- Copper-Catalyzed Synthesis of Trifluoroethylarenes from Benzylic Bromodifluoroacetates
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Trifluoroethylarenes are found in a variety of biologically active molecules, and strategies for accessing this substructure are important for developing therapeutic candidates and biological probes. Trifluoroethylarenes can be directly accessed via nucleophilic trifluoromethylation of benzylic electrophiles; however, current catalytic methods do not effectively transform electron-deficient substrates and heterocycles. To address this gap, we report a Cu-catalyzed decarboxylative trifluoromethylation of benzylic bromodifluoroacetates. To account for the tolerance of sensitive functional groups, we propose an inner-sphere mechanism of decarboxylation.
- Ambler, Brett R.,Zhu, Lingui,Altman, Ryan A.
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- Photobromination of Side-Chain Methyl Groups on Arenes with N-Bromosuccinimide - Convenient and Selective Syntheses of Bis(bromomethyl)- and (Bromomethyl)methylarenes -
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Photobromination of side-chain methyl groups on arenes with N-bromosuccinimide (NBS) was investigated.Visible light irradiation in benzene solvent was extremely effective in increasing the selectivity of the reaction and the efficiency for product purification.The photobromination of 1,4-, 1,8, 2,3-, and 2,6-dimethylnaphthalenes, 4,4'-dimethylbiphenyl, and p-xylene with 2.2 mol equivalents of NBS quantitatively afforded the corresponding bis(bromomethyl)arenes, respectively.The (bromomethyl)methylarenes were also obtained in good yields in the photobromination reactions of the above dimethylarenes with 1.1 mol equivalents of NBS.
- Futamura, Shigeru,Zong, Zhi-Min
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- Kinetics and activation energy of the oxidation of para-tolyl radical by cobalt(III) in acetic acid: Competition kinetics
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The title reaction gives rise to a benzylic cation that is rapidly transformed to its bromide in competition with the reaction of the radical with carbon tetrachloride. Experiments were carried out over 17-69°C in acetic acid containing cobalt(II) acetate, para-xylene, hydrobromic acid, carbon tetrachloride, and meta-chloroperoxybenzoic acid. The product ratio, ArCH 2Cl/ArCH2Br, in combination with other pertinent rate constants, was used to determine the rate constant for the step of interest: log script k sign (L mol-1 s-1) = 19.9 - (75 ± 11 kJ mol-1/2.303 RT). The large pre-exponential factor, which gives ΔS? = 128 J K-1 mol-1, signals an unusual transition state, because a negative value of ΔS? would be expected for a simple bimolecular reaction. The production of the ion pair ArCH 2+||OAc- in HOAc, which has the same dielectric constant as benzene, may be responsible, at least in part. Furthermore, inner sphere reorganization of cobalt may also contribute.
- Espenson, James H.,Yiu, Douglas Tak-Yeung
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- [1,3]-Claisen rearrangement via removable functional group mediated radical stabilization
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A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermal rearrangement via stabilization of a radical intermediate. Experimental and theoretical evidence for dissociative radical pair formation, its captodative stability via aminothiophenol, and a unique solvent effect are presented. The aminothiophenol was deprotected from rearrangement products as well as after derivatization to useful synthons.
- Alam, Md Nirshad,Dash, Soumya Ranjan,Mukherjee, Anirban,Pandole, Satish,Marelli, Udaya Kiran,Vanka, Kumar,Maity, Pradip
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supporting information
p. 890 - 895
(2021/02/01)
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- Synthesis, Docking, and Biological activities of novel Metacetamol embedded [1,2,3]-triazole derivatives
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ERα controls the breast tissue development and progression of breast cancer. In our search for novel compounds to target Estrogen Receptor Alpha Ligand-Binding Domain, we identified “N-(3-((1H-1,2,3-triazol-4-yl)methoxy)phenyl)acetamide” derivatives as lead compounds. The Docking studies indicated good docking score for Metacetamol derivatives when docked into the 1XP6. A series of metacetamol derivatives have been synthesized, characterized and evaluated for cytotoxicity, anti bacterial and anti oxidant activities. Among the tested twelve hybrid compounds, “7a, 7g, 7h and 7i” derivatives showed promising cytotoxicity with IC50 value of 50 value of 30 μM, whereas Compounds “7a, 7b, 7c, 7d, 7g, 7j, 7k and 7l” showed moderate anti bacterial activity with the MIC value of 300 μM.
- Battu, Satyanarayana,Joolakanti, Hima Bindhu,Kamepalli, Ramanjaneyulu,Miryala, Jeevanreddy
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- New 3-(1H-benzo[d]imidazol-2-yl)quinolin-2(1H)-one-based triazole derivatives: Design, synthesis, and biological evaluation as antiproliferative and apoptosis-inducing agents
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A series of 1,2,3-triazole derivatives based on the quinoline–benzimidazole hybrid scaffold was designed, synthesized, and screened against a panel of NCI-60 humanoid cancer cell lines for in vitro cytotoxicity evaluation, which revealed that compound Q6 was the most potent cytotoxic agent with excellent GI50, TGI, and LC50 values on multiple cancer cell lines. Q6 was tested further on the BT-474 breast cancer line to evaluate the mechanism of action. Preliminary screening studies based on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay revealed that compound Q6 had an excellent antiproliferative effect against human breast cancer cells, BT-474, with IC50 values of 0.59 ± 0.01 μM. The detailed study based on the acridine orange/ethidium bromide staining (AO/EB) and the 4′,6-diamidino-2-phenylindole (DAPI) assay suggested that the antiproliferative activity shown was due to the induction of apoptosis on exposure to Q6. Further, DCFDA staining showed the generation of reactive oxygen species, altering the mitochondrial potential and leading to the initiation of apoptosis. This was further supported by JC-1 staining, indicating that this scaffold can contribute to the development of more potent derivatives.
