- Overcoming the Deallylation Problem: Palladium(II)-Catalyzed Chemo-, Regio-, and Stereoselective Allylic Oxidation of Aryl Allyl Ether, Amine, and Amino Acids
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We report herein a Pd(II)/bis-sulfoxide-catalyzed intramolecular allylic C-H acetoxylation of aryl allyl ether, amine, and amino acids with the retention of a labile allyl moiety. Mechanistically, the reaction proceeds through a distinct double-bond isomerization from the allylic to the vinylic position followed by intramolecular carboxypalladation and the β-hydride elimination pathway. For the first time, C-H oxidation of N-allyl-protected amino acids to furnish five-membered heterocycles through 1,3-syn-addition is established with excellent diastereoselectivity.
- Begam, Hasina Mamataj,Jana, Ranjan,Manna, Kartic,Samanta, Krishanu
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p. 7443 - 7449
(2020/10/09)
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- Cobalt-catalyzed cyclization with the introduction of cyano, acyl and aminoalkyl groups
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An efficient synthesis of carbo-and heterocycles using CC, CO and CN bonds under cobalt catalysis is described. The substituents on olefins are key for controlling the regio-and chemoselectivity in the initial hydrogen atom transfer step and quaternary carbons are efficiently constructed under mild conditions. Cyclopropane cleavage and tandem cyclization give highly functionalized bicyclic skeletons in a single operation.
- Hori, Hiroto,Arai, Shigeru,Nishida, Atsushi
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supporting information
p. 4783 - 4788
(2019/05/24)
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- Development of Macrocyclic Peptides Containing Epoxyketone with Oral Availability as Proteasome Inhibitors
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Macrocyclization has been frequently utilized for optimizing peptide or peptidomimetic-based compounds. In an attempt to obtain potent, metabolically stable, and orally available proteasome inhibitors, 30 oprozomib-derived macrocyclic peptides with structural diversity in their N-terminus and linker were successively designed and synthesized for structure-activity relationship (SAR) studies. As a consequence, the macrocyclic peptides with N-methyl-pyrazole (24p, 24x), imidazole (24t), and pyrazole (24v) as their respective N-termini exhibited favorable in vitro activity and metabolic stability, which translated into their potent in vivo proteasome inhibitory activity after oral administration. In particular, compound 24v, as the most distinguished one among this series, displayed excellent chymotrypsin-like (ChT-L, β5) inhibitory potency (IC50 = 16 nM), low nanomolar antiproliferative activity against all three of the tested cell lines, and superior metabolic stability in mouse liver microsome (MLM), as well as favorable inhibition against ChT-L compared to that of oprozomib in BABL/c mice following po administration at a comparatively low dose, thereby representing a promising candidate for further development.
- Li, Daqiang,Zhang, Xiaotuan,Ma, Xiaodong,Xu, Lei,Yu, Jianjun,Gao, Lixin,Hu, Xiaobei,Zhang, Jiankang,Dong, Xiaowu,Li, Jia,Liu, Tao,Zhou, Yubo,Hu, Yongzhou
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p. 9177 - 9204
(2018/10/24)
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- Mild and versatile potassium fluoride/tetrabutylammonium fluoride protocol for ester hydrolysis
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A mild and versatile protocol of potassium fluoride/tetrabutylammonium fluoride (KF/TBAF) in aqueous tetrahydrofuran for ester hydrolysis has been developed. The method is applied on variety of aliphatic and aromatic ester moieties bearing acid or base sensitive functional groups. The conditions have been also applied on acetates to yield alcohols. The chirality of optically pure esters remained intact with the conditions of the reaction.
