丁烯-1异构化复杂反应动力学

MoBiP_1:8/SiO₂催化剂的X衍射实验证实存在BiPO₄物相,用吸附指示剂正丁胺滴定法测定了催化剂显中等强度酸性。催化剂上吸附吡啶的红外光谱实验证实催化剂存在质子酸和Lewis酸中心。用脉冲法测定了丁烯-1及丁烯-2的吸附热。     

One-Pot synthesis of gamma,delta-unsaturated carbonyl compounds from allyl alcohols and vinyl or isopropenyl acetates catalyzed by [IrCl(cod)]2

One-pot synthesis of gamma,delta-unsaturated carbonyl compounds from allyl alcohols and vinyl or isopropenyl acetates was achieved through in situ generation of allyl vinyl ethers by the action of the [IrCl(cod)]2 complex followed by Claisen rearrangement of the resulting ethers. For instance, the reaction of trans-2-methyl-3-phenyl-2-propen-1-ol with isopropenyl acetate in the presence of [IrCl(cod)]2 (1 mol %) and Cs2CO3 (5 mol %) at 100 degrees C for 3 h followed by 140 degrees C for 15 h afforded 5-methyl-4-phenyl-5-hexen-2-one in 72% yield. When vinyl acetate was employed in place of isopropenyl acetate, 4-methyl-3-phenyl-4-pentenal was obtained in 83% yield.     

Metabolic studies of methenolone acetate in horses

Methenolone acetate (17β-acetoxy-1-methyl-5α-androst-1-en-3-one), a synthetic anabolic steroid, is frequently abused in human sports. It is preferred for its therapeutic efficiency and lower hepatic toxicity compared with its 17α-alkylated analogs. As with other anabolic steroids, methenolone acetate may be used to enhance performance in racehorses. Metabolic studies on methenolone acetate have been reported for humans, whereas little is known about its metabolic fate in horses. This paper describes the investigation of in vitro and in vivo metabolism of methenolone acetate in racehorses.Studies on the in vitro biotransformation of methenolone acetate with horse liver microsomes were carried out. Methenolone (M1, 1-methyl-5α-androst-1-en-17β-ol-3-one) and seven other metabolites (M2-M8) were detected in vitro. They were 1-methyl-5α-androst-1-ene-3,17-dione (M2), 1-methyl-5α-androst-1-en-6-ol-3,17-dione (M3) and two stereoisomers of 1-methylen-5α-androstan-2-ol-3,17-dione (M4 and M5), 1-methyl-5α-androst-1-en-16-ol-3,17-dione (M6) and monohydroxylated 1-methyl-5α-androst-1-en-17-ol-3-one (M7 and M8). After oral administration of Primobolan^® (80 tablets × 5 mg of methenolone acetate each) to two thoroughbred geldings, the parent steroid ester was not detected in the post-administration urine samples. However, seven metabolites, namely M1, M6-M8, two stereoisomers of M7 (M9 and M10) and 1-methyl-5α-androst-1-en-17α-ol-3-one (M11), could be detected. The metabolic pathway for methenolone acetate is postulated. This study has shown that metabolite M1 could be targeted for controlling the abuse of methenolone acetate in horses.     

Synthesis of optically active vicinal fluorohydrins by lipase-catalyzed deracemization

Three microbial lipases have been used to deracemize trans-2-fluorocycloalkanols 2 both by hydrolysis of the corresponding acetates 3 or chloroacetates 4 and by esterification of the fluorohydrins 2 using vinyl acetate and vinyl chloroacetate, respectively. Pseudomonas cepacia lipase was the most selective for the six- and the seven-membered-ring compounds, while the lipase from Candida rugosa was most useful for the eight-membered-ring compounds. Both lipases transform the (R)-enantiomers preferentially. In contrast the lipase from Candida antarctica hydrolyzed the esters of trans-2-fluorocyclohexanol 2a and esterified the fluorohydrin itself with very low enantiopreference for the (R)-isomers. The seven- and the eight-membered ring esters and the corresponding fluorohydrins were also transformed with low, but reverse, enantioselectivity.     

