脱氢松香酸甲酯类衍生物的合成

以脱氢松香酸甲酯为原料, 经溴代、硝化、还原、重氮化等步骤合成了6种12位取代的脱氢松香酸甲酯衍生物, 研究了12位上不同取代基对它们紫外、荧光性质的影响; 然后再分别以得到的12-氯脱氢松香酸甲酯和12-溴脱氢松香酸甲酯为起始物, 经双硝化、氧化、脱异丙基硝化等步骤合成了一系列重要的脱氢松香酸甲酯卤代硝化衍生物, 并对12-氯脱氢松香酸甲酯、12-溴-13,14-二硝基脱氢松香酸甲酯的单晶进行了X射线衍射表征.     

The vaporization enthalpies and vapor pressures of a series of unsaturated fatty acid methyl esters by correlation gas chromatography

Vaporization enthalpies for methyl myristoleate (methyl Z 9-tetradecenonate), methyl 10-pentadecenoate, methyl palmitoleate (methyl Z 9-hexadecenoate), methyl Z 10-heptadecenoate, methyl oleate (methyl Z 9-octadecenoate), methyl linoleate (methyl Z,Z 9,12-octadecadienoate), methyl linolenate (methyl Z,Z,Z 9,12,15-octadecatrienoate), methyl Z 11-eicosenoate, methyl Z,Z 11,14-eicosadienoate, methyl Z,Z,Z 11,14,17-eicosatrieneoate, methyl arachidonate (methyl Z,Z,Z,Z 5,8,11,14-eicosatetraeneoate), methyl Z,Z,Z,Z,Z 5,8,11,14,17-eicosapentaeneoate, methyl erucate (methyl Z 13-docosaneoate), methyl Z,Z 13,16-docosadienoate, methyl Z,Z,Z,Z,Z,Z 4,7,10,13,16,19-docosahexaenoate and methyl nervonate (methyl Z 15-tetracosenoate) are evaluated at T = 298.15 and vapor pressures are evaluated over the temperature range T = 298.15-450 K by correlation gas chromatography. The results are generated by an interpolative process using literature values for the saturated fatty acid methyl esters (FAMEs) from methyl decanoate to methyl tetracosanoate, exclusive of methyl nonadecanoate, heneicosanoate and tricosanoate, as standards. Relationships for calculating vapor pressures for all of the compounds studied from T = 298.15 to 450 K are provided.     

Gas-liquid chromatography and mass spectrometry of methyl ethers of methyl N-acetyl-N-methyl-β-d-neuraminate methyl glycoside

Partial methylation of methyl N-acetyl-β-d-neuraminate methyl glycoside using methyl iodide and silver oxide gives a mixture of methyl ethers of methyl N-acetyl-N-methyl-β-d-neuraminate methyl glycoside, which was fractionated by chloroform-water partition followed by preparative column chromatography on silica gel. After trimethylsilylation of the fractions, gas-liquid chromatography on OV-101 and mass spectrometry facilitated the identification of 13 methyl ethers.     

High-performance liquid chromatography of xanthines. Effects of N-methyl and C-8 hydroxyl substitution on the retention times

The capacity factors of 26 xanthine derivatives were measured by reversed-phase high-performance liquid chromatography. N-Methyl substitution increased the capacity factor and the related lipid solubility. The descending order of the increase in capacity factor by the N-methyl group is: N-1 methyl greater than N-3 methyl greater than N-7 methyl greater than N-9 methyl. C-8 hydroxylation reduces the capacity factor in the xanthines. The reduction factor is 3.34 in xanthines with N-3 methyl substitution, 2.41 in xanthines with N-1 and/or N-7 methyl substitution and 1.68 in xanthines with N-9 methyl substitution.     

叶绿素-b的结构修饰及其二氢卟吩类衍生物的合成

在含有5％的硫酸甲醇溶液中,通过去除金属镁离子和酯交换反应将叶绿素-b降解为脱镁叶绿酸-b甲酯,在二苯醚中的热裂解进一步将其转化为焦脱镁叶绿酸-b甲酯.通过乙酸中的空气氧化得到132-羟基脱镁叶绿酸-b甲酯和132-羟基焦脱镁叶绿酸-b甲酯,前者和脱镁叶绿酸-b甲酯在碱性条件下继续与空气中氧分子作用均给出相应的氧化产物.C3-乙烯基与重氮甲烷1,3偶极环加成及热裂解反应生成C3-吡唑啉基和环丙基取代的二氢卟吩衍生物;C7-甲酰基与溴化三苯基苄基鳞的Wittig反应给出C7-苯亚甲基取代的二氢卟吩衍生物.所合成新的二氢卟吩类衍生物均经UV,IR,1HNMR光谱及元素分析证明其结构.与此同时,对相应的反应提出了可能的反应机理.     