- Vijayalakshmi,Balakrishna,Mustafa, Shaik
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p. 309 - 311
(2018/01/11)
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- Repurposing a Library of Human Cathepsin L Ligands: Identification of Macrocyclic Lactams as Potent Rhodesain and Trypanosoma brucei Inhibitors
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Rhodesain (RD) is a parasitic, human cathepsin L (hCatL) like cysteine protease produced by Trypanosoma brucei (T. b.) species and a potential drug target for the treatment of human African trypanosomiasis (HAT). A library of hCatL inhibitors was screened, and macrocyclic lactams were identified as potent RD inhibitors (Ki 50 400 nM). SARs addressing the S2 and S3 pockets of RD were established. Three cocrystal structures with RD revealed a noncovalent binding mode of this ligand class due to oxidation of the catalytic Cys25 to a sulfenic acid (Cys-SOH) during crystallization. The P-glycoprotein efflux ratio was measured and the in vivo brain penetration in rats determined. When tested in vivo in acute HAT model, the compounds permitted up to 16.25 (vs 13.0 for untreated controls) mean days of survival.
- Giroud, Maude,Dietzel, Uwe,Anselm, Lilli,Banner, David,Kuglstatter, Andreas,Benz, J?rg,Blanc, Jean-Baptiste,Gaufreteau, Delphine,Liu, Haixia,Lin, Xianfeng,Stich, August,Kuhn, Bernd,Schuler, Franz,Kaiser, Marcel,Brun, Reto,Schirmeister, Tanja,Kisker, Caroline,Diederich, Fran?ois,Haap, Wolfgang
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supporting information
p. 3350 - 3369
(2018/05/01)
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- Organoselenium and DMAP co-catalysis: Regioselective synthesis of medium-sized halolactones and bromooxepanes from unactivated alkenes
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A catalytic system consisting of bis(4-methoxyphenyl)selenide and 4-(dimethylamino)pyridine (DMAP) has been developed for the regioselective synthesis of medium-sized bromo/iodo lactones and bromooxepanes possessing high transannular strain. 77Se NMR, mass spectrometry and theoretical studies reveal that the reaction proceeds via a quaternary selenium intermediate.
- Verma, Ajay,Jana, Sadhan,Prasad, Ch. Durga,Yadav, Abhimanyu,Kumar, Sangit
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p. 4179 - 4182
(2016/03/19)
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- Ring-closing metathesis reaction-based synthesis of new classes of polyether macrocyclic systems
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Ring closing metathesis (RCM) reactions of suitable substrates having terminal olefins, which are assembled from various linkers and hydroxy benzaldehydes and syntheses of a wide range of 16-30 membered, new crown ether-type polyether, aza-polyether, bis aza-polyether macrocycles and dilactone moiety embedded polyether macrocycles (macrolides) are reported. After the ring-closure reaction, installation of different functional groups and functional group modification on the periphery of the synthesized polyether/crown ether macrocycles obtained in the RCM reactions are accomplished using the epoxidation, oxidation and catalytic hydrogenation-based synthetic transformations. Along this line, the syntheses of a variety of polyether macrocycles possessing epoxide or α-hydroxy ketone or 1,2-diol functionalities at the periphery have been shown. Furthermore, the synthesized α-hydroxy ketone functionality installed polyether macrocycles were subjected to the allylation and Reformatsky type reactions to obtain homoallyl alcohol moiety-based and lactone ring-appended polyether macrocycles.
- Naveen,Babu, Srinivasarao Arulananda
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p. 7758 - 7781
(2015/09/08)
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- Oxidative cyclization of alkenoic acids promoted by AgOAc
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Alkenoic acids derived from salicylic acid and analogues undergo an unexpected oxidative cyclization process triggered by AgOAc leading to 4H-benzo[d][1,3]dioxin-4-ones. The process is affected by the substitution on the aryl and the allyl units.
- Carrillo-Arcos, Ulises A.,Rojas-Ocampo, Jonathan,Porcel, Susana
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p. 479 - 483
(2016/01/09)
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- Efficient medium ring size bromolactonization using a sulfur-based zwitterionic organocatalyst
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Catalytic bromolactonization of long-chain olefinic acids resulting in the efficient synthesis of medium-sized lactones is reported using a zwitterionic catalyst and stoichiometric N-bromosuccinimide halogen source. The reaction was found to be more efficient at 0 °C than at room temperature, which could be attributed to the temperature dependence of the zwitterionic catalyst.
