1613-43-0Relevant articles and documents
Polar Effects in Free-Radical Reactions. Homolytic Heteroaromatic Substitutions by Alkyl Bromides
Minisci, Francesco,Fontana, Francesca,Pianese, Guiseppe,Yan, Yong Ming
, p. 4207 - 4211 (1993)
Alkyl bromides have been utilized for the first time as radical sources for heteroaromatic substitution.A variety of procedures was revealed to be successful for bromine abstraction: Bu3SnH with AIBN, (Me3Si)3SiH with AIBN, Ph2SiH2, or Et3SiH associated with peroxides (H2O2, t-BuOOH, (t-BuO)2, (t-BuOOCO)2, (PhCOO)2).The importance of the polar effects is discussed.
Minisci-Type Alkylation of N-Heteroarenes by N-(Acyloxy)phthalimide Esters Mediated by a Hantzsch Ester and Blue LED Light
Li, Jiacheng,Siang Tan, Suan,Kyne, Sara Helen,Wai Hong Chan, Philip
, p. 802 - 810 (2022/01/11)
A synthetic method that enables the Hantzsch ester-mediated Minisci-type C2-alkylation of quinolines, isoquinolines and pyridines by N-(acyloxy)phthalimide esters (NHPI) under blue LED (light emitting diode) light (456 nm) is described. Achieved under mild reaction conditions at room temperature, the metal-free synthetic protocol was shown to be applicable to primary, secondary and tertiary NHPIs to give the alkylated N-heterocyclic products in yields of 21–99%. On introducing a chiral phosphoric acid, an asymmetric version of the reaction was also realised and provided product enantiomeric excess (ee) values of 53–99%. The reaction mechanism was delineated to involve excitation of an electron-donor acceptor (EDA) complex, formed from weak electrostatic interactions between the Hantzsch ester and NHPI, which generates the posited radical species of the redox active ester that undergoes addition to the N-heterocycle.
Visible-light-mediated photoredox minisci C-H alkylation with alkyl boronic acids using molecular oxygen as an oxidant
Dong, Jianyang,Yue, Fuyang,Song, Hongjian,Liu, Yuxiu,Wang, Qingmin
supporting information, p. 12652 - 12655 (2020/11/02)
Herein, we report a protocol for direct visible-light-mediated Minisci C-H alkylation reactions of heteroarenes with alkyl boronic acids using molecular oxygen as the sole oxidant. This mild protocol uses an inexpensive, green oxidant; permits efficient functionalization of various N-heteroarenes with a broad range of primary and secondary alkyl boronic acids; and is scalable to the gram level. We demonstrated the practicality and sustainability of the protocol by preparing or functionalizing several pharmaceuticals and natural products.
Minisci C?H Alkylation of Heteroarenes Enabled by Dual Photoredox/Bromide Catalysis in Micellar Solutions**
Santos, Marilia S.,Cybularczyk-Cecotka, Martyna,K?nig, Burkhard,Giedyk, Maciej
supporting information, p. 15323 - 15329 (2020/10/26)
Aromatic heterocycles are omnipresent structural motifs in various natural products, pharmaceuticals and agrochemicals. This work describes a photocatalytic Minisci-type C?H functionalization of heteroarenes with non-activated alkyl bromides. The reaction avoids stoichiometric radical-promoters, oxidants, or acids, and is conducted using blue LEDs as the light source. The reactive carbon-centered alkyl radicals are generated by merging the photoredox approach with bromide anion co-catalysis and spatial pre-aggregation of reacting species in the micellar aqueous solutions. The obtained data highlight the critical importance of microstructuring and organization of the components in the reaction mixture.
Visible-Light-Mediated C-H Alkylation of Pyridine Derivatives
Rammal, Fatima,Gao, Di,Boujnah, Sondes,Gaumont, Annie-Claude,Hussein, Aqeel A.,Lakhdar, Sami
, p. 7671 - 7675 (2020/10/09)
We report herein a visible-light-mediated C-H alkylation of pyridine derivatives that proceeds by simple combination of a large variety of N-alkoxypyridinium ions with alkanes in the presence of 2 mol % of fac-Ir(ppy)3 under blue illumination. The mild reaction conditions together with the high group functional tolerance make of this process a useful synthetic platform for the construction of structurally strained heterocycles. Detailed mechanistic investigations, including density functional theory calculations and quantum yield measurement, allowed us to understand factors controlling the reactivity and the selectivity of the reaction.