- Gaikwad, Nikhil B.,Bansode, Sapana,Biradar, Shankar,Ban, Mayuri,Srinivas, Nanduri,Godugu, Chandraiah,Yaddanapudi, Venkata M.
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- Triptycenyl Sulfide: A Practical and Active Catalyst for Electrophilic Aromatic Halogenation Using N-Halosuccinimides
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A Lewis base catalyst Trip-SMe (Trip = triptycenyl) for electrophilic aromatic halogenation using N-halosuccinimides (NXS) is introduced. In the presence of an appropriate activator (as a noncoordinating-anion source), a series of unactivated aromatic compounds were halogenated at ambient temperature using NXS. This catalytic system was applicable to transformations that are currently unachievable except for the use of Br2 or Cl2: e.g., multihalogenation of naphthalene, regioselective bromination of BINOL, etc. Controlled experiments revealed that the triptycenyl substituent exerts a crucial role for the catalytic activity, and kinetic experiments implied the occurrence of a sulfonium salt [Trip-S(Me)Br][SbF6] as an active species. Compared to simple dialkyl sulfides, Trip-SMe exhibited a significant charge-separated ion pair character within the halonium complex whose structural information was obtained by the single-crystal X-ray analysis. A preliminary computational study disclosed that the πsystem of the triptycenyl functionality is a key motif to consolidate the enhancement of electrophilicity.
- Nishii, Yuji,Ikeda, Mitsuhiro,Hayashi, Yoshihiro,Kawauchi, Susumu,Miura, Masahiro
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p. 1621 - 1629
(2020/02/04)
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- Photochemical benzylic bromination in continuous flow using BrCCl3 and its application to telescoped p-methoxybenzyl protection
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BrCCl3 represents a rarely used benzylic brominating reagent with complementary reactivity to other reagents. Its reactivity has been revisited in continuous flow, revealing compatibility with electron-rich aromatic substrates. This has brought about the development of a p-methoxybenzyl bromide generator for PMB protection, which was successfully demonstrated on a pharmaceutically relevant intermediate on 11 g scale, giving 91% yield and a PMB-Br space-time-yield of 1.27 kg L?1 h?1
- Otake, Yuma,Williams, Jason D.,Rincón, Juan A.,De Frutos, Oscar,Mateos, Carlos,Kappe, C. Oliver
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supporting information
p. 1384 - 1388
(2019/02/14)
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- Anti-oligomerization sheet molecules: Design, synthesis and evaluation of inhibitory activities against α-synuclein aggregation
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Aggregation of α-synuclein (α-Syn) play a key role in the development of Parkinson Disease (PD). One of the effective approaches is to stabilize the native, monomeric protein with suitable molecule ligands. We have designed and synthesized a series of sheet-like conjugated compounds which possess different skeletons and various heteroatoms in the two blocks located at both ends of linker, which have good π-electron delocalization and high ability of hydrogen-bond formation. They have shown anti-aggregation activities in vitro towards α-Syn with IC50 down to 1.09 μM. The molecule is found binding in parallel to the NACore within NAC domain of α-Syn, interfering aggregation of NAC region within different α-Syn monomer, and further inhibiting or slowing down the formation of α-Syn oligomer nuclei at lag phase. The potential inhibitor obtained by our strategy is considered to be highly efficient to inhibit α-Syn aggregation.
- Liu, Hao,Chen, Li,Zhou, Fei,Zhang, Yun-Xiao,Xu, Ji,Xu, Meng,Bai, Su-Ping
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supporting information
p. 3089 - 3096
(2019/06/14)
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- COMBINATION TREATMENTS COMPRISING ADMINISTRATION OF 1H-PYRAZOLO[4,3-B]PYRIDINES
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The present invention provides 1H-pyrazolo[4,3-b]pyridin-7-amines of formula (I) as PDE1 inhibitors together with a second compound useful in the treatment of a neurodegenerative disorder and their combined use as a medicament, in particular for the treatment of neurodegenerative and/or cognitive disorders.
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Page/Page column 109
(2019/07/19)
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- 1H-PYRAZOLO[4,3-B]PYRIDINES AS PDE1 INHIBITORS
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The present invention provides 1H-pyrazolo[4,3-b]pyridines of formula (I) as PDE1 inhibitors and their use as a medicament, in particular for the treatment of neurodegenerative disorders and psychiatric disorders.
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Paragraph 0512-0513
(2019/07/10)
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- COMBINATION TREATMENTS COMPRISING ADMINISTRATION OF 1H-PYRAZOLO[4,3-B]PYRIDINES
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The present invention provides 1H-pyrazolo[4,3-b]pyridin-7-amines of formula (I) as PDE1 inhibitors together with a second compound which compound is useful in the treatment of a psychiatric disorder and their combined use as a medicament, in particular for the treatment of psychiatric and/or cognitive disorders.
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Page/Page column 106
(2019/07/19)
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- Promotion of Appel-type reactions by N-heterocyclic carbenes
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N-Heterocyclic carbenes (NHCs) have been extensively used as a versatile class of catalysts and ligands in organocatalytic and organometallic chemistry. However, there are only a small number of synthetic applications where they act as reagents. Here we demonstrate that NHCs can be used as stoichiometric redox reagents for Appel-type halogenation reactions of alcohols. This new reactivity reveals a fresh and interesting aspect and enriches the chemistry of NHCs in an underexplored area. The potential of performing this chemical transformation at the catalytic level using an NHC-oxide derivative is also investigated.
