Didemnaketal A类似物的合成研究──C8-C15中间体的合成

DidemnaketalA是一类具有明显抗艾滋病活性的天然螺环缩酮类化合物^[1],但至今未见有关合成及立体化学研究的报道.为进一步研究这类螺环缩酮类化合物的生理活性,我们开展了侧链简化的类似物(如化合物1)的合成研究.     

Dawson型磷钨钒杂多酸催化合成环己酮乙二醇缩酮

环己酮乙二醇缩酮又称1,4-二氧杂螺[4,5]癸烷,系缩酮类化合物,是重要的化工中间体,可作为特殊的反应溶剂及羰基保护基团。由于缩酮具有优于母体羰基化合物特殊的香气,其作为新型香晶、香料在日用化工和食品工业中已得到广泛应用。环己乙二醇缩酮通常在腐蚀酸无机酸如硫酸作用下     

碘催化合成环己酮乙二醇缩酮

环缩酮类香料性能优良,在日用香精和食品香精中用途广泛。合成缩酮的传统催化剂为硫酸,反应时间长,副反应多,对反应设备腐蚀严重,废液排放量大,后处理工艺复杂,人们一直在寻求更优良的催化剂。本文利用单质碘催化剂合成了环己酮缩乙二醇。     

环十二碳酮与苯基乙二醇反应产物的分离及确定

环十二碳酮(1)与苯基乙二醇(2)在对甲苯磺酸催化下的反应粗产物具有浓郁的花香,最初我们以为这种香气来源于缩酮2-苯基-1,4-二氧杂螺[4,11]十六烷(3):但该反应粗产物经反复重结晶后得到的无色晶体却没有香气、经红外、~1H核磁等谱图及碳氢分析鉴定该无色晶体确是缩酮3.既然缩酮3没有气味,则反应粗产物的香气必然来自反应中的副产物。薄层色谱分析表明,该反应中副产物较多。我们猜测,副反应可能主要来自2。     

简法合成二氢茉莉酮酸甲酯和二氢新茉莉酮酸甲酯

以环戊二烯为原料,先合成了环戊-2-烯酮(1),(1)经过Michael加成反应得到3-酮-环戊基乙酸甲酯(4)。再经过Aldol缩合反应和催化氢化,得到二氢茉莉酮酸甲酯和二氢新茉莉酮酸甲酯。     

氯氧化锆催化合成缩酮

氯氧化锆催化合成缩酮;氯氧化锆;环己酮丁二醇缩酮;缩酮合成;Br?nsted酸     

α-氧代烯酮环二硫代缩酮化学(ⅩⅫ) ——硫醇(酚)为亲核体的α-氧代烯酮环二硫代缩酮与2-甲基烯丙基氯化镁加成物的取代-环合芳构化反应

缩酮基为五元和六元环的α-氧代烯酮环二硫代缩酮与2-甲基烯丙基氯化镁反应得1,2-加成产物。所得加成产物在酸催化条件下以乙硫醇为亲核体时生成芳基乙基硫醚;苯硫酚为亲核体时,产物为芳基苯基硫醚。同样实验条件下,缩酮基为甲硫基的α-氧代烯酮二硫代缩酮与2-甲基烯丙基氯化镁的1,2-加成则生成芳构化产物芳基甲基硫醚。本实验从亲核体的选用上进一步拓展了所述取代-环合芳构化反应,并进一步验证了缩酮基结构对反应活性的影响。     