Preparation of 2-Arylquinolines from 2-Arylethyl Bromides and Aromatic Nitriles with Magnesium and N -Iodosuccinimide
Naruto, Hiroki,Togo, Hideo
, p. 1122 - 1130 (2020/04/01)
Treatment of 2-arylethylmagnesium bromides, prepared from 2-arylethyl bromides and magnesium, with aromatic nitriles, followed by reaction with water and then with N -iodosuccinimide under irradiation with a tungsten lamp, gave the corresponding 2-arylquinolines in good to moderate yields under transition-metal-free conditions. 2-Alkylquinolines could be also obtained in moderate yields by the same procedure with 2-arylethyl bromides, magnesium, aliphatic nitriles bearing a secondary alkyl group, and N -iodosuccinimide.
Visible-light-mediated Minisci C-H alkylation of heteroarenes with unactivated alkyl halides using O2 as an oxidant
Dong, Jianyang,Lyu, Xueli,Wang, Zhen,Wang, Xiaochen,Song, Hongjian,Liu, Yuxiu,Wang, Qingmin
, p. 976 - 982 (2019/02/03)
Herein, we report a protocol for direct visible-light-mediated Minisci C-H alkylation of heteroarenes with unactivated alkyl halides using molecular oxygen as an oxidant at room temperature. This mild protocol is compatible with a wide array of sensitive
Green synthesis of silver nanoparticles using green alga (Chlorella vulgaris) and its application for synthesis of quinolines derivatives
Mahajan, Akhil,Arya, Anju,Chundawat, Tejpal Singh
supporting information, p. 1926 - 1937 (2019/05/17)
Nanoparticles have been used century ago but have regained their importance in recent years being simple, ecofriendly, pollutant free, nontoxic, low-cost approach, and due good atom economy. In this report, we have demonstrated the synthesis of silver nanoparticles using green algae (Chlorella vulgaris) which in turn was used for synthesis of biologically important quinolines. Algal extract was prepared and treated with silver nitrate solution for the synthesis of silver nanoparticles. Synthesized nanoparticles were characterized with the help of analytical tools like UV, FTIR, X-ray, and SEM and used as a catalyst for the synthesis of quinolines.
Organocatalyzed, Visible-Light Photoredox-Mediated, One-Pot Minisci Reaction Using Carboxylic Acids via N-(Acyloxy)phthalimides
Sherwood, Trevor C.,Li, Ning,Yazdani, Aliza N.,Dhar, T. G. Murali
, p. 3000 - 3012 (2018/03/09)
An improved, one-pot Minisci reaction has been developed using visible light, an organic photocatalyst, and carboxylic acids as radical precursors via the intermediacy of in situ-generated N-(acyloxy)phthalimides. The conditions employed are mild, demonstrate a high degree of functional group tolerance, and do not require a large excess of the carboxylic acid reactant. As a result, this reaction can be applied to drug-like scaffolds and molecules with sensitive functional groups, enabling late-stage functionalization, which is of high interest to medicinal chemistry.
A visible light-driven minisci-type reaction with N-hydroxyphthalimide esters
Kammer, Lisa Marie,Rahman, Aliyaah,Opatz, Till
, (2018/04/06)
A visible light-promoted protocol for the redox-neutral coupling of N-hydroxyphthalimide esters with different N-heterocyclic compounds is described. The reaction proceeds through an alkyl radical intermediate generated by reductive decarboxylation of N-hydroxyphthalimide esters. In contrast to the original Minisci protocol, polyalkylation can largely be avoided. Mechanistic investigations revealed a radical chain mechanism which in some cases can proceed even if no photocatalyst is added. This valuable and functional group-tolerant reaction produces substituted heterocycles in moderate to excellent yield. The use of inexpensive starting materials and LEDs as the light source are key features of this C–C bond formation.
