- Formation of gas-phase dianions and distonic ions as a general method for the synthesis of protected reactive intermediates. Energetics of 2,3- and 2,6-dehydronaphthalene
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New methods for the regioselective formation of radical anions are described. Dicarboxylates are generated by electrospray ionization mass spectrometry and lose carbon dioxide and an electron upon collision-induced dissociation to afford distonic ions. These radical anions also can be synthesized via laser desorption, chemical ionization, and electron ionization of dibenzyl esters. Subsequent fragmentation of the remaining CO2 affords new radical anions corresponding to neutral reactive intermediates. By measuring the proton affinities and electron binding energies of these species, quantitative energetic information on carbenes, biradicals, and other transient molecules can be obtained. This approach is demonstrated by measuring the heats of formation of 2,3- and 2,6-dehydronaphthalene, ancillary thermochemical data also are derived, and the results are compared to either o- or p-benzyne.
- Reed,Hare,Kass
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Read Online
- Ynoate-Initiated Selective C-N Esterification of Tertiary Amines under Transition-Metal and Oxidant-Free Conditions
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An efficient and selective method for metal-and oxidant-free deaminated esterification of tertiary amines is presented. In this protocol, ynoates play a key role to activate the Csp 3-N bond through a process of in situ generation of zwitterionic salts. The transformations show that Csp 3-N bond in the zwitterionic species has a lower dissociation energy than Csp 2-N bond, leading to break preferentially and be trapped by carboxylic acids to generate the corresponding products in moderate to good yield.
- Sun, Feixiang,Feng, Huangdi,Huang, Liliang,Huang, Junhai
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supporting information
p. 713 - 717
(2021/01/14)
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- Reusable ionic liquid-catalyzed oxidative esterification of carboxylic acids with benzylic hydrocarbons via benzylic Csp3-H bond activation under metal-free conditions
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A metal-free protocol for the direct oxidative esterification of the Csp3-H bond in benzylic hydrocarbons with carboxylic acids using heterocyclic ionic liquid as catalyst has been reported. The catalyst 1-butylpyridinium iodide could be easily recycled and reused for at least four cycles without obvious loss of catalytic activity.
- Mou, Fen,Sun, Yadong,Jin, Weiwei,Zhang, Yonghong,Wang, Bin,Liu, Zhiqing,Guo, Lei,Huang, Jianbin,Liu, Chenjiang
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p. 23041 - 23045
(2017/07/10)
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- Cyclic polybutylene terephthalate preparation
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The invention specifically discloses a preparation method of novel cyclicpolybutylece terephthalate (PBT) dimer, wherein paraphthaloyl chloride and 1,4-butanediol are used as the raw materials for oriented synthesis of the cyclicpolybutylece terephthalate dimer through a protection and deprotectionstrategy, and the method is used for contrast analysis and detection of cyclicpolybutylece terephthalate dimer impurities in a PBT plastic. The chemical structural formula of the cyclicpolybutylece terephthalate dimer is described in the specification.
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Paragraph 0049; 0050; 0051
(2017/07/01)
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- NOVEL SINGLE STEP ESTERIFICATION PROCESS OF ALDEHYDES USING A HETEROGENEOUS CATALYST
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The present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using a heterogeneous catalyst with high yields. More particularly, the present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using Titanium superoxide with greater than 80% yields.
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Page/Page column 9; 14
(2016/06/20)
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- Polybutylene terephthalate cyclic trimerization preparation of (by machine translation)
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The invention specifically has described a kind of new cyclic trimeric butylene terephthalate (Cyclic PBT Dimer) method for preparing, in the terephthalic chloride and 1, the 4 the protecting [...] butanediol as raw material with oriented synthesis strategy of deprotection of the polybutylene terephthalate cyclic trimerization, in the plastics can be used for the PBT polybutylene terephthalate cyclic trimerization contrast analysis of the impurity with the detection. Said product of this invention the chemical structural formula is: (by machine translation)
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Paragraph 0034; 0035; 0036
(2018/01/19)
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- Mirror symmetry breaking in cubic phases and isotropic liquids driven by hydrogen bonding
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Achiral supramolecular hydrogen bonded complexes between rod-like 4-(4-alkoxyphenylazo)pyridines and a taper shaped 4-substituted benzoic acid form achiral (Ia3d) and chiral “Im3m-type” bicontinuous cubic (I432) phases and a chiral isotropic liquid mesophase (Iso1[*]). The chiral phases, resulting from spontaneous mirror symmetry breaking, represent conglomerates of macroscopic chiral domains eventually leading to uniform chirality.
