- Novel Synthesis of Carbamic Ester from Carbon Dioxide, Amine, and Ortho Ester
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Carbon dioxide reacted with aliphatic amines and ortho esters to form carbamic esters in good yields.The influence of different ortho esters on the carbamate synthetic reaction is described.In the case of orthocarbonates, carbamic esters were obtained in high yields.The reaction of carbon dioxide, amines, and ortho esters may involve a competitive reaction between the esterification of carbamic acid produced by a reaction of carbon dioxide with amine, and the alkylation of amine.
- Ishii, Shideru,Nakayama, Hidenobu,Yoshida, Yasuhiko,Yamashita, Tadataka
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- Mild Hydrogenation of Amides to Amines over a Platinum-Vanadium Bimetallic Catalyst
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Hydrogenation of amides to amines is an important reaction, but the need for high temperatures and H2 pressures is a problem. Catalysts that are effective under mild reaction conditions, that is, lower than 30 bar H2 and 70 °C, have not yet been reported. Here, the mild hydrogenation of amides was achieved for the first time by using a Pt-V bimetallic catalyst. Amide hydrogenation, at either 1 bar H2 at 70 °C or 5 bar H2 at room temperature was achieved using the bimetallic catalyst. The mild reaction conditions enable highly selective hydrogenation of various amides to the corresponding amines, while inhibiting arene hydrogenation. Catalyst characterization showed that the origin of the catalytic activity for the bimetallic catalyst is the oxophilic V-decorated Pt nanoparticles, which are 2 nm in diameter.
- Mitsudome, Takato,Miyagawa, Kazuya,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Yamasaki, Jun,Kitagawa, Yasutaka,Kaneda, Kiyotomi
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- The Me3Si Substituent Effect on the Reactivity of Silanes. Structural Correlations between Silyl Radicals and Their Parent Silanes
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Good linear correlations exist both between the bond dissociation energy of an Si-H bond and the corresponding SiH stretching frequency and between the (29)Si hyperfine splitting of a silicon-centered radical and J((29)Si-H) for the corresponding silane, when the successive substitution at the Si-H function takes place inside a family, i.e., (Me3Si)3-nSi(H)Men, n = 0-3.Explanations for these phenomena are advanced.Such structural correlations allow the characterization of (Me3Si)2Si(H)Me as a radical-based reducing agent with low hydrogen-donating abilities.Rate constants for the reaction of primary alkyl radicals with (Me3Si)2Si(H)Me have been measured over a range of temperatures by using competing unimolecular radical reactions as timing devices.The radical trapping abilities of this silane and other common radical-based reducing agents are compared.
- Chatgilialoglu, C.,Guerrini, A.,Lucarini, M.
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- Leishmanicidal potential of N-substituted morpholine derivatives: Synthesis and structure-activity relationships
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A series of N-substituted morpholines 2-20 was synthesised by reacting various acid chlorides and alkyl halides with morpholine (1). All of the synthesised compounds 2-20 were screened for their leishmanicidal effects using amphotericin B (IC50 = 0.24 μg L-1) and pentamidine (IC50 = 2.56 μg mL-1) as standards and a structure-activity relationship (SAR) study was established. The compounds 2 (IC50 = 48 μg mL-1), 3 (IC50 = 30.0 μg mL-1), 10 (IC50 = 41.0 μg mL-1), 15 (IC50 = 33.0 μg mL-1), 16 (IC50 = 35.0 μg mL-1) and 20 (IC50 = 47.0 μg mL-1) showed weak leishmanicidal activities.
- Khan, Khalid Mohammed,Khan, Muhammad Zarrar,Taha, Muhammad,Maharvi, Ghulam Murtaza,Saify, Zafar Saeed,Parveen, Shahnaz,Choudhary, Muhammad Iqbal
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- Selective Synthesis of Secondary and Tertiary Amines by Reductive N-Alkylation of Nitriles and N-Alkylation of Amines and Ammonium Formate Catalyzed by Ruthenium Complex
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A new ruthenium catalytic system for the syntheses of secondary and tertiary amines via reductive N-alkylation of nitriles and N-alkylation of primary amines is proposed. Isomeric complexes 8 catalyze transfer hydrogenation and N-alkylation of nitriles in ethanol to give secondary amines. Unsymmetrical secondary amines can be produced by N-alkylation of primary amines with alcohols via the borrowing hydrogen methodology. Aliphatic amines were obtained with excellent yields, while only moderate conversions were observed for anilines. Based on kinetic and mechanistic studies, it is suggested that the rate determining step is the hydrogenation of intermediate imine to amine. Finally, ammonium formate was applied as the amination reagent for alcohols in the presence of ruthenium catalyst 8. Secondary amines were obtained from primary alcohols within 24 hours at 100 °C, and tertiary amines can be produced after prolonged heating. Secondary alcohols can only be converted to secondary amines with moderate yield. Based on mechanistic studies, the process is suggested to proceed through an ammonium alkoxy carbonate intermediate, where carbonate acts as an efficient leaving group.