由有机硼烷立体选择合成(Z)、(E)链烯-1-醇乙酸酯类昆虫性信息素

等摩尔的甲硼烷甲硫醚(H₃B·SMe₂)与四溴化碳在60℃下反应20h,定量得到一溴硼烷甲硫醚。从链端烯烃、一卤硼烷甲硫醚和2-[7-辛炔-1-氧基]四氢吡喃及其8-溴代衍生物出发,经硼氢化反应和Zweifel的顺-,反-烯烃合成法,立体选择地合成了鳞翅目昆虫性信息素:(Z)-7-十四烯-1-醇乙酸酯9a、(Z)-7-十六烯-1-醇乙酸酯9b、(E)-7-十四烯-1-醇乙酸酯12及其相应的醇13。产物经GC分析和MS、¹H及¹³C NMR数据证实了它们的纯度和几何构型。     

Preparation and Characterization of Head-to-Head Polymers. III. Head-to-Head Poly (methyl Crotonate)

Alternating copolymers of cis-butene-2 and maleic anhydride were esterfied to the methylester which corresponds to head to head (H-H) poly(methyl crotonate).

The chemical, physical, and mechanical properties and thermal degradation behavior of H-H poly (methyl crotonate) was studied and compared with the properties of head to tail (H-T) poly(methyl crotonate). This latter polymer was made by a known anionic polymerization technique and was, unlike the amorphous H-H polymer, partially crystalline. The T_g of H-H polymer was found to be higher than that of the H-T polymer. Thermal degradation behavior of H-H and H-T polymer was between the degradation behavior of H-H and H-T poly(methyl cinnamate) and poly (methyl acrylate). Poly (methyl crotonates) degraded to a substantial part to small molecules and char; methyl crotonate was found among the degradation products. H-H Poly (methyl crotonate) gave also butene-2 and a mixture of dimethyl maleate and dimethyl fumarate on pyrolysis.     

Kinetic resolution of ketone cyanohydrin acetates with a microbial enzyme

Incubation of d1-1-cyano-1-methylalkyl (or alkenyl) acetates (methyl ketone cyanohydrin acetates) with cells of IAM 4682 afforded optically active acetates and the corresponding ketones via asymmetric hydrolysis. Resulting (S)-2-cyano-2-undecyl acetate was converted to the aminofuranone derivative without losing its optical purity.     

Salting-Out of Some Alkyl Acetates in Aqueous Sodium Chloride Solutions

Summary.  Solubilities of methyl acetate (MeOAc), ethyl acetate (EtOAc), 1-propyl acetate (1-PrOAc), 1-butyl acetate (1-BuOAc), 2-methyl-1-propyl acetate (iso-BuOAc), 2-butyl acetate (sec-BuOAc), 2-methyl-2-propyl acetate (ter-BuOAc), 1-pentyl acetate (1-PeOAc) and 1-hexyl acetate (1-HeOAc) in water and in aqueous sodium chloride solutions at concentrations ranging up to 1.0 molċdm⁻³ were determined at 25.0°C by analyzing the saturated aqueous or salt solutions. Solubility ratios of alkyl acetates in pure water and in aqueous sodium chloride solution were calculated and found to be linearly dependent on the concentration of sodium chloride. The solubility ratios were also calculated by the approach of the scaled particle theory and according to the theories of McDevit and Long, Cross, Conway et al., and Aveyard. All these theories, except that of Conway, correctly predict the order of magnitude of the experimental results, but do not discriminate between isomeric butyl acetates. The theoretical values obtained from the scaled particle and Aveyard theories coincide well with the experimental values, especially for the higher alkyl acetates. The purely electrostatic theory of Conway et al. not even predicts the salting-out effect for the alkyl acetates investigated. Received July 12, 1999. Accepted September 23, 1999     

Salting-Out of Some Alkyl Acetates in Aqueous Sodium Chloride Solutions

 Solubilities of methyl acetate (MeOAc), ethyl acetate (EtOAc), 1-propyl acetate (1-PrOAc), 1-butyl acetate (1-BuOAc), 2-methyl-1-propyl acetate (iso-BuOAc), 2-butyl acetate (sec-BuOAc), 2-methyl-2-propyl acetate (ter-BuOAc), 1-pentyl acetate (1-PeOAc) and 1-hexyl acetate (1-HeOAc) in water and in aqueous sodium chloride solutions at concentrations ranging up to 1.0 molċdm⁻³ were determined at 25.0°C by analyzing the saturated aqueous or salt solutions. Solubility ratios of alkyl acetates in pure water and in aqueous sodium chloride solution were calculated and found to be linearly dependent on the concentration of sodium chloride. The solubility ratios were also calculated by the approach of the scaled particle theory and according to the theories of McDevit and Long, Cross, Conway et al., and Aveyard. All these theories, except that of Conway, correctly predict the order of magnitude of the experimental results, but do not discriminate between isomeric butyl acetates. The theoretical values obtained from the scaled particle and Aveyard theories coincide well with the experimental values, especially for the higher alkyl acetates. The purely electrostatic theory of Conway et al. not even predicts the salting-out effect for the alkyl acetates investigated.     