- Hussein, Mohanad A.,Nguyen, Thanh Vinh
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supporting information
p. 7962 - 7965
(2019/07/12)
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- Combretastatin A4 analogue containing cyanoethylene joining chain and application in preparing antitumor drugs
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The invention a Combretastatin A4 analogue containing a cyanoethylene joining chain and an application in preparing antitumor drugs, which relates to the field of a medicinal compound. A structural formula (I-IV) is shown as the specification, an anticancer candidate compound which has strong inhibitory activity against cancer cells and is not toxic to normal cells is currently lacked, for the reason, the method prepares 19 I-IV series compounds, and the para and meta positions of the B ring (benzene ring) introduce various alkyl groups, alkoxy groups or amino substituents or replace the B ring (benzene ring) with various heterocyclic rings. In the I-series compound, when the para position of the B ring (benzene ring) is substituted with an ethyl group, an isopropyl group, a dimethylaminogroup or a diethylamino group, the proliferation resistance of the cancer cells is very strong, and toxicity is weak for the L-02 normal cells, a selective anticancer activity coefficient (an IC50 value ratio of L-02 normal cells to cancer cells) can even exceed 10,000, and the four compounds have the potential to be developed into safe and highly effective anticancer drugs.
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Paragraph 0096; 0103; 0104; 0105
(2019/03/15)
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- Synthesis of Alkyl Halides from Aldehydes via Deformylative Halogenation
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An unprecedented deformylative halogenation of aldehydes to alkyl halides is presented. Under oxidative conditions, 1,4-dihydropyridine (DHP), derived from an aldehyde, generated a C(sp3)- radical that coupled with a halogen radical that was generated from inexpensive and atom-economical halogen sources (NaBr, NaI, or HCl), to yield an alkyl halide. Because of the mild conditions, a wide range of functional groups were tolerated, and excellent site selectivity was achieved.
- Liang, Shengzong,Kumon, Tatsuya,Angnes, Ricardo A.,Sanchez, Melissa,Xu, Bo,Hammond, Gerald B.
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supporting information
p. 3848 - 3854
(2019/05/24)
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- 1H-PYRAZOLO[4,3-B]PYRIDINES AS PDE1 INHIBITORS
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The present invention provides 1H-pyrazolo[4,3-b]pyridin-7-amines of formula (I) as PDE1 inhibitors and their use as a medicament, in particular for the treatment of neurodegenerative disorders and psychiatric disorders.
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Page/Page column 100
(2018/09/25)
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- Synthesis and pharmacological evaluation of 2,3-diphenyl acrylonitriles-bearing halogen as selective anticancer agents
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Eighteen novel 2,3-diphenyl acrylonitrile derivatives bearing halogens were designed, synthesized, and evaluated for biological activity. Preliminary in vitro results indicated that the majority of the compounds with a para-substituted halogen had considerable antiproliferative activity against five human cancer cell lines, including MGC-803, AGS, and BEL-7402, with IC50 values in the range of 0.46–100?μm. No significant toxic effects on the non-cancerous human liver cell line L-02 were observed. The selective inhibitory activities against cancer cells were significantly better than that of the control lead compound CA-4 and CA-4P. Particularly, potent activities were found for the derivatives of 3-(4-halogen phenyl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile, such as 5c (4-fluoro), 5f (4-bromo), 5h (4-chloro), and 5k (4-trifluoro- methyl), for AGS with IC50 values of 0.75?±?0.24, 0.68?±?0.21, 0.41?±?0.05, and 1.49?±?0.92?μm, respectively. The antiproliferative effects of 5f were attributed to cell-cycle arrest in the G2/M phase, induction of cellular apoptosis, suppression of cell migration, and inhibition of cell colony formation in AGS cells.
- Li, Jia-Jun,Ma, Jun,Xin, Ya-Bing,Quan, Zhe-Shan,Tian, Yu-Shun
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p. 1419 - 1428
(2018/06/06)
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- Preparation and uses of combretastatin A4 analogs containing cyano and halogen
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The present invention provides preparation and uses of combretastatin A4 analogs containing cyano and halogen, and relates to the field of medicinal compounds, wherein the structure of the combretastatin A4 analog is represented by the following formula defined in the specification. In the prior art, the selective anticancer activity compounds with characteristics of strong inhibition activity oncancer cells and no toxicity to normal cells are necessary to the generation of novel anticancer drugs while the compounds are absent. According to the present invention, based on the requirements inthe prior art, 11 series I combretastatin A4 analogs with fluorine, chlorine, bromine or trifluoromethyl at the ortho position, meta position or para position of the B ring, and 7 series II analogs are synthesized; in the series I compounds, when the para position of the B ring is substituted by fluorine, chlorine, bromine or trifluoromethyl, the good selective anticancer activity can be achieved,and the toxicity to L-02 normal cells is weak; when the para position is substituted by fluorine, chlorine or bromine, a ratio of the IC50 value in AGS cancer cells to the IC50 value in L-02 normal cells is greater than 100; when the para position is substituted by trifluoromethyl, a ratio of the IC50 value in MGC-803 cancer cells to the IC50 value in L-02 normal cells is greater than 100; and the selective anticancer activity of the four compounds is good.