Physical properties of diblock methylcellulose derivatives with regioselective functionalization patterns: First direct evidence that a sequence of 2,3,6‐tri‐O‐methyl‐glucopyranosyl units causes thermoreversible gelation of methylcellulose

This article describes detailed structure‐property relationships of 5 regioselectively methylated celluloses and 10 diblock cellulose derivatives with regioselective functionalization patterns: methyl 2,3,6‐tri‐O‐ ( 1 , 236MC), methyl 2,3‐di‐O‐ ( 2 , 23MC), methyl 2,6‐di‐O‐ ( 3 , 26MC), methyl 3‐O‐ ( 4 , 3MC), methyl 6‐O‐methyl‐cellulosides ( 5 , 6MC), methyl β‐D‐glucopyranosyl‐(1→4)‐2,3,6‐tri‐O‐methyl‐ ( 6 , G‐236MC), methyl β‐D‐glucopyranosyl‐(1→4)‐2,3‐di‐O‐methyl‐ ( 7 , G‐23MC), methyl β‐D‐glucopyranosyl‐(1→4)‐2,6‐di‐O‐methyl‐ ( 8 , G‐26MC), methyl β‐D‐glucopyranosyl‐(1→4)‐3‐O‐methyl‐ ( 9 , G‐3MC), methyl β‐D‐glucopyranosyl‐(1→4)‐6‐O‐methyl‐ ( 10 , G‐6MC), methyl β‐D‐glucopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→4)‐2,3,6‐tri‐O‐methyl‐ ( 11 , GG‐236MC), methyl β‐D‐glucopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→4)‐2,3‐di‐O‐methyl‐ ( 12 , GG‐23MC), methyl β‐D‐glucopy‐ranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→4)‐2,6‐di‐O‐methyl‐ ( 13 , GG‐26MC), methyl β‐D‐glucopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→4)‐3‐O‐methyl‐ ( 14 , GG‐3MC), and methyl β‐D‐glucopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→4)‐6‐O‐methyl‐cellulosides ( 15 , GG‐6MC). Surface tension, differential scanning calorimetry, fluorescence, and dynamic light scattering measurements of aqueous solutions of compounds 1 – 15 revealed that there was no relationship between aggregation behaviors and gel formation, gelation occurred only when the hydrophobic environments formed by hydrophobic interactions between the sequences of 2,3,6‐tri‐O‐methyl‐glucopyranosyl units upon heating. The diblock structure consisting of cellobiosyl block and approx. ten 2,3,6‐tri‐O‐methyl‐glucopyranosyl units was of crucial importance for thermoreversible gelation of methylcellulose. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1539–1546, 2011     

The reactivity of 1,4-dihydronicotinamides towards reduction of 1,1′,1″-trifluoro-acetophenone : influence of methyl substitution on the pyridine ring.

In a series of methyl substituted 1-(2′,6′-dichlorobenzyl)-1,4-dihydronicotinamides those compounds with the methyl α to the pyridine nitrogen are at least one order of magnitude more reactive than the analogues without methyl or methyl on the 5-position.     

Intermolecular methyl transfer on pyrolysis of carpronium chloride

The methyl transfer occurring in the production of methyl N,N-dimethyl-γ-aminobutyrate by pyrolysis of carpronium chloride was examined by means of pyrolysis gas chromatography mass spectrometry with the aid of some deuterated compounds. The mass spectra of methyl N,N-dimethyl-γ-aminobutyrate, produced from deuterated derivatives of carpronium chloride, showed inter alia, characteristic molecular ion peaks which indicated that the methyl of the trimethylammonium group transfers and displaces the methyl of the carbomethoxy group of the tertiary amino compound. The results show that an intermolecular methyl transfer occurs in part on pyrolysis of carpronium chloride, to form methyl N,N-dimethyl-γ-aminobutyrate in which the methyl oxygen is replaced by a methyl from the nitrogen of the original compound. The mechanism presented involves the bimolecular reaction between zwitterionic intermediates formed by ionic O-demethylation of carpronium chloride.     