2-(6′-甲氧羰基己基)环戊-2-烯酮的新合成方法

以环戊二烯为起始原料,制得6-乙氧羰基己基环戊二烯,后者在甲醇溶液中与溴作用后经酸性水解,得到2-(6＇-甲氧羰基己基)环戊-2-烯酮。     

2,8-二甲基-1,7-二氧杂螺[5,5]十一烷的合成

果蝇 ( Tephritidae)对水果生产有严重的危害 .热带果蝇寿命较长 ,具有很强的迁徙能力和繁殖能力 .因此开展果蝇生物防治和控制措施的相关研究具有重要的意义 [1,2 ] .Baker等 [3]发现性成熟的雌B.dorsalis果蝇 ,性腺分泌物中包含有螺环缩酮化合物 2 ,8-二甲基 - 1 ,7-二氧杂螺 [5 ,5 ]十一烷 ( 1 ) .Bactrocera Latifrons( Hendel)果蝇的雄性腺体分泌物中也存在螺环缩酮 1 [4 ] ,另外在 rove甲虫腹梢分泌物中也分离出 1 [5] ,螺环缩酮不仅作为性信息素组分存在于许多果蝇腺体中 ,而且作为结构单元存在于许多复杂的有强烈生理活性的天然…     

γ-卤-对羟基苯丁酮和相关化合物在形成乙二醇缩酮中的不同行为

γ-卤-对羟基苯丁酮(1a, 1b)、γ-羟基-对苄氧基苯丁酮(2)、β-(对羟苯甲酰基)丙酸(5)、对羟基苯乙酮(8)及其同系物在形成乙二醇缩酮的标准条件下(与乙二醇和催化量对甲苯磺酸在苯中回流脱水)均不形成缩酮; 除8外, 分别形成相应的γ-乙二醇单醚(3,4)和乙二醇单酯(6)。当对位羟基转化成醚、酯或其他基团和2的羟基被苯甲酰化时, 则分别形成稳定性相差颇大的乙二醇缩酮。通过邻近基团参与过程说明了这些不同的行为。     

Enantioselektive Reaktionen an porphinoiden Nickelkomplexen

Enantioselective Reactions on Porphine Type Nickel Complexes The thermodynamically controlled addition of alcohols to (+)-(1R)-[1-methyl-8H-HDP]nickelperchlorate ( 1 ; e.e. 92%) yields exclusively the corresponding cis-1,11-disubstituted porphinoids. Chemical transformation of functional groups in the alkoxy side-chain of the chiral addition product followed by acid catalyzed elimination yields the derived alcohols and 1 . By this procedure, the following enantioselective transformations were studied: methylation of meso-2,3-butandiol ( 5 ) to (+)-(2R,3S)-3-methoxy-2-butanol ( 8a ; e.e. 87%), diimide reduction of 2-ethylallyl alcohol ( 9 ) to (+)-(2R)-2-methyl-1-butanol ( 12a ; e.e. 15%), and hydride reduction of 4-hydroxy-2-butanone ( 13 ) to (+)-(3S)-1,3-butandiol ( 16a ; e.e. 20%). Addition of 2,2-dimethyl-1,3-propandiol ( 17 ) to 4 , followed by esterification of the free hydroxy group with trifluoromethanesulfonic anhydride and solvolysis of the sulfonate 19 yielded a bridged complex with unrearranged alkyl chain for which structure 20 is proposed.     

A new pentacoordinate polymeric copper(II) complex with 2-amino-2-methyl-1,3-propandiol: Structural investigations using XRD and DFT

Journal of Structural Chemistry - A novel mononuclear copper complex [Cu(NH2mpdH)(NH2mpd)2Cl] (1) is synthesized from 2-amino-2-methyl-1,3-propandiol (ampdH4). The crystal structure of (1) is...     

Solid-plastic transitions kinetics by DSC

The kinetic parameters of solid-plastic transitions on alcohols derived from neopentane were determined using differential scanning calorimetry (DSC) by a single or multiple scan analysis. The methods studied (Borchard-Daniels, Ellerstein, Multilinear law, Freeman-Carroll, Ozawa, Kissinger), never used before for that kind of transition, imply a single Arrhenius behaviour. These methods werre applied to 2,2-dimethyl 1-propanol (DP), 2,2-dimethyl 1,3-propanediol or neopentylglycol (NPG), 2-hydroxymethyl 2-methyl 1,3-propanediol or pentaglycerine (PG), and 2,2-dihydroxymethyl 1,3-propanediol or pentaerythritol (PE). A simple isothermal test is recommended to check the validity of activation energies experimentally obtained and Arrhenius frequency factors. Taking some restrictions on the heating rate for the heat evolution methods, the results are in agreement with the data obtained by isothermal tests. We have noted a linear dependence of the activation energy values on the number of hydroxyl groups with the exception of pentaerythritol. Isothermal simulations of the solid-plastic transition are an example of industrial applications.

