- (±)-torreyunlignans A-D, Rare 8-9′ linked neolignan enantiomers as phosphodiesterase-9A inhibitors from torreya yunnanensis
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(±)-Torreyunlignans A-D (1a/1b-4a/4b), four pairs of new 8-9′ linked neolignan enantiomers featuring a rare (E)-2-styryl-1,3-dioxane moiety, were isolated from the trunk of Torreya yunnanensis. The structures were determined by combined spectroscopic and chemical methods, and the absolute configurations were elucidated by ECD calculations. The compounds were screened by using tritium-labeled adenosine 3′,5′-cyclic monophosphate ([3H]-cGMP) as a substrate for inhibitory affinities against phosphodiesterase-9A (PDE9A), which is a potential target for the treatment of diabetes and Alzheimer's disease. All of the enantiomers exhibited inhibition against PDE9A with IC50 values ranging from 5.6 to 15.0 μM. This is the first report of PDE9A inhibitors from nature.
- Cheng, Zhong-Bin,Lu, Xiao,Bao, Jing-Mei,Han, Qing-Hua,Dong, Zhen,Tang, Gui-Hua,Gan, Li-She,Luo, Hai-Bin,Yin, Sheng
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Read Online
- Discovery of novel diphenylbutene derivative ferroptosis inhibitors as neuroprotective agents
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Ferroptosis is a regulated and iron-dependent cell death. Ferroptosis inhibitors are promising for treating many neurological diseases. Herein, with phenotypic assays, we discovered a new diphenylbutene derivative ferroptosis inhibitor, DPT. Based on this hit, we synthesized fourteen new diphenylbutene derivatives, evaluated their ferroptosis inhibitory activities in HT22 mouse hippocampal neuronal cells, and found that three compounds exhibited improved inhibitory activities compared with DPT. Among these active compounds, compound 3f displayed the most potent anti-ferroptosis activity (EC50 = 1.7 μM). Further studies demonstrated that 3f is a specific ferroptosis inhibitor. And we revealed that different from the classic ferroptosis inhibitors, 3f blocked ferroptosis by increasing FSP1 protein level. Moreover, 3f can penetrate blood-brain barrier (BBB). In a rat model of ischemic stroke, 3f effectively mitigated cerebral ischemic injury. Therefore, we are confirmed that 3f, as a novel ferroptosis inhibitor with a new scaffold, is promising for further development as an agent against neurological diseases.
- Fang, Yuying,Gu, Qiong,Tan, Qingyun,Xu, Jun,Zhou, Huihao
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- An efficient Pd@Pro-GO heterogeneous catalyst for the α, β-dehydrogenation of saturated aldehyde and ketones
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An Efficient Pd@Pro-GO heterogeneous catalyst was developed that can promote the α, β-dehydrogenation of saturated aldehyde and ketones in the yield of 73% ? 92% at mild conditions without extra oxidants and additives. Pd@Pro-GO heterogeneous catalyst was synthesized via two steps: firstly, the Pro-GO was obtained by the esterification reaction between graphene oxide (GO) and N-(tert-Butoxycarbonyl)-L-proline (Boc-Pro-OH), followed by removing the protection group tert-Butoxycarbonyl (Boc), which endowed the proline-functionalized GO with both the lewis acid site (COOH) and the bronsted base site (NH), besides, the pyrrolidine of proline also can form imine with aldehydes to activate these substrates; Second, palladium was dispersed on the proline-functionalized GO (Pro-GO) to obtained heterogeneous catalyst Pd@Pro-GO. Mechanistic studies have shown that the Pd@Pro-GO-catalyzed α,β-dehydrogenation of saturated aldehyde and ketones was realized by an improved heterogeneously catalyzed Saegusa oxidation reaction. Based on the obove characteristics, the Pd@Pro-GO will be widely used in the transition metal catalytic field.
