional groups (R' and R=tert-butyl 8 and R=methyl 9, methoxy 10, bromo 11, triisopropylsilylethynyl 12) and four ortho-imine nitrogen atoms. The dibromo derivative 11 is a useful precursor for the formation of a mono ethynyl 13 and diethynyl 14 substituted polyphenylene. Changing the dienophile to di(2-thienyl)acetylene gives an S-heteroatom polyphenylene 15. The compounds were fully characterized by using (1)H, (13)C and a range of 2 D NMR spectroscopic techniques, elemental analysis, and mass spectrometry. Oxidative cyclodehydrogenation of dimethoxy hexaphenylbenzene 10 by using iron(III) chloride results in the formation of a spirocyclic dienone 16, which in a separate reaction undergoes dienone/phenol rearrangement to give the first 4-fused-ring, N-heterosuperbenzene (HSB) 17. Six single crystal molecular structures reveal the commonality of unidirectional twisting of the external aromatic rings in these heteroatom polyphenylenes. The twist angles and any H-bonding or interdigitation in these structures are discussed.     

6-溴-N-芳基噻吩[2,3-d]并嘧啶-4-胺类化合物的合成新方法

研究了6-溴-N-[3-氯-4-(3-氟苄氧基)苯基]噻吩[2,3-d]并嘧啶-4-胺的合成新方法.以相对廉价的2,5-二羟基-1,4-二噻烷和丙二腈为原料,依次通过Gewald反应、芳环溴代、缩合、环合以及Dimroth重排四步反应得到目标产物6-溴-N-[3-氯-4-(3-氟苄氧基)苯基]噻吩[2,3-d]并嘧啶-4-胺,总产率为56.9%.用1H NMR,IR,MS和HRMS对产物进行了结构表征.并应用该方法,合成了一系列的6-溴-N-芳基噻吩[2,3-d]并嘧啶-4-胺类化合物.研究表明该方法具有原料易得、操作简便、收率较高,且产物容易分离纯化等优点.     

含P_H键苯并磷杂环化合物与醛反应的研究

利用含P_H键苯并磷杂环化合物与醛的反应,设计合成了新的A2羟基膦酸衍生化喹唑啉酮含磷类似物2或Ò,并研究了含P_C_O结构的2或Ò转化为含P_O_C结构的3或Ó的重排反应,目标化合物的结构经NMR,IR,MS和元素分析证实.结合NMR数据,探讨了化合物2因具有C^*和P^*两个手性中心而产生的非对映异构现象及其氢谱特征.对所合成的化合物进行了初步生物活性测试,发现部分化合物具有很好的抗植物病原真菌(苹果斑点落叶病菌)作用和一定的人体疱疹病毒抑制活性.     

The Newman-Kwart rearrangement re-evaluated by microwave synthesis

The Newman-Kwart rearrangement (NKR) has been re-evaluated by microwave heating. Microwave technology has proven to be ideal for investigating this high temperature rearrangement and facilitated the confirmation of many aspects of this valuable reaction. Comparisons between thermal and microwave results indicate no evidence of a significant microwave effect.     

Synthesis of fluorinated fused benzofurans and benzothiophenes: Smiles-type rearrangement and cyclisation of perfluoro(het)aryl ethers and sulfides

Lithium-bromine exchange in 2-bromophenyl perfluoroaryl ethers or sulfides affords fused fluorinated benzofurans or benzothiophenes respectively by S(N)Ar substitution of the adjacent fluorine in the perfluoroaryl substituent. The structures of the new compounds were confirmed by NMR spectroscopy and single crystal X-ray diffraction analysis. In the case of 2-bromophenyl tetrafluoropyrid-4-yl ether, lithiation promoted a Smiles-type rearrangement which led to formation of 4-(2-hydroxyphenyl)tetrafluoropyridine, for which the structure was confirmed by X-ray crystallography.     

Co(II)与烟酸类分子形成的配位聚合物的晶体结构与孔道稳定性

利用烟酸与异烟酸两种配体分别与硝酸钴在N,N'-二甲基甲酰胺(DMF)中采用溶剂热法合成了三种新的配位聚合物[CO₂(μ₂-H₂O)(nicotinic acid)₄·(DMF)] (1), [CO₂(isonicotinic acid)₄·(DMF)] (2), [Co(isonicotinicacid)₂·(DMF)] (3), 并利用单晶X射线衍射(XRD)和元素分析获得其结构信息. 通过傅里叶变换红外(FTIR)光谱、粉末X射线衍射(XRD)、热重分析(TGA)和比表面积分析等手段对结构中孔道的热稳定性进行了表征. 结果表明化合物1 具有类金刚石的拓扑结构, 结构中含有稳定的一维(1D)孔道空间. 化合物2 和3 是以异烟酸为配体, 分别在100 和160 °C下合成, 二者结构中配体以完全不同的方式与Co(II)配位, 从而使其具有不同的结构.化合物2和3的一维孔道在热处理脱附DMF分子的过程中不能稳定存在.     