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Paragraph 0075; 0080; 0081
(2018/09/29)
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- Synthesis and characterisation of (Z)-styrylbenzene derivatives as potential selective anticancer agents
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To identify anticancer agents with high potency and low toxicity, a series of (Z)-styrylbenzene derivatives were synthesised and evaluated for anticancer activities using a panel of nine cancer cell lines and two noncancerous cell lines. Most derivatives exhibited significant anti-proliferative activities against five cancer cell lines, including MGC-803 and BEL-7402. (Z)-3-(p-Tolyl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile (6h) showed a strong inhibitory effect on MGC-803 cells (IC50 50 50 value of 6h in L-02 cells was 10,000-fold higher than in MGC-803 cells. Compound 6h inhibited proliferation of BEL-7402 cells by arresting at the G2/M phase through up-regulation of cyclin B1 expression, down-regulation of cyclin A and D1 expression, and induction of apoptosis. In addition, 6h inhibited the migration of BEL-7402 cells and the formation of cell colonies.
- Xin, Ya-Bing,Li, Jia-Jun,Zhang, Hong-Jian,Ma, Jun,Liu, Xin,Gong, Guo-Hua,Tian, Yu-Shun
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p. 1554 - 1564
(2018/10/02)
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- Method for preparing benzyl bromide
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The invention provides a method for preparing benzyl bromide. The method comprises the following steps: by taking bromine released from a redox reaction between bromates and negative bromide ions in the presence of an acid as a bromine source in an organic solvent, carrying out a benzyl radical substitution reaction with a methylbenzene compound shown as a formula I under initiation of an initiator, thereby obtaining a corresponding benzyl bromide compound shown a formula II, wherein in the formula II, m represents the number of Br and is equal to 1 or 2; when m is equal to 1, the formula II shows a benzyl monobromo compound; and when m is equal to 2, the formula II shows a benzyl dibromo compound. The reaction is carried out in an organic solvent, the initiator is combined and used, the radical substitution reaction is high in selectivity and wide in substrate application range, the substituent group replacing methylbenzene may be an electron-withdrawing group or an electron-donating group and can give extremely high yield on strong electron-donating groups (such as methoxy group). Moreover, the method disclosed by the invention is also applicable to preparation of benzyl dibromo compounds, and the product yield is high.
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Paragraph 0055-0057
(2017/10/05)
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- Synthesis of Phenanthridines through Palladium-Catalyzed Cascade Reaction of 2-Halo-N-Ms-arylamines with Benzyl Halides/Sulfonates
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An efficient palladium-catalyzed nucleophilic substitution/C–H activation/aromatization cascade reaction between readily available 2-halo-N-Ms-arylamines (Ms = methanesulfonyl) and benzyl halides/sulfonates has been described. A wide variety of phenanthridines were synthesized in a one-pot fashion in moderate to high yields (37–86 %). Notably, this method provides a straightforward, facile approach for the synthesis of phenanthridines. The practicality was further substantiated by successfully carrying out a gram-scale preparation.
- Yang, Si-Yi,Han, Wen-Yong,Zhang, Ding-Lei,Zhou, Xiao-Jian,Bai, Mei,Cui, Bao-Dong,Wan, Nan-Wei,Yuan, Wei-Cheng,Chen, Yong-Zheng
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p. 996 - 1003
(2017/02/15)
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- 2,6-DIOXO,-2,3-DIHYDRO-1H-PURINE COMPOUNDS USEFUL FOR TREATING DISORDERS RELATED TO THE ACTIVITY OF THE TRPA1 CHANNEL
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Compounds of formula (VIII) and compositions for treating disorders related to TRPA1 are described herein.
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Paragraph 0624
(2017/07/14)
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- Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids
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The silver-catalyzed Hunsdiecker bromination of aliphatic carboxylic acids is described. With Ag(Phen)2OTf as the catalyst and dibromoisocyanuric acid as the brominating agent, various aliphatic carboxylic acids underwent decarboxylative bromination to provide the corresponding alkyl bromides under mild conditions. This method not only is efficient and general but also enjoys wide functional group compatibility. An oxidative radical mechanism involving Ag(II) intermediates is proposed.
- Tan, Xinqiang,Song, Tao,Wang, Zhentao,Chen, He,Cui, Lei,Li, Chaozhong
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supporting information
p. 1634 - 1637
(2017/04/11)
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- Preparation method of cyclic di-p-xylyene
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The invention discloses a preparation method of cyclic di-p-xylyen. The method mainly includes the steps of: taking p-xylene as the starting raw material, performing bromination to obtain p-methylbenzyl bromide, and then carrying out reaction with triethylamine to obtain a corresponding quaternary ammonium salt, and finally adding the quaternary ammonium salt into a system containing a mixed solvent, alkali liquor and a mixed catalyst dropwise, and carrying out reaction for certain period of time to obtain cyclic di-p-xylyene, and finally performing aftertreatment to obtain a cyclic di-p-xylyene pure product. The method provided by the invention has the advantages of cheap and easily available raw materials, short reaction time, strong continuity, high yield, high purity and small solvent consumption, etc., and can be used for large-scale production.
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Paragraph 0038; 0039
(2016/10/07)
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- A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane
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We report a green and convenient protocol to prepare 4,7,12,15-tetrachloro[2.2]paracyclophane, the precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2-HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination-dimerization step, using aqueous sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way.
- Pan, Donghui,Wang, Yanbin,Xiao, Guomin
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p. 2443 - 2449
(2016/12/07)
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- Direct halogenation of alcohols with halosilanes under catalyst- and organic solvent-free reaction conditions
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A chemoselective method for the direct halogenation of different types of alcohols with halosilanes under catalyst- and solvent-free reaction conditions (SFRC) is reported. Various primary, secondary and tertiary benzyl alcohols and tertiary alkyl alcohols were directly transformed to the corresponding benzyl and alkyl halides, respectively, using chlorotrimethylsilane (TMSCl) and bromotrimethylsilane (TMSBr).