- Pan, Gao-Fei,Wang, Zhe,Chang, Yi-Yuan,Hao, Yue,Wang, Yi-Chen,Xing, Rui-Guang
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supporting information
(2021/12/30)
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- Potent Inhibition of Nicotinamide N-Methyltransferase by Alkene-Linked Bisubstrate Mimics Bearing Electron Deficient Aromatics
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Nicotinamide N-methyltransferase (NNMT) methylates nicotinamide (vitamin B3) to generate 1-methylnicotinamide (MNA). NNMT overexpression has been linked to a variety of diseases, most prominently human cancers, indicating its potential as a therapeutic target. The development of small-molecule NNMT inhibitors has gained interest in recent years, with the most potent inhibitors sharing structural features based on elements of the nicotinamide substrate and the S-adenosyl-l-methionine (SAM) cofactor. We here report the development of new bisubstrate inhibitors that include electron-deficient aromatic groups to mimic the nicotinamide moiety. In addition, a trans-alkene linker was found to be optimal for connecting the substrate and cofactor mimics in these inhibitors. The most potent NNMT inhibitor identified exhibits an IC50 value of 3.7 nM, placing it among the most active NNMT inhibitors reported to date. Complementary analytical techniques, modeling studies, and cell-based assays provide insights into the binding mode, affinity, and selectivity of these inhibitors.
- Buijs, Ned,Campagna, Roberto,Emanuelli, Monica,Gao, Yongzhi,Innocenti, Paolo,Jespers, Willem,Martin, Nathaniel I.,Parsons, Richard B.,Sartini, Davide,Van Haren, Matthijs J.,Van Westen, Gerard J. P.,Zhang, Yurui,Gutiérrez-De-Terán, Hugo
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p. 12938 - 12963
(2021/09/11)
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- Tandem oxidation-dehydrogenation of (hetero)arylated primary alcohols via perruthenate catalysis
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Tandem oxidative-dehydrogenation of primary alcohols to give a,b-unsaturated aldehydes in one pot are rare transformations in organic synthesis, with only two methods currently available. Reported herein is a novel method using the bench-stable salt methyltriphenylphosphonium perruthenate (MTP3), and a new co-oxidant NEMO&middoPF6 (NEMO = N-ethyl-N-hydroxymorpholinium) which provides unsaturated aldehydes in low to moderate yields. The Ley-Griffith oxidation of (hetero)arylated primary alcohols with N-oxide co-oxidants NMO (NMO = N-methylmorpholine N-oxide)/NEMO, is expanded by addition of the N-oxide salt NEMO&middoPF6 to convert the intermediate saturated aldehyde into its unsaturated counterpart. The discovery, method development, reaction scope, and associated challenges of this method are highlighted. The conceptual value of late-stage dehydrogenation in natural product synthesis is demonstrated via the synthesis of a polyene scaffold related to auxarconjugatin B.
- Bettencourt, Christian J.,Chow, Sharon,Moore, Peter W.,Read, Christopher D.G.,Jiao, Yanxiao,Bakker, Jan Peter,Zhao, Sheng,Bernhardt, Paul V.,Williams, Craig M.
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p. 652 - 659
(2021/09/08)
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- Selective Rhodium-Catalyzed Hydroformylation of Terminal Arylalkynes and Conjugated Enynes to (Poly)enals Enabled by a π-Acceptor Biphosphoramidite Ligand
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The hydroformylation of terminal arylalkynes and enynes offers a straightforward synthetic route to the valuable (poly)enals. However, the hydroformylation of terminal alkynes has remained a long-standing challenge. Herein, an efficient and selective Rh-catalyzed hydroformylation of terminal arylalkynes and conjugated enynes has been achieved by using a new stable biphosphoramidite ligand with strong π-acceptor capacity, which affords various important E-(poly)enals in good yields with excellent chemo- and regioselectivity at low temperatures and low syngas pressures.
- Zhao, Jiangui,Zheng, Xueli,Tao, Shaokun,Zhu, Yuxin,Yi, Jiwei,Tang, Songbai,Li, Ruixiang,Chen, Hua,Fu, Haiyan,Yuan, Maolin
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supporting information
p. 6067 - 6072
(2021/08/16)
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- One-Pot Preparation of (E)-α,β-Unsaturated Aldehydes by a Julia-Kocienski Reaction of 2,2-Dimethoxyethyl PT Sulfone Followed by Acid Hydrolysis
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(E)-α,β-Unsaturated aldehydes were synthesized by the Julia-Kocienski reaction of 2,2-dimethoxyethyl 1-phenyl-1H-tetrazol-5-yl (PT) sulfone 3 with various aldehydes, followed by acid hydrolysis. The reaction could be carried out in one pot, and various (E)-α,β-unsaturated aldehydes were obtained in a short time and with high yields.