- Alshakova, Iryna D.,Nikonov, Georgii I.
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- In situ DRIFTS study on the synthesis of N-alkylmorpholines
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In situ diffuse reflectance Fourier-transform infrared spectroscopy was used to perform mechanistic investigation on the synthesis of N-alkylmorpholines from diethylene glycol (DEG), alcohol and ammonia. The results showed that the synthesis of N-alkylmorpholines on a heterogeneous catalyst proceeded along the reaction path between DEG and alkylamine when choosing CuO-NiO/γ-Al 2O3 as a suitable catalyst. In addition, the yield of methylmorpholine and ethylmorpholine was 86.4 and 76.6 %, respectively.
- Luo, Chenxi,Luo, Hu,Qian, Chao,Chen, Yunbin,Feng, Lie,Chen, Xinzhi
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- SYNTHESIS OF NITROGEN-CONTAINING HETEROCYCLES OF AN IRON CATALYST. 2. THE CONVERSIONS OF 1,4-BUTANEDIOL AND DIETHYLENEGLYCOL IN THE PRESENCE OF AMMONIA AND HYDROGEN
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The gas-phase interaction of 1,4-butanediol and diethylene glycol with ammonia and/or hydrogen on a reduced, fused, iron catalyst has been investigated.
- Kliger, G. A.,Lesik, O. A.,Marchevskaya, E. V.,Mikaya, A. I.,Zaikin, V. G.,et al.
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- Mild N-Alkylation of Amines with Alcohols Catalyzed by the Acetate Ru(OAc)2(CO)(DiPPF) Complex
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The acetate complex Ru(OAc)2(DiPPF) (2) obtained from Ru(OAc)2(PPh3)2 (1) and 1,1′-bis(diisopropylphosphino)ferrocene (DiPPF) reacts cleanly with formaldehyde affording Ru(OAc)2(CO)(DiPPF) (3) in high yield. The monocarbonyl complex 3 (0.4-2 mol %) efficiently catalyzes the N-alkylation of primary and secondary alkyl and aromatic amines using primary alcohols ROH (R=Et, nPr, nBu, PhCH2) under mild reaction conditions (30–100 °C) with an alcohol/amine molar ratio of 10-100. Formation of the monohydride RuH(OAc)(CO)(DiPPF) (4) has been observed by reaction of 3 with iPrOH in the presence of NEt3 at RT through an equilibrium reaction.
- Figliolia, Rosario,Baldino, Salvatore,Nedden, Hans G.,Zanotti-Gerosa, Antonio,Baratta, Walter
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- Hydrogenation of amides by the use of bimetallic catalysts consisting of group 8 to 10, and group 6 or 7 metals
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Hydrogenation of amides can be catalyzed by bimetallic systems, which consist of Group 8 to 10 late transition-metals and Group 6 or 7 early transition-metals, under the mild conditions to afford the corresponding amines selectively in good to excellent yields.
- Hirosawa, Chitaru,Wakasa, Noriko,Fuchikami, Takamasa
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- Ionic liquid/H2O-mediated synthesis of mesoporous organic polymers and their application in methylation of amines
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Mesoporous Tr?ger's base-functionalized polymers (Meso-TBPs) were prepared using a sulfonic acid group functionalized ionic liquid/H2O system, with surface areas up to 431 m2 g-1 and pore sizes of 3-15 nm. Ir(ii) coordinated Meso-TBPs exhibited extraordinary catalytic performance in the N-methylation of amines using methanol.
