Catalytic oxidations of enolizable ketones using 2-alkylidene-4-oxothiazolidine vinyl bromide

Direct oxidation of enolizable ketones to α-hydroxy derivatives, vicinal dicarbonyls or tricarbonyl compounds has been achieved by a catalytic amount of 2-alkylidene-4-oxothiazolidine vinyl bromide in DMSO as a solvent. The yields range from moderate to good.     

Transformations of 2-alkylidene-4-oxothiazolidine vinyl bromides initiated by bromophilic attack of neutral and anionic nucleophiles

Vinyl bromides derived from 2-alkylidene-4-oxothiazolidines represent a class of vinyl halides, which readily undergo a bromophilic attack by a range of nucleophiles. With Ph₃P, AcS⁻, CN⁻, I⁻, F⁻, Ac₂CH⁻ and N₃⁻ the attack ends up with reductive debromination, whereas the bromine substitution takes place with KSCN. When acetate anion and organic bases, such as pyridine, Et₃N or morpholine, are employed as nucleophiles the initial bromophilic attack is followed by bromine migration to the C(5) position of the ring, allowing the C(5) functionalization of this heterocyclic system.     

Direct C(sp3)-H functionalization of 2-methylazaarenes using 4-substituted-TEMPO

An efficient and direct C(sp³)-H functionalization of 2-methyl azaarenes with persistent nitroxide radical 4-substituted-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) under neutral conditions has been developed. A broad of 2-methylazaarenes could be reacted with 4-substituted TEMPOs to afford corresponding azaarene 2-methoxylamines by using cheaper copper (II) acetate hydrate as oxidant.     

Structure, configuration, conformation and quantification of the push-pull effect of 2-alkylidene-4-thiazolidinones and 2-alkylidene-4,5-fused bicyclic thiazolidine derivatives

Structures of a series of push-pull 2-alkylidene-4-thiazolidinones and 2-alkylidene-4,5-fused bicyclic thiazolidine derivatives were optimized at the B3LYP/6-31G(d) level of theory in the gas phase and discussed with respect to configurational and conformational stability. Employing the GIAO method, ¹³C NMR chemical shifts of the C-2, C-2′, C-4 and C-5 atoms were calculated at the same level of theory in the gas phase and with inclusion of solvent, and compared with experimental data. Push-pull effect of all compounds was quantified by means of the quotient π^∗/π, length of the partial double bond, ¹³C NMR chemical shift difference (Δδ_CC) and ¹H NMR chemical shifts of olefinic protons. The effect of bromine on donating and accepting ability of other substituents of the push-pull CC double bond is discussed, too.     

Cr(CNR)_3Cl_3和Cr(CNR)_3Cl_2B(C_8H_5)_4·H_2O(R=CH_2C_8H_5)的合成和性质研究

长期以来人们对羰基配合物进行了较为充分的研究,但忽略了与之对应的异腈配合物领域。本文在四氢呋喃溶剂中制得两个过渡金属异腈配合物,初步研究了它们的性质,并讨论了它们的红外光谱和热重分析。 1 实验部分 1。1 试剂和仪器 CrCl_3(thf)_3按文献合成。CNCH_2C_6H_5和NaB(C_6H_5)_4购自Aldrich试剂     

Regioselective TEMPO oxidation of 2-alkylidene-1,3-propanediols to (E)-2-hydroxymethyl-2-alkenals and application to 4-alkylidene-2-penten-5-olide synthesis

The oxidation system comprised of TEMPO and (diacetoxyiodo)benzene (stoichiometric) is enhanced during the conversion of primary alcohols to aldehydes by adding a catalytic amount of acids, p-TsOH and PPTS. 2-Alkylidene-1,3-propanediols, available from 1,3-dihydroxyacetone, are oxidized under the stated conditions to the corresponding (E)-2-hydroxymethyl-2-alkenals, which are utilized as an intermediate for the expeditious synthesis of 4-alkylidene-2-penten-5-olides.     