- Cheng, Yi An,Chen, Tao,Tan, Chong Kiat,Heng, Jun Jie,Yeung, Ying-Yeung
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supporting information
p. 16492 - 16495,4
(2020/09/15)
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- Facile synthesis of 2,3-dihydrobenzofuran-3-ylacetic acids by novel electrochemical sequential aryl radical cyclization-carboxylation of 2-allyloxybromobenzenes using methyl 4-tert-butylbenzoate as an electron-transfer mediator
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Facile synthesis of 2,3-dihydrobenzofuran-3-ylacetic acids and related analogues was successfully carried out by a novel electrochemical aryl radical generation and its 5-exo cyclization followed by a carboxylation sequence of 2-allyloxybromobenzenes by u
- Senboku, Hisanori,Michinishi, Jun-Ya,Hara, Shoji
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supporting information; experimental part
p. 1567 - 1572
(2011/08/03)
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- Regioselective silver-mediated Kondakov-Darzens olefin acylation
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Enone construction: A silver-mediated olefin acylation reaction is described, in which five-, six-, and -seven-membered rings, tetrasubstituted olefins, bridged bicycles, spirocycles, and benzoxepinones are prepared. Highly selective intermolecular reactions are coupled to a Nazarov cyclization for the effective preparation of cyclopentenones, including the core of modhephene (see scheme). Copyright
- Barczak, Nicholas T.,Jarvo, Elizabeth R.
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supporting information; experimental part
p. 12912 - 12916
(2011/12/04)
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- Benzoylureas as removable cis amide inducers: Synthesis of cyclic amides via ring closing metathesis (RCM)
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Rapid and high yielding synthesis of medium ring lactams was made possible through the use of a benzoylurea auxiliary that serves to stabilize a cisoid amide conformation, facilitating cyclization. The auxiliary is released after activation under the mild conditions required to deprotect a primary amine, such as acidolysis of a Boc group in the examples given here. This methodology is a promising tool for the synthesis of medium ring lactams, macrocyclic natural products and peptides.
- Brady, Ryan M.,Khakham, Yelena,Lessene, Guillaume,Baell, Jonathan B.
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p. 656 - 658
(2011/03/22)
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- AZOLYLMETHYLENEHYDRAZINE DERIVATIVE AND USE THEREOF
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An azolylmethylidenehydrazine derivative represented by the formula (I) wherein Ar is an aryl group optionally having substituent(s), a heteroaryl group optionally having substituent(s) or a heteroaryl group optionally having substituent(s), R1
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Page/Page column 33; 70
(2010/04/25)
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- Formation of dibenzofurans by flash vacuum pyrolysis of aryl 2-(allyloxy)benzoates and related reactions
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Flash vacuum pyrolysis (FVP) of aryl 2-(allyloxy)benzoates 5 and of the corresponding aryl 2-(allylthio)benzoates 6 at 650°C, gives dibenzofurans 19 and dibenzothiophenes 20, respectively. The mechanism involves generation of phenoxyl (or thiophenoxyl) radicals by homolysis of the O-allyl (or S-allyl) bond, followed by ipso attack at the ester group, loss of CO2 and cyclisation of the resulting aryl radical. Synthetically, the procedure works well for p-substituted substrates, which lead to 2-substituted dibenzofurans 19b-f (73-90%) and dibenzothiophenes 20b-c (90-94%). Little selectivity is shown in the cyclisation of m-substituted substrates and competing interactions of the radical with the substituent - and ipso-attack - complicate the pyrolyses of o-substituted substrates. FVP of related radical precursors including 2-(allyloxy)phenyl benzoates 43 gave no dibenzofurans, whereas 2-(allyloxy-5-methyl)azobenzene 44 gave a much reduced yield. No carbazoles were obtained by FVP of 4-methylphenyl 2-(allylamino)benzoate 42.
- Black, Michael,Cadogan,McNab, Hamish
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scheme or table
p. 2961 - 2967
(2010/09/06)
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- Facile and chemoselective cleavage of allyl carboxylic ester utilizing NaBH4 in DMSO
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A new method for deprotection of allyl carboxylic ester has been observed by using the inexpensive reagent sodium borohydride in dimethyl sulfoxide (DMSO). Aliphatic and aromatic allyl carboxylic ester undergo deprotection smoothly. The allyl ester group can selectively deprotect better than phenol.
