621-02-3Relevant articles and documents
Kinetic Control over CdS Nanocrystal Nucleation Using a Library of Thiocarbonates, Thiocarbamates, and Thioureas
Hamachi, Leslie S.,Jen-La Plante, Ilan,Coryell, Aidan C.,De Roo, Jonathan,Owen, Jonathan S.
, p. 8711 - 8719 (2017/10/30)
We report a family of substituted thiocarbonates, thiocarbamates, and thioureas and their reaction with cadmium oleate at 180-240 °C to form zincblende CdS nanocrystals (d = 2.2-5.9 nm). To monitor the kinetics of CdS formation with UV-vis spectroscopy, t
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
Moon, Hyun Kyung,Sung, Gi Hyeon,Yoon, Yong-Jin,Yoon, Hyo Jae
supporting information, p. 1577 - 1581 (2016/06/14)
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.
Synthesis of organic carbonates with alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates and ROH/AlCl3under ambient condition
Sung, Gi Hyeon,Bo, Ram Kim,Ryu, Ki Eun,Kim, Jeum-Jong,Yoon, Yong-Jin
, p. 2758 - 2764 (2015/04/22)
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.
Direct synthesis of diphenyl carbonate by mediated electrocarbonylation of phenol at Pd2+-supported activated carbon anode
Murayama, Toru,Hayashi, Tomohiko,Arai, Yuji,Yamanaka, Ichiro
experimental part, p. 2926 - 2933 (2011/05/16)
Mediated electrocarbonylation of phenol to diphenyl carbonate (DPC) at a PdCl2-supported activated carbon anode in 1 atm CO at 298 K was studied. A dry CH2Cl2 or CH3CN solvent and a galvanostatic electrolysis of 1 mA were necessary for formation of DPC, while the addition of a base and a supporting electrolyte was also essential. A combination of triethylamine (Et3N) and tetrabutylammonium perchlorate (Bu4NClO4) was suitable in various combinations. The addition of 2 equiv. of Et3N to the electrolyte (C6H5OH/Bu4NClO4/CH 2Cl2) at 1-h intervals was more efficient in the formation of DPC than a single initial addition of the same amount of Et3N. The yield of DPC was 130% based on Pd and its current efficiency (CE) was 42% for 6 h. The CE of the CO2 formation was only 3%. Sodium phenoxide (PhONa) showed dual functionality as a base and supporting electrolyte. When the mediated electrocarbonylation was conducted in a C6H 5OH/PhONa/CH3CN electrolyte, DPC was produced in 172% yield and 40% CE for 6 h. The CE of the CO2 formation was 10%. DPC formed continuously after a single initial addition of 4 equiv. of PhONa. Li or K phenoxide also worked as promoters for the mediated electrocarbonylation of phenol to DPC.
Transesterification of dimethyl carbonate with phenol using Br?nsted and Lewis acidic ionic liquids
Deshmukh, Krishna M.,Qureshi, Ziyauddin S.,Dhake, Kishor P.,Bhanage, Bhalchandra M.
experimental part, p. 207 - 211 (2011/09/12)
Transesterification reaction of dimethyl carbonate with phenol to methylphenyl carbonate and diphenyl carbonate using dibutyltin oxide catalyst in conjunction with Br?nsted and Lewis acidic ionic liquids was studied. It was observed that the use of ionic liquids significantly enhances the yield of diphenyl carbonate. The ionic liquid having p-toluenesulfonate as anion and metal halide (e.g. ZnCl2) as Lewis acid precursor exhibited higher activity and selectivity for diphenyl carbonate formation. Furthermore, the Br?nsted and Lewis acidity of ionic liquids was measured by IR spectroscopy using pyridine as a probe and their Lewis acidity order was also determined.
Double- and triple-consecutive O-insertion into tert-butyl and triarylmethyl structures
Krasutsky, Pavel A.,Kolomitsyn, Igor V.,Krasutsky, Sergiy G.,Kiprof, Paul
, p. 2539 - 2542 (2007/10/03)
(Matrix Presented) The concecutive Criegee rearrangement reactions were studied for tert-butyl trifluoroacetate, triarylcarbinols, and benzophenone ketales with trifluoroperacetic acid (TFPAA) in trifluoroacetic acid (TFA). The formation of methyl acetate and methyl trifluoroacetate indicates that the consecutive double-O-insertion process has taken place for tert-butyl trifluoroacetate. The intermediate dimethoxymethylcarbonium ion was detected below 5°C. A consecutive triple-O-insertion process has been observed for triarylmethanols and benzophenone ketals. A new high yield method of corresponding diaryl carbonates synthesis was developed.