Behavior of dialkylallyl(4-hydroxybut-2-ynyl)ammonium bromides toward powdered sodium hydroxide and aqueous alkali

Under the influence of a twofold molar quantity of powdered sodium hydroxide in the presence of a few drops of methanol at room temperature dialkylallyl(4-hydroxybut-2-ynyl)ammonium bromides undergo a Stevens rearrangement with transfer of the reaction center, forming substituted amino alcohols with an allene group. Intramolecular cyclization of the products and concurrent hydration lead to the formation of a mixture of dialkyl(4-allyl-2,5-dihydrofuran-2-yl)amines and dialkylamino-3-allyl-4-hydroxybutanones with overall yields of 37-41%. During the aqueous-alkali cleavage of dialkylallyl(4-hydroxybut-2-ynyl)ammonium bromides the products from intramolecular cyclization were obtained with yields of 38-41%. Under the conditions both of Stevens rearrangement and of aqueous-alkali cleavage the secondary amines are also formed with yields of 15-17%. As nonamine products mixtures of compounds, which according to the IR spectra contain unconjugated and conjugated carbonyl groups, were obtained. The presence of an aldehyde group was established by a silver mirror reaction. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 354-360, March, 2009.     

2-Polyfluoroalkylchromones. 14. Synthesis of 4-chloro-3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles

3-Chloro-2-polyfluoroalkyl- and 3-chloro-6-nitro-2-polyfluoroalkylchromones were synthesized. These compounds react with N₂H₄·2HCl on boiling in ethanol to form 4-chloro-3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles.     

液相色谱-质谱联用分析土壤中的双(2-羟乙基)亚砜

建立了液相色谱 质谱联用技术测定土壤中双(2 羟乙基)亚砜的方法。对影响检测灵敏度的流动相组成、流速、探头温度等因素进行了优化,在优化实验条件下,方法线性范围在0.05～20mg L之间,最低检测质量浓度为0.025mg L(S N>3),对比了3种萃取剂对4种土壤中的双(2 羟乙基)亚砜的萃取率,结果表明,用水作萃取剂的萃取效果最佳,回收率在92%以上,RSD均小于4%。     

Asymmetric Syntheses of Osmundalactones and 5-Hydroxy-2-hexen 4-olides from 4-Benzyloxy-5-hydroxy-2（E）-hexenoate

( )-(4S,5R)-Osmundalactone 1 was isolated from the fungus Paxillus atrotomentosus (Paxillaceae) by Buchanan1. (-)-(4R,5S)-Osmundalactone 1 and ( )-(4R,5S)-5-hydroxy- 2-hexen-4-olide 2 were isolated from Osmunda japonica (Osmundaceae) as feeding inhibitors…     

New Method of Synthesis of 2-Amino-4(5H)-oxothiophenes

A new method is proposed for the synthesis of 2-amino-4(5H)-oxothiophenes with aryl and hetaryl substituents in position 3 of the molecule by the acylation of aryl- and 2-azahetarylacetonitriles with mercaptoacetic acid ethyl ester.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 202–205, February, 2005.     

A highly enantioselective synthesis of 5-(l-menthyloxy )-4-substituted-3-chloro-2(5H )-furanones

In this paper, stereocontrolled tandem Michael addition-elimination reaction of the novel chiral source, 5-(l-menthyloxy)-3,4-dichloro-2(5H)-furanone, with various thiols and amines has been investigated. A series of new enantiomerically pure compounds, 5–(l-menthyloxy)-4-substituted-3-chloro-2(5H)-furanones, were obtained in good yields with d. e. ? 98% under mild conditions.     

B(C2H5)2q及其衍生物电子光谱性质的密度泛函理论研究

采用密度泛函理论(DFT)B3LYP、abinitioHF和单激发组态相互作用(CIS)等方法分别优化了有机配合物B(C2H5)2q及其衍生物的基态及最低激发单重态几何结构.用含时密度泛函理论(TD-DFT)对B(C2H5)2q及其衍生物的电子光谱进行了研究.发现该类物质是配体发光配合物,其发光源于8-羟基喹啉配体内π*     

5-(S)-烷氧基-3，4-二卤-2(5H)-呋喃酮在二甲基甲酰胺中的Michael加成-消除反应

5-羟基 - 2 (5H) -呋喃酮是一些具有生理活性天然产物的重要结构组份 [1] ,γ-内酯类的结构片段在一些抗病毒药物或前体结构中也常出现 ,由于内酯环的立体构型与药物的生物活性密切相关 ,因此它的合成具有十分重要的价值[2 ] .近年来利用天然手性助剂薄菏醇和冰片等的手性 5-烷氧基 - 2 (5H) -呋喃酮合成天然产物已引起人们的广泛关注 [1,3～ 13] .我们在研究手性 5-烷氧基 - 3,4-二卤 - 2 (5H) -呋喃酮 (4a_ 4 d)与 Wittig- Horner试剂 (O,O-二乙氧基丙酮基膦酸二乙酯 ) (5)的反应时 ,当以 DMF为溶剂 ,金属钠为催化剂时 ,并未得到目标…     

Solid-phase extraction of 4(5)-methylimidazole (4MeI) and 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole (THI) from foods and beverages with subsequent liquid chromatographic-electrospray mass spectrometric quantification

A method for the simultaneous determination of 4(5)-methylimidazole (4MeI) and 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole (THI) was developed using SPE and HPLC/MS. Solid-phase extraction using SCX Disc cartridges was used for isolation of the analytes from liquid samples. The lower LOQwas 0.1 ng/mL for 4MeI and 0.2 ng/ mL for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients >0.999. The CV for the intra- and inter-day precision was <5% (n = 6); the accuracy was in the range 98-103%. The recovery was > or = 97 and > or = 98% for THI and 4MeI, respectively. The method was used to determine THI and 4MeI in beverages, coffee, caramel colours and other samples.     

3-氯-4-二苄胺基-5-甲氧基-2(5H)-呋喃酮的合成与晶体结构

在THF溶液中合成了标题化合物3-氯-4-二苄胺基-5-甲氧基-2(5H)-呋喃酮,并用FT-IR、UV-Vis、1HNMR、13C NMR、MS、元素分析和X-射线衍射等进行了表征。结果表明此化合物属正交晶系,空间群为Pbca,晶胞参数为:a=15.891(16),b=11.126(11),c=19.778(19),α=β=γ=90°,V=3497(6)3,Z=8,Dc=1.306Mg/m3,μ=0.234 mm-1,F(000)=1440。在化合物的分子结构中,两个苯环几乎垂直于呋喃酮平面,且它们与呋喃酮平面的两面角分别为89.38°和88.19°。     

Practical Synthesis of 4-Benzylidene-2-phenyl-5(4H)-oxazolones

A simple and alternative method has been developed for the synthesis of 4-benzylidene-2-phenyl-5(4H)-oxazolones via reactions of hippuric acid with various aldehydes in the presence of 2-chloro-4,6-dimethoxy-1,3,5-triazine/N-methylmorpholine at 75 °C.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis,Crystal Structure and Anticancer Property of （Z）-N-（4-Bromo-5-ethoxy-3,5-dimethyl-furan-2（5H）-ylidene）-4-methylbenzenesulfonamide

The novel title compound(Z)-N-(4-bromo-5-ethoxy-3,5-dimethylfuran-2(5H)-yli-dene)-4-methylbenzenesulfonamide 1(C15H18BrNO4S) has been unexpectedly synthesized by the aminohalogenation reaction of ethyl 2-methylpenta-2,3-dienoate with TsNBr2,and characterized by mp,IR,1H NMR,EIMS,ESIHRMS and single-crystal X-ray diffraction.It crystallizes in mono-clinic,space group P21/c with a = 11.714(5),b = 14.106(5),c = 10.402(4) ,β = 97.298(8)°,V = 1704.9(12) 3,Mr = 388.27,Z = 4,Dc = 1.513 g/cm3,μ(MoKα) = 2.549 mm-1,F(000) = 792,the final R = 0.033 and wR = 0.062 for 3098 observed reflections(Ⅰ 2σ(Ⅰ)).     

亚砜还原法合成聚苯醚硫醚的结构与性能研究

以氟苯和氯化亚砜反应合成了4,4’-二氟二苯亚砜,并将其与4,4’二羟基二苯硫醚在N-甲基吡咯烷酮溶剂中进行亲核取代反应合成了聚苯醚硫醚醚亚砜,用乙二酰氯/四丁基碘化铵还原该亚砜聚合物制备了聚苯醚硫醚。用红外光谱和核磁共振谱对合成单体的结构进行了确认,同时对聚合物进行了红外光谱、核磁共振、元素分析、X射线光电子能谱、X射线衍射、DSC分析、TG/DTG以及溶解性测试。结果表明聚苯醚硫醚样品具有氧醚和硫醚交替的线性结构,特性粘度为0.55 dL/g的PPSE熔点达236℃,在氮气条件下,样品起始分解温度和最大分解速率处温度分别为359℃和514℃,在700℃时的重量保留率为43.3%,且在加热条件下能溶解于N-甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)等极性有机溶剂中。     

Mechanism of the recyclization of 2-amino-5-benzylidene-1,3-thiazol-4(5H)-one into derivatives of 2-amino-5-benzylidene-1,5-dihydro-4H-imidazol-4-one

Mechanisms are given for reactions taking place upon heating 2-amino-5-benzylidene-1,3-thiazol-4(5H)-one in a medium consisting of a secondary amine. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 111–114, January, 2008.