- Ando, Kaori,Watanabe, Haruka,Zhu, Xiaoxian
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p. 6969 - 6973
(2021/05/06)
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- Iron-Catalyzed ?±,?-Dehydrogenation of Carbonyl Compounds
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An iron-catalyzed α,β-dehydrogenation of carbonyl compounds was developed. A broad spectrum of carbonyls or analogues, such as aldehyde, ketone, lactone, lactam, amine, and alcohol, could be converted to their α,β-unsaturated counterparts in a simple one-step reaction with high yields.
- Zhang, Xiao-Wei,Jiang, Guo-Qing,Lei, Shu-Hui,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 1611 - 1615
(2021/03/03)
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- Visible-light mediated facile dithiane deprotection under metal free conditions
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Visible light mediated facile and selective dithiane deprotection under metal free conditions is developed. Eosin Y (1 mol%) proved to be an effective catalyst for the dithiane deprotection under the ambient photoredox conditions. The standard household compact fluorescent light source (CFL bulb) proved to be effective under open-air conditions in aqueous acetonitrile at room temperature. The protocol that exhibits a broad substrate scope and functional group tolerance has been shown to expand to a range of transformations for the electron-rich and -deficient thioacetals and thioketals. The synthetic utility of this protocol has also been demonstrated by gram-scale application.
- Dharpure, Pankaj D.,Bhowmick, Anindita,Warghude, Prakash K.,Bhat, Ramakrishna G.
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- Iron(III)/O2-Mediated Regioselective Oxidative Cleavage of 1-Arylbutadienes to Cinnamaldehydes
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A simple, efficient, and environmentally benevolent regioselective oxidative cleavage of 1-arylbutadienes to cinnamaldehydes mediated by iron(III) sulfate/O2 has been developed. The reaction offered good yields and excellent regioselectivity and showed good functional group tolerance (31 examples). The method is important, as few reports with limited substrate scope are available for such excellent oxidative cleavage of conjugated dienes.
- Bhowmik, Amit,Fernandes, Rodney A.
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supporting information
p. 9203 - 9207
(2019/11/14)
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- Palladium-catalyzed hydroformylation of terminal arylacetylenes with glyoxylic acid
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A simple, practical and governable palladium-catalyzed hydroformylation of terminal arylacetylenes has been disclosed. The reaction proceeds under syngas-free conditions, using readily available glyoxylic acid as the formyl source, under mild conditions, giving rise to a broad range of α,β-unsaturated aldehydes.
- Liu, Yang,Cai, Liangzhen,Xu, Sheng,Pu, Weiwen,Tao, Xiaochun
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supporting information
p. 2166 - 2168
(2018/03/06)
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- Novel Staphyloxanthin Inhibitors with Improved Potency against Multidrug Resistant Staphylococcus aureus
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Diapophytoene desaturase (CrtN) is a potential novel target for intervening in the biosynthesis of the virulence factor staphyloxanthin. In this study, 38 1,4-benzodioxan-derived CrtN inhibitors were designed and synthesized to overwhelm the defects of leading compound 4a. Derivative 47 displayed superior pigment inhibitory activity, better hERG inhibitory properties and water solubility, and significantly sensitized MRSA strains to immune clearance in vitro. Notably, 47 displayed excellent efficacy against pigmented S. aureus Newman, Mu50 (vancomycin-intermediate MRSA, VISA), and NRS271 (linezolid-resistant MRSA, LRSA) comparable to that of linezolid and vancomycin in vivo.