- Yu, Xiaoxiao,Yang, Zhenzhen,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liiu, Zhenghui,Ji, Guipeng,Liu, Zhimin
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- Intermolecular rhodium-catalysed hydroamination of non-activated olefins: Effect of olefin, amine, phosphine and phosphonium salt
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The catalytic system RhCl3·3H2O/2P(p-CH3C6H4)3/65nBu4PI/2I2, which was discovered recently in our research group, allows the highest catalytic activity ever reported for the intermolecular hydroamination of ethylene, 1-butene, and 1-hexene with aniline-type amines (0.3 mol% catalytic precursor) to give the expected N-alkyl- (N-ethyl-, 1) and N,N-dialkyl-anilines (N,N-diethyl-, 2) along with 2-methyl quinolines (3; in the case of ethylene). The effects of time and temperature, as well as the nature of the phosphonium salt, phosphine, and amine on the catalytic activity of this reaction have been studied. This system is particularly efficient for the hydroamination of ethylene with aniline in the presence of 2,2′-bis(diphenylphosphino)- 1,1′-binaphthyl (CE=460) and tri(p-tolyl)phosphine (CE= 520). Good to excellent activities were also found by combining Wilkinson′s catalysts (RhI complexes) with nBu4PI and I2. The simple association of PPh3 and I2 has been shown to be a very efficient "in-situ generated" source of I- promoters. CE (catalytic efficiency)=TON1+2TON2+2TON3.
- Rodriguez-Zubiri, Mireia,Baudequin, Christine,Bethegnies, Aurelien,Brunet, Jean-Jacques
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- Transition-metal complex-catalyzed reduction of amides with hydrosilanes: A facile transformation of amides to amines
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The reaction of amides with hydrosilanes is catalyzed by a variety of transition-metal complexes in the presence or absence of halides and amines as co-catalysts to afford the corresponding amines in good yields.
- Igarashi, Mamoru,Fuchikami, Takamasa
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- Electroactivated alkylation of amines with alcohols: Via both direct and indirect borrowing hydrogen mechanisms
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A green, efficient N-alkylation of amines with simple alcohols has been achieved in aqueous solution via an electrochemical version of the so-called "borrowing hydrogen methodology". Catalyzed by Ru on activated carbon cloth (Ru/ACC), the reaction works well with methanol, and with primary and secondary alcohols. Alkylation can be accomplished by either of two different electrocatalytic processes: (1) in an undivided cell, alcohol (present in excess) is oxidized at the Ru/ACC anode; the aldehyde or ketone product condenses with the amine; and the resulting imine is reduced at an ACC cathode, combining with protons released by the oxidation. This process consumes stoichiometric quantities of current. (2) In a membrane-divided cell, the current-activated Ru/ACC cathode effects direct C-H activation of the alcohol; the resulting carbonyl species, either free or still surface-adsorbed, condenses with amine to form imine and is reduced as in (1). These alcohol activation processes can alkylate primary and secondary aliphatic amines, as well as ammonia itself at 25-70 °C and ambient pressure.
- Appiagyei, Benjamin,Bhatia, Souful,Keeney, Gabriela L.,Dolmetsch, Troy,Jackson, James E.
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supporting information
p. 860 - 869
(2020/02/21)
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- Mild catalytic deoxygenation of amides promoted by thorium metallocene
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The organoactinide-catalyzed (Cp*2ThMe2) hydroborated reduction of a wide range of tertiary, secondary, and primary amides to the corresponding amines/amine-borane adductsviadeoxygenation of the amides is reported herein. The catalytic reactions proceed under mild conditions with low catalyst loading and pinacolborane (HBpin) concentration in a selective fashion. Cp*2ThMe2is capable of efficiently catalysing the gram-scale reaction without a drop in efficiency. The amine-borane adducts are successfully converted into free amine products in high conversions, which increases the usefulness of this catalytic system. A plausible mechanism is proposed based on detailed kinetics, stoichiometric, and deuterium labeling studies.
- Eisen, Moris S.,Saha, Sayantani
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supporting information
p. 12835 - 12841
(2020/10/05)
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- Deoxygenation of tertiary amine N-oxides under metal free condition using phenylboronic acid
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A simple and efficient method for the deoxygenation of amine N-oxides to corresponding amines is reported using the green and economical reagent phenylboronic acid. Deoxygenation of N,N-dialkylaniline N-oxides, trialkylamine N-oxides and pyridine N-oxides were achieved in good to excellent yields. The reduction susceptible functional groups such as ketone, amide, ester and nitro groups are well tolerated with phenylboronic acid during the deoxygenation process even at high temperature. In addition, an indirect method for identification and quantification of tert-amine N-oxide is demonstrated using UV–Vis spectrometry which may be useful for drug metabolism studies.
