1149-24-2Relevant academic research and scientific papers
Reductive amination of aldehydes and ketones by a Hantzsch dihydropyridine using scandium triflate as a catalyst
Itoh, Takashi,Nagata, Kazuhiro,Kurihara, Ayako,Miyazaki, Michiko,Ohsawa, Akio
, p. 3105 - 3108 (2002)
Direct reductive amination of aldehydes and ketones was carried out using a Hantzsch dihydropyridine as a reducing agent in the presence of a catalytic amount of a Lewis acid.
Oxidative-aromatization of hantzsch ester 1,4-dihydropyridines by KBrO 3/Cocl2.6H2O under mild condition
Dilmaghani, Karim Akbari,Zeynizadeh, Behzad,Mirzaei, Mansoor
, p. 139 - 142 (2007)
KBrO3/CoCl2.6H2O system was used as an effective oxidizing agent for the oxidation of 1,4-dihydropyridines to the corresponding pyridine derivatives in refluxing CH3CN. The products were obtained in high to exce
Photoinduced Aromatization of Dihydropyridines
Lu, Zheng,Yang, Yong-Qing,Li, Hong-Xia
, p. 4221 - 4227 (2016)
The combination of tris(bipyridine)ruthenium(II)/visible light/air is found to be effective for the aromatization of many dihydropyridines. A low catalyst loading of just 0.02 mol% is required.
A novel, facile, simple and convenient oxidative aromatization of Hantzsch 1,4-dihydropyridines to pyridines using polymeric iodosobenzene with KBr
Kumar, Parvin
, p. 1429 - 1433 (2010)
An easy, safe, effective and handy method for oxidative aromatization of Hantzsch 1,4-dihydropyridines catalyzed by hypervalent iodine (iodosobenzene) and potassium bromide to corresponding pyridine derivatives in high-yields and within short span of time was described. Dealkylation in case of 4-n-alkyl substituted 1,4-dihydropyridines was not obtained.
Histidine-Specific Peptide Modification via Visible-Light-Promoted C-H Alkylation
Chen, Xiaoping,Ye, Farong,Luo, Xiaosheng,Liu, Xueyi,Zhao, Jie,Wang, Siyao,Zhou, Qingqing,Chen, Gong,Wang, Ping
, p. 18230 - 18237 (2019)
Histidine (His) carries a unique heteroaromatic imidazole side chain and plays irreplaceable functional roles in peptides and proteins. Existing strategies for site-selective histidine modification predominantly rely on the N-substitution reactions of the moderately nucleophilic imidazole group, which inherently suffers from the interferences from lysine and cysteine residues. Chemoselective modification of histidine remains one of the most difficult challenges in peptide chemistry. Herein, we report peptide modification via radical-mediated chemoselective C-H alkylation of histidine using C4-alkyl-1,4-dihydropyridine (DHP) reagents under visible-light-promoted conditions. The method exploits the electrophilic reactivity of the imidazole ring via a Minisci-type reaction pathway. This method exhibits an exceptionally broad scope for both peptides and DHP alkylation reagents. Its utility has been demonstrated in a series of important peptide drugs, complex natural products, and a small protein. Distinct from N-substitution reactions, the unsubstituted nitrogen groups of the modified imidazole ring are conserved in the C-H alkylated products.
Formation of pyridines from N-methylpyrimidinium iodide and enaminoesters
Gromov, S. P.,Razinkin, M. A.
, p. 1272 - 1275 (1995)
The reaction of N-methylpyrimidinium iodide with enaminoesters yiels a mixture of 3-ethoxycarbonyl-2-methylpyridine and 3,5-diethoxycarbonyl-2,6-dimethylpyridine.Mechanisms of the transformations of the pyrimidine ring found are suggested. - Keywords: N-methylpyridinium iodide; enaminoesters; ring transformation; pyridines; β-substituted.
The Aromatization of Hantzsch Dihydropyridines with Nitric Oxide (NO)
Itoh, Takashi,Nagata, Kazuhiro,Okada, Mamiko,Ohsawa, Akio
, p. 2269 - 2272 (1995)
Hantzsch dihydropyridines were readily oxidized by nitric oxide to give corresponding pyridines in quantitative yields.This reaction system required no work-up procedure.In the presence of oxygen, it was possible to reduce nitric oxide to less than an equ
Additive-controlled synthesis of 1- and 2-dexoysugars from thioglycosides
Gao, Chen-Fei,Wu, Biao,Wu, Xia,Xiong, De-Cai,Ye, Xin-Shan
, (2021/12/29)
Two photoreactions for the synthesis of 1- and 2-deoxysugars from thioglycosides were developed. In the presence of Hantzsch ester as an additive, a wide range of 1-deoxysugars were synthesized in moderate to excellent yields under irradiation with UV light without an exogenous photosensitizer. On the other hand, the utilization of 2,4,6-tri-tert-butylpyrimidine (TTBP) as the additive furnished a variety of 2-deoxysugars as the main products from their corresponding thioglycosides. The reported methodology has a broad substrate scope and high functional group tolerance and is scalable to gram-scale reaction.
The photoredox-catalyzed hydrosulfamoylation of styrenes and its application in the novel synthesis of naratriptan
Zhang, Mingjun,Chen, Miaomiao,Ding, Xin,Kang, Jin,Gao, Yongyue,He, Xingxing,Wang, Ziwen,Lu, Aidang,Wang, Qingmin
supporting information, p. 9140 - 9143 (2021/09/14)
The hydrosulfamoylation of diverse aryl olefins provides facile access to alkylsulfonamides. Here we report a novel protocol utilizing radical-mediated addition and a thiol-assisted strategy to achieve the hydrosulfamoylation of diverse styrenes in modest to excellent yields under mild and economic reaction conditions. The methodology was found to provide an efficient and convenient approach for the synthesis of the anti-migraine drug naratriptan and it also can be used for the late-stage functionalization of natural products or medicines.
Visible-light-driven external-photocatalyst-free alkylative carboxylation of alkenes with CO2
Niu, Ya-Nan,Jin, Xing-Hao,Liao, Li-Li,Huang, He,Yu, Bo,Yu, Yu-Ming,Yu, Da-Gang
, p. 1164 - 1169 (2021/06/17)
Herein, we report a novel protocol for visible-light-driven alkylative carboxylation of alkenes with CO2 in the absence of external photocatalyst. Under the irradiation of visible light, a variety of 4-alkyl-1,4-dihydropyridines (alkyl-DHPs) serve as not only alkyl radical precursors but also photoexcited reductants probably with the potential to reduce benzyl radicals. Several styrenes and acrylates are applicable in this reaction to give structurally diverse carboxylic acids in good to excellent yields. These reactions feature mild reaction conditions (1 atm of CO2, room temperature, visible light, photocatalyst- and transition metal-free), good functional group tolerance, easy scalability, as well as high regio-, and chemo-selectivity. Mechanistic investigations provide evidence that alkyl radical, benzyl radical and carbanion might be involved in this reaction, providing a novel strategy for CO2 utilization.[Figure not available: see fulltext.]
