- Are diazides really dangerous compounds under ordinary conditions?
-
An investigation into the stability of three commonly used diazides (1,3-diazido-propane, 1,3-diazido-propan-2-ol, and 1,3-diazido-propanone) was performed. Despite their use in synthesis, no previous investigation of their thermal stability has been repo
- Farias, Ravir R.,Mascarenhas, Artur J.S.,Santos, Tatiane de J.,Victor, Mauricio M.
-
-
Read Online
- Synthesis, radiolabeling, and evaluation of a potent β-site APP cleaving enzyme (BACE1) inhibitor for PET imaging of BACE1 in vivo
-
The β-site APP-cleaving enzyme 1 (BACE1) plays important roles in the proteolytic processing of amyloid precursor protein, and can be regarded as an important target for the diagnosis and treatment of AD. This study aimed to report the synthesis and evaluation of an 18F-labeled 2-amino-3,4-dihydroquinazoline analog as a potential BACE1 radioligand. A fluoropropyl side chain was introduced to the phenyl of this 3,4-dihydroquinazoline scaffold to generate the radioligand. Our preliminary data indicated that although the 2-amino-3,4-dihydroquinazoline scaffold possessed favorable in-vitro properties as a PET ligand, its poor brain uptake hindered the in-vivo imaging of BACE1. Further investigation would be required to optimize the scaffold for the development of a blood-brain-barrier-permeable BACE1-targeted PET ligand.
- Cai, Huawei,He, Qian,Li, Yunchun,Pan, Lili,Wang, Yuxi,Wu, Xiaoai,Wu, Yi,Yang, Bo,Zhang, Ni
-
supporting information
(2022/01/24)
-
- Metal-ligand complexes having electron withdrawing group, catalyst composition for ethylene-based polymerization containing the same, and production methods of ethylene-based polymers using the same
-
A metal - ligand complex having a strong electron donor group and an electron withdrawing group at the same time. The present invention relates to a catalyst composition for ethylene polymerization and a method for preparing an ethylene-based polymer usin
- -
-
Paragraph 0144-0145; 0158-0160
(2021/07/13)
-
- Macrocyclic compound, and preparation method and application thereof
-
The invention discloses a macrocyclic kinase inhibitor, and a compound, or a stereoisomer or a pharmaceutically acceptable salt thereof as shown in a formula (I). Experiments show that the novel compound shown in the formula (I) shows good TRK inhibitory
- -
-
Paragraph 0206-0208
(2021/06/23)
-
- Method for preparing diazacyclooctane intermediate and diazacyclooctane
-
The invention provides a method for preparing a diazacyclooctane intermediate and diazacyclooctane. The preparation method comprises the following steps: synthesizing 1,5-bis(p-toluenesulfonyl)-1,5-diazacyclooctane from 1,3-bis(p-toluenesulfonyl)-1,3-dioxypropane, 1,3-bis(p-toluenesulfonyl)-1,3-propane diamine and sodium methoxide under a temperature condition of 60-100 DEG C; then synthesizing 1,5-diazacyclooctane bromate from 1,5-bis(p-toluenesulfonyl)-1,5-diazacyclooctane, phenol and hydroacetic acid; and finally, synthesizing 1,5-diazacyclooctane from 1,5-diazacyclooctane bromate and sodium methoxide. According to the method, the yield of the 1,5-bis(p-toluenesulfonyl)-1,5-diazacyclooctane can be increased, and the reaction time for synthesizing the 1,5-diazacyclooctane can be shortened.
- -
-
Paragraph 0019; 0023; 0029; 0034; 0039; 0044
(2020/06/17)
-
- PYRIDINE AND PYRAZINE DERIVATIVES AS PREFERENTIAL CANNABINOID 2 AGONISTS
-
The invention relates to a compound of formula (I), wherein A1, A2 and R1-R5 are as defined in the description and in the claims. The compound of formula (I) can be used as cannabinoid 2 preferential agonist.