- Pawar, Bharati V.,Lokhande, Pradeep D.
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experimental part
p. 2445 - 2453
(2009/12/06)
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- Cyclization and ring-expansion processes involving samarium diiodide promoted reductive formation and subsequent oxidative ring opening of cyclopropanol derivatives
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Samarium diiodide promoted reaction of various α-bromornethyl cycloalkanones, followed by subsequent treatment with trimethylsilyl chloride, leads to the production of cyclopropyl silyl ethers embedded in bicyclo[m.l.0]alkane frameworks. Treatment of the ethers with oxidative electron-transfer reagents, such as Fe(III), Ce(IV), and Mn(III) salts, generates ring-expanded ketones that convert to cyclic conjugated enones in moderate to good yields. In addition, the reduction-oxidation reaction sequences can be successfully performed in one pot. The regioselectivities of cyclopropane ring opening in the bicyclic substrates depend on the oxidizing agents used. For example, reactions promoted by FeCl3 with pyridine lead to the expected ring-expansion process involving internal-bond cleavage of bicycloalkane and yielding cyclic enones as final products. In contrast, reactions with Ce(NH4)I(NO3)6 or Mn(OAc) 3 as oxidizing agents proceed by way of external-bond cleavage to give α-iodomethyl cycloalkanones.
- Tsuchida, Hiroyuki,Tamura, Mutsuko,Hasegawa, Eietsu
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supporting information; experimental part
p. 2467 - 2475
(2009/07/18)
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- Concise strategy for the synthesis of elevenmembered and ansa-bridged thirteen-membered lactone macrolides by ring-closing metathesis reaction
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The eleven-membered macrolides and thirteen-membered ansa-bridged macrolides have been synthesized successfully ring-closing metathesis reaction in the absence of the additive Ti(OiPr)4, which is essential for the metathesis of the ester precursors.
- Majumdar, Krishna C.,Chattopadhyay, Buddhadeb,Ansary, Inul
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experimental part
p. 472 - 477
(2009/10/17)
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- Facile and selective deallylations of esters under 'aqueous' free-radical conditions
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The conversion of allyl esters into carboxylic acids using radical initiators has been achieved in high yields in aqueous media. Georg Thieme Verlag Stuttgart.
- Perchyonok, V. Tamara,Ryan, Sarah J.,Langford, Steven J.,Hearn, Milton T.,Tuck, Kellie L.
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body text
p. 1233 - 1235
(2009/04/05)
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- Synthesis of novel aromatic macrolactones via ring closing metathesis of substituted phenylalkanoic acid allylic esters
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(Chemical Equation Presented) Stable aromatic macrolactones have been synthesized and characterized from 2- and 3-substituted phenylalkanoic acid systems in modest yields.
- Brown, David P.,Duong, Hoan Q.
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p. 435 - 443
(2008/09/19)
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- An efficient chemoselective etherification of phenols in polyfunctional aromatic compounds
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A simple and efficient chemoselective alkylation of phenols in polyfunctional aromatic compounds with different alkyl halides in the presence of K2CO3/TBAB is reported. The method is successful with various hydroxy aromatic acids or oximes possessing other functional groups.
- Pandey, Jyoti,Mishra, Mridul,Bisht, Surendra Singh,Sharma, Anindra,Tripathi, Rama P.
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p. 695 - 698
(2008/09/17)
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- ALLYLQXY AND ALKYLOXY BENZOIC ACID DELIVERY AGENTS
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The present invention relates to pharmaceutical compounds for delivering active agents, such as biologically or chemically active agents, to a target. The invention also relates to pharmaceutical compositions comprising at least one delivery agent compound of the present invention and at least one active agent, and unit dosage forms comprising such compositions. Methods for the preparation and administration of the pharmaceutical compositions are also disclosed.