- Alaasar, Mohamed,Poppe, Silvio,Dong, Qingshu,Liu, Feng,Tschierske, Carsten
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supporting information
p. 13869 - 13872
(2016/12/06)
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- Titanium superoxide-a stable recyclable heterogeneous catalyst for oxidative esterification of aldehydes with alkylarenes or alcohols using TBHP as an oxidant
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Titanium superoxide efficiently catalysed the oxidative esterification of aldehydes with alkylarenes or alcohols, under truly heterogeneous conditions, to afford the corresponding benzyl and alkyl esters in excellent yields. Mechanistic studies have established that this "one pot" direct oxidative esterification process proceeds through a radical pathway, proven by a FTIR spectral study of a titanium superoxide-aldehyde complex as well as spin trapping experiments with TEMPO. The intramolecular version of this protocol has been successfully demonstrated in the concise synthesis of 3-butylphthalide, an anti-convulsant drug.
- Dey, Soumen,Gadakh, Sunita K.,Sudalai
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p. 10631 - 10640
(2015/11/17)
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- Electrogenerated N-heterocyclic carbene in ionic liquid: An insight into the mechanism of the oxidative esterification of aromatic aldehydes
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An N-heterocyclic carbene (NHC), generated by cathodic reduction of BMIm BF4, mediates the oxidative esterification of aromatic aldehydes with organic bromides in the corresponding ionic liquid as solvent. The product recovery by simple extractive work-up with diethyl ether allowed the ionic liquid to be recycled up to 9 times for subsequent electrolyses, with no significant loss in the product yield. The isolation of an intermediate, whose structure was confirmed by synthesis and transformation into the ester, provided the key for a mechanistic insight into the reaction.
- Forte, Gianpiero,Chiarotto, Isabella,Inesi, Achille,Loreto, Maria Antonietta,Feroci, Marta
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p. 1773 - 1781
(2014/06/09)
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- In situ generated "lanthanum(iii) nitrate alkoxide" as a highly active and nearly neutral transesterification catalyst
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In situ generated lanthanum(iii) nitrate alkoxide is a highly active and nearly neutral transesterification catalyst, which can promote non-epimerized transesterification of α-substituted chiral carboxylic esters under reflux conditions.
- Hatano, Manabu,Kamiya, Sho,Ishihara, Kazuaki
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supporting information
p. 9465 - 9467
(2012/10/29)
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- Synthesis of benzoic acids and polybenzamides containing tertiary alkylamino functionality
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The high-yielding and easily scalable synthesis of a number of benzoic acids bearing a tertiary alkylamino functionality has been achieved. The flexible synthesis began from readily available aminobenzoic acids or terephthaloyl chloride and requires almost no chromatography. Coupling of the synthesised amino acids to a range of substituted anilines was achieved when utilizing a specific combination of DIC, HOBt and DMAP.
- Khan, Gul Shahzada,Dickson, Benjamin D.,Barker, David
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experimental part
p. 1790 - 1801
(2012/03/11)
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- Ionic liquids as solvent for efficient esterification of carboxylic acids with alkyl halides
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The selective esterification of carboxylic acid derivatives with a variety of alkyl halides was carried out using ionic liquid as solvent in the presence of triethylamine. The reaction was found to proceed under relatively mild conditions with excellent conversions (up to 99%) and selectivities. The ionic liquid was recycled and reused. TUeBITAK.