- -
-
Page/Page column 71; 72
(2020/01/24)
-
- The synthesis of precursor of FP- (+) DTBZ
-
A synthetic route to the precursor of FP- (+) DTBZ was disclosed, in which 3-hydroxy-4-methoxybenzaldehyde was employed as a starting material. In the method, the benzyl-protecting protocol and the in-situ Diels-Alder reaction made the procedure more practical because of the mild conditions for selectively deprotection and the accelerated reaction process.
- Wu, Caijiao,Li, Hui,Sun, Feiyang,Bao, Changshun,Bao, Xuefei,Chen, Guoliang
-
supporting information
p. 3218 - 3225
(2019/09/13)
-
- Synthesis and recognition properties of calix[4]arene semitubes as ditopic hosts for: N -alkylpyridinium ion pairs
-
A series of calix[4]arene semitubes (4a-c) having alkyl bridging spacers of different lengths and flexibilities on their lower rim was synthesised and characterised in solution and in the solid state by 1H NMR spectroscopy and X-ray crystallogr
- Vita, Francesco,Vorti, Michela,Orlandini, Guido,Zanichelli, Valeria,Massera, Chiara,Ugozzoli, Franco,Arduini, Arturo,Secchi, Andrea
-
p. 5017 - 5027
(2016/07/07)
-
- Synthesis,18 F-Radiolabelling and Biological Characterization of Novel Fluoroalkylated Triazine Derivatives for in Vivo Imaging of Phosphodiesterase 2A in Brain via Positron Emission Tomography
-
Phosphodiesterase 2A (PDE2A) is highly and specifically expressed in particular brain regions that are affected by neurological disorders and in certain tumors. Development of a specific PDE2A radioligand would enable molecular imaging of the PDE2A protei
- Schr?der, Susann,Wenzel, Barbara,Deuther-Conrad, Winnie,Teodoro, Rodrigo,Egerland, Ute,Kranz, Mathias,Scheunemann, Matthias,H?fgen, Norbert,Steinbach, J?rg,Brust, Peter
-
p. 9591 - 9615
(2015/08/06)
-
- CATALYST SYSTEMS FOR OLEFIN POLYMERIZATION
-
The instant invention provides procatalysts and catalyst systems for olefin polymerization, olefin based polymers polymerized therewith, and process for producing the same. In one embodiment, the instant invention provides a procatalyst comprising a metal
- -
-
-
- Synthesis and evaluation of a 18F-labeled spirocyclic piperidine derivative as promising σ1receptor imaging agent
-
Several spirocyclic piperidine derivatives were designed and synthesized as σ1receptor ligands. In vitro competition binding assays showed that the fluoroalkoxy analogues with small substituents possessed high affinity towards σ1rece
- Chen, Yuan-Yuan,Wang, Xia,Zhang, Jin-Ming,Deuther-Conrad, Winnie,Zhang, Xiao-Jun,Huang, Yiyun,Li, Yan,Ye, Jia-Jun,Cui, Meng-Chao,Steinbach, J?rg,Brust, Peter,Liu, Bo-Li,Jia, Hong-Mei
-
p. 5270 - 5278
(2014/12/11)
-
- Development of a new thiol site-specific prosthetic group and its conjugation with [Cys40]-exendin-4 for in vivo targeting of insulinomas
-
A new tracer, N-5-[18F]fluoropentylmaleimide ([ 18F]FPenM), for site-specific labeling of free thiol group in proteins and peptides was developed. The tracer was synthesized in three steps (18F displacement of the aliphatic tosylate, di-Boc removal by TFA to expose free amine, and incorporation of the free amine into a maleimide). The radiosynthesis was completed in 110 min with 11-17% radiochemical yield (uncorrected), and specific activity of 20-49 GBq/μmol. [18F]FPenM showed comparable labeling efficiency with N-[2-(4-[18F] fluorobenzamido)ethyl]maleimide ([18F]FBEM). Its application was demonstrated by conjugation with glucagon-like peptide type 1 (GLP-1) analogue [cys40]-exendin-4. The cell uptake, binding affinity, imaging properties, biodistribution, and metabolic stability of the radiolabeled [ 18F]FPenM-[cys40]-exendin-4 were studied using INS-1 tumor cells and INS-1 xenograft model. Positron emission tomography (PET) results showed that the new thiol-specific tracer, [18F]FPenM-[cys 40]-exendin-4, had high tumor uptake (20.32 ± 4.36%ID/g at 60 min postinjection) and rapid liver and kidney clearance, which was comparable to the imaging results with [18F]FBEM-[cys40]-exendin-4 reported by our group.