Diaryloxycarbenes from oxadiazolines
Lu,Reid,Warkentin
, p. 319 - 327 (2007/10/03)
Symmetric and unsymmetric 2,2-diaryloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines were synthesized by oxidative cyclization of aryloxycarbonyl hydrazones of acetone with lead tetraacetate and subsequent treatment of the product mixture with a phenol in acidic solution. Thermolysis of the oxadiazolines in benzene solution at 110°C afforded carbonyl ylide intermediates that cyclize, in part, to the corresponding 2,2-diaryloxyoxirane intermediates. The oxiranes, which were not observed, are required to account for the 1,1-diaryloxy-2-methylpropenes (ketene acetals) that were isolated. Most of the carbonyl ylides fragment to acetone and diaryloxycarbenes. The latter form dimers (tetraaryloxyethenes) or they can be trapped with phenols to form orthoformates. Diphenoxycarbene was also trapped with dimethyl acetylenedicarboxylate (DMAD). The method appears to be the first for generating the parent diphenoxycarbene under relatively mild conditions in solution, and the only one to date for generating unsymmetrically substituted diaryloxycarbenes. Minor competing fragmentations of the oxadiazolines to 2-diazopropane and the appropriate diaryl carbonates, were also observed.
The reactions of difluorodiiodomethane with nucleophiles
Guo, Yong,Chen, Qing-Yun
, p. 105 - 109 (2007/10/03)
Treatment of difluorodiiodomethane with phenoxides (ArO-) in DMF at room temperature gives ArOCF2I in 7-15%, the carbonates (ArOCO2Ar) being the major products, while with thiophenoxides affords difluoromethylene derivativ
Synthesis of ring-substituted phenyl hydrazinecarboxylates and study of their protonation in dimethyl sulfoxide solutions
Vlasak, Petr,Parik, Patrik,Klicnar, Jiri,Mindl, Jaromir
, p. 793 - 802 (2007/10/03)
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.
Hydrolysis of aryl orthocarbonates by general acid catalyzed and spontaneous processes. Characterization of the water reaction of (ArO)3COAr′ and (ArO)3CN3
Kandanarachchi, Pramod,Sinnott, Michael L.
, p. 5592 - 5600 (2007/10/02)
Twenty-four aryl orthocarbonates of formula (Aro)4C, (ArO)2C(OAr′)2, or (ArO)3COAr′ have been made by coupling of the copper phenoxides with carbon disulfide, and their hydrolyses have been examined in 60% water-40% acetonitrile (I = 1.00 M, KCl) at 70.0 °C. Their hydrolysis by general acid catalyzed and, in the case of (ArO)3COAr′ when Ar′ = p-nitrophenyl and p-cyanophenyl, spontaneous processes yields aryl carbonates. The initial, rate-determining event for both processes is the cleavage of the bond between the central carbon and the least basic phenoxy group: with mixed orthocarbonates of phenols differing in pK by 6H4O)3C-O-P-C6H 4NO2 and (X-C6H4O)3C-O-p-C6H4CN where the σ value of X varies from -0.23 to 0.22 are 4-10 times slower than reactions of p-nitrophenyl tetrahydropyrans reported in the literature and give rise to nonlinear Hammett plots. However, plots against the pKa of X-C6H4OH are linear, and the derived β(reaction center) values indicate substantial buildup of positive charge on the central carbon atom. A similar plot is obtained for the spontaneous reactions of five azides (XC6H4O)3CN3 for which common ion inhibition experiments have been performed. The derived selectivities (M-1) of the tris(aryloxy)carbenium ion intermediates between azide ion and water vary from 8.5 × 103 to 6.6 × 103 as the σ value of X changes from -0.28 to 0.06. The lifetime of the tris(aryloxy)carbenium ion intermediates in water is therefore likely to be >10-6 s. The slow formation and slow hydrolysis of tris(aryloxy)carbenium ions suggests that (in the formation direction) development of conjugative stabilization lags behind carbon-oxygen bond cleavage and (in the hydrolysis direction) precedes carbon-oxygen bond formation. The stereochemistry of tetraaryl orthocarbonates immediately suggests reasons why this should be so.