- Ni, Shuaishuai,Li, Baoli,Chen, Feifei,Wei, Hanwen,Mao, Fei,Liu, Yifu,Xu, Yixiang,Qiu, Xiaoxi,Li, Xiaokang,Liu, Wenwen,Hu, Linghao,Ling, Dazheng,Wang, Manjiong,Zheng, Xinyu,Zhu, Jin,Lan, Lefu,Li, Jian
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supporting information
p. 233 - 237
(2018/03/21)
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- Hendrickson reagent induced rearrangement of aryl propargyl alcohols to α,β-unsaturated aldehydes
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The Hendrickson reagent (triphenylphosphonium anhydride trifluoromethanesulfonate), prepared from the reaction of triphenylphosphine oxide (Ph3PO) and triflic anhydride (Tf2O) (2:1 stoichiometry), promotes dehydrations and various coupling reactions. The reagent has been used to transform oximes to nitriles and to prepare esters, amides and many other functional groups through the intermediacy of an alkoxyphosphonium salt. The reagent proved useful in heterocycle synthesis of thiazolines, imidazolines, quinoline precursors, isoquinolines, β-carbolines, phenanthridines, 11H-indolo[3,2-c]quinolines, quinoline-lactones, furoquinolinones, and indolizino[1,2-b]quinolin-9(11H)-ones. Moreover, the reagent has been key to the successful total synthesis of several natural products. Aryl propargyl alcohols with a terminal α-acetylenic group undergo rapid conversion to the corresponding α,β-unsaturated aldehydes at room temperature in dichloromethane in the presence of one equivalent of triphenylphosphonium anhydride trifluoromethanesulfonate. The reaction involved adding freshly distilled Tf2O (1.0 mmol) to a solution of Ph3PO (2.0 mmol) in CH2Cl2 (10 mL) at 0oC under N2 atmosphere. After stirring for 10 min, the propargyl alcohol (1.0 mmol) was added as a CH2Cl2 solution (2 mL), followed by the addition of water and Et3N (2.0 mmol) and further stirring at room temperature for 1h. Subsequent workup with 5% NaHCO3 (20 mL) and purification afforded α,β-unsaturated aldehydes. Eighteen aryl propargyl alcohol substrates with a terminal α-acetylenic group were transformed in good to excellent yields (71-85%) to enals. The methodology proved successful with secondary and tertiary alcohols with stereoselectivity favouring exclusively the E isomer. All the synthesized compounds are known and were characterized (1H,13C, and M.P) and compared to literature values. The method offers several advantages such as exclusive stereoselectivity, short reaction time, good yield, mild reaction conditions, and simple operational procedure.
- Moussa, Ziad,Aljuhani, Ateyatallah
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p. 845 - 853
(2018/11/06)
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- Novel Inhibitors of Staphyloxanthin Virulence Factor in Comparison with Linezolid and Vancomycin versus Methicillin-Resistant, Linezolid-Resistant, and Vancomycin-Intermediate Staphylococcus aureus Infections in Vivo
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Our previous work (Wang et al. J. Med. Chem. 2016, 59, 4831-4848) revealed that effective benzocycloalkane-derived staphyloxanthin inhibitors against methicillin-resistant Staphylococcus aureus (S. aureus) infections were accompanied by poor water solubility and high hERG inhibition and dosages (preadministration). In this study, 92 chroman and coumaran derivatives as novel inhibitors have been addressed for overcoming deficiencies above. Derivatives 69 and 105 displayed excellent pigment inhibitory activities and low hERG inhibition, along with improvement of solubility by salt type selection. The broad and significantly potent antibacterial spectra of 69 and 105 were displayed first with normal administration in the livers and hearts in mice against pigmented S. aureus Newman, Mu50 (vancomycin-intermediate S. aureus), and NRS271 (linezolid-resistant S. aureus), compared with linezolid and vancomycin. In summary, both 69 and 105 have the potential to be developed as good antibacterial candidates targeting virulence factors.
- Ni, Shuaishuai,Wei, Hanwen,Li, Baoli,Chen, Feifei,Liu, Yifu,Chen, Wenhua,Xu, Yixiang,Qiu, Xiaoxia,Li, Xiaokang,Lu, Yanli,Liu, Wenwen,Hu, Linhao,Lin, Dazheng,Wang, Manjiong,Zheng, Xinyu,Mao, Fei,Zhu, Jin,Lan, Lefu,Li, Jian
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supporting information
p. 8145 - 8159
(2017/10/18)
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- Diarylpentadienone derivatives (curcumin analogues): Synthesis and anti-inflammatory activity
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A series of new (2E,4E)-1-(substitutedphenyl)-5-(substitutedphenyl)penta-2,4-dien-1-one derivatives were designed and synthesized. Compounds 3i, 3k were determined by X-ray. All of the compounds have been screened for their anti-inflammatory activity characterized by evaluating their inhibition against LPS-induced IL-6 and TNF-α release in cell RAW 264.7 stimulated with LPS. Compound 3i showed the highest anti-inflammatory activity on decreasing IL-6 and TNF-α. The further study showed that title compound 3i inhibited expression of proteins p-p65, iNOS, COX-2 LPS-induced. Immunofluorescence also revealed compound 3i could lightly reduce activation p65 in nuclei. These results indicate that compound 3i anti-inflammatory role may partly due to its inhibitory effect on the NF-κB signaling pathway.