- Yue, Xuyi,Kiesewetter, Dale O.,Guo, Jinxia,Sun, Zhongchan,Zhang, Xiaoxiang,Zhu, Lei,Niu, Gang,Ma, Ying,Lang, Lixin,Chen, Xiaoyuan
-
p. 1191 - 1200
(2013/08/23)
-
- PROCESS FOR SELECTIVELY POLYMERIZING ETHYLENE AND CATALYST THEREFOR
-
The present invention generally relates to a process that selectively polymerizes ethylene in the presence of an alpha-olefin, and to a metal-ligand complex (precatalyst) and catalyst useful in such processes, and to related compositions. The present invention also generally relates to ligands and intermediates useful for preparing the metal-ligand complex and to processes of their preparation.
- -
-
Page/Page column
(2013/03/26)
-
- Synthesis of new bis-BINOL-2,2′-ethers and bis-H8BINOL-2,2′-ethers evaluation of their Titanium complexes in the asymmetric ethylation of benzaldehyde
-
The preparation by means of different synthetic paths of a series of bis-BINOL and bis-H8BINOL ligands is described. The ligands consist of two BINOL or H8BINOL fragments, joined by diverse linkages through the oxygen at the 2′-position of the arylic fragments. These ligands were applied to the Ti(OiPr)4 catalyzed asymmetric alkylation of benzaldehyde with Et2Zn. The performance of these catalysts is very sensitive to the nature of the ether linkage. The ligand with a propylene link shows better enantioselectivity (ca. 70%) than those with two or four carbon atoms joining the BINOL fragments. Furthermore, using the propylene link, but replacing (R)-BINOL by (R)-H8BINOL, a significant improvement in the stereoselectivity of the catalysts was achieved (ca. 80% ee in (R)-1-phenylpropan-1-ol). A cooperative effect was observed between the chirality at the BINOL fragment and that of a (S,S)-4,5-bis(methylene)-2,2-dimethyl-1,3-dioxolane link, derived from tartaric acid. When this chiral link combines with two (S)-BINOL fragments, the alkylation of benzaldehyde in toluene produces 70% ee of (S)-1-phenylpropan-1-ol, while the (R)-BINOL derivative ligand with the same link, in identical conditions, yields only 40% ee of the (R)-alcohol.
- Abreu, Artur R.,Pereira, Mariette M.,Bayón, J. Carles
-
experimental part
p. 743 - 749
(2010/09/14)
-
- New atropisomeric N-N ligands for CO/vinyl arene copolymerization reaction
-
New atropisomeric bidentate bipyridine-based ligands (3,3′- (ethylenedioxy)-2,2′-bipyridine 3; 3,3′-(propylenedioxy)-2,2′- bipyridine 4; 3,3′-(butylenedioxy)-2,2′-bipyridine 5) containing a bridge between the 3,3′ positions of the aromatic rings have been prepared. Together with the previously reported analogous ligands ((R)-3,3′-(1-methylethylenedioxy)-2,2′-bipyridine) 1 and ((S,S)-3,3′-(1,2-dimethylethylenedioxy)-2,2′-bipyridine) 2, they were used to synthesize the corresponding bis-chelated dicationic complexes [Pd(N-N)2][PF6]2. Crystal structures and comparison of the data obtained by X-ray analysis on four of these complexes is reported. These palladium compounds were used as precatalysts in the CO/styrene and CO/4-Me-styrene copolymerization reactions, where they showed that small variations in the ligand backbone remarkably affects the productivity of the catalytic system. The Royal Society of Chemistry 2008.