- Goek, Yetkin,Alici, Buelent,Cetinkaya, Enginc,OeZdemir, Ismail,Oezeroglu, Ozlem
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experimental part
p. 187 - 191
(2010/09/11)
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- HYDRAULIC FLUID AND HYDRAULIC SYSTEM
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A hydraulic fluid of the present invention contains, as a base oil, an ester having two or more ring structures, the two or more ring structures being at least one selected from an aromatic ring and a saturated naphthenic ring. Particularly, the hydraulic fluid contains an ester having two or more aromatic rings as the base oil. The hydraulic fluid has low energy loss due to compression and exhibits excellent responsiveness when being used in a hydraulic circuit. Consequently, the hydraulic fluid realizes energy-saving, high-speed operation and high precision of control in the hydraulic circuit.
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- SYNTHESIS AND LIQUID-CRYSTALLINE PROPERTIES OF NEW CHIRAL POLYESTERS WITH AROMATIC TRIAD MESOGEN AND SPACER OF DIFFERENT OPTICAL PURITY
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A series of new chiral liquid-crystalline polyesters 1-x, comprising a terephthalate-methylhydroquinone-terephthalate mesogen and an (R)-3-methyl-1,6-hexanediyl spacer segment of varying optical purity, x (0, 20, 50, 70, or 95percent) has been prepared and studied with respect to the thermotropic properties.The polyesters were synthesized by direct polycondensation of a diacid and a diphenol in pyridine solution at 120 deg C in the presence of p-tosyl chloride as a condensing agent and dimethylformamide as an activator.High molecular weights (Mw = 61,000-73,000, by SEC) and narrow molecular weight distributions (Mw/Mn = 1.1-2.4) were obtained for all of the polyesters.Depending on the optical purity of the spacer, a nematic or a chiral nematic mesophase was formed that extended over a very broad range between the glass and the isotropization temperatures (Tg-Ti >= 179 deg C).X-Ray diffraction patterns proved the chiral mesophase to remain frozen-in in the glassy state.Polyesters 1-x appear to be suitable candidates for electro-optical investigations in the unwound chiral nematic mesophase.
- Farah, Abdiaziz Ali,Galli, Giancarlo,Chiellini, Emo,Gallot, Bernard
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p. 279 - 284
(2007/10/02)
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- Tetralin esters of phenols or benzoic acids having retinoid like activity
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Retinoid-like activity is exhibited by compounds of the formula STR1 where the R groups are independently hydrogen, or lower alkyl; A is --C(O)O--, --OC(O)--, --C(O)S--, or --SC(O)--; n is 0-5; and Z is H, --COB where B is --OH or a pharmaceutically acceptable salt, or B is --OR 1 where R 1 is an ester-forming group, or B is --N(R) 2 where R is hydrogen or lower alkyl, or Z is --OE where E is hydrogen or an ether-forming group or --COR 2 where R 2 is hydrogen, lower alkyl, phenyl or lower alkyl phenyl, or Z is --CHO or an acetal derivative thereof, or Z is --COR 3 where R 3 is --(CH 2) m CH 3 where m is 0-4 and the sum of n and m does not exceed 4.
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- Optically active substance and liquid crystal composition comprising same
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Disclosed is an optically active substance represented by the formula: STR1 wherein m is an integer of 1 to 14, Y is STR2 R is --Cn H2n+1, --OCn H2n+1, --OCOCn H2n+1 or --COOCn H2n+1 (in which n is an integer of 1 to 18), each of the asterisked carbon atoms is an asymmetric carbon atom, X a single bond, --CO2 --, or --OCO--, and A1 and A2 is hydrogen, fluorine, chlorine, bromine, cyano or methoxy.
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- Thiochroman esters of phenols and terephthallates having retinoid-like activity
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Compounds of formula I STR1 in which: the R groups are independently hydrogen or lower alkyl; one of A and B is O or S and the other is --C(O)--, A being attached to the thiochroman ring at the 6 or 7-position; n is 0-5; and Z is H, an acid or acid derivative, an alcohol or alcohol derivative, acetal or acetal derivative or ketone or ketone derivative, or a pharmaceutically acceptable salt, have retinoid-like activity.