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Zusammenfassung Mittels DSC wurden in einem Single-bzw. Multiscananalyse die kinetischen Parameter der fest-plastischen Umwandlung einiger von Neopentan abgeleiteten Alkohole bestimmt. Die untersuchten Verfahren (Borchard-Daniels, Eilerstein, Multilineares Gesetz, Freeman-Carroll, Ozawa, Kissinger), die noch nie für diese Umwandlung angewendet wurden, lassen auf ein einfaches Arrheniussches Verhalten schließen. Diese Verfahren wurden bei 2,2-Dimethyl-1-propanol (DP), 2,2-Dimethyl-1,3-propandiol oder Neopentylglykol (NPG), 2-Hydroxymethyl-2-methyl-1,3-propandiol oder Pantaglycerin (PG) sowie bei 2,2-Dihydroxymethyl-1,3-propandiol oder Pentaerythrit (PE) angewendet. Es wird ein einfacher isothermer Test vorgeschlagen, um die Gültigkeit der experimentell ermittelten Aktivierungsenergien und der Arrheniusschen Frequenzfaktoren zu überprüfen. Unter einer gewissen Einschränkung der Aufheizgeschwindigkeit stimmen die Ergebnisse mit denen des isothermen Testes überein. Mit Ausnahme von Pentaerythrit konnten wir einen linearen Zusammenhang zwischen den Werten für die Aktivierungsenergie und der Anzahl der Hydroxylgruppen feststellen. Die isothermen Simulierungen von fest-plastischen Umwandlungen sind Beispiele für industrielle Anwendungen.

     

Influence of additives including amine and hydroxyl groups on aqueous ammonia absorbent for CO2 capture

Aqueous ammonia absorbent (10 wt %) was modified with four kinds of additives (1 wt %) including amine and hydroxyl groups, i.e., 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-methyl-1,3-propandiol (AMPD), 2-amino-2-ethyl-1,3-propandiol (AEPD), and tri(hydroxymethyl) aminomethane (THAM), for CO(2) capture. The loss of ammonia by vaporization was reduced by additives, whereas the removal efficiency of CO(2) was slightly improved. These results were attributed to the interactions between ammonia and additives or absorbents and CO(2) via hydrogen bonding, as verified by FT-IR spectra and computational calculation. Molecular structures as well as binding energies were obtained from the geometries of (ammonia + additives) and (ammonia + additives + CO(2)) at the optimized state. These experimental and theoretical findings demonstrate that additives including amine and hydroxyl group are suitable for modifying aqueous ammonia absorbent for CO(2) removal.     

Determination of 1,3-dichloro-2-propanol and 3-chloro-1,2-propandiol in soy sauce by headspace derivatization solid-phase microextraction combined with gas chromatography-mass spectrometry

This study proposes a method for identifying 1,3-dichloro-2-propanol and 3-chloro-1,2-propandiol in aqueous matrices by using headspace on-fiber derivatization following solid-phase microextraction combined with gas chromatography-mass spectrometry. The optimized SPME experimental procedures for extracting 1,3-dichloro-2-propanol and 3-chloro-1,2-propandiol in aqueous solutions involved a 85 μm polyacrylate-coated fiber at pH 6, a sodium chloride concentration of 0.36 g mL⁻¹, extraction at 50 °C for 15 min and desorption of analytes at 260 °C for 3 min. Headspace derivatization was conducted in a laboratory-made design with N-methyl-N-(trimethylsilyl)-trifluoroacetamide vapor following solid-phase microextraction by using 3 μL N-methyl-N-(trimethylsilyl)-trifluoroacetamide at an oil bath temperature of 230 °C for 40 s. This method had good repeatability (R.S.D.s ≤ 19%, n = 8) and good linearity (r² ≥ 0.9972) for ultrapure water and soy sauce samples that were spiked with two analytes. Detection limits were obtained at the ng mL⁻¹. The result demonstrated that headspace on-fiber derivatization following solid-phase microextraction was a simple, fast and accurate technique for identifying trace 1,3-dichloro-2-propanol and 3-chloro-1,2-propandiol in soy sauce.     

