- Resorcylic acid lactone biosynthesis relies on a stereotolerant macrocyclizing thioesterase
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Zearalenone and radicicol are highly related resorcylic acid lactones with the rare property of having opposite stereochemical configurations of the secondary alcohol involved in lactone formation. The ability of the thioesterases from the zearalenone and radicicol biosynthetic pathways to macrocyclize both d and l configured synthetic substrate analogs was biochemically characterized and showed that both enzymes were highly stereotolerant, macrocyclizing both substrates with similar kinetic parameters. This observed stereotolerance is consistent with a proposed evolution of both natural products from a common ancestral resorcylic acid lactone.
- Heberlig, Graham W.,Wirz, Monica,Wang, Meng,Boddy, Christopher N.
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- Syntheses of 6,7-Benzotropolone by Using Ring-Closing Metathesis Variants Obviating a Strongly Acidic Hydrolysis Thereafter
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A Wittig reaction of 3-hydroxyphtalide (11) gave ortho-styrene-2-carboxylic acid (12). Its Weinