First synthesis and full characterization of mexiletine N-carbonyloxy β-d-glucuronide

A simple, convergent synthesis of the N-carbonyloxy β-d-glucuronide of mexiletine (sodium salt) in moderate yield is described. The compound is now available as an authentic reference standard for analytical studies, enabling more detailed investigation on the metabolism of mexiletine.     

Syntheses of 2- or 6-Substituted Chromones and Chromone Ring-opening Reaction in Polyphosphoric Acid

In an attempt to find new antitumor agents, a novel class of chromone compounds with a benzimidazoleor a benzoxazole ring in positions 2 or 6 were synthesized νia condensation in polyphosphoric acid(PPA) byusing chromone acids as the starting materials. During the preparation process, it was found that PPA couldcleave the chromone ring to produce a ring-opening compound(6). The molar ratio of the chromone com-pound (5) to the ring-opening compound (6) varied with the change of reaction temperature and time. Basedon MTT protocol, the antitumor activity of each of the compounds obtained was evaluated against three hu-man cancer cell lines: KB(oral epidermal), A2780(ovary) and Be17402 (liver). The IC50 varied from 54.7μmol/L to more than 180 μmol/L.     

Tri-n-butylphosphane catalyzed ring opening of aziridines with secondary amines

Ring opening of aziridine with dialkyl amine took place readily in the presence of catalytic amounts of tri-n-butylphosphane （10 mol%） in the mixture of CH₃CN/H₂O（10:1）,giving corresponding vicinal diamines in mediate to high yields（58-95%） with good regioselectivitie,while aromatic secondary amine could not react under the same conditions.Tri-n-butylphosphane exhibited different catalytic selectivity to amines from Lewis acid catalysts.     

Synthesis and structure of an air-stable bis(pentamethylcyclopentadienyl) zirconium pentafluorbezenesulfonate and its application in catalytic epoxide ring-opening reactions

An air-stable mononuclear complex of bis(pentamethylcyclopentadienyl) zirconium pentafluorbezenesulfonate was successfully synthesized by treating C₆F₅SO₃Ag with [(CH₃)₅Cp]₂ZrCl₂, which showed the cationic uninuclear structure of [{(CH₃)₅Cp}₂Zr(CH₃CN)₂(H₂O)][OSO₂C₆F₅]₂·CH₃CN (1) confirmed by the X-ray analysis. Complex 1 was also characterized by other techniques and found to have the good nature of air-stability, water tolerance, thermally-stability and strong Lewis-acidity. Moreover, the complex showed high catalytic activity and recyclability in catalytic epoxide ring-opening reactions by amines or alcohols. This catalytic system affords a simple and efficient approach for synthesis of β-amino alcohols or β-alkoxy alcohols.     

Synthesis of 3,4-Substituted Phenylmethylene-(2-carboxyphenyl)amines and Their Antitumor Activity

Previously unknown azomethines 3a-z and 4a-j were prepared in methanol by condensation of anthranilic acid 1 with vanillin, vanillal, and esters of these compounds 2.__________Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 164–169, March–April, 2005.     

Organocatalysts of tertiary-phosphines and amines catalyzed reactions of α-keto esters with cyclopent-2-enone

The reaction of α-keto esters with cyclopent-2-enone catalyzed by tertiary-phosphines provides the corresponding Baylis-Hillman adducts. Among the catalysts, diphenylmethylphosphine was found to be the most effective promoter allowing the reaction to proceed smoothly at room temperature and to give the corresponding adducts in higher yields in the presence of p-nitrophenol. Whereas, the similar reaction of α-keto esters with cyclopent-2-enone catalyzed by tertiary-amine of DBU furnishes the corresponding aldol adducts with syn-configuration exclusively.     

2-Aryl-3,4-dihydropyrans as building blocks for organic synthesis: ring-opening reactions with nucleophiles

An electrophilic ring-opening reaction of 2-aryl-3,4-dihydropyran with many nucleophiles, such as thiophenols, thiols, benzenesulfinic acid, resorcin, 2-methylfuran, benzamide and allyltrimethylsilane, was developed. In the presence of an appropriate catalyst, a product that contains not only a moiety of the nucleophile but also a fragment of 1,3-dicarbonyl compound was obtained.     