Products of mercuric salt addition to dis ubstituted acetylenes

Summary The syntheses and properties of cls and trans-1-methyl-2-acetoxy -1-propen-1-ylmercury acetate, 1-methyl2-acetoxy-2-propen-1-ylmercury acetate and 1,2-diphenyl-2-acetoxy-1-ylmercury acetate are described.     

在Fe-Zn-Mg-Cr尖晶石结构催化剂上丁烯-2氧化动力学

用玻璃外循环无梯度反应器研究了在Fe-Zn-Mg-Cr尖晶石结构催化剂上丁烯-2氧化脱氢动力学。丁烯-2氧化脱氢动力学服从三步骤Redox机理。用脉冲法研究了催化剂用丁烯-2还原及还原催化剂用氧再氧化步骤。用脉冲法测定了丁烯-2吸附热。丁烯-2及丁二烯深度氧化动力学服从经验速度方程。用正交设计法估计了动力学方程的参数。丁烯-2氧化脱氢速度比丁烯-1要快。     

Studies on Chemical Ingredients of Fruit of Alpinia Galanga, (L.) Swarts(Ⅱ) -Four Esters and Their Hydrolysis

Four esters have been isolated from a Chinese medicinal herb, fruit of Alpinia galanga(L.) Swarts, and identified as 1'-acetoxychavicol acetate(1) , trans-p-acetoxycinnamyl acetate(2), 1'-acetoxyeugenol acetate(3), and trans-3'-acetoxytsoeugenol acetate(4). Among them compound 2 has not been reported in literature and compound 4 has nor been found in natural product before. Compound 1 and 3 were hydrclysed rapidly in boiling wacerinto 1'-hydroxychavicol acetate(5), tians-p-acetoxycinudmic alcnhol (6), 1 '-hydroxyeugenol acetate (7) and trans-3' - hydroxyisoeueugenol acetate(8) respectively. The mechanism of these hydrolyses is discussed. The mass spectrometric fragmentations of these compounds are proposed.     

Synthetic studies in steroidal sapogenins and alkaloids—XII : Synthesis of sceptrumgenin and isonuatigenin

The Michael adduct of 5-nitro-2,2-ethylene-dioxypentan-1-ol acetate with E-5,17(20)-pregnadien-3β-ol-16-one gave on reduction with sodium borohydride and deketalisation, spirost-5-en-3β-ol-25-one. This intermediate was converted to sceptrumgenin through reaction with triphenyl phosphonium methylide and to isonuatigenin by treatment with dimethyl oxosulfonium methylide followed by lithium aluminium hydride.     

Novel acetate binding modes in [Na2Cu(CH3COO)4(H2O)].H2O

A new copper(II) acetate, [Na(2)Cu(CH(3)COO)(4)(H(2)O)].H(2)O (1), has been crystallized from an aqueous solution containing sodium acetate and copper(II) acetate monohydrate in a 4:1 ratio and the structure determined by X-ray crystallography. 1 crystallizes in the monoclinic space group P2(1)/c, with a = 16.638(3) A, b = 11.781(2) A, c = 15.668(3) A, beta = 90.11(3) degrees, V = 3071.0(11) A(3), and Z = 4. In the asymmetric unit, sodium ions bridge two crystallographically unique square planar [Cu(CH(3)COO)(4)](2-) units to their symmetry-generated neighbors to form corrugated 2D sheets of Na(2)Cu(CH(3)COO)(4), which are held together by H-bonding interactions involving the waters of crystallization. In contrast, the structures of known sodium copper acetates are better described as 3D frameworks. The metal centers are bridged by a number of acetates in novel coordination modes. The square planar Cu(II) geometry generated by oxygen atoms from four different acetates is an unexpected feature given the weak ligand field provided by the acetate ligands.     

