3488-00-4Relevant academic research and scientific papers
N-Heterocyclic Carbene Catalyzed Ester Synthesis from Organic Halides through Incorporation of Oxygen Atoms from Air
Tan, Hui,Wang, Shen-An,Yan, Zixi,Liu, Jianzhong,Wei, Jialiang,Song, Song,Jiao, Ning
supporting information, p. 2140 - 2144 (2020/12/01)
Oxygenation reactions with molecular oxygen (O2) as the oxygen source provides a green and straightforward strategy for the construction of O-containing compounds. Demonstrated here is a novel N-heterocyclic carbene (NHC) catalyzed oxidative transformation of simple and readily available organic halides into valuable esters through the incorporation of O-atoms from O2. Mechanistic studies prove that the deoxy Breslow intermediate generated in situ is oxidized to a Breslow intermediate for further transformation by this oxidative protocol. This method broadens the field of NHC catalysis and promotes oxygenation reactions with O2.
Cesium Carbonate Catalyzed Esterification of N-Benzyl- N-Boc-amides under Ambient Conditions
Ye, Danfeng,Liu, Zhiyuan,Chen, Hao,Sessler, Jonathan L.,Lei, Chuanhu
supporting information, p. 6888 - 6892 (2019/09/07)
We report a general activated amide to ester transformation catalyzed by Cs2CO3. Using this approach, esterification proceeds under relatively mild conditions and without the need for a transition metal catalyst. This method exhibits broad substrate scope and represents a practical alternative to existing esterification strategies. The synthetic utility of this protocol is demonstrated via the facile synthesis of crown ether derivatives and the late-stage modification of a representative natural product and several sugars in reasonable yields.
Synthesis of (E)-cinnamyl ester derivatives via a greener Steglich esterification
Lutjen, Andrew B.,Quirk, Mackenzie A.,Barbera, Allycia M.,Kolonko, Erin M.
, p. 5291 - 5298 (2018/05/04)
Cinnamic acid derivatives are known antifungal, antimicrobial, antioxidant, and anticancer compounds. We have developed a facile and mild methodology for the synthesis of (E)-cinnamate derivatives using a modified Steglich esterification of (E)-cinnamic acid. Using acetonitrile as the solvent, rather than the typical chlorinated solvent, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) as the coupling agent enables ester conversion in 45 min with mild heating (40–45 °C) and an average yield of 70% without need for further purification. These conditions were used to couple (E)-cinnamic acid with 1° and 2° aliphatic alcohols, benzylic and allylic alcohols, and phenols. This work demonstrates a facile and greener methodology for Steglich esterification reactions.
Bioactivity and structure–activity relationship of cinnamic acid derivatives and its heteroaromatic ring analogues as potential high-efficient acaricides against Psoroptes cuniculi
Chen, Dong-Dong,Zhang, Bing-Yu,Liu, Xiu-Xiu,Li, Xing-Qiang,Yang, Xin-Juan,Zhou, Le
supporting information, p. 1149 - 1153 (2018/03/05)
A series of cinnamic acid derivatives and its heteroaromatic ring analogues were synthesized and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. Among them, eight compounds showed the higher activity with median lethal concentrations (LC50) of 0.36–1.07 mM (60.4–192.1 μg/mL) and great potential for the development of novel acaricidal agent. Compound 40 showed both the lowest LC50 value of 0.36 mM (60.4 μg/mL) and the smallest median lethal time (LT50) of 2.6 h at 4.5 mM, comparable with ivermectin [LC50 = 0.28 mM (247.4 μg/mL), LT50 = 8.9 h], an acaricidal drug standard. SAR analysis showed that the carbonyl group is crucial for the activity. The type and chain length of the alkoxy in the ester moiety and the steric hindrance near the ester group significantly influence the activity. The esters were more active than the corresponding thiol esters, amides, ketones or acids. Replacement of the phenyl group of cinnamic esters with α-pyridyl or α-furanyl significantly increase the activity. Thus, a series of cinnamic esters and its heteroaromatic ring analogues with excellent acaricidal activity emerged.
Bioactivity and structure-activity relationship of cinnamic acid esters and their derivatives as potential antifungal agents for plant protection
Zhou, Kun,Chen, Dongdong,Li, Bin,Zhang, Bingyu,Miao, Fang,Zhou, Le
, (2017/04/26)
A series of cinnamic acid esters and their derivatives were synthesized and evaluated for antifungal activities in vitro against four plant pathogenic fungi by using the mycelium growth rate method. Structure-activity relationship was derived also. Almost all of the compounds showed some inhibition activity on each of the fungi at 0.5 mM. Eight compounds showed the higher average activity with average EC50 values of 17.4-28.6 μg/mL for the fungi than kresoxim-methyl, a commercial fungicide standard, and ten compounds were much more active than commercial fungicide standards carbendazim against P. grisea or kresoxim-methyl against both P. grisea and Valsa Mali. Compounds C1 and C2 showed the higher activity with average EC50 values of 17.4 and 18.5 μg/mL and great potential for development of new plant antifungal agents. The structure-activity relationship analysis showed that both the substitution pattern of the phenyl ring and the alkyl group in the alcohol moiety significantly influences the activity. There exists complexly comprehensive effect between the substituents on the phenyl ring and the alkyl group in the alcohol moiety on the activity. Thus, cinnamic acid esters showed great potential the development of new antifungal agents for plant protection due to high activity, natural compounds or natural compound framework, simple structure, easy preparation, low-cost and environmentally friendly.