Chemistry of Dioxacyclanes: X. Synthesis and Properties of Chlorinated 1,3-Dioxolanes Derived from 4-Cyclohexenecarbaldehydes

4-Cyclohexenecarbaldehyde, its 2-methyl-, 4-methyl-, 2'4-dimethyl derivatives werereacted with 1,2-diols [1,2-propanediol and 3-chloro-, 3-(2-chloroethoxy)-, and 3-(2-chloro-1-chloromethyl-ethoxy-1,2-propandiol] to synthesize the corresponding 2,4-disubstituted 1,3-dioxolanes. Epoxidation and bromination of the products were performed, as well as their condensation with hexachlorocyclopentadiene.     

Conformational equilibria in diols: the rotational spectrum of chiral 1,3-butandiol

The rotational spectra of five conformers of 1,3-butandiol have been measured by pulsed jet Fourier transform microwave spectroscopy. All of them are stabilized by an internal hydrogen bond and all of them have a GG' or a G'G arrangement of the two hydroxyl oxygens, which means that both oxygen atoms are on the same side with respect to the C1C2C3 plane. Apart from the spectroscopic constants, the relative abundances in the supersonic expansion are provided.     

Efficient and convenient nonaqueous workup procedure for the preparation of arylboronic esters

An efficient one-pot synthetic protocol for the synthesis of arylboronic esters has been established. The concentrated addition mixture of trimethylborate with aryl Grignard reagents was treated with low molecular weight diols (ethylene glycol, 1,3-propandiol) and toluene, the corresponding arylboronic esters were isolated in a convenient way with high yields. The diols not only serve as water replacement for the workup step, but also as well as the reagent for the preparation of arylboronic esters.     

Zur Stellungsisomerisierung beim Umsatz von Halohydrinen mit NaN3 und Darstellung des 1-Phenyl-1-amino-2,3-propandiols

Zusammenfassung 1-Phenyl-2-brom-1,3-propandiol (II) aus Zimtalkohol (I) ergab beim Umsatz mit NaN₃ unter Stellungsisomerisierung (Hydroxyl-Azidgruppe) 1-Phenyl-1-azido-2,3-propandiol (III). Dies wurde durch Perjodsäurespaltung von (III) zu CH₂O und dem nicht isolierten 1-Azido-phenylacetaldehyd bewiesen, der zu 2-Oxy-1-phenyläthylamin umgeformt wurde. Auf verschiedenen Wegen wurde (III) in das 1-Phenyl-1-amino-2,3-propandiol (IV) in guter Ausbeute übergeführt. Der Stellungsisomerisierung beim Umsatz von Halohydrinen mit NaN₃ zu Azidohydrinen wird ein paralleler BefundLevenes gegenübergestellt.Auszugsweise vorgetragen beim Chemikertreffen in Innsbruck am 31. 3. 1953. H. Bretschneider undH. Hörmann, Mh. Chem.84, 1021 (1953). H. Bretschneider undH. Hörmann, Mh. Chem.84, 1033 (1953).     

气相色谱法测定甘油与盐酸反应过程的混合物

采用气相色谱方法分析了甘油与盐酸反应过程中的主要物质. 使用KB-WAX毛细管柱及FID检测器, 以乙二醇作内标和甲醇定容, 并用内标法计算. 结果表明, 在程序升温下, 气相色谱内标法能使GLY, DCP, CPD等几种物质达到基线分离, 该方法能满足测试要求.