Ring-opening reactions of diarylvinylidenecyclopropanes by iodine and bromine

Diarylvinylidenecyclopropanes undergo a novel ring-opening reaction upon treatment with iodine or bromine at 0-25 °C in 1,2-dichloroethane to give the corresponding iodinated or brominated naphthalene derivatives in good to high yields within 3 h. The further transformation of the corresponding iodinated or brominated naphthalene derivatives has been disclosed.     

1,3-取代吲哚-2-酮衍生物的合成与肿瘤细胞毒活性研究

以苯胺为原料,通过肟化、环合生成二氢吲哚-2,3-二酮,再对其进行N-烷基化、亲核加成和磺酰化反应得到目标化合物5a～5g和7a～7e。通过¹H NMR、¹³C NMR确认其结构。采用噻唑蓝（MTT）法测试了目标化合物对乳腺癌细胞MDA-MB-231、鼠黑色素瘤细胞B16、鼠结肠癌细胞CT26三种肿瘤细胞的体外抑制活性。结果表明,化合物7d、7e具有明显的肿瘤细胞毒活性,其中化合物7d对MDA-MB-231的细胞毒活性比阳性药五氟尿嘧啶更强,IC₅₀为4.63±0.14μmol/L。本文结果可为进一步研究具有肿瘤细胞毒活性的吲哚酮类衍生物提供参考。     

Synthesis of 2-oxooxazolo[5,4-b]pyridines and their reactions with amines

Riga Technical University, Riga, LV-1658. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 271–272, February, 1995. Original article submitted December 29, 1994.     

环氧化丁基橡胶的合成与表征

以正己烷为溶剂、间氯过氧苯甲酸(mCPBA)为环氧化试剂对丁基橡胶(IIR)进行环氧化改性研究,考察了原料配比、反应温度、胶液浓度等反应条件对环氧化反应的影响,并对反应过程中发生的副反应进行了探究.采用核磁共振氢谱(1H-NMR)对合成的环氧化丁基橡胶(EIIR)的结构进行了表征,并对环氧化度进行了定量计算.确定了最优...     

Efficient synthesis of polysubstituted pyrrole-3-carbonitriles via reactions of 1,1-dicyano-2,3-diarylcyclopropanes with aromatic imines

Co(ClO₄)₂ smoothly catalyzed the reactions of 1,1-dicyano-2,3-diarylcyclopropanes with aromatic imines to give the novel polysubstituted pyrrole-3-carbonitriles bearing an 2-arylidenimino group in good to high yields in refluxing THF.     

Palladium-catalyzed reactions of cyclopropanols bearing oxazoline directing group

Cyclopropanols bearing oxazoline directing group were investigated in palladium-catalyzed reactions. When the directing group and cyclopropanol unit were bonded through two- or three-carbon spacer, formation of unusual products was observed. Oxidative ring opening proceeded with uncommon regioselectivity providing linear enones as main products. The reaction of such cyclopropanols with aryl iodides and silver acetate furnished diarylated α-methylene ketones, which cannot be obtained from cyclopropanols lacking oxazoline ring under the same conditions.     

Mechanism of the copper-free palladium-catalyzed Sonagashira reactions: multiple role of amines

Amines used as bases in copper-free, palladium-catalyzed Sonogashira reactions play a multiple role. The oxidative addition of iodobenzene with [Pd(0)(PPh(3))(4)] is faster when performed in the presence of amines (piperidine>morpholine). Amines also substitute one ligand L in trans-[PdI(Ph)(L)(2)] (L=PPh(3), AsPh(3)) formed in the oxidative addition. This reversible reaction, which gives [PdI(Ph)L(R(2)NH)], is favored in the order AsPh(3)>PPh(3) and piperidine>morpholine. Two mechanisms are proposed for Sonogashira reactions, depending on the ligand and the amine. When L=PPh(3), its substitution by the amine in trans-[PdI(Ph)(PPh(3))(2)] is less favored than that of the alkyne. A mechanism involving prior coordination of the alkyne is suggested, followed by deprotonation of the ligated alkyne by the amine. When L=AsPh(3), its substitution in trans-[PdI(Ph)(AsPh(3))(2)] by the piperidine is easier than that by the alkyne, leading to a different mechanism: substitution of AsPh(3) by the amine is followed by substitution of the second AsPh(3) by the alkyne to generate [PdI(Ph)(amine)(alkyne)]. Deprotonation of the ligated alkyne by an external amine leads to the coupling product. This explains why the catalytic reactions are less efficient with AsPh(3) than with PPh(3) as ligand.     

