1226-63-7Relevant articles and documents
Solid-phase synthesis of 2-methoxyaniline derivatives by the traceless silicon linker strategy
Curtet, Sophie,Langlois, Michel
, p. 8563 - 8566 (1999)
Application of the silicon linkage strategy to the solid-phase synthesis of the rich-electron o-anisidine derivatives is described. The protective t-Boc group was easily removed with B-catechol borane and the isocyanate was successfully prepared with the mild reagent (t-Boc)2O/DMAP. Carbamates, ureas or amides were prepared and released by cleavage with TFA at room temperature. This method can be used to prepare small focused libraries with biological activity at serotonin receptors.
Photodecomposition of Pigment Yellow 74, a pigment used in tattoo inks
Cui, Yanyan,Spann, Andrew P.,Couch, Letha H.,Gopee, Neera V.,Evans, Frederick E.,Churchwell, Mona I.,Williams, Lee D.,Doerge, Daniel R.,Howard, Paul C.
, p. 175 - 184 (2004)
Tattooing has become a popular recreational practice among younger adults over the past decade. Although some of the pigments used in tattooing have been described, very little is known concerning the toxicology, phototoxicology or photochemistry of these pigments. Seven yellow tattoo inks were obtained from commercial sources and their pigments extracted, identified and quantitatively analyzed. The mono- azo compound Pigment Yellow 74 (PY74; CI 11741) was found to be the major pigment in several of the tattoo inks. Solutions of commercial PY74 in tetrahydrofuran (THF) were deoxygenated using argon gas, and the photochemical reaction products were determined after exposure to simulated solar light generated by a filtered 6.5 kW xenon arc lamp. Spectrophotometric and high-pressure liquid chromatography (HPLC) analyses indicated that PY74 photodecomposed to multiple products that were isolated using a combination of silica chromatography and reversed-phase HPLC. Three of the major photodecomposition products were identified by nuclear magnetic resonance and mass spectrometry as N-(2-methoxyphenyl)-3-oxobutanamide (o-acetoacetanisidide), 2-(hydroxyimine)-N-(2-methoxyphenyl)-3-oxobutanamide and N,N″-bis(2- methoxyphenyl)urea. These results demonstrate that PY74 is not photostable in THF and that photochemical lysis occurs at several sites in PY74 including the hydrazone and amide groups. The data also suggest that the use of PY74 in tattoo inks could potentially result in the formation of photolysis products, resulting in toxicity at the tattoo site after irradiation with sunlight or more intense light sources.
Depalladation of neutral monoalkyne- and dialkyne-inserted palladacycles and alkyne insertion/depalladation reactions of cationic palladacycles derived from N, N ′, N ″-triarylguanidines as facile routes for guanidine-containing heterocycles/carbocycles: Synthetic, structural, and mechanistic aspects
Saxena, Priya,Thirupathi, Natesan,Nethaji, Munirathinam
, p. 5554 - 5565 (2014)
Depalladation of the monoalkyne-inserted cyclopalladated guanidines [κ2(C,N)Pd(2,6-Me2C5H3N)Br] (I and II) in PhCl under reflux conditions and that of the dialkyne-inserted cyclopalladated guanidine [κ2(C,N):n2(C=C)PdBr] (III) in pyridine under reflux conditions afforded a guanidine-containing indole (1), imidazoindole (2), and benzazepine (3) in 80%, 67%, and 76%, yields, respectively. trans-[L2PdBr2] species (L = 2,6-Me2C5H3N, C5H5N) were also isolated in the aforementioned reactions in 35%, 42%, and 40% yields. Further, the reaction of the cyclopalladated guanidine [κ2(C,N)Pd(μ-Br)]2 (IV) with AgBF4 in a CH2Cl2/MeCN mixture afforded the cationic pincer type cyclopalladated guanidine [κ3(C,N,O)Pd(MeCN)][BF4] (4) in 85% yield and this palladacycle upon crystallization in MeCN and the reaction of [κ2(C,N)Pd(μ-Br)]2 (V) with AgBF4 in a CH2Cl2/MeCN mixture afforded the cationic palladacycles [{κ2(C,N)Pd(MeCN)2][BF4] (5 and 6) in 89% and 91% yields, respectively. The separate reactions of 4 with 2 equiv of methyl phenylpropiolate (MPP) or diphenylacetylene (DPA) and the reaction of 5 with 2 equiv of MPP in PhCl at 110 °C afforded the guanidine-containing quinazolinium tetrafluoroborate 7 in 25-32% yields. The reaction of 6 with 2 equiv of DPA under otherwise identical conditions afforded the unsymmetrically substituted guanidinium tetrafluoroborate 8, containing a highly substituted naphthalene unit, in 82% yield. Compounds 1-8 were characterized by analytical and spectroscopic techniques, and all compounds except 4 were characterized by single-crystal X-ray diffraction. The molecular structures of 2 and 3 are novel, as the framework in the former arises due to the formation of two C-N bonds upon depalladation while the butadienyl unit in the latter revealed cis,cis stereochemistry, a feature unprecedented in alkyne insertion chemistry. Plausible pathways for the formation of heterocycles/carbocycles are proposed. The influence of substituents on the aryl rings of the cyclopalladated guanidine moiety and those on alkynes upon the nature of the products is addressed. Heterocycles 1 and 7 revealed the presence of two rotamers in about a 1.00:0.43 ratio in CDCl3 and in about a 1.00:0.14 ratio in CD3OD, respectively, as detected by 1H NMR spectroscopy while in CD3CN and DMSO-d6 (1) and CD3CN and CDCl3 (7), these heterocycles revealed the presence of a single rotamer. These spectral features are attributed to the restricted C-N single-bond rotation of the CN3 unit of the guanidine moiety, which possibly arises from steric constraint due to the formation of a N-H···Cl hydrogen bond with CDCl3 (1) and N-H···O and O-D···O hydrogen bonds with CD3OD (7).
