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.
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).
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.
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