Synthesis of alkyl methyl ethers and alkyl methyl carbonates by reaction of alcohols with dimethyl carbonate in the presence of tungsten and cobalt complexes

Alkyl methyl ethers and alkyl methyl carbonates were synthesized by reaction of alcohols with dimethyl carbonate in the presence of tungsten and cobalt carbonyls. Optimal reactant and catalyst ratios, as well as reaction conditions, were found for selective formation of alkyl methyl ethers or alkyl methyl carbonates.     

Standard enthalpies of combustion and formation for fatty acid esters in the condensed state

The energies of combustion are determined for methyl heptadecanoate (crys.), methyl stearate (crys.), ethyl stearate (crys.), methyl behenate (crys.), methyl oleate (liq.), and methyl erucate (liq.) by bomb calorimetry method. The standard enthalpies of combustion and formation are calculated for these compounds in the condensed state.     

用气相色谱/质谱法分析醚化后催化裂化轻汽油中的醚及相关烯烃

用气相色谱／质谱联用仪对醚化工艺过程中醚化前后的催化裂化轻汽油组成进行了定性定量分析。由定性结果分析汽油中的活泼烯烃和生成醚的类型,由定量结果分析活泼烯烃转化成醚后的量的变化情况及生成醚的多少。最终鉴定出６种烯烃参与了醚化过程,生成了４种醚。经查证,这些醚对提高汽油辛烷值均有贡献。     

A tracer study of the hydrolysis of methyl methacrylate and methyl acrylate units in homopolymers and copolymers

Homopolymers and copolymers were prepared from methyl methacrylate, methyl acrylate, and styrene by radical reactions at 60°C. Monomers suitably labeled with carbon-14 were used so that it was possible to monitor the hydrolysis of ester groups in the polymers during treatment under alkaline conditions. It was found that methyl acrylate units were hydrolyzed completely whatever their environment in a polymer chain. Under the same conditions only about 9% of the ester groups in a homopolymer of methyl methacrylate reacted; the proportion was increased by the introduction of comonomer units into the polymer chain. For copolymers of methyl methacrylate with methyl acrylate the extent of reaction may be correlated with the lengths of the sequences of methyl methacrylate units.     

Phosphorylation of D-glucose derivatives with inorganic monoimido-cyclo-triphosphate

Phosphorylation of several D-glucose derivatives has been achieved using inorganic monoimido-cyclo-triphosphate (MCTP, Na(3)P(3)O(8)NH) in aqueous solution. In the phosphorylation of D-glucose, D-glucuronic acid, 2-deoxy-D-glucose and D-galactose, 1-O-diphosphoramidophosphono-beta-D-glucose, 1-O-diphosphoramidophosphono-beta-D-glucuronic acid, 1-O-diphosphoramidophosphono-2-deoxy-beta-D-glucose, and 1-O-diphosphoramidophosphono-beta-D-galactose were stereoselectively synthesized with yields of 54, 32, 37 and 46%, respectively. In the case of methyl alpha-D-glucoside, the phosphorylated products were methyl 3-O-diphosphoramidophosphono-alpha-D-glucoside and methyl 4-O-diphosphoramidophosphono-alpha-D-glucoside, and in the case of methyl beta-D-glucoside the products were methyl 2-O-diphosphoramidophosphono-beta-D-glucoside, methyl 3-O-diphosphoramidophosphono-beta-D-glucoside, and methyl 4-O-diphosphoramidophosphono-beta-D-glucoside. For D-mannose and D-allose, several phosphorylated products were obtained and the main products were 1-O-diphosphoramidophosphono-beta-D-aldoses.     

Reactions of hydro(pero)xy derivatives of polyunsaturated fatty acids/esters with nitrite ions under acidic conditions. Unusual nitrosative breakdown of methyl 13-hydro(pero)xyoctadeca-9,11-dienoate to a novel 4-nitro-2-oximinoalk-3-enal product

13(S)-hydroperoxy- and 13(S)-hydroxyoctadeca-9,11-dienoic acids (1a/b), 15(S)-hydroperoxy- and 15(S)-hydroxyeicosa-5,8,11,13-tetraenoic acids (2a/b), and their methyl esters reacted smoothly with NO2- in phosphate buffer at pH 3-5.5 and at 37 degrees C to afford mixtures of products. 1b methyl ester gave mainly the 9-nitro derivative 3b methyl ester (11% yield) and a peculiar breakdown product identified as the novel 4-nitro-2-oximinoalk-3-enal derivative 4 methyl ester (15% yield). By GC-MS hexanal was also detected among the products. Structures 3b and 4 methyl esters were secured by 15N NMR analysis of the products prepared from 1b methyl ester upon reaction with Na15NO2. 4 methyl ester (14% yield) was also obtained from 1a methyl ester along with the nitrated hydroperoxy derivative 3a methyl ester (10% yield). Under the same conditions, 2a/b methyl esters gave mainly the corresponding nitrated derivatives 5a/b, with no detectable breakdown products, whereas the model compound (E,E)-2,4-hexadienol (6) afforded two main nitrated derivatives identified as 7 and 8. A reaction pathway for 1a/b methyl esters was proposed involving conversion of nitronitrosooxyhydro(pero)xy intermediates which would partition between two competing routes, viz., loss of HNO2, to give 3a/b methyl esters, and a remarkably facile fission leading to 4 methyl ester and hexanal.     