- Ajvazi, Njomza,Stavber, Stojan
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supporting information
p. 2430 - 2433
(2016/05/19)
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- One-Step Synthesis of Substituted Benzofurans from ortho- Alkenylphenols via Palladium-Catalyzed C=H Functionalization
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A dehydrogenative oxygenation of C(sp2)=H bonds with intramolecular phenolic hydroxy groups has been developed, which provides a straightforward and concise access to structurally diversely benzofurans from ortho-alkenylphenols. The reaction is catalyzed by palladium on carbon (Pd/C) without any oxidants and sacrificing hydrogen acceptors.
- Yang, Dejun,Zhu, Yifei,Yang, Na,Jiang, Qiangqiang,Liu, Renhua
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supporting information
p. 1731 - 1735
(2016/06/09)
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- Visible-Light-Induced Cyclization of Electron-Enriched Phenyl Benzyl Sulfides: Synthesis of Tetrahydrofurans and Tetrahydropyrans
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A new approach to the preparation of tetrahydrofurans and tetrahydropyrans through a photoredox catalytic process is described. The introduction of a phenylsulfanyl auxiliary group permits the substrates to be readily oxidized to form cationic intermediates for sequential intramolecular cyclization. The method features mild reaction conditions and operational simplicity.
- Li, Wei,Yang, Chao,Gao, Guo-Lin,Xia, Wujiong
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supporting information
p. 1391 - 1396
(2016/06/01)
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- Tribromoisocyanuric acid as a green reagent for benzylic bromination of alkylarenes
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The reaction of diverse alkylarenes with tribromoisocyanuric acid (0.34 mol equiv) in reflux EtOAc in the absence of any catalysts or light irradiation produced the corresponding benzyl bromides in 53-88% yield.
- De Almeida, Leonardo S.,Esteves, Pierre M.,De Mattos, Marcio C.S.
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p. 6843 - 6845
(2015/11/27)
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- Generation of α-imino gold carbenes through gold-catalyzed intermolecular reaction of azides with ynamides
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The generation of α-imino gold carbenes via gold-catalyzed intermolecular reaction of azides and ynamides is disclosed. This new methodology allows for highly regioselective access to valuable 2-aminoindoles and 3-amino-β-carbolines in generally good to excellent yields. A mechanistic rationale for this tandem reaction, especially for the observed high regioselectivity, is supported by DFT calculations.
- Shu, Chao,Wang, Yong-Heng,Zhou, Bo,Li, Xin-Ling,Ping, Yi-Fan,Lu, Xin,Ye, Long-Wu
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supporting information
p. 9567 - 9570
(2015/08/18)
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- P(NMe2)3-Mediated Umpolung Alkylation and Nonylidic Olefination of α-Keto Esters
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A commercial phosphorus-based reagent (P(NMe2)3) mediates umpolung alkylation of methyl aroylformates with benzylic and allylic bromides, leading to either Barbier-type addition or ylide-free olefination products upon workup. The reaction sequence is initiated by a two-electron redox addition of the tricoordinate phosphorus reagent with an α-keto ester compound (Kukhtin-Ramirez addition). A mechanistic rationale is offered for the chemoselectivity upon which the success of this nonmetal mediated C-C bond forming strategy is based.
- Wang, Sunewang Rixin,Radosevich, Alexander T.
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supporting information
p. 3810 - 3813
(2015/08/18)
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- Clay-Supported Cu(II) Catalyst: An Efficient, Heterogeneous, and Recyclable Catalyst for Synthesis of 1,4-Disubstituted 1,2,3-Triazoles from Alloxan-Derived Terminal Alkyne and Substituted Azides Using Click Chemistry
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A novel series of alloxan-derived 1,4-disubstituted 1,2,3-triazoles was synthesized in excellent yields under catalytic conditions using a click reaction strategy through 1,3-dipolar cycloaddition. Their structures have been ascertained on the basis of spectroanalytical and elemental analysis data. Synthesis of hybrid compounds with varying substitutions in the triazole ring was achieved by reaction between alloxan-derived terminal alkyne and a pertinent azide derivative in the presence of clay-Cu(II) as the catalyst in methanolic medium. Also, comparative evaluation of various catalytic systems [viz., CuI, CuSO4, CuI-zeolite, K10Ti, and clay-Cu(II)] was investigated. Of these catalytic systems, clay-Cu(II) was observed to be the best. The catalyst was recyclable for several runs without showing significant loss in its activity. The good selectivity, cost-efficiency, short reaction time, milder reaction conditions, and simple workup procedure are the added salient features of this synthetic protocol.
