5867-45-8Relevant articles and documents
Synthesis of unsymmetrical urea from aryl- or pyridyl carboxamides and aminopyridines using PhI(OAc)2via in situformation of aryl- or pyridyl isocyanates
Hunjan, Mandeep Kaur,Laha, Joydev K.,Singh, Neha
, p. 18815 - 18823 (2021/10/26)
A tandem synthesis of unsymmetrical ureas (N-aryl-N′-pyridylurea andN,N′-bipyridylurea) from aryl- or pyridyl carboxamides and aminopyridinesviaHofmann rearrangement has been reported. In particular, benzamides, picolinamide, nicotinamide, and isonicotinamide generate reactive intermediate isocyanates,in situ, in the presence of PhI(OAc)2, which upon further reaction with aminopyridines form urea derivatives. As the formation of pyridylisocyanates from their corresponding carboxamidesviaHofmann rearrangement remained unexplored previously, attempts have been made to trap the isocyanates. While the three pyridylisocyanates were trapped as their corresponding carbamates, 3-pyridylisocyanate was isolated and characterized. Unlike closely related previous methods reported for urea synthesis, the current method avoids direct use of isocyanates or eliminates the use of toxic phosgene for thein situgeneration of isocyanates.
Photorelease of Pyridines Using a Metal-Free Photoremovable Protecting Group
Dong, Zaizai,Fang, Xiaohong,Kou, Xiaolong,Tan, Weihong,Tang, Xiao-Jun,Wu, Yayun,Zhang, Zhen,Zhao, Rong,Zhou, Wei
supporting information, p. 18386 - 18389 (2020/08/24)
The photorelease of bioactive molecules has emerged as a valuable tool in biochemistry. Nevertheless, many important bioactive molecules, such as pyridine derivatives, cannot benefit from currently available organic photoremovable protecting groups (PPGs). We found that the inefficient photorelease of pyridines is attributed to intramolecular photoinduced electron transfer (PET) from PPGs to pyridinium ions. To alleviate PET, we rationally designed a strategy to drive the excited state of PPG from S1 to T1 with a heavy atom, and synthesized a new PPG by substitution of the H atom at the 3-position of 7-dietheylamino-coumarin-4-methyl (DEACM) with Br or I. This resulted in an improved photolytic efficiency of the pyridinium ion by hundreds-fold in aqueous solution. The PPG can be applied to various pyridine derivatives. The successful photorelease of a microtubule inhibitor, indibulin, in living cells was demonstrated for the potential application of this strategy in biochemical research.
Sulfuryl Fluoride Mediated Synthesis of Amides and Amidines from Ketoximes via Beckmann Rearrangement
Gurjar, Jitendra,Fokin, Valery V.
supporting information, p. 10402 - 10405 (2020/07/25)
A metal-free and redox-neutral method for Beckmann rearrangement employing inexpensive and readily available SO2F2 gas is described. The reported transformation proceeds at ambient temperature and is compatible with a wide range of sterically and electronically diverse aromatic, heteroaromatic, aliphatic and lignin-like oximes providing amides in good to excellent yields. The reaction proceeds through the formation of an imidoyl fluoride intermediate that can also be used for the synthesis of amidines.
Catalyst-free, direct electrochemical synthesis of annulated medium-sized lactams through C-C bond cleavage
Ackermann, Lutz,Huang, Zhixing,Kuniyil, Rositha,Li, Yueheng,Ruan, Zhixiong,Xu, Zhongnan,Zhang, Chao
supporting information, p. 1099 - 1104 (2020/03/11)
A catalyst-free, direct electrochemical synthesis of synthetically challenging medium-sized lactams through C-C bond cleavage has been developed. In contrast to previous typical amidyl radical cyclization, this electrosynthetic approach enabled step-economical ring expansion through a unique remote amidyl migration under mild, metal- and external-oxidant-free conditions in a simple undivided cell. The strategy features unparalleled broad substrate scope with all ring sizes of (hetero)aryl-fused 8-11-membered rings and hetero atom-tethered rings, high yields, and good functional group tolerance. Our experimental and computational findings provided strong support for a SET-based reaction manifold.
