Prostanoids: LXXXII. Synthesis of Key Precursors of 9-LO Thromboxans

Starting from levoglucosan, methyl 2,4-dideoxy-3-O-mesyl-4-C-[(2Z)-octenyl]--D-arabino-hexopyranoside and (+)-2-methoxy-6-[6-methoxycarbonyl-3-oxo-(1E)-hexenyl]-5-[(2Z)-octenyl]pyran-3-one were synthesized as potential building blocks for preparation of 9-LO thromboxanes.     

Prostanoids: LXXXVIII. Chlorocyclopentenone Building Blocks in the Synthesis of Marine Prostanoids

Starting from 2,3-dichloro-4,4-ethylenedioxy-2-cyclopentenone, a practical procedure has been developed for the synthesis of a series of 4-substituted 2-chloro-4-hydroxycyclopentenones.     

Synthesis of Some Pyrimidine 2-Oxo(Thio)-4,6-Dione Derivatives

5-Arylidenes 1a and 1b, on reaction with ethyl cyanoacetate and diethyl malonate in the presence of ammonium acetate under Michael condensation, yield pyridine derivatives 2 and 3, respectively. Cyclopentapyrimidine derivative 4 can also be obtained by the reaction of 1a with malononitrile in the presence of piperidine. The reaction of 5-arylidene lb with monochloroacetic acid in an alkaline medium gives the thiazol derivative 5. Also, spiro-[3′, 5′]cyclohexenyl pyrimidine derivative 6 could be obtained from the reaction of 1d with maleic anhydride. On the other hand, 5-arylidene 1e reacts with maleic anhydride to give 2-thiobarbituric acid derivative 7. The condensation reaction of 2-thiovioluric acid 8 with some hydrazines affords the triazole derivatives 9a-d. Finally, barbituric acid condenses with isatin to give 5-arylidene 1f, which can be cyclized with phosphorous pentoxide to afford 10.     

Heteroadamantanes and Their Derivatives: XXV. Synthesis of 3,6-Diazahomoadamantane-9-spirothiiranes

By treating 3,6-diazahomoadamantane-9-spirooxiranes with potassium thiocyanate 3,6-diazahomoadamantane-9-spirothiiranes were obtained which further by reductive desulfuration were converted into 3-methyl- and 9-methylene-3,6-diazahomoadamantanes.     

Prostanoids: LXXV. Synthesis of 4-Hydroxy-2-octyl-2-cyclopentenone

The title compound was synthesized by Ad_NE addition of n-octyl cuprate to 2,3-dichloro-4,4-ethylenedioxy-2-cyclopentenone, followed by alcoholysis and reduction with NaBH₄.     

Synthesis of 9-Substituted Berberine Derivatives with Microwave Irradiation

Hyperglycemia is frequently accompanying with hyperlipidemia. To explore the potent drugs with dual-activity and dual-site effects that could reduce blood glucose and blood lipid at the same time, fibrate group with lipid-lowering effect on the 9th position of berberine(BBR) was introduced using the drug design combination principle and the multi-target collaborative treatment method. Moreover, the molecular structure of BBR was modified, and six 9-substituted derivatives of BBR were designed and synthesized, among which, five compounds have never been reported before. In addition, the molecular structures of these derivatives were identified using liquid chromatography-mass spectrometry(LC-MS), ¹H nuclear magnetic resonance(¹H NMR) and ¹³C NMR, respectively. Furthermore, the microwave irradiation experimental technique was applied in the synthesis reaction using the novel microwave synthesizer, which accelerated the reaction rate, enhanced the reaction yield, reduced the reaction by-products, and simplified the post-processing steps. In the meantime, the 9-position regioselective demethylation of BBR was explored through quantum chemical calculation during the synthesis of berberrubine. The computations were consistent with the experimental results, which contributed to deducing the mechanism of its selective methylation.     