2,2,6,6-Tetramethylpiperidinium triflate (TMPT): a highly selective and self-separated catalyst for esterification
Gao, Lan,Liu, Taoping,Tao, Xiaochun,Huang, Yongmin
supporting information, p. 4905 - 4909 (2016/10/24)
An eco-friendly and readily accessible 2,2,6,6-tetramethylpiperidinium triflate was found as highly-selective and self-separated catalyst for esterification under solvent-free condition. The X-ray crystallography revealed that it formed a ‘hydrophobic wall’ which could effectively eliminate the generated water from the reactive sites. Moreover, it could precipitate from the reaction system with excellent recovery ratio (>99%) and be reused for ten times without any significant loss of activity.
Nickel-Catalyzed Esterification of Aliphatic Amides
Hie, Liana,Baker, Emma L.,Anthony, Sarah M.,Desrosiers, Jean-Nicolas,Senanayake, Chris,Garg, Neil K.
, p. 15129 - 15132 (2016/11/25)
Recent studies have demonstrated that amides can be used in nickel-catalyzed reactions that lead to cleavage of the amide C?N bond, with formation of a C?C or C?heteroatom bond. However, the general scope of these methodologies has been restricted to amides where the carbonyl is directly attached to an arene or heteroarene. We now report the nickel-catalyzed esterification of amides derived from aliphatic carboxylic acids. The transformation requires only a slight excess of the alcohol nucleophile and is tolerant of heterocycles, substrates with epimerizable stereocenters, and sterically congested coupling partners. Moreover, a series of amide competition experiments establish selectivity principles that will aid future synthetic design. These studies overcome a critical limitation of current Ni-catalyzed amide couplings and are expected to further stimulate the use of amides as synthetic building blocks in C?N bond cleavage processes.
Antiallergic activity of rosmarinic acid esters is modulated by hydrophobicity, and bulkiness of alkyl side chain
Zhu, Fengxian,Xu, Zhongming,Yonekura, Lina,Yang, Ronghua,Tamura, Hirotoshi
, p. 1178 - 1182 (2015/10/05)
Methyl, propyl and hexyl esters of rosmarinic, caffeic and p-coumaric acids were tested for antiallergic activity, and rosmarinic acid propyl ester exhibited the greatest β-hexosaminidase release suppression (IC50, 23.7 μM). Quadratic correlations between pIC50 and cLogP (r2 = 0.94, 0.98, and 1.00, respectively) were observed in each acid ester series. The antiallergic activity is modulated by hydrophobicity, and alkyl chain bulkiness.
SO3H and NH2+ functional carbon-based solid acid catalyzed transesterification and biodiesel production
Cai, Liangzhen,Meng, Decai,Zhan, Shaoqi,Yang, Xiaoxia,Liu, Taoping,Pu, Huiming,Tao, Xiaochun
, p. 72146 - 72149 (2015/09/08)
A SO3H and NH2+ functional carbon-based solid acid was used as a highly active heterogeneous catalyst for the transesterification of various carboxylic methyl esters with alcohols under mild conditions. It also showed high catalytic performance for transesterification of triolein with methanol or isopropanol. Furthermore, it was able to catalyze simultaneous esterification and transesterification of rice oil and butter respectively, the yields of biodiesel obtained were up to 94%, and the catalyst could be easily recovered and reused more than ten times without loss of activity, which indicated the carbon-based solid acid was a potential catalyst for the biodiesel industry.
The carbon material functionalized with NH2+ and SO3H groups catalyzed esterification with high activity and selectivity
Zhan, Shaoqi,Tao, Xiaochun,Cai, Liangzhen,Liu, Xiaohui,Liu, Taoping
supporting information, p. 4649 - 4653 (2015/02/19)
A novel carbon-based solid acid was conveniently prepared by heating a mixture of d-glucose, p-toluenesulfonic acid and diphenylammonium tosylate. Its structure was measured by XRD, FT-IR, XPS, 13C MAS NMR and EA to illustrate that the carbon material has been functionalized with NH2+ and SO3H groups and has a strong "hydrophobic effect". It can be used to catalyze the esterification reaction of carboxylic acids with equimolar amounts of sterically demanding and acid-sensitive alcohols with high reactivity (yield up to 90%) and selectivity (up to 95%) in heptane at 80 °C. It could be easily recovered and reused more than ten times without loss of activity.