- Wang, Zhi Sen,Chen, Liu Zeng,Liu, Xin Hua,Chen, Fei Hu
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p. 1803 - 1807
(2017/04/04)
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- Stereoselective organocatalytic oxidation of alcohols to enals: A homologation method to prepare polyenes
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A novel method for organocatalytic oxidation through oxidative enamine catalysis was developed with excellent compatibility for the direct syntheses of enals from simple saturated alcohols. By using this amine-catalyzed IBX-oxidation, a wide range of aromatic and aliphatic substituted enals were successfully generated in high yields and exclusively stereoselective E-geometry. Moreover, varying the solvents and/or the loading amounts of IBX allowed for the selective oxidation of alcohols and aldehydes. Importantly, the homologous application of this method provided a selective and efficient way of preparing various highly sensitive conjugated polyene frameworks, which are enriched in natural products.
- Chen, Xiaobei,Zhang, Yinan,Wan, Huixin,Wang, Wei,Zhang, Shilei
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supporting information
p. 3532 - 3535
(2016/03/04)
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- NMO·TPB: A selectivity variation on the Ley-Griffith TPAP oxidation
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A non-hygroscopic tetraphenylborate salt of N-methylmorpholine-N-oxide (NMO) is reported (NMO·TPB), which modulates the standard Ley-Griffith oxidation such that benzylic and allylic alcohols are oxidised selectively. An attractive feature of this new protocol is that anhydrous conditions are not required for this selective tetra-n-propylammonium perruthenate (TPAP) oxidation, superseding the requirement of molecular sieves.
- Moore, Peter W.,Mirzayans, Paul M.,Williams, Craig M.
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supporting information
p. 3567 - 3571
(2015/03/04)
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- N,N,N′,N′-Tetramethylenediamine dioxide (TMEDAO2) facilitates atom economical/open atmosphere Ley-Griffith (TPAP) tandem oxidation-Wittig reactions
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N,N,N′,N′-Tetramethylethylenediamine dioxide (TMEDAO2) was explored as a more atom economical co-oxidant for the Ley-Griffith oxidation of alcohols to aldehydes. TMEDAO2 was found to selectivity oxidise benzylic and allylic alcohols in comparable yields to that of the standard Ley-Griffith co-oxidant (NMO). Importantly TMEDAO2 facilitated tandem Ley-Griffith-Wittig reactions with stabilised ylides, in good to excellent yields, without the requirement of anhydrous conditions.
- Read, Christopher D. G.,Moore, Peter W.,Williams, Craig M.
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supporting information
p. 4537 - 4540
(2015/09/15)
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- Br?nsted acid-catalyzed meyer-schuster rearrangement for the synthesis of α, β -unsaturated carbonyl compounds
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An efficient and simple protocol for the Meyer-Schuster rearrangement of propargyl alcohols into α,β-unsaturated carbonyl compounds has been developed using catalytic amounts of p-toluenesulfonic acid in 1,2-dichloroethane.
- Park, Jungmin,Yun, Jihee,Kim, Jaehyun,Jang, Dong-Jin,Park, Cheol Ho,Lee, Kooyeon
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p. 1924 - 1929
(2014/07/07)
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- NOVEL DEORDORISING COMPOSITIONS AND DEODORISING PRODUCTS CONTAINING SAME
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The invention relates to novel deodorant compositions containing at least one compound of the family of acetylenic ketones and the deodorant products containing them. A particularly preferred composition according to the invention comprises at least one compound of the family of the α-acetylenic ketones and a mixture of aldehydes chosen from two different families.
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- Direct oxidative conversion of 3-aryl propionaldehydes to 3-aryl acroleins promoted by SOMO catalysis
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A new direct oxidative transformation of 3-aryl propionaldehydes to 3-aryl acroleins promoted by SOMO catalysis has been realized with high efficiency under mild reaction conditions.
