- Photo-on-Demand Base-Catalyzed Phosgenation Reactions with Chloroform: Synthesis of Arylcarbonate and Halocarbonate Esters
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Carbonate esters are utilized as solvents and reagents for C1 building blocks in organic synthesis. This study reports a novel photo-on-demand in situ synthesis of carbonate esters with CHCl3 solutions containing a mixture of an aromatic or haloalkyl alcohol having relatively high acidity, and an organic base. We found that the acid-base interaction of the alcohol and base in the CHCl3 solution plays a key role in enabling the photochemical reaction. This reaction allows practical syntheses of diphenyl carbonate derivatives, haloalkyl carbonates, and polycarbonates, which are important chemicals and materials in industry.
- Dai, Namin,Eda, Kazuo,Harada, Hidefumi,Hashimoto, Yuka,Hosokawa, Sasuga,Kakiuchi, Toshifumi,Liang, Fengying,Okazoe, Takashi,Suzuki, Yuto,Tana, Gegen,Tsuda, Akihiko
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p. 9811 - 9819
(2021/07/20)
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- CARBONATE DERIVATIVE PRODUCTION METHOD
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The objective of the present invention is to provide a method for producing a carbonate derivative in a safe and efficient manner. The method for producing a carbonate derivative according to the present invention is characterized in comprising irradiating light on a composition containing a C1-4 halogenated hydrocarbon having one or more kinds of halogen atoms selected from the group consisting of a chlorine atom, a bromine atom and an iodine atom, a nucleophilic functional group-containing compound and the specific base in the presence of oxygen.
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Paragraph 0135-0136; 0143-0144
(2020/04/09)
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- Alkyl and aryl 4,5-dichloro-6-oxopyridazin-1(6 H)-carboxylates: A practical alternative to chloroformates for the synthesis of symmetric and asymmetric carbonates
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Symmetric and asymmetric carbonates were synthesized by using alkyl or aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates. Five aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates were converted into the corresponding diaryl carbonates in good to excellent yields by treatment with potassium carbonate in refluxing THF. When the 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates were treated with aliphatic or aromatic alcohols in the presence of potassium tert-butoxide in toluene at room temperature, they gave the corresponding symmetric or asymmetric carbonates in moderate to excellent yields. Alkyl and aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates are therefore efficient, stable, and ecofriendly alternatives to chloroformates.
- Moon, Hyun Kyung,Sung, Gi Hyeon,Yoon, Yong-Jin,Yoon, Hyo Jae
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supporting information
p. 1577 - 1581
(2016/06/14)
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- Synthesis of organic carbonates with alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates and ROH/AlCl3under ambient condition
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We demonstrated the synthesis of organic carbonates using alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates and alcohol in the presence of aluminum chloride. Alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates were reacted with alcohol in the presence of AlCl3 in toluene at room temperature to afford the corresponding unsymmetric and symmetric organic carbonates in good to excellent yields. These are efficient and convenient processes. Alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates are solid, stable and non-toxic CO2/CO2R(Ar) source. It is noteworthy that the reaction is carry out under an ambient and acidic conditions, the easy-to prepare and readily available starting materials and the quantitative isolation of reusable 4,5-dichloropyridazin-3(2H)-one.
- Sung, Gi Hyeon,Bo, Ram Kim,Ryu, Ki Eun,Kim, Jeum-Jong,Yoon, Yong-Jin
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p. 2758 - 2764
(2015/04/22)
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- Study of the kulinkovich synthesis of 1-methylcyclopropanol and its conversion into 1-methylcyclopropyl 4-nitrophenyl carbonate
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A detailed investigation of the preparation of 1-methylcyclopropanol via the Kulinkovich reaction is presented. Reaction and workup parameters were optimized to provide a reproducible procedure for the synthesis of multigram quantities of 1-methylcyclopropanol. Key improvements were the use of titanium tetra(2-ethyl)hexyloxide as catalyst, reduction in the volume of reaction solvent, addition of the methyl acetate starting material in portions, and azeotropic distillation to remove by-products. The preparation of the 4-nitrophenyl carbonate ester was likewise studied and optimized. Georg Thieme Verlag Stuttgart New York.