Synthesis and analgetic activity of sulfur-containing morphinans and related compounds

3-Acylthiomorphinans, 3-carbamoylthio-3-deoxydihydromorphine and 3-benzoylthio-9-aza-17-carbamorphinan were synthesized by Newman-Kwart rearrangement of the corresponding O-thiocarbamates. The analgetic activities were lower than that of pentazocine, and the opioid receptor binding affinities were very weak. These acylthiomorphinans showed low antinociceptive activity compared with corresponding sulfur-containing benzomorphans. 3-Carbamoylthio-deoxydihydromorphine had no significant analgetic activity.     

Partially O-alkylated thiacalix[4]arenes: synthesis, molecular and crystal structures, conformational behavior

NMR spectroscopy, X-ray diffraction analysis, and quantum chemical calculations were used for conformational behavior study of partially alkylated thiacalix[4]arenes bearing methyl (1), ethyl (2), or propyl (3) groups at the lower rim. The conformational properties are governed by two basic effects: (i) stabilization by intramolecular hydrogen bonds, and (ii) sterical requirements of the alkoxy groups at the lower rim. While the monosubstituted derivatives 1a and 3a adopt the cone conformation in solution, distally disubstituted compounds 1b, 1'b, 2b, 2'b, 3b, and 3'b exhibit several interesting conformational features. They prefer pinched cone conformation in solution, and, except for 3'b, they form also 1,2-alternate conformation, which is flexible and undergoes rather fast transition between two identical structures. The crystal structures of the compounds 1b, 2b, 2'b, and 3b revealed yet quite rare 1,2-alternate conformation forming molecular channels held together by pi-pi interactions. Different channels-with hexagonal symmetry, 0.26 nm wide-are formed in the crystal structure of the pinched cone conformation of 3b. An uncommon hydrogen bonding pattern was found in dimethoxy and dipropoxy derivatives 1'b and 3'b that adopt distorted cone conformations in crystal. Trialkoxy-substituted compounds 1c and 3c adopt the partial cone conformation in solution. A higher mobility of methyl derivative 1c enables also existence of the cone conformer.     

Facile Hydrazine‐Hydrothermal Syntheses and Characterizations of Two Quaternary Thioarsenates(III): Two‐Dimensional SrAg4As2S6⋅2 H2O and One‐Dimensional BaAgAsS3

Two new quaternary thioarsenates(III), SrAg₄As₂S₆?2 H₂O ( 1 ) and BaAgAsS₃ ( 2 ), have been prepared through a hydrazine‐hydrothermal method at low temperature. Compound 1 possesses a two‐dimensional (2D) layer network, while compound 2 features a one‐dimensional (1D) column structure. The detailed structure analysis indicates that Sr²⁺ and Ba²⁺ cations have different directing effects on the structures of thioarsenates(III). Both experimental and theoretical studies demonstrate that compounds 1 and 2 are narrow‐gap semiconductors. Our success in synthesizing these two quaternary thioarsenates(III) proves that the hydrazine‐hydrothermal technique is a powerful yet facile synthetic method for exploring new complex chalcogenides with diverse crystal structures and interesting physical properties.     

Chlorotrimethylsilane catalyzed synthesis of 1,3-diphenyl-2-propenones and their antimicrobial activities

The base- or acid-catalyzed Claisen–Schmidt condensation reaction is the common synthetic route for the synthesis of 1,3-diphenyl-2-propenone (known as chalcone). A variety of different synthetic pathways have been used over the decades in the synthesis of chalcone. Microwave irradiation in absence of solvent is employed successfully and presented here with prominent improvement over the existing methods. The reaction is incredibly accelerated in the presence of the catalyst chlorotrimethylsilane (CTMS) and found superior in terms of reaction time, product yield, safer synthetic route, and easy removal of catalyst etc. Products were characterized by elemental analysis and spectroscopy. Single crystal X-ray diffraction was used to determine crystal structures. All compounds were treated for antimicrobial activity. The profound response against bacteria and fungus pathogens by these compounds is impressive and opens up opportunities for further physiological activity studies.