取代芴—9—羧酸酯衍生物的合成

报道了以９，１０－菲醌为起始原料，通过在碱性条件下重排，再经过氯化、酯化及Ｎ杂环取代反应，合成了２０个新的含氮杂环芴－９－羧酸酯类似物，其结构经ＩＲ，＾１Ｈ ＮＭＲ及元素分析所证实。并对其合成方法进行了研究。同时还对合成的新化合物的抗霉菌生物活性进行了简单的测定。     

6-氯-8-烃基-9-芳基嘌呤类衍生物的合成

以4,6-二氯-5-氨基嘧啶为原料,经N-烃基化反应、缩合反应和氯化反应,合成了一系列未见文献报道的6-氯-8-烃基-9-芳基嘌呤衍生物,所有化合物均通过1H NMR、MS和元素分析确定其结构。 研究结果表明,N-烃基化反应时,芳胺使用盐酸作催化剂,芳基脂肪胺用有机碱三乙胺作催化剂,缩合反应时,多聚磷酸(PPA)用量过多会影响传质效果,影响反应的收率。 讨论了微波反应方式对氯化反应的影响。     

Prostanoids: LXXX. Analogs of "Marine" Prostanoids. (±)-11-Chlorochlorvulone II

Analog of chlorvulone II containing an extra chlorine atom at C11 was synthesized starting with 1,4-dioxa-6,7-dichlorospiro[4.4]non-6-ene.     

Prostanoids: LXXXVII. Synthesis of 3-Hydroxy-2-phenylsulfonyl-2-cyclopentenone and Its Ethylene Acetal

By oxidation of 3-phenylmercapto-2-chloro-4,4-ethylenedioxycyclopet-2-en-1-one with H₂O₂ in AcOH (or with m-ClC₆H₄CO₃H in CH²Cl²2) was obtained 2-chloro-3-phenylsulfonyl-4,4-ethylenedioxycyclopent-2-en-1-one which on reduction with NaBH₄ or LiAlH₄ afforded respectively 3-hydroxy-2-phenylsulfonylcyclopent-2-en-1-one and its ethyleneketal.     

Highly Emissive 9-Borafluorene Derivatives: Synthesis,Photophysical Properties and Device Fabrication

A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 % for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m⁻². These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability.     

Synthesis and Properties of β-Oxo Sulfides of the Dioxothiolane Series

It was shown that the hydroxy group in β-hydroxy sulfides of the dioxothiolane series can be oxidized selectively to a carbonyl group in the presence of a sulfide group. A sequence of transformations leading to the final β-oxo sulfides was proposed and was confirmed experimentally. A new original method was developed for the production of β-oxo sulfides. Some characteristics of the synthesized compounds were studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 974–985, July, 2005.     

Prostanoids: LXXXVI. Synthesis and Reductive Transformations of 2-Chloro-4,4-ethylenedioxy-3-phenylsulfanyl-2-cyclopentenone

The reduction of 2-chloro-4,4-ethylenedioxy-3-phenylsulfanyl-2-cyclopentenone with sodium tetra-hydridoborate in ethanol yields 3-chloro-4-hydroxy-2-phenylsulfanyl-2-cyclopentenone, while with the use of lithium aluminum hydride in tetrahydrofuran or the system Zn/NH₄Cl in methanol products of more profound reduction are obtained.     

Prostanoids: LXXIV. 2,3-Dichloro- 4,4-ethylenedioxy-2-cyclopentenone in the Synthesis of Analogs of Marine Prostanoid

Transformations of readily accessible 2,3-dichloro-4,4-ethylenedioxy-2-cyclopentenone resulted in formation of previously unknown 2,3-dichloro-4-hydroxy-4-[(Z)-2-octenyl]-2-cyclopentenone which is a universal block synthon for analogs of marine prostanoids.     

Synthesis of 9-Substituted Derivatives of 6-(Nitroimidazolyl)thiopurines

The synthesis has been achieved of a series of 9-substituted derivatives of 6-(4-nitroimidazol-5-yl)- and 6-(5-nitroimidazol-4-yl)thiopurines by the reaction of 6-(nitroimidazolyl)thiopurines with alkyl and aralkyl halides, haloalcohols, haloacids and their esters, halo ketones, halo aldehyde acetals, and arylsulfonate esters using potassium carbonate in DMF.     

Synthesis of 5-Oxo and 7-Oxopyrido[2,3-d]pyrimidines

The synthesis of 4-amino-2-methylthio-5-oxopyrido[2,3-d]pyrimidine 4 and its isomer, 4-amino-2-methyl-thio-7-oxopyrido[2,3-d]pyrimidine 6 is described. The regiochemistry of the reaction of 4,6-diamino-2-methyl-thiopyrimidine 9 and diethyl ethoxymethylene malonate 12 is discussed.