- Wright, Stephen W.,Darout, Etzer,Stevens, Benjamin D.
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p. 2481 - 2484
(2013/09/23)
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- Photochemical molecular storage of Cl2, HCl, and COCl 2: Synthesis of organochlorine compounds, salts, ureas, and polycarbonate with photodecomposed chloroform
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Chloroform is available as not only an organic solvent but also photochemical molecular storage for synthetically important chemicals such as Cl2, HCl, and COCl2. We have succeeded in synthesizing organochlorine compounds, hydrochloric salt of amines, ureas, organic carbonates, and polycarbonate in practical high yields with photodecomposed chloroform.
- Kuwahara, Yuki,Zhang, Ailing,Soma, Haruka,Tsuda, Akihiko
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supporting information; experimental part
p. 3376 - 3379
(2012/08/08)
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- Protein micro- and nanopatterning using aminosilanes with protein-resistant photolabile protecting groups
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An approach to the integration of nanolithography with synthetic chemical methodology is described, in which near-field optical techniques are used to selectively deprotect films formed by the adsorption of aminosilanes protected by modified 2-nitrophenylethoxycarbonyl (NPEOC) groups. The NPEOC groups are functionalized at the m- or p-position with either a tetraethyleneglycol or a heptaethylene glycol adduct. We describe the synthesis of these bioresistant aminosilanes and the characterization of the resulting photoreactive films. Photodeprotection by exposure to UV light (λ = 325 nm) yielded the amine with high efficiency, at a similar rate for all four adsorbates, and was complete after an exposure of 2.24 J cm-2. Following photodeprotection, derivatization by trifluoroacetic anhydride was carried out with high efficiency. Micropatterned samples, formed using a mask, were derivatized with aldehyde-functionalized polymer nanoparticles and, following derivatization with biotin, were used to form patterns of avidin-coated polymer particles. Fluorescence microscopy and atomic force microscopy data demonstrated that the intact protecting groups conferred excellent resistance to nonspecific adsorption. Nanometer-scale patterns were created using scanning near-field photolithography and were derivatized with biotin. Subsequent conjugation with avidin-functionalized polymer nanoparticles yielded clear fluorescence images that indicated dense attachment to the nanostructures and excellent protein resistance on the surrounding surface. These simple photocleavable protecting group strategies, combined with the use of near-field exposure, offer excellent prospects for the control of surface reactivity at nanometer resolution in biological systems and offer promise for integrating the top-down and bottom-up molecular fabrication paradigms.
- Alang Ahmad, Shahrul A.,Wong, Lu Shin,Ul-Haq, Ehtsham,Hobbs, Jamie K.,Leggett, Graham J.,Micklefield, Jason
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p. 2749 - 2759
(2011/04/23)
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- Structural features of phenoxycarbonylimino neonicotinoids acting at the insect nicotinic receptor
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Substituted-phenoxycarbonylimino neonicotinoid ligands with an electron-donating group showed significantly higher affinity to the insect nicotinic receptor relative to that of the analogue with an electron-withdrawing substituent, thereby establishing in silico binding site interaction model featuring that the phenoxy ring of neonicotinoids and the receptor loop D tryptophan indole plane form a face-to-edge aromatic interaction.
- Ohno, Ikuya,Tomizawa, Motohiro,Miyazu, Nozomi,Kushibiki, Gohito,Noda, Kumiko,Hasebe, Yasunori,Durkin, Kathleen A.,Miyake, Taiji,Kagabu, Shinzo
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scheme or table
p. 5933 - 5935
(2010/11/18)
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- Stereoselective synthesis of α-Keto-deoxy-D-glycero-D- galactononulosonic acid glycosides by means of the 4,5-O-carbonate protecting group
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(Figure Presented) Unrivaled: A 1-adamantyl thioglycoside derivative of the nonulosonic acid KDN, carrying a 4,5-O-carbonate protecting group, is a highly efficient and a-selective KDN donor when activated using N-iodosuccinimide (NIS) and trifluoromethanesulfonic acid (TfOH). Glycosylates conducted with this protecting group do not suffer from competing glycal formation.