- Gupta, Surabhi,Sureshbabu, Popuri,Singh, Adesh Kumar,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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supporting information
p. 909 - 913
(2017/02/15)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 14848 - 14859
(2017/10/27)
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- Ruthenium-catalyzed N-alkylation of amines with alcohols under mild conditions using the borrowing hydrogen methodology
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Using a simple amino amide ligand, ruthenium-catalyzed one-pot alkylation of primary and secondary amines with simple alcohols was carried out under a wide range of conditions. Using the alcohol as solvent, alkylation was achieved under mild conditions, even as low as room temperature. Reactions occurred with high conversion and selectivity in many cases. Reactions can also be carried out at high temperatures in organic solvent with high selectivity using stoichiometric amounts of the alcohol.
- Enyong, Arrey B.,Moasser, Bahram
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p. 7553 - 7563
(2014/09/17)
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- Catalytic hydrogenation of amides to amines under mild conditions
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Under (not so much) pressure: A general method for the hydrogenation of tertiary and secondary amides to amines with excellent selectivity using a bimetallic Pd-Re catalyst has been developed. The reaction proceeds under low pressure and comparatively low temperature. This method provides organic chemists with a simple and reliable tool for the synthesis of amines. Copyright
- Stein, Mario,Breit, Bernhard
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supporting information
p. 2231 - 2234
(2013/03/28)
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- Selective N-alkylation of amines using nitriles under hydrogenation conditions: Facile synthesis of secondary and tertiary amines
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Nitriles were found to be highly effective alkylating reagents for the selective N-alkylation of amines under catalytic hydrogenation conditions. For the aromatic primary amines, the corresponding secondary amines were selectively obtained under Pd/C-catalyzed hydrogenation conditions. Although the use of electron poor aromatic amines or bulky nitriles showed a lower reactivity toward the reductive alkylation, the addition of NH4OAc enhanced the reactivity to give secondary aromatic amines in good to excellent yields. Under the same reaction conditions, aromatic nitro compounds instead of the aromatic primary amines could be directly transformed into secondary amines via a domino reaction involving the one-pot hydrogenation of the nitro group and the reductive alkylation of the amines. While aliphatic amines were effectively converted to the corresponding tertiary amines under Pd/C-catalyzed conditions, Rh/C was a highly effective catalyst for the N-monoalkylation of aliphatic primary amines without over-alkylation to the tertiary amines. Furthermore, the combination of the Rh/C-catalyzed N-monoalkylation of the aliphatic primary amines and additional Pd/C-catalyzed alkylation of the resulting secondary aliphatic amines could selectively prepare aliphatic tertiary amines possessing three different alkyl groups. According to the mechanistic studies, it seems reasonable to conclude that nitriles were reduced to aldimines before the nucleophilic attack of the amine during the first step of the reaction.
- Ikawa, Takashi,Fujita, Yuki,Mizusaki, Tomoteru,Betsuin, Sae,Takamatsu, Haruki,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
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supporting information; experimental part
p. 293 - 304
(2012/02/01)
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- A novel method for N-alkylation of aliphatic amines with ethers over ?3-Al2O3
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A novel and simple method for the N-alkylation of amines with different ethers as alkylating reagents has been developed, using cheap ?3-Al2O3 as the catalyst at atmospheric pressure in the temperature range of 260-320?°C. For example, the reaction of equ
- Chen, Hangeng,Zhang, Tao,Qian, Chao,Chen, Xinzhi
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p. 537 - 540
(2015/03/05)
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- METHOD FOR THE CONTINUOUS SEPARATION OF MIXTURES COMPRISING MORPHOLINE (MO), MONOAMINODIGLYCOL (ADG), AMMONIA AND WATER BY MEANS OF DISTILLATION
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Processes for the continuous fractional distillation of a mixture comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water from a reaction of diethylene glycol (DEG) with ammonia, the process comprising: (i) separating off ammonia from the mixture at a top of a first distillation column K10; (ii) feeding a bottom fraction from K10 to a second distillation column K20 in which water and organic products are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.1 to 15 bar, (iii) feeding a bottom fraction from K20 to a third distillation column K30, wherein the column K30 is a dividing wall column (DWC) which preferably has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region (1), a lower combined column region (6), an inflow part (2, 4) having an enrichment section (2) and a stripping section (4), and also an offtake part (3, 5) having an enrichment section (3) and a stripping section (5), with the bottoms from K20 being fed in in the upper or middle third of the inflow part (2, 4), based on the number of theoretical plates of the inflow part, ADG and organic products having a boiling point of >190° C. (1.013 bar) being discharged at the bottom, organic products having a boiling point of ≦128° C. (1.013 bar) being discharged at the top and MO being discharged from the middle or lower third of the offtake part (3, 5) (side offtake), based on the number of theoretical plates of the offtake part.