Unusual transformations of lithium enolate of ethyl 4,4,4-trifluoro-3-oxobutanoate

The present paper describes unusual reactions of lithium enolate of ethyl 4,4,4-trifluoro-3-oxobutanoate with ammonium acetate and 1-aminonaphthalene. These reactions produce 4-amino-2,6-bis(trifluoromethyl)pyridine and 4-trifluoromethyl-2-[(Z)-1,1,1-trifluoroprop-1-en-2-ol-1-yl]benzo[h]quinoline, respectively. The reaction of 1,1,7,7,7-hexafluoroheptane-2,4,6-trione hydrate with 1-naphthylamine gives a mixture of 4-trifluoromethyl-2-[(Z)-1,1,1-trifluoroprop-1-en-2-ol-1-yl]benzo[h]quinoline and N,N??-bis(naphth-1-yl)-2,6-bis(trifluoromethyl)pyridine-4(1H)-imine, respectively.     

Practical Syntheses of Some Insect Sex Pheromones, 10- and 12-Alken-1-ol Acetates

Some insect sex pheromones 10-dodecen-1-ol acetates 5a(Z/E) and 12-tetradecen-1-ol acetates 5b(Z/E) have been synthesized from cis-13-docosenoic acid la and cis-15-tetracosenoic acid Ib via the isomerization of key intermediates 11-dodecen-1-ol acetate 4a and 13-tetradodecen-1-ol acetate 4b.     

Polymerization of butene-2 with isomerization to butene-1

An attempt has been made to prepare a high molecular weight isotactic polybutene-1 from cis- or trans-butene-2. Polymerization of butene-2 did not occur due to the steric effect of the substituents. In the presence of TiCl₃–Al(C₂H₅)₃ catalyst, however, both butene-2 monomers were found to polymerize at a slower rate than butene-1 and to give polymers consisting of the repeating unit of butene-1. From the gas chromatographic determination of the isomer distribution of the butenes recovered after the polymerization, it was found that the butenes isomerized, in the presence of the catalyst system containing TiCl₃, to approach the thermodynamic equilibrium mixture of butene-1, cis-butene-2, and trans-butene-2. It was also found that the rates of polymerization of butene-2 for the catalyst systems used were proportional to the isomerization rates. These results show that butene-2 isomerizes first to butene-1 which has less steric hindrance and then polymerizes as butene-1, through ordinary vinyl polymerization by a coordinated anionic mechanism. This type of polymerization was observed in some other linear β-olefins such as n-pentene-2 and n-hexene-2.     

Inter- and intramolecular palladium-catalyzed allyl cross-coupling reactions using allylindium generated in situ from allyl acetates, indium, and indium trichloride

Inter- and intramolecular palladium-catalyzed allyl cross-coupling reactions using allylindium generated in situ by treatment of allyl acetates with indium and indium trichloride in the presence of Pd(0) catalyst and nBuNMe(2) in DMF were successfully demonstrated. Allylindium species generated in situ by reductive transmetalation of pi-allylpalladium(II) complexes, obtained from a variety of allyl acetates in the presence of Pd(0) catalyst together with indium and indium trichloride, were found to be capable of acting as effective nucleophilic coupling partners in Pd-catalyzed cross-coupling reactions. A variety of allyl acetates such as but-1-en-3-yl acetate, crotyl acetate, and 2-methylallyl acetate afforded the corresponding allylic compounds in good yields in cross-coupling reactions. Various electrophilic cross-coupling partners such as aryl iodides and vinyl bromides and triflates participate in these reactions. Not only intermolecular but also intramolecular Pd-catalyzed cross-coupling reactions work equally well to produce the desired allylic coupling products in good yields.     

Characterization of cellulose acetates by nuclear magnetic resonance

An NMR method for determining the distribution of acetyl groups in cellulose acetates was developed. Treatment of cellulose acetates with acetyl-d₃ chloride gave products having simple spectra which could be analyzed quantitatively to give the distribution of acetyl groups in the original sample. The method was applied to studying (1) the hydrolysis of cellulose triacetate with ammonia, (2) the acetylation of cellulose acetate with acetyl chloride, and (3) the acetylation of cellulose acetate with acetic anhydride.     

Mixtures formed of alkyl acetates with olive oil at 298.15 k

Enthalpies of mixing and heat capacities of the systems formed of alkyl acetates (ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate and isobutyl acetate) with olive oil were measured at 298.15 K. The mixing of acetates with the oil was strongly endothermic, and the highest measured enthalpies per mole of mixture were 2000 J mol^-1 for ethyl acetate at an acetate mole fraction of 0.6. The heat capacities of the mixtures were calculated too and values were decreasing as the mole fraction of acetate increases and varied from 296 to 3929 J K^-1 mol^-1. This revised version was published online in July 2006 with corrections to the Cover Date.