Method for photocatalytic synthesis of substituted urea compound
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Paragraph 0051-0052; 0057, (2021/06/09)
The invention relates to the technical field of organic synthesis, in particular to a method for photocatalytic synthesis of a substituted urea compound. The method specifically comprises the following steps: mixing tetrahalomethane and a solvent, then adding an amine compound and a catalyst in sequence, stirring and reacting under an oxygen-containing atmosphere and an illumination condition, and then separating and purifying to obtain the substituted urea compound, according to the synthesis method, the raw materials are wide in source, by-products produced after the reaction are halogen simple substances and high in additional value, on one hand, phosgene, triphosgene and the like which are high in toxicity are prevented from being adopted as raw materials, on the other hand, generation of a large amount of waste is avoided, the catalyst can be recycled, the influence of the preparation process on the environment is reduced, and the atom utilization rate of the reaction is improved.
An Improved Synthesis of Urea Derivatives from N -Acylbenzotriazole via Curtius Rearrangement
Agrahari, Anand K.,Singh, Anoop S.,Singh, Sumit K.,Tiwari, Vinod K.,Yadav, Mangal S.
, p. 3443 - 3450 (2019/09/07)
The good leaving tendency of the benzotriazole moiety has been exploited for the synthesis of symmetric, unsymmetric, N -acyl, and cyclic ureas in good yields from N -acylbenzotriazoles by treating the latter with various amines in the presence of TMSN 3 /Et 3 N in a sealed tube. The salient features of the devised protocol includes the high-yield, mild, metal-free, one-pot reaction conditions, and short reaction time. Furthermore, in many cases, no column chromatography is required for the purification.
Sulfated polyborate-catalyzed efficient and expeditious synthesis of (un)symmetrical ureas and benzimidazolones
Rekunge, Deelip S.,Khatri, Chetan K.,Chaturbhuj, Ganesh U.
supporting information, p. 4304 - 4307 (2017/10/12)
The excellent catalytic potential of sulfated polyborate is utilized in the synthesis of (un)symmetrical ureas and benzimidazolones by heating amines or substituted OPDA and urea or N-phenylureas under a solvent-free condition at 120 °C is described. The key advantages of the present protocol are phosgene-free, and other hazardous reagents or organic solvent free, high reaction rates and yields, simple workup procedure, and recyclability of the catalyst.
An efficient one-pot synthesis of: N, N ′-disubstituted ureas and carbamates from N -acylbenzotriazoles
Singh, Anoop S.,Kumar, Dhananjay,Mishra, Nidhi,Tiwari, Vinod K.
, p. 84512 - 84522 (2016/10/12)
A facile and high-yielding one-pot synthesis of carbamates and N,N′-disubstituted symmetrical ureas from N-acylbenzotriazoles has been devised. It is believed that, the intermediate acyl-azide undergo Curtius rearrangement and in different solvents gives different products i.e. carbamates in alcohols and N,N′-disubstituted symmetrical urea in THF.
Aromatic oligureas as hosts for anions and cations
Connor, Alan L.,Hu, Ting,Detchou, Cadnel S.F.,Liu, Rui,Pulavarti, Surya V.S.R.K.,Szyperski, Thomas,Lu, Zhonglin,Gong, Bing
supporting information, p. 9905 - 9908 (2016/08/11)
Aromatic oligoureas 3 and 4 have urea moieties engaging in weak intramolecular H-bonding that constrains their backbones. The shorter 3a and 3b are able to bind chloride and acetate but not their corresponding counterion. The longer 4 binds both an anion
A simple and efficient synthesis of diaryl ureas with reduction of the intermediate isocyanate by triethylamine
Zhou, Shuguang,Yao, Ting,Yi, Jicheng,Li, Dashuai,Xiong, Jing
, p. 315 - 319 (2013/07/27)
Thirty symmetrical diaryl urea derivatives were synthesised in moderate to excellent yields from arylamine and triphosgene with triethylamine as a reducing agent for the intermediate, isocyanate. It was significant that part of the products could be collected in almost quantitative yield without column chromatography. The procedure under mild reaction conditions was tolerant of a wide range of functional groups. The structures of the compounds were determined by NMR, MS and X-ray crystallographic analyses.
Palladium-catalyzed aromatic azidocarbonylation
Miloserdov, Fedor M.,Grushin, Vladimir V.
supporting information; experimental part, p. 3668 - 3672 (2012/05/20)
Aryl iodides smoothly react with NaN3 and CO in the presence of a Pd/Xantphos catalyst to give aroyl azides (ArCON3) in 75-92 % yield. The reaction occurs under mild reaction conditions (1 atm, 20-50 °C) and exhibits high functional-group tolerance. (Xantphos=9,9-dimethyl-4,5- bis(diphenylphosphino)xanthene)