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Page/Page column 5-6
(2010/04/30)
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- NOVEL REMEDIES FOR ALLERGIC DISEASES
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Disclosed are anti-inflammatory agents, antiallergic agents, particularly prophylactically and/or therapeutically effective drugs for type I and/or IV allergic conditions, and further pharmaceutical drugs for prophylactically and/or therapeutically treating bronchial asthma, atopic diseases, etc. The inventive drugs comprising a prophylactically and/or therapeutically effective amount of a hydroxamic acid derivative are active in the prophylaxis and/or therapy of allergy, especially type I and/or IV allergy, etc. The drugs are active in prophylactically and/or therapeutically treating inflammation, rhinitis, conjunctivitis, bronchial asthma, atopic diseases (including dermatitis, enteritis, etc.), or allergic gastroenterocolitis (allergic inflammation in digestive tract). The application of such drugs leads to (A) reduction of cells (such as lymphocytes, neutrophils, mast cells, eosinophils, basophils, macrophages and monocytes) at a diseased site, and/or (B) alleviation of inflammatory symptoms caused by migration, infiltration or accumulation of cells (such as lymphocytes, neutrophils, mast cells, eosinophils, basophils, macrophages and monocytes) to (or at) the diseased site, (C) inhibition of pathophysiological functions in cells (such as lymphocytes, neutrophils, mast cells, eosinophils, basophils, macrophages, monocytes, Langerhans cell and dendritic cells), and/or (D) reducing the blood level or inhibiting the production, of antibodies, especially IgE. Accordingly, the drugs are useful in the prophylaxis and/or therapy of diseases, disorders or ill conditions at the site.
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- A Study on the Reducing Abilities of Tris(alkylthio)silanes
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Tris(methylthio)silane and tris(isopropylthio)silane effectively reduce a variety of organic substrates via free radical mechanisms.These silanes can also be used as hydrosilylating agents for alkenes having electron-donating substituents.The bond dissociation energy of the Si-H bonds have been measured by photoacoustic calorimetry and found to be around 83 kcal mol-1.The absolute rate constants for the reaction of the tert-butoxyl radical with (RS)3SiH have been measured by a laser flash photolysis technique and the optical absorption spectra of the correspondingradicals have been obtained.Multiple scattering Xα calculations showed that the dominant absorption detected in the UV-vis region was due to ?Si-S(e) -> SOMO and SOMO -> ?*Si-S(e) transitions.
- Chatgilialoglu, C.,Guerra, M.,Guerrini, A.,Seconi, G.,Clark, K. B.,et al.
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p. 2427 - 2433
(2007/10/02)
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- Tris(trimethylsilyl)silane as a Radical-Based Reducing Agent in Synthesis
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Tris(trimethylsilyl)silane is an effective reducing agent for organic halides, selenides, xanthates, and isocyanides, as well as an effective hydrosilylating agent for dialkyl ketones and alkenes.The silane functions as a mediator in the formation of intermolecular carbon-carbon bonds via radicals and allows a variety of organic substrates to be used as alkyl radical precursors.Absolute rate constants for the reaction of (Me3Si)3Si* radicals with a variety of organic compounds have been measured in solution by laser flash photolysis.At 294 K rate constants are >5 x 107 M-1 s-1 for C=C double bonds that are activated by neighboring ?-electron systems or by electron-withdrawing groups.For other substrates, reactivities decreased in the order xanthate > selenide > isocyanide > nitro > sulfide.
- Ballestri, M.,Chatgilialoglu, C.,Clark, K. B.,Griller, D.,Giese, B.,Kopping, B.
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p. 678 - 683
(2007/10/02)
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- BENZOTRIAZOLE-ASSISTED SYNTHESIS OF ENAMINES
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A new, facile preparation of enamines was achieved via a two-step sequence: (i) the ready formation of an N-(α-aminoalkyl)benzotriazole derivative from equimolar amounts of benzotriazole, an aldehyde, and a secondary amine, (ii) the elimination of benzotriazole from the derivative by sodium hydride in tetrahydrofuran (THF).The method provides enamines in good yields based on the quantity of amine used.