Formation of lactones in the heck reaction

The Heck reaction of methyl 2-bromobenzoate with methyl acrylate gave a mixture of alkene 1 and lactone 9 . Acrylonitrile and methyl 2-bromobenzoate gave lactone 10 . Ethyl 2-bromobenzoate and methyl acrylate or acrylonitrile gave the alkenes 2 and 4 respectively.     

Analysis of Seven Herbicides by Gas-Liquid Chromatography

Simutaneous analysis of seven commonly used herbicides, 2,4-D methyl ester, 2,4-D methyl ester, 2,4,5-T methyl ester, silvex methyl ester, ramrod, CIPC and DEF, by gas-liquid chromatography with an electron capture detector was attempted. Two packed columns (which are generally used for the analysis of chlorinated pesticides) and two chemically bonded fused silica capillary columns were used for the analysis. When the packed columns were used, ramrod always interfered with the analysis of 2,4-D methyl ester and/or silvex methyl ester. Complete separation with reasonable analysis time can be achieved using one of the chemically bonded fused silica capillary columns.     

Functional Polymers. XXV. Fluorescence Spectra of Derivatives of Methyl Salicylate and Copolymers of Methyl Vinylsalicylates

Ultraviolet absorption and fluorescence spectra of methyl salicylate, isomers of methyl salicylate derivatives, and polymers with units of isomers of methyl salicylate have been investigated. The λ_max of methyl salicylate and its derivatives is centered around 310 nm. When the phenolic hydroxyl group is acetylated, the maximum is at 285 nm. Fluorescent emission maxima depend on the excitation wavelength. Two groups of maxima centered at 350 and 460 nm indicate that two molecular species (already present in the ground state) of the methyl salicylate moiety, probably tautomers, play essential parts as photoexcited states in the photophysics of methyl salicylate derivatives.     

Addition of methyl dibromoacetate and methyl tribromoacetate to acrylic compounds in the presence of various initiating systems

Conclusions 1. At 70–100° the system, iron pentacarbonyl + dimethylaniline and ferric chloride + dimethylaniline, efficiently initiate the addition of methyl dibromoacetate to methyl acrylate and methyl methacrylate, and also of methyl tribromoacetate to methyl acrylate, with the predominant formation of adducts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 592–595, March, 1973     

具有叶绿素基本碳架的苯并咪唑并红紫素-18衍生物的合成

脱镁叶绿酸-a甲酯与邻苯二胺发生缩合和重排反应,分别给出(2,3-n)-苯并咪唑并红紫素-18甲酯、(2,3-o)-苯并咪唑并红紫素-18甲酯、(2,3-n)-喹喔啉并焦脱镁叶绿酸甲酯和二氢卟吩-p6三甲酯.针对苯并咪唑并红紫素-18的20-meso-位和12-位甲基进行氟代、氯代、溴代、碘代和空气氧化反应,完成了一系列具有叶绿素基本碳架的苯并咪唑并二氢卟吩类衍生物的合成.所得新的叶绿素衍生物的化学结构均经UV,IR,1H NMR,质谱及元素分析予以证实.     

Preparation of terminal alkenic esters by an oxidative radical reaction

A general method is described for the conversion of(mono)alkenic esters with the double bond at the n^th C atom to terminal alkenic esters of (n?1) C atoms in length, with the double bond at n?2. Ozonolysis, either in methanol or in light petroleum, is followed by reaction with a mixture of ferrous and cupric salts. Methyl 10-undecenoate, methyl oleate (methyl (Z)-9-octadecenoate) and methyl erucate (methyl (Z)-13-docosenoate) were converted to methyl 8-nonenoate, methyl 7-octenoate and methyl 11-dodecenoate respectively. An improved preparation of 5-hexenoic acid is also described.