咪唑啉酮胺类衍生物的合成

咪唑啉酮胺类衍生物的合成;咪唑啉二酮;4H-咪唑啉酮;aza-Wittig反应;合成     

Synthesis of 9-chloro-1,10-anthraquinone and its reactions with amines

1-Dichlorophosphoryloxy-9,9-dichloroanthrone, a product of the reaction between 1-hydroxyanthraquinone and PCl₅, reacts with primary amines in benzene to give first 1-(diaminophosphoryloxy)-9,9-dichloroanthrones and then the corresponding 9-imines. The reaction in DMF occurs with elimination of the phosphoryloxy group and generation of 9-chloro-1,10-anthraquinone that undergoes amination followed by substitution of the hydrogen atom in position 4 rather than a chlorine atom in position 9, which is the most active position in 2,4,9-trichloro-1,10-anthraquinone. The second step of amination results in 4,9-di(alkylamino)-1,10-anthraquinone. The literature data on obtaining individual 9-chloro-1,10-anthraquinone under the action of bases on 1-dichorophosphoryloxy-9,9-dichloroanthrone were not experimentally supported.     

A convenient synthesis of N-vinyl enamides via the lithiation and ring-opening reaction of 2-phenyl-2-oxazolines

A simple and efficient synthesis of N-vinyl enamides via the lithiation and ring-opening reaction of 2-phenyl-2-oxazolines with lithium diisopropylamide at room temperature has been developed. This method is especially suitable for the synthesis of multifunctional enamides. Good yields have been obtained when the reactions were amplified to gram scale.     

Hydroxyl-terminated Polyethylenes Bearing Functional Side Groups: Facile Synthesis and Their Properties

A series of hydroxyl-terminated polyethylenes(HTPE) bearing various functional side groups(e.g. carboxyl, ester and butane groups)were synthesized by the combination of ring-opening metathesis polymerization(ROMP) and visible light photocatalytic thiol-ene reaction. The products are named as α,ω-dihydroxyl-poly[(propionyloxythio)methinetrimethylene](HTPE~(carboxyl)), α,ω-dihydroxyl-poly[(methylpropionatethio)methinetrimethylene](HTPE~(ester)) and α,ω-dihydroxyl-poly[(butylthio) methinetrimethylene](HTPE~(butane)), respectively. The investigation of ROMP indicated that the molecular weight of resultant hydroxyl-terminated polybutadiene(HTPB) can be tailored by varying the feed ratios of monomer to chain transfer agent(CTA). The exploration of the photocatalytic thiol-ene reaction between HTPB precursor and methyl 3-mercaptopropionate revealed that blue light as well as oxygen accelerated the reaction. 1 H-NMR and ~(13) C-NMR results verified all the double bonds in HTPB can be modified, and the main chain of resultant polymer can be considered as polyethylene. Subsequently, relationship between the structure of side groups and the thermal properties of functional PEs was studied. And the results suggested that the T_g was in the order of HTPE~(butane)HTPE~(ester)HTPE~(carboxyl). Greater interaction between side groups resulted in higher T_g. Moreover, all the functional PE samples exhibited poor thermostability as compared to HTPB. Finally, the promising applications for functional PEs were explored. HTPE~(carboxyl) can be utilized as a smart material with p H-responsive properties due to its p H-dependent ionization of carboxyl side groups. HTPE~(butane) can be employed as a macro-initiator for building the triblock copolymer due to the presence of active hydroxyl end groups. HTPE~(ester) can serve as a plasticizer for PVC which can enhance the ductility of PVC without obviously sacrificing strength.     

Gewald-type reaction of double activated 2,3-diarylcyclopropanes with elemental sulfur for synthesis of polysubstituted 2-aminothiophenes

A new synthetic procedure for the polysubstituted 2-aminothiophenes was developed via Gewald type ring-opening reaction of 1,1-dicyano-2,3-diarylcyclopropanes with elemental sulfur in N,N-dimethylformamide in the presence of morpholine as base.     

2-取代苯并噻唑衍生物的合成

以2-甲基苯并噻唑或2-乙基苯并噻唑,2-碘乙醇或1,4-二溴丁烷为原料,合成了4个新的2-取代苯并噻唑衍生物,其结构经^1H NMR,IR,MS及元素分析表征。