- Katritzky, Alan R.,Long, Qiu-He,Lue, Ping,Jozwiak, Andrzej
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p. 8153 - 8160
(2007/10/02)
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- Synthesis of hGRF (somatocrinin) in liquid phase and intermediate peptides
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A process for the synthesis, in liquid phase and by fragments, of hGRF 1-44 and hGRF 1-40. This process consists in coupling, one after the other and in the order of the sequence of the GRF, (1) on the one hand, the following fragments: ______________________________________H--Ala--Arg--Ala--Arg--Leu--NH2 called hGRF Frag- (40-44) or ment A alaninamide (40)H--Gln--Glu--Arg--Gly--OH called hGRF Frag- (36-39) ment B'1H--Glu--Ser--Asn--OH called hGRF Frag- (33-35) ment B'2H--Ser--Arg--Gln--Gln--Gly--OH called hGRF Frag- (28-32) ment CH--Leu--Gln--Asp--Ile--Met--OH called hGRF Frag- (23-27) ment D'H--Arg--Lys--Leu--OH called hGRF Frag- (20-22) ment E'1______________________________________ to obtain the peptide K1 [(hGRF (20-44)] on the corresponding peptide having the sequence (20-40) and (2) on the other hand, the following fragments:______________________________________H--Gln--Leu--Ser--Ala called hGRF Frag- (16-19) ment F1H--Tyr--Arg--Lys--Val--Leu--Gly OH called hGRF Frag- (10-15) ment G1H--Ile--Phe--Thr--Asn--Ser--OH called hGRF Frag- (5-9) ment H1______________________________________ to obtain the peptide J [hGRF (5-19)] and thereafter to couple together the peptides J and K1 in order to form the peptide having the sequence hGRF (5-44) or hGRF (5-40) and finally to couple the resulting peptide with the peptide H-Tyr-Ala-Asp-Ala-H, called fragment I hGRF (1-4).
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- Synthesis of hpGRF (Somatocrinin) in liquid phase and intermediate peptides
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The invention relates to synthesis of hpGRF (Somatocrinin) in liquid phase and to intermediate peptides, comprising:--coupling, one after the other and in the order of the sequence of the GRF, the fragments in which: (a) the side acid functions of the aspartic and glutamic acids and the side amine function of the lysine are protected by protector groups stable in the conditions of deprotection of the group Boc, (b) the guanidine function of the arginine is protected by protonation, and (c) the N-terminal amino acid is protected on the amine by the Boc group;--selectively eliminating the group Boc from the N-terminal amine of the peptide in phase of elongation by hydrolysis with trifluoroacetic acid, said coupling being effected in an aprotic polar solvent and--eliminating, at the end of sequence, all the protector groups by hydrolysis with the aid of a 0.1 to 1M solution of methanesulfonic or trifluoromethanesulfonic acid in trifluoroacetic acid.
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- Derivatives of leukotrienes A and C
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The present invention provides novel derivatives of leukotrienes A and C which are useful in inhibiting the smooth muscle contracting effects of SRS-A; inhibiting platelet aggregation; and inhibiting the biosynthesis of thromboxane A2.
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- SODIUM HYDROGEN TELLURIDE AS A USEFUL NUCLEOPHILIC REAGENT FOR THE CLEAVAGE OF EPOXIDES AND OF QUATERNARY AMMONIUM SALTS
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Sodium hydrogen telluride opens many epoxides cleanly by an SN2 process to give telluro-alcohols, which by reduction with nickel boride afford alcohols.An intermediate telluro-alcohol was converted to olefin in high yield by treatment with p-toluene-sulphonyl chloride in pyridine.Quaternary ammonium salts are also cleaved efficiently by sodium hydrogen telluride.
- Barton, Derek H. R.,Fekih, Abdelwaheb,Lusinchi, Xavier
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p. 6197 - 6200
(2007/10/02)
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- 19-Hydroxy-PGI2 compounds
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Prostacyclin and prostacyclin-type derivatives having a 19-hydroxy feature are disclosed, including processes for preparing them and the appropriate intermediates. The compounds are useful for pharmacological purposes such as inhibition of blood platelate aggregation.
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- 2-Decarboxy-2-hydroxymethyl-19-hydroxy-PG1 analogs
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Prostaglandin derivatives having a 19,20-didehydro, a 19-hydroxy, or a 19-keto feature are disclosed, including processes for preparing them and the appropriate intermediates. A typical 19-hydroxy compound of this invention is 19-hydroxy-19-methyl-PGF2α, methyl ester, represented by the formula STR1
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