- Durand, Jerome,Zangrando, Ennio,Carfagna, Carla,Milani, Barbara
-
p. 2171 - 2182
(2008/09/20)
-
- Syntheses, conformations, and basicities of bicyclic triamines
-
The multistep syntheses of several bicyclic triamines are described, all of which have an imbedded 1,5,9-triazacyclododecane ring. In 1,5,9-triazabicyclo[7.3.3]pentadecanes 12, 13, 15, and 16, two nitrogens are bridged by three carbons. The monoprotonated forms of these triamines are highly stabilized by a hydrogen-bonded network involving the bridge and both bridgehead nitrogens, producing a difference of more than 8 pKa units in acidities of their monoprotonated and diprotonated forms. The one- and zero-carbon bridges in 1,5,9-triazabicyclo[9.1.1]tridecane (23) and 7-methyl-1,5,9-triazabicyclo[5.5.0]dodecane (39) do not enhance the stabilities of their monoprotonated forms. X-ray crystal structures and computational studies of 12·HI and 16·HI reveal similar, but somewhat weaker, hydrogen-bonded networks, relative to 15·HI. The activation free energies for conformational inversion of 13·HI (14.4 ± 0.2 kcal/mol), 16·HI (15.0 ± 0.1 kcal/mol) and 16 (8.8 ± 0.3 kcal/mol) were measured by variable-temperature 1H and 13C NMR spectroscopy. These experimental barriers give an estimate of 6.2 kcal/mol for the strength of the bifurcated hydrogen bond between the bridge nitrogen and cavity proton in 16·HI. Computational studies support the hypothesis that N-inversion occurs in an open conformation, leading to an estimate of 10.32 kcal/mol for the enthalpy of the bifurcated hydrogen bond in 16·HI in the gas phase.
- Bell, Thomas W.,Choi, Heung-Jin,Harte, William,Drew, Michael G. B.
-
p. 12196 - 12210
(2007/10/03)
-
- Synthesis of a series of triaza-macrocyclicanes
-
Condensation of the N, N′, N″-tris(p-toluenesulfonyl)diethylenetrimine-N,N″-disodium with bissulphonate esters of two-, three-, four- and six-carbon diols gives the corresponding 9-, 10-,11-, 13-membered triamine macrocycles containing N-ptoluenesulfonyl group, respectively. The p-tuluenesulfonyl groups are removed with concentrated sulfuric acid, acetic acidhydrobromic acid or LiAlH4 which give the ammonium salts of 1,4,7-triazacyclononane, 1,4,7-triazacyclodecane, 1,4,7-triazacycloundecane, 1,4,7-triazacyclotridecane, respectively. Comparison and details of the different synthetic procedures of the triamine macrocycles are described as well.
- Gao, Jinzhang,He, Hui,Zhang, Xuan,Lu, Xiaoquan,Kang, Jingwan
-
p. 372 - 375
(2007/10/03)
-
- Substitution effect, absorption, and fluorescence behaviors of 11,12-benzo-1,7,10,13-tetraoxa-4-azacyclopentadec-11-ene (Benzoaza-15-crown-5) derivatives upon cation complexation in solvent extraction
-
Substitution effect, absorption, and fluorescence behaviors of some benzoaza-15-crown-5 derivatives upon cation complexation in solvent extraction were studied. The introduction of a substituent on the nitrogen atom in benzoaza-15-crown-5 enhanced extractabilities in the solvent extraction of aqueous alkali metal picrates. The nondonating substituents raised the cation selectivity for Na+ over K+, but the donating substituents reduced the cation selectivity. The absorption and fluorescence spectral behavior was different with the alkali metal cations.
- Nakamura, Mitsunobu,Yokono, Hideaki,Tomita, Ken-Ichi,Ouchi, Mikio,Miki, Masamichi,Dohno, Reizo
-
p. 3533 - 3536
(2007/10/03)
-
- Silver(I) oxide mediated highly selective monotosylation of symmetrical diols. Application to the synthesis of polysubstituted cyclic ethers
-
(Matrix Presented) The reaction of symmetrical diols and oligo(ethylene glycol)s with a stoichiometric amount of p-toluenesulfonyl chloride in the presence of silver(I) oxide and a catalytic amount of potassium iodide led selectively to the monotosylate derivatives in high yields. Polysubstituted cyclic ethers were obtained readily upon treatment of the corresponding diols with an excess of silver oxide. The high selectivity was explained on the basis of the difference in acidity between the two hydroxy groups, which undergo an intramolecular hydrogen bonding.