- Crich, David,Navuluri, Chandrasekhar
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supporting information; experimental part
p. 3049 - 3052
(2010/07/05)
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- Telluroxides exhibit hydrolysis capacity
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It has long been known that tellurium compounds are rather toxic to living organisms, and tellurium has not been found in natural biomacromolecules to date. The principles of telluride toxicity in biological processes are still controversial partly because of the lack of information on the biochemical features of tellurium. In this contribution, we report our finding for the first time that telluroxides exhibit hydrolysis capacity. For instance, 6,6′-telluroxy-bis(6-deoxy-β-cyclodextrin) acts as a hydrolase mimic and shows a significant rate acceleration of 106 000 for the hydrolysis of 4,4′-dinitrodiphenyl carbonate.
- Dong, Zeyuan,Li, Xiangqiu,Liang, Kai,Mao, Shizhong,Huang, Xin,Yang, Bing,Xu, Jiayun,Liu, Junqiu,Luo, Guimin,Shen, Jiacong
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p. 606 - 609
(2007/10/03)
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- Controlled drug delivery system using the conjugation of drug to biodegradable polyester
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The present invention relates to the molecular sustained controlled release system constructed by the conjugation of molecules to be released with biodegradable polyester polymer via covalent bond and method for preparation thereof. In accordance with the present invention, the system may be formulated into microspheres, nanoparticles, or films. The molecular release rate from the above system can be regulated to be proportional to the chemical degradation rate of the biodegradable polyester polymers, resulting in near zero order kinetics profile of release without showing a burst effect. Moreover, the high loading efficiency of hydrophilic drugs can be achieved.
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- Synthesis of ring-substituted phenyl hydrazinecarboxylates and study of their protonation in dimethyl sulfoxide solutions
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The pKa values of nineteen phenyl hydrazinecarboxylate hydrochlorides R-C6H4OCONHNH2.HCl (R = H, 3-and 4-Cl, 3-and 4-O2N, 4-Me) and their 1-methyl or 2-methyl derivatives were determined by potentiometric titration with tetrabutylammonium hydroxide in DMSO. IR spectra of the hydrazinecarboxylates and their hydrochlorides revealed that the hydrazinecarboxylate protonation occurs at N2. The methods of synthesis of phenyl hydrazinecarboxylate and their N-methyl derivatives were optimized.
- Vlasak, Petr,Parik, Patrik,Klicnar, Jiri,Mindl, Jaromir
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p. 793 - 802
(2007/10/03)
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- Aminediol protease inhibitors
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Novel aminediol compounds, pharmaceutical compositions containing these compounds, and methods of using these compounds in inhibiting retroviral protease, particularly useful in the treatment and/or prevention of HIV infection (AIDS).
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- Dioxolenylmethyl carbamates pro moieties for amine drugs
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This invention relates to a the use of new oxodioxolenylmethyl carbamates to produce bioreversible neutral prodrugs from primary and secondary amines.
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- Synthesis and Anionic Ring-Opening Polymerization of a Novel Aromatic Cyclic Carbonate Having Binapthyl Structure
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A novel aromatic cyclic carbonate (3) having binaphthyl structure was prepared by reaction of 2,2'-binapthol with 4-nitrophenyl chloroformate in the presence of a tert-amine. 3 polymerized very efficiently with potassium tert-butoxide at 20 deg C to give coresponding linear polycarbonate with Mn 12800 (Mw/Mn 1.34) in 94percent yield.
- Takata, Toshikazu,Matsuoka, Hideo,Endo, Takeshi
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p. 2091 - 2094
(2007/10/02)
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- Regioselective nitration of diphenyl compounds
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A regioselective nitration process for diphenyl compounds which can be carried out at about ambient temperature in which each ring of the diphenyl compound is selectively nitrated in the para position to form the corresponding di(4-nitrophenyl) compound. Such compounds as diphenyl carbonate, 2,2-diphenylpropane, 2,2-diphenylhexafluoropropane, diphenyl sulfide, diphenyl ketone, diphenyl sulfone, and the like can be converted to an isomeric mixture containing an enhanced amount of the corresponding di(4-nitrophenyl) compound, which mixture may be reduced or purified and reduced to the di(4-aminophenyl) analogues for use in the manufacture of polyamides, polyimides, and polyamide-imides.