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- Selectivity in the tandem cyclization - Carboxylation reaction of unsaturated haloaryl ethers catalyzed by electrogenerated nickel complexes
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The electrochemical reduction of a series of 2-haloaryl ethers containing allyl and propargyl groups under CO2 allows the synthesis of benzofuranacetic acid derivatives. This novel intramolecular cyclization- carboxylation reaction is carried out in single-compartment cells and is catalyzed by [Ni(cyclam)Br2].
- Olivero,Du?ach
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p. 1885 - 1891
(2007/10/03)
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- Chemoselectivity and stereoselectivity of cyclisation of α-diazocarbonyls leading to oxygen and sulfur heterocycles catalysed by chiral rhodium copper catalysts
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Good levels of enantioselectivity have been achieved in intramiolecular C-H insertion reactions of α-diazocarbonyl compounds leading to six-membered oxygen heterocycles (chromanones) through the use of chiral rhodium(II) carboxylates as catalysts.Competition between C-H insertion and sigmatropic rearrangement, the latter leading to five-membered oxygen heterocycles (furanones), was observed with precursors containing a proximal O-allyl side chain.Whereas rhodium carboxylates produced C-H insertion products predominantly, a copper catalyst produced sigmatropic rearrangement products exclusively.A precursor with S-allyl side chain exhibited cyclisation via sigmatropic rearrangement with both copper and rhodium catalyst.
- Ye, Tao,Garcia, Concepcion Fernandez,McKervey, M. Anthony
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p. 1373 - 1380
(2007/10/02)
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- Ester composition
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The invention relates to a method for preparing an ester composition in which at least one activated phenolic ether group of a molecule is reacted with at least one haloformyl group of another molecule.
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- Photochemistry of Triethylamine-Acid Chloride Charge-transfer Complexes
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Charge-transfer (CT) complexes formed between various para-substituted benzoyl chlorides and triethylamine in acetonitrile have been studied spectrophotometrically.Photoactivation of these CT complexes lead to products arising from the reactions of acyl and aminoalkyl radicals.These photochemical processes have been utilized to generate acyl radicals from O-allysalicylyl chloride which undergoes intramolecular cyclization to form 3-methylchroman-4-one 20 in good yields.
- Das, Suresh,Rajesh, C. S.,Thanulingam, T. L.,Ramaiah, D.,George, M. V.
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p. 1545 - 1548
(2007/10/02)
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- Pyrolysis of O-Allyl Salicylic Amides and Esters, and Related Compounds: Foemation of Isoindolones and Phthalides
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Flash vacuum pyrolysis of O-allyl salicylic alkylamides and alkyl esters gives isoindolones and phthalides, respectively, in low (20-40percent) yield.The mechanism involves generation of the phenoxyl radical, regiospecific hydrogen-atom transfer from the alkylamide (or alkyl ester) group and cyclization.A similar sequence was observed with thiophenoxyl radicals.
- Black, Michael,Cadogan, J. I. G.,McNab, Hamish
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p. 155 - 160
(2007/10/02)
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- 2,3-Dihydro-7-benzofurancarboxylic Acids
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The syntheses of a series of title compounds 1 a-f bearing methyl groups in the heterocyclic part were described.Depending on the substitution pattern the Claisen rearrangement (path A) or the methodology of directed lithiations (path B) were used as the
- Stanetty, Peter,Koller, Herbert,Puerstinger, Gerhard
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p. 883 - 891
(2007/10/02)
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- Intramolecular Cycloaddition Reactions of N-Sulfonyl Nitrile Imides Bearing Alkenyl Groups
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The reaction of the p-tolyl(or phenyl)sulfonylhydrazones of some 2-(alkenyloxy)benzaldehydes with lead tetraacetate leads, via the nitrile imide intermediates, Ar-C(+)=N-N(-)-SO2-C6H4-X-p, to intramolecular 1,3-dipolar cycloadducts and 1-acetyl-2-aroyl-1-
- Shimizu, Tomio,Hayashi, Yoshiyuki,Nagano, Yoshio,Teramura, Kazuhiro
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p. 429 - 434
(2007/10/02)
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