Donor Strength Determination of Pyridinylidene-amide Ligands using Their Palladium-NHC Complexes
Huynh, Han Vinh,Vossen, Jeroen Thomas
supporting information, p. 12486 - 12493 (2020/09/02)
Pyridinylidene-amides (PYAs) are a relatively new type of N-donor ligands that can exist in three isomeric forms and adopt various resonance structures. This makes them electronically flexible, and in order to evaluate their electronic profile using the Huynh electronic parameter (HEP), seven structurally diverse mixed N-heterocyclic carbenes (NHCs)/PYA palladium complexes of the type trans-[PdBr2(iPr2-bimy)(PYA)] were prepared and fully characterized by various spectroscopic and spectrometric methods. This study shows that PYAs are among the strongest, formally neutral N-donors, but they are still weaker than phosphines and organometallic ligands such as NHCs. Notably, the donating abilities of isomeric PYAs are distinct and can be further fine-tuned by the choice of two substituents making them structurally and electronically versatile. These characteristics and the ease of their preparation hold promise for a wide applicability in coordination chemistry.
BICYCLIC COMPOUNDS AS INHIBITORS OF PD1/PD-L1 INTERACTION/ACTIVATION
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Paragraph 00098, (2019/10/04)
The compounds of Formula I is described herein along with their polymorphs, stereoisomers, tautomers, prodrugs, solvates, and pharmaceutically acceptable salts thereof. The compounds described herein, their polymorphs, stereoisomers, tautomers, prodrugs, solvates, and pharmaceutically acceptable salts thereof are bicyclic compounds that are inhibitors of PD-1/PD-L1 interaction/activation.
Mild, calcium catalysed Beckmann rearrangements
Kiely-Collins,Sechi,Brennan,McLaughlin
supporting information, p. 654 - 657 (2018/02/06)
A mild calcium catalysed Beckmann rearrangement has been realised, which forgoes the more traditional harsh reactions conditions associated with the transformation. The catalyst system is shown to be tolerant towards a wide variety of functional groups relevant to natural product synthesis and medicinal chemistry and the synthetic utility of the reaction has also been investigated. A preliminary mechanistic investigation was performed to understand the nature of the incoming nucleophile and a possible reaction pathway is described.
A reliable one-pot synthesis of aryl azides from aryl amines using organotin azides as effective and recoverable reagents
Godoy Prieto, Leonela,Lo Fiego, Marcos J.,Chopa, Alicia B.,Lockhart, María T.
, p. 26 - 32 (2016/12/18)
A mild and mass-efficient procedure based on the one-pot diazotization-azidodediazoniation of aromatic amines is described. A wide range of aryl azides are obtained in moderate to high yields by using tributyltin azide as an effective and reusable azide source in the presence of p-toluenesulfonic acid at room temperature. The method was also successfully applied employing an insoluble polymer-supported organotin azide.
A new transformation of aminopyridines upon diazotization in acetonitrile with the formation of N-pyridinylacetamides
Chudinov,Dovbnya,Krasnokutskaya,Ogorodnikov,Filimonova
, p. 2312 - 2314 (2017/05/12)
Diazotization of aminopyridines upon treatment with NaNO2 and H3PO4 in acetonitrile led to the formation of N-pyridinylacetamides. This reaction constitutes a convenient and general preparative method for the synthesis of 2-, 3-, and 4-N-pyridinylacetamides under mild conditions in good yields. The in situ oxidation of the thus obtained N-pyridinylacetamides with hydrogen peroxide gave good yields of pyridinylacetamide N-oxides.
2-Aminopyridines as an α-Bromination Shuttle in a Transition Metal-Free One-Pot Synthesis of Imidazo[1,2-a]pyridines
Roslan, Irwan Iskandar,Ng, Kian-Hong,Chuah, Gaik-Khuan,Jaenicke, Stephan
, p. 364 - 369 (2016/04/26)
A wide range of imidazo[1,2-a]pyridines are accessible from cheap and readily available 2-aminopyridines and 1,3-dicarbonyl compounds using a unique CBrCl3/2-aminopyridine system for bromination at the α-carbon. 2-Aminopyridine is not only the substrate but also acts as a bromination shuttle, transferring the bromine atom from CBrCl3 to the α-carbon of the 1,3-dicarbonyl. The reaction mechanism involves a series of reversible steps, including an addition reaction with cyclic transition state, to form a bromo-hemiaminal intermediate. Isolated yields of up to 97% were obtained under mild conditions and at short reaction times in this transition metal-free, one-pot synthesis.