- Dubey, Nitin,Sharma, Pratibha,Kumar, Ashok
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p. 2608 - 2626
(2015/11/28)
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- Iron catalyzed halogenation of benzylic aldehydes and ketones
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A simple and efficient iron-catalyzed method for chlorination of aromatic carbonyl compounds is reported. By using 4-10 mol% Fe(iii) oxo acetate catalyst, prepared by solid state atmospheric oxidation of Fe(ii) acetate, in combination with triethylsilane and chlorotrimethylsilane, hydrosilylation of benzylic carbonyl compounds with subsequent chlorination is achieved within a few hours at room temperature. This new method is mild and rapid compared to the conventional two step approach involving reduction and chlorination reactions in separate stages. Development of synthetic methodology is also supplemented here by kinetic investigation of the reaction mechanism, which supports the tentative mechanisms suggested previously for similar reactions. This journal is
- Savela, Risto,W?rn?, Johan,Murzin, Dmitry Yu.,Leino, Reko
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p. 2406 - 2417
(2015/04/14)
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- On the ionizing properties of supercritical carbon dioxide: Uncatalyzed electrophilic bromination of aromatics
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Supercritical carbon dioxide (scCO2), a solvent with a zero dipole moment, low dielectric constant, and no hydrogen bonding behavior, is a suitable medium to perform the uncatalyzed electrophilic bromination of weakly activated aromatics with no interference of radical pathways. The ability of scCO2 to promote these reactions matches those of strongly ionizing solvents such as aqueous acetic and trifluoroacetic acids. Conversely, carbon tetrachloride, with similar polarity parameters to scCO2, leads exclusively to side chain functionalization. The strong quadrupole moment, and the acidic, but non basic, Lewis character of carbon dioxide, are proposed as key factors for the singular performance of scCO2 in reactions involving highly polar and ionic intermediates.
- Delgado-Abad, Thais,Martnez-Ferrer, Jaime,Reig-Lpez, Javier,Mello, Rossella,Acerete, Rafael,Asensio, Gregorio,Gonzlez-Nez, Mara Elena
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p. 51016 - 51021
(2015/01/16)
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- One-pot transformation of methylarenes into aromatic aldehydes under metal-free conditions
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On the basis of studies of the transformation of benzylic bromides into the corresponding aromatic aldehydes by treatment with N-methylmorpholine N-oxide, various methylarenes were treated either with DBDMH in the presence of AIBN in acetonitrile at reflux (Method A) or with NBS in CCl4 under irradiation with a tungsten lamp at 30 °C (Method B), followed by treatment with N-methylmorpholine N-oxide to provide aromatic aldehydes in good yields. These methods could be adopted in one-pot transformations of methylarenes into aromatic aldehydes under conditions free of less toxic reagents and transition metals. Copyright
- Tabata, Masayuki,Moriyama, Katsuhiko,Togo, Hideo
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p. 3402 - 3410
(2014/06/09)
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- Palladium(0)-catalyzed cyclopropanation of benzyl bromides via C(sp 3)-H bond activation
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A novel and highly efficient Pd(0)-catalyzed domino reaction to prepare cyclopropane derivatives has been established. The process involves a Heck-type coupling reaction and a C(sp3)-H bond activation. Preliminary DFT calculations suggest that a four-membered palladacycle intermediate is involved. This journal is the Partner Organisations 2014.
- Mao, Jiangang,Zhang, Shuo-Qing,Shi, Bing-Feng,Bao, Weiliang
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supporting information
p. 3692 - 3694
(2014/04/03)
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- CuI-catalyzed coupling of gem-dibromovinylanilides and sulfonamides: An efficient method for the synthesis of 2-amidoindoles and indolo[1,2-a] quinazolines
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A Cu(I)-catalyzed, intermolecular protocol for the synthesis of 2-amidoindoles and tetrahydroindolo[1,2-a]quinazolines in shorter time and high yields is reported. The key highlight of this disclosure is the formation of 2-amidoindole and tetrahydroindolo[1,2-a]quinazoline moieties directly from gem-dibromovinylanilides and sulfonamides in a one-pot fashion through the in situ formation of ynamides followed by a base-promoted intramolecular hydroamidation.
- Kiruthika, Selvarangam E.,Perumal, Paramasivan Thirumalai
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supporting information
p. 484 - 487
(2014/04/03)
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- Synthesis of pyrrolo-/indolo[1,2-a ]quinolines and naphtho[2,1- b ]thiophenes from gem -dibromovinyls and sulphonamides
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A highly efficient and simple route for the synthesis of pyrrolo-/indolo[1,2-a]quinolines and naphtho[2,1-b]thiophenes from gem-dibromovinyls and sulphonamides is reported. The noteworthy feature of this report is that the methodology involves a two-step protocol to synthesize tri- and tetracyclic heterocycles in a one-pot fashion through the Cu(I)-catalyzed formation of ynamide followed by a Ag(I)-assisted intramolecular hydroarylation. The photophysical properties of representative examples of pyrrolo- and indolo[1,2-a]quinolines in solid and solution states have also been studied.
- Kiruthika, Selvarangam E.,Nandakumar, Avanashiappan,Perumal, Paramasivan Thirumalai
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supporting information
p. 4424 - 4427
(2015/02/05)
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- Synthesis of combretastatin A4 analogues on steroidal framework and their anti-breast cancer activity
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Combretastatin A4 analogues were synthesized on steroidal framework from gallic acid with a possibility of anti-breast cancer agents. Twenty two analogues were synthesized and evaluated for cytotoxicity against human breast cancer cell lines (MCF-7 & MDA-MB 231). The best analogue 22 showed potent antitubulin effect. Docking experiments also supported strong binding affinity of 22 to microtubule polymerase. In cell cycle analysis, 22 induced apoptosis in MCF-7 cells significantly. It was found to be non-toxic up to 300 mg/kg dose in Swiss albino mice in acute oral toxicity. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".
- Parihar, Swati,Kumar, Amit,Chaturvedi, Amit K.,Sachan, Naresh Kumar,Luqman, Suaib,Changkija, Bendangla,Manohar, Murli,Prakash, Om,Chanda,Khan, Feroz,Chanotiya,Shanker, Karuna,Dwivedi, Anila,Konwar, Rituraj,Negi, Arvind S.