- Bouzide, Abderrahim,Sauve, Gilles
-
p. 2329 - 2332
(2007/10/03)
-
- Pseudo-macrocyclic chelation control in remote asymmetric induction. Highly efficient 1,7-asymmetric inductive hydride reduction and Grignard reaction of γ-keto esters of 1,1′-binaphthalen-2-ols bearing an appropriate oligoether group as the 2′-substituent
-
Highly efficient 1,7-asymmetric induction was achieved in DIBAL-H reduction and Grignard reaction of γ-keto esters of podand-type 1,1′-binaphthalen-2-ol derivatives bearing an appropriate oligoether group as the 2′-substituent. Thus, the DIBAL-H reduction of keto esters 4 in dichloromethane-toluene at -78°C in the presence of an excess of MgBr2·OEt2 afforded, after further, reduction of the resulting diastereomeric hydroxy esters, 1,4-diol 8 with up to 92% optical yield. A similar treatment of keto esters 4, 5 and 7 with Grignard reagents gave the corresponding 4,4-disubstituted butan-4-olides 10-13 with up to 99% optical yield. The complexation experiments of keto ester 4b suggested that the highly efficient 1,7-asymmetric induction originated from the formation of a pseudo-macrocyclic magnesium complex composed of the podand keto ester and MgBr2.
- Tamai, Yasufumi,Hattori, Tetsutaro,Date, Masamitsu,Koike, Shinji,Kamikubo, Yoshinori,Akiyama, Masahiro,Seino, Kazuhiro,Takayama, Hideki,Oyama, Tomohito,Miyano, Sotaro
-
p. 1685 - 1694
(2007/10/03)
-
- Synthesis and characterization of lipophilic 1-[18F]fluoroalkyl-2- nitroimidazoles for imaging hypoxia
-
In order to develop new imaging markers for brain hypoxia, two lipophilic nitroimidazoles, 1-(3-fluoropropyl)-2-nitroimidazole (FPN) and 1- (8-fluorooctyl)-2-nitroimidazole (FON) were synthesized and labeled with fluorine-18. The octanol/water partition c
- Yamamoto, Fumihiko,Oka, Hidenobu,Antoku, Shigetoshi,Ichiya, Yu-Ichi,Masuda, Kouji,Maeda, Minoru
-
p. 590 - 597
(2007/10/03)
-
- Synthesis and Complexation Properties of Suitcase-Shaped Macrotricyclic and Butterfly-Shaped Macrobicyclic Polyether Ligands
-
Ten suitcase-shaped macrotricyclic polyethers (1-10) containing nitrogen and carbon bridgehead atoms have been synthesized.These new cage compounds were prepared by connecting together two hydroxymethyl-substituted or two secondary amine-containing butterfly-shaped macrobicyclic polyethers by means of linear bifunctional connecting groups.Intermediate bis(hydroxymethyl)-substituted butterfly-shaped macrobicyclic polyether 14 was prepared by treating N,N'-bis(2-hydroxyethyl)ethylenediaamine with 5-methylene-3,7-dioxane-1,9-diyl ditosylate to give bislariat 1,4-diaza-13-crown-4 (11) which was cyclized with 3-chloro-2-(chloromethyl)-1-propene followed by hydroboration.Intermediate bissecondary amine-containing butterfly-shaped macrobicyclic polyethers 18 and 19 were prepared by treating N,N'-bis(2-hydroxyethyl)ethylenediamine with 6-tosyl-3,9-dioxa-6-aza-1,11-undecanediyl ditosylate (33) to give N-tosyl-N',N"-bis(2-Hydroxyethyl)triaza-15-crown-5 (12).Lariat crown ether 12 was cyclized with 33 followed by reduction with LiAlH4 to give 18, or with 4-tosyl-4-aza-1,7-heptanediyl ditosylate (36 to give 19.Some of the suitcase-shaped macrotricycles interacted with various cations.One was selective for Pb(2+) ions and another interacted strongly with Hg(2+).A crystal structure for the 13-NaClO4 complex also is reported.