- Zhu, Jin,Yu, Shunting,Lu, Wenchao,Deng, Jing,Li, Jian,Wang, Wei
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scheme or table
p. 1207 - 1209
(2012/03/26)
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- Emission wavelength prediction of a full-color-tunable fluorescent core skeleton, 9-aryl-1,2-dihydropyrrolo[3,4-b]indolizin-3-one
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In this paper we report on a novel fluorescent core skeleton, 9-aryl-1,2-dihydropyrrolo[3,4-b]indolizin-3-one, which we named Seoul-Fluor, having tunable and predictable photophysical properties. Using a concise and practical one-pot synthetic procedure, a 68-member library of new fluorescent compounds was synthesized with diverse substituents. In Seoul-Fluor, the electronic characteristics of the substituents, as well as their positional changes, have a close correlation with their photophysical properties. The systematic perturbation of electronic densities on the specific positions of Seoul-Fluor, guided with the Hammett constant, allows emission wavelength tunability covering the full color range. On the basis of these observations and a computational analysis, we extracted a simple first-order correlation of photophysical properties with the theoretical calculation and accurately predicted the emission wavelength of Seoul-Fluors through the rational design. In this study, we clearly demonstrate that Seoul-Fluor can provide a powerful gateway for the generation of desired fluorescent probes without the need for a tiresome synthesis and trial-and-error process.
- Kim, Eunha,Koh, Minseob,Lim, Byung Joon,Park, Seung Bum
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supporting information; experimental part
p. 6642 - 6649
(2011/06/19)
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- Efficient preparation of trans-α,β-unsaturated aldehydes from saturated aldehydes by oxidative enamine catalysis
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A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to (E) selective α,β-unsaturated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to iminium ions in a catalytic fashion.
- Zhang, Shilei,Xie, Hexin,Song, Aiguo,Wu, Deyan,Zhu, Jin,Zhao, Sihan,Li, Jian,Yu, Xinhong,Wang, Wei
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experimental part
p. 1932 - 1936
(2012/03/09)
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- Iron(III) chloride-promoted isomerization of propargyl alcohols to α,β-unsaturated carbonyl compounds
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Aryl propargyl alcohols bearing a terminal alkynyl moiety can undergo a facile iron(III) chloride-promoted transformation to the corresponding α,β-unsaturated aldehyde in good yield and excellent stereoselectivity.
- El Douhaibi, Ahmad Samih,Judeh, Zaher M. A.,Basri, Hedaya,Moussa, Ziad,Messali, Mouslim,Qi, Gao
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p. 533 - 540
(2011/04/22)
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- Rare earth triflates/chlorotrimethylsilane induced activation of triethylamine as a latent acetaldehyde anion: a new synthesis of α,β-unsaturated aldehydes
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A synthetic methodology for α,β-unsaturated aldehydes employing rare earth triflate is reported. Activated triethylamine reacts with aldehydes to form two carbon extended aldehydes, which is promoted by a catalytic amount of Yb, Sc, Y, and In(OTf)3, in the presence of chlorotrimethylsilane. We investigated the conditions applicable to aromatic aldehydes as well as heterocyclic compounds as substrates. A deuterium labeling experiment supported our proposed reaction mechanism.
- Kagawa, Natsuko,Sasaki, Yoshiko,Kojima, Hideo,Toyota, Masahiro
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experimental part
p. 482 - 484
(2010/10/02)
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- Microwave-assisted InCl3-catalyzed Meyer-Schuster rearrangement of propargylic aryl carbinols in aqueous media: a green approach to α,β-unsaturated carbonyl compounds
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A novel, efficient, simple and environmentally benign protocol for the Meyer-Schuster isomerization of propargylic aryl carbinols into α,β-unsaturated carbonyl compounds has been developed using catalytic amounts of InCl3, pure water as the solvent, and microwave irradiation as the heating source.
- Cadierno, Victorio,Francos, Javier,Gimeno, José
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experimental part
p. 4773 - 4776
(2011/03/19)
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- Inhibition of chitin synthases and antifungal activities by 2′-benzoyloxycinnamaldehyde from Pleuropterus ciliinervis and its derivatives
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In the course of search for potent chitin synthase inhibitors from natural resources, a novel chitin synthases inhibitor, 2′-benzoyloxycinnamaldehyde (2′-BCA) (I), was isolated from the aerial parts of Pleuropterus ciliinervis NAKAI. 2′-BCA inhibited chit
- Kang, Tae Hoon,Hwang, Eui Il,Yun, Bong Sik,Park, Ki Duk,Kwon, Byoung Mog,Shin, Chul Soo,Kim, Sung Uk
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p. 598 - 602
(2008/02/02)
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- An efficient and chemoselective deprotection of aryl- and styrenyldithioketals (acetals)
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In this Letter, an efficient and chemoselective deprotection of aryl- and styrenyldithioketals (acetals) is described. After being carefully examined, 10% Pd/C and Amberlite 120 in refluxing methanol was found to be an excellent condition for the chemoselective deprotection of aryl- and styrenyldithioketals (acetals) in good yields. Under this condition, no deprotection and no reduction of alkyldithioketals (acetals) was observed.