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p. 332 - 344
(2013/11/19)
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- Carbon–carbon bond formation via benzoyl umpolung attained by photoinduced electron-transfer with benzimidazolines
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A photoreaction between benzoyl compounds, such as benzoylformate derivatives, and 2-(p-anisyl)-1,3-dimethylbenzimidazoline in the presence of allyl bromide was found to give various allylated alcohols. In the reaction of benzoylformates, α-hydroxy ester enolates, for which the negative charge occurs on the carbonyl carbon of benzoyl (umpolung reactivity), are proposed to be generated as intermediates by electron-transfer from benzimidazolines to the photoexcited benzoylformates; these species react with allyl bromide to produce α-allyl-α-hydroxy esters.
- Igarashi, Tomohito,Tayama, Eiji,Iwamoto, Hajime,Hasegawa, Eietsu
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supporting information
p. 6874 - 6877
(2019/04/10)
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- Polyvinylpyrrolidone-bromine complex: An efficient polymeric reagent for selective preparation of benzyl bromides in the presence of hexamethyldisilane
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Benzylic bromides were conveniently obtained in high yields via the reaction of the corresponding alcohols with crosslinked polyvinylpyrrolidone- bromine complex (PVPP-Br2)/hexamethyldisilane in chloroform at reflux condition. Selective conversion of benzyl alcohol to benzyl bromide in the presence of primary aliphatic alcohols, e.g. 2-phenylethanol was also achieved.
- Mokhtary, Masoud,Lakouraj, Moslem M.
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p. 305 - 309
(2012/10/29)
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- Synthesis of silica bromide as heterogeneous reagent and its application to conversion of alcohols to alkyl bromides
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Silica bromide as heterogeneous reagent is prepared from the reaction of silica gel with PBr3 as a nonhydroscopic, filterable, cheap, and stable yellowish powder that can be stored for months. The results show that the silica bromide is a suitable and efficient reagent for conversion of alcohols to alkyl bromides under mild conditions at room temperature. The easy availability of this reagent makes this simple procedure attractive and a practical alternative to the existing methods.
- Mohanazadeh, Farajollah,Sedrpoushan, Alireza,Zolfigol, Mohammad A.,Veisi, Hojat
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p. 598 - 603,6
(2012/12/11)
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- Versatile gold catalyzed transglycosidation at ambient temperature
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Glycosidation with stable alkyl glycosyl donors using a catalytic amount of gold salts is promising. Herein, 1-ethynylcyclohexanyl glycosides are identified as novel donors at room temperature and mechanistic investigation showed that the leaving group simply extrudes out.
- Kayastha, Abhijeet K.,Hotha, Srinivas
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scheme or table
p. 7161 - 7163
(2012/07/31)
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- Synthesis of 3-(o-stilbenyl)sydnone and 3-(o-stilbenyl)-4- substitutedsydnone derivatives and their antitumor evaluation
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A series of novel stilbene-sydnone derivatives were synthesized by the following sequence of reactions: Starting from methyl anthranilate via glycine- and nitrosoglycine derivatives the corresponding 3-(o-carbomethoxyphenyl)-4-H/ Me/Ph-sydnones were prepared and transformed to 3-(o-formylphenyl)-4-H/Me/Ph- sydnones, starting materials for Wittig reaction with various phosphonium salts to stilbenylsydnone derivatives. Final products were evaluated for their cytotoxic properties on five cancer cell lines, whereby the cis-4-methyl-3-[2- [2-(4-methylphenyl)ethenyl]phenyl]sydnone 5 and cis-4-phenyl-3-[2-[2-(4- chlorophenyl)ethenyl]-phenyl]sydnone 10 showed the most pronounced activity. ARKAT-USA, Inc.
- Butkovic, Kristina,Marinic, Zeljko,Sindler-Kulyka, Marija
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experimental part
p. 1 - 15
(2011/09/16)
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- Synthesis of benzyl bromides with hexabromoacetone: An alternative path to drug intermediates
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A series of benzyl bromides were efficiently prepared from the corresponding alcohols with Br3CCOCBr3/PPh3 at low temperatures and under neutral conditions. The present protocol was applied to the heterocyclic analogues and to the successful synthesis of the precursor of the antiulcer drug omeprazole, thus furnishing an alternate, mild method for the preparation of these drug intermediates. A significant steric factor was observed throughout both series supporting a SN2 mechanism.
- Joseph, Kara M.,Larraza-Sanchez, Isabel
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experimental part
p. 13 - 16
(2011/02/25)
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- N -((1-benzyl-1 H -1,2,3-triazol-4-yl)methyl)arylamide as a new scaffold that provides rapid access to antimicrotubule agents: Synthesis and evaluation of antiproliferative activity against select cancer cell lines
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A series of N-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)arylamides was synthesized by copper-catalyzed azide-alkyne cycloaddition (CuAAC) and afforded inhibitors of cancer cell growth. For example, compound 13e had an IC 50 of 46 nM against MCF-7 human breast tumor cells. Structure-activity relationship (SAR) studies demonstrated that (i) meta-phenoxy substitution of the N-1-benzyl group is important for antiproliferative activity and (ii) a variety of heterocyclic substitutions for the aryl group of the arylamide are tolerated. In silico COMPARE analysis of antiproliferative activity against the NCI-60 human tumor cell line panel revealed a correlation to clinically useful antimicrotubule agents such as paclitaxel and vincristine. This in silico correlation was supported by (i) in vitro inhibition of tubulin polymerization, (ii) G2/M-phase arrest in HeLa cells as assessed by flow cytometry, and (iii) perturbation of normal microtubule activity in HeLa cells as observed by confocal microscopy. The results demonstrate that N-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)arylamide is a readily accessible small molecule scaffold for compounds that inhibit tubulin polymerization and tumor cell growth.