- An, Haoyun,Bradshaw, Jerald S.,Krakowiak, Krzysztof E.,Zhu, Chengyue,Dalley, N. Kent,Izatt, Reed M.
-
p. 4998 - 5005
(2007/10/02)
-
- Synthesis of a New P2N2 Ligand N,N'-Bispropane-1,3-diamine, H2L2, and some of its Complexes with Elements of the Nickel Triad and Rhodium: X-Ray Structure Analyses of the Neutral Complex 2> and the tr
-
The new multidentate phosphorus-nitrogen P2N2 hybride ligand N,N'-bispropane-1,3-diamine, H2L2, has been prepared by demetallation of its neutral deprotonated nickel complex 2>, (1a), obtained from th
- Cooper, Mervyn K.,Duckworth, Paul A.,Hambley, Trevor W.,Organ, Gregory J.,Henrick, Kim,et al.
-
p. 1067 - 1074
(2007/10/02)
-
- Synthesis and Liquid Crystal Properties of Dimethylene Linked Compounds Incorporating the Cyclobutane or Spiroheptane Rings
-
The preparation of sixteen dimethylene linked compounds is described heptane ring>, and a comparison is made between the transition temperatures of these compounds and those of the corresponding esters.This comparison once again highlights the fact that the cyclobutane ring should be regarded, in terms of its ability to promote nematic thermal stability, as a "chain stiffener rather than as a ring system.A comparison is also made of the nematic thermal stabilities of the trans-cyclobutane and the spiroheptane systems and of the trans-cyclohexane and the spiroundecane systems.
- Chan, L. K. M.,Gemmell, P. A.,Gray, G. W.,Lacey, D.,Toyne, K. J.
-
p. 229 - 246
(2007/10/02)
-
- A THERMOMETRIC TITRIMETRIC STUDY OF THE COMPLEXATION OF ALKALINE-EARTH METALS BY MACROCYCLIC POLY(AMINOCARBOXYLIC) ACIDS
-
Thermometric titrimetry has been employed to determine K, ΔH and ΔS data for the complexation reaction in aqueous solution of 1,4-piperazine-N,N'-diacetic acid, 1,5-diazacyclooctane-N,N'-diacetic acid, 1-oxa-4,7-diazacyclononane-N,N'-diacetic acid, 4-oxa-1,7-diazacyclodecane-N,N'-diacetic acid and 1,11-dioxa-4,8-diazacyclotridecane-N,N'-diacetic acid with alkaline earth metal cations.Factors influencing the thermodynamic stability of these complexes are discussed.
- Ewin, Gavin,Hill, John O.
-
p. 3501 - 3519
(2007/10/02)
-
- Improved Richman-Atkins Syntheses of Cyclic Polyamines Particularly 1,4,7-Triazacyclononane (tacn) and 1,4,7-Triazacyclodecane (tacd), with the Aid of Cation-Exchange in Purification and Isolation
-
Richman-Atkins cyclization syntheses for the cyclic triamines 1,4,7-triazacyclononane (tacn) and 1,4,7-triazacyclodecane (tacd) with the alternative possible sets of reagents asd tosyl derivatives have been examined in detail and compared.The cyclizations from the tritosyl derivative of diethylenetriamine (dientt) and the appropriate diols as ditosylates proceeded relatively cleanly, although there were small amounts of higher products and some carry through of dientt for tacn.The alternative cyclizations, from 2,2'-(tosylimino)bisethyl ditosylate and a ditosyl diamine, gave little reaction to form tacn as the tritosyl derivative.The reaction to form tritosyl tacd proceeded further, but was accompanied by significant formation of higher condensation products, particularly the hexamines 1,4,7,11,14,17-hexaazacycloeicosane (2:2 cyclic dimer) and 3,7,10,13-tetraazahexadecane-1,16-diamine.A cation-exchange procedure, applied after the detosylation stage, is described for obtaining the required pure 1 : 1 cyclic polyamines as their hydrochloride salts with high recovery.This is an effective method for removing higher co-products.These may be recovered, and by this means the above hexamines were isolated in admixture.
- Searle, Graeme H.,Geue, Rodney J.
-
p. 959 - 970
(2007/10/02)
-