- Wang, Eng-Chi,Wu, Chien-Huang,Chien, Shih-Chang,Chiang, Wen-Chang,Kuo, Yueh-Hsiung
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p. 7706 - 7708
(2008/03/30)
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- Oxidative coupling of benzenes with α,β-unsaturated aldehydes by the Pd(OAc)2/molybdovanadophosphoric acid/O2 system
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The oxidative coupling reaction of benzene with an α,β- unsaturated aldehyde was examined by the combined catalytic system of Pd(OAc)2 with molybdovanadophosphoric acid (HPMoV) under atmospheric dioxygen. Thus, the reaction of benzene with acrolein under dioxygen (1 atm) by the use of catalytic amounts of Pd(OAc)2 and H4PMo 11VO40·26H2O in the presence of dibenzoylmethane as a ligand in propionic acid at 90 °C for 1.5 h afforded cinnamaldehyde in 59% yield and β-phenylcinnamaldehyde in 5% yield. This catalytic system was extended to the direct oxidative coupling through the C-H bond activation of various arenes with acrolein and methacrolein.
- Yamada, Tomoyuki,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 5471 - 5474
(2008/04/18)
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- An efficient palladium-catalyzed synthesis of cinnamaldehydes from acrolein diethyl acetal and aryl iodides and bromides
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(Matrix presented) The reaction of aryl iodides and bromides with acrolein diethyl acetal in the presence of Pd(OAc)2, nBu 4NOAc, K2CO3, KCl, and DMF, at 90°C until the disappearance of the acetal followed by the addition of 2 N HCl to the crude reaction mixture, affords cinnamaldehydes in good to high yields. A variety of functional groups are tolerated in the aryl halides, including ether, aldehyde, ketone, ester, dialkylamino, nitrile, and nitro groups. The presence of substituents close to the oxidative addition site does not hamper the reaction.
- Battistuzzi, Gianfranco,Cacchi, Sandro,Fabrizi, Giancarlo
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p. 777 - 780
(2007/10/03)
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- Solid-support-bound 1-aminoimidazolium chlorochromate: A selective, efficient and recyclable oxidant
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A series of polymer-bound imidazolium chlorochromates have been synthesised and used as selective oxidants for benzylic and cinnamylic alcohols. Solid-support-bound 1-amino-imidazolium chlorochromate proved to be the most convenient system due to its efficiency, selectivity and ease of recycling the material.
- Linares,Sánchez,Alajarín,Vaquero,Alvarez-Builla
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p. 382 - 388
(2007/10/03)
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- Sodium bismuthate mediated oxidation of allylic and benzylic alcohols
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A simple and readily available oxidation of primary allylic and benzylic alcohols to the corresponding aldehydes is carried out by sodium bismuthate in acetic acid.
- Banik, Bimal K.,Ghatak, Anjan,Venkatraman,Becker, Frederick F.
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p. 2701 - 2705
(2007/10/03)
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- Phase transfer Wittig reaction with 1,3-dioxolan-2-yl-methyltriphenyl phosphonium salts: An efficient method for vinylogation of aromatic aldehydes
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Aldehydes were efficiently transformed into allylic dioxolanes by a Wittig-type reaction, using 1,3-dioxolan-2-yl-methyltriphenylphosphonium bromide under phase transfer conditions. The substituent kinetic effects were studied, and related to Hammett values and electrochemical potentials.
- Daubresse, Nicolas,Francesch, Charlette,Rolando, Christian
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p. 10761 - 10770
(2007/10/03)
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- Electrocyclization of 3-azahexa-1,3,5-trienes: A convenient iminophosphorane-mediated preparation of 4-arylpyridines
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Aza Wittig reaction of iminophosphoranes 1, derived from α-azido- α,β-unsaturated esters and β-arylpropenals 2 leads to 4-arylpyridines in moderate to good yields.
- Molina, Pedro,Pastor, Aurelia,Vilaplana, Maria Jesus
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p. 3773 - 3776
(2007/10/02)
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