- Stefely, Jonathan A.,Palchaudhuri, Rahul,Miller, Patricia A.,Peterson, Rebecca J.,Moraski, Garrett C.,Hergenrother, Paul J.,Miller, Marvin J.
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supporting information; scheme or table
p. 3389 - 3395
(2010/09/04)
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- Microwave-promoted, one-pot conversion of alkoxymethylated protected alcohols into their corresponding nitriles, bromides, and iodides using [bmim][InCl4] as a green catalyst
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The Lewis acid room temperature ionic liquid, [bmim][InCl4], was found to be an efficient and green catalyst for the highly chemoselective and one-pot conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides, and iodides under microwave irradiation. The procedures are simple, rapid, and high yielding. The catalyst exhibited a remarkable reactivity and is reusable.
- Mirjafari, Arsalan,Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza
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supporting information; experimental part
p. 3274 - 3276
(2010/07/18)
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- Environmentally benign electrophilic and radical bromination 'on water': H2O2-HBr system versus N-bromosuccinimide
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A H2O2-HBr system and N-bromosuccinimide in an aqueous medium were used as a 'green' approach to electrophilic and radical bromination. Several activated and less activated aromatic molecules, phenylsubstituted ketones and styrene were efficiently brominated 'on water' using both systems at ambient temperature and without an added metal or acid catalyst, whereas various non-activated toluenes were functionalized at the benzyl position in the presence of visible light as a radical activator. A comparison of reactivity and selectivity of both brominating systems reveals the H2O2-HBr system to be more reactive than NBS for benzyl bromination and for the bromination of ketones, while for electrophilic aromatic substitution of methoxy-substituted tetralone it was higher for NBS. Also, higher yields of brominated aromatics were observed when using H2O2-HBr 'on water'. Bromination of styrene reveals that not just the structure of the brominating reagent but the reaction conditions: amount of water, organic solvent, stirring rate and interface structure, play a key role in defining the outcome of bromination (dibromination vs bromohydroxylation). In addition, mild reaction conditions, a straightforward isolation procedure, inexpensive reagents and a lower environment impact make aqueous brominating methods a possible alternative to other reported brominating protocols.
- Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
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experimental part
p. 4429 - 4439
(2009/10/09)
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- Visible-light-promoted Wohl-Ziegler functionalization of organic molecules with N-bromosuccinimide under solvent-free reaction conditions
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The visible-light-induced transformation of toluenes with N-bromosuccinimide (NBS) under solvent-free reaction conditions (SFRC) was studied. The reaction took place in spite of the very restricted molecular motion; toluenes could be regioselectively converted to benzyl bromides. Selective radical-chain reactions with NBS were carried out in liquid/liquid and in solid/solid systems; furthermore, reactions could be performed in the presence of air. The radical scavenger TEMPO (=2,2,6,6-tetramethylpiperidin-1- yloxy) completely suppressed the side-chain bromination of toluenes with NBS under SFRC. Electron-withdrawing groups decreased the reactivity of the toluenes, and the Hammett reaction constant ρ+ = -1.7 indicated involvement of polar radical intermediates with electrophilic character.
- Jereb, Marjan,Zupan, Marko,Stavber, Stojan
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experimental part
p. 555 - 566
(2009/09/06)
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- Poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide), N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide and novel poly(N,N′-dibromo-N-phenylbenzene-1,3-disulfonamide) as powerful reagents for benzylic bromination
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N,N,N′,N′-Tetrabromobenzene-1,3-disulfonamide [TBBDA], poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS], and novel poly(N,N′-dibromo-N-phenylbenzene-1,3-disulfonamide) [PBPS] can be used for bromination of benzylic positions in solvent.
- Ghorbani-Vaghei, Ramin,Chegini, Mohammad,Veisi, Hojat,Karimi-Tabar, Mehdi
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scheme or table
p. 1861 - 1865
(2009/07/19)
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- Highly efficient fluorine-promoted intramolecular condensation of benzo[c]phenanthrene: A new prospective on direct fullerene synthesis
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Various functional groups have been tested as alternative promoters of the intramolecular condensation of benzo-[c]phenanthrene under flash vacuum pyrolysis conditions. Methyl and fluorine functionalization were found to be promising approaches. Unexpectedly high selectivity was observed in the cyclization of fluorinated benzo[c]phenanthrenes. The mechanism for the condensation reaction and the advantages of fluorine as a promoter for the rational synthesis of fullerenes are discussed. Wiley-VCH Verlag GmbH & Co. KGaA.
- Amsharov, Konstantin Yu.,Kabdulov, Mikhail A.,Jansen, Martin
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experimental part
p. 6328 - 6335
(2011/03/19)
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- Contrasting chemoselectivities in the ultrasound and microwave assisted bromination reactions of substituted alkylaromatics with N-bromosuccinimide
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Ultrasound and microwave assisted bromination reactions of various alkylaryls with N-bromosuccinimide, either neat or in water, shows diverse chemoselectivity. Thus, ring substitution occurs in water with ultrasound, whereas with microwaves both side-chain α-bromination and ring substitution occur. With neat reactants, side-chain α-bromination predominates for microwave assisted reactions. In the presence of water the chemoselectivity with microwave-promoted bromination is similar to that observed using classical methods.
- Heropoulos, Georgios A.,Cravotto, Giancarlo,Screttas, Constantinos G.,Steele, Barry R.
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p. 3247 - 3250
(2008/02/02)
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