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- A New Convenient Method for the Synthesis of Symmetrical and Unsymmetrical N,N'-Disubstituted Ureas
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A new method is described for the preparation of symmetrically and unsymmetrically disubstituted ureas by aminolysis of bis(4-nitrophenyl) carbonate.The second substitution is slower than the first one, and it is possible to isolate monosubstituted intermediates when equimolar amounts of substrates are used.The reaction of the intermediates with different amines give unsymmetrical derivatives of urea.
- Izdebski, Jan,Pawlak, Danuta
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p. 423 - 425
(2007/10/02)
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- Bicyclic Imides with Bridgehead Nitrogen. Synthesis and X-ray Crystal Structure of a Bicyclic 2,4-Oxazolidinedione
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The first successful synthesis of bicyclic 2,4-oxazolidinediones with bridgehead nitrogen, examples of anti-Bredt imides, was accomplished.The synthetic approaches involved three homologous bridging sizes, and the smallest product capable of preparation was 1-aza-8,9-dioxo-7-oxa-6-phenylbicyclononane, for which the structure was verified by X-ray diffraction.Also prepared was 1-aza-9,10-dioxo-8-oxa-7-phenylbicyclodecane.These results were accurately predicted by using anti-Bredt olefins as models, suggesting that resonance effects may be essential for the stability of anti-Bredt imides.
- Brouillette, Wayne J.,Einspahr, Howard M.
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p. 5113 - 5116
(2007/10/02)
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- Process for the preparation of 4,4'-dinitrodiphenyl carbonate
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A process for preparing 4,4'-dinitro-diphenyl carbonate which comprises adding to a sulfuric acid solution of diphenyl carbonate maintained at a temperature between -40 and +40° C a nitric acid in a stoichiometric or slight stoichiometric excess.
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- Carbonic anhydrase catalyzed hydrolysis and decarboxylation. Kinetic studies of enzyme catalyzed decomposition of mono- and disubstituted derivatives of carbonic acid
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The effect of bovine carbonic anhydrase on the stepwise hydrolysis of carbonate diesters is examined. While biphasic enzyme kinetics cannot be detected in the case of bis(4 nitrophenyl) carbonate, it is demonstrated that at pH 10.45 methyl 4 nitrophenyl carbonate is enzymatically hydrolyzed to produce an intermediate monoester, methyl carbonate, which does not undergo enzyme catalyzed decarboxylation. However, it is shown that at pH 7.27 methyl carbonate decarboxylation is accelerated by carbonic anhydrase. The enzymatic pH rate profile for methyl 4 nitrophenyl carbonate release of 4 nitrophenol rises with increasing pH, while the pH dependency for the enzyme catalyzed decarboxylation of methyl carbonate is such that it decreases with increasing pH. In this respect, the kinetic behavior of bovine carbonic anhydrase in regard to methyl 4 nitrophenyl carbonate hydrolysis appears to be similar to that observed in CO2 hydration; in both the rate varies as though dependent on the ionization of a group in the enzyme with pK near 7, only the basic form being active. On the other hand the enzyme catalyzed decarboxylation of methyl carbonate appears to be formally similar to that of bicarbonate; with these two anions the rate varies as though dependent on the ionization of a group in the enzyme of essentially the same pK(7) with only the acid form being active. Although at pH 7.27 the first order rate coefficient, k(buf), for methyl carbonate decomposition is 1.8 times larger than that for bicarbonate dehydration, the second order enzymatic rate coefficient, k(enz), for bicarbonate is three orders of magnitude greater than that for methyl carbonate. The large differences in these k(enz) values are discussed in terms of the role of the labile bicarbonate proton in the mechanism of carbonic anhydrase catalysis.
- Pocker,Guilbert
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p. 70 - 78,71,75
(2007/10/13)
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