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- Optically active compound having XI-valerolactone ring and liquid crystal composition comprising same
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An optically active compound having a δ-valerolactone ring which is a ferroelectric liquid crystal and is represented by the following general formula (I): STR1 wherein m is an integer of from 1 to 8, Z is a group represented by the following formula: STR2 in which each of l and k is a number of 1 or 2 and l and k satisfy the requirement of 2≤(l+k)≤3, X stands for a direct bond, STR3 Y stands for STR4 and A1 and A2 independently stand for --H, --F or --Cl, STR5 R stands for STR6 in which n is an integer of from 1 to 18, and * indicates the asymmetric carbon atom.
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- Thiochroman esters of phenols and terephthallates having retinoid-like activity
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Compounds of formula I STR1 in which: the R groups are independently hydrogen or lower alkyl; one of A and B is O or S and the other is --C(O)--, A being attached to the thiochroman ring at the 6 or 7-position;n is 0-5; andZ is H, an acid or acid derivative, an alcohol or alcohol derivative, acetal or acetal derivative or ketone or ketone derivative, or a pharmaceutically acceptable salt, have retinoid-like activity.
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- Molecular structure and smectic properties. Part 1. The effect of linkages on smectic A thermal stability in three aromatic ring compounds linked by ester groups
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The thermal properties of phenyl 4-(4-alkoxybenzoyloxy)benzoates (1), 4-alkoxyphenyl 4-benzoyloxybenzoates (2), 4-(4-alkoxybenzoyloxy) benzoyloxyxylenes (3), and phenyl 4-(4-alkoxyphenoxycarbonyl)benzoates (4) have been examined. In spite of the structural similarity, the smectic nature of the series is quite different. Series (1) shows a stable smectic A phase starting with the hexyloxy homologue. Series (2) and (3) do not show any smectic phases, and the potential smectic stabilities evaluated from the binary phase diagrams are quite low. Although series (4) shows no smectic phase because of higher melting points, this series intrinsically possesses a smectic A nature, where the potential smectic A - nematic transition temperatures are as high as those of series (1). The difference in the smectic nature for these four series is discussed in terms of the geometrical and electrocstatic properties of the molecules, and a new basis for the thermal stability of the smectic A phase has been proposes.
- Sakurai, Yoshiaki,Takenaka, Shunsuke,Miyake, Hajime,Morita, Hidefumi,Ikemoto, Tetsuya
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p. 1199 - 1204
(2007/10/02)
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- Thermal and X-Ray Diffraction Studies of Some Liquid Crystals Having a Nitro Group at the Lateral Position
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3-Nitrophenyl 4-(4-octyloxy- and 4-(4-nonyloxybenzoyloxy)-benzoates (compound 1), 4-(4-octyloxyphenoxycarbonyl)phenyl 3-nitrobenzoate (compound 2), 4-(4-octyloxy- and 4-(4-decyloxybenzoyloxy)phenyl 3-nitrobenzoates (compound 3), and 3-nitrophenyl 4-(4-octyloxy- and 4-(4-nonyloxyphenoxycarbonyl)benzoates (compound 4) have been prepared.All the compounds show smectic A and nematic phases, where the molecular arrangement in the smectic A phase is dependent on the orientation of the ester linkages.The smectic A phase for compounds 1 and 3 has a monolayer rearrangement of the molecules, while the smectic A phase for compound 3 also involves a small contribution of a partially bilayer nature near the smectic A-nematic transition.The smectic A phase for compound 2 has a bilayer arrangement, and compounds 4 probably the bilayer one.A dipole correlation within the smectic A phases has been discussed. - Keywords: polar liquid crystals; smectic A modification; x-ray diffraction; lateral substituent effect.
- Takenaka, S.,Sakurai, Y.,Takeda, H.,Kusabayashi, S.,Sugiura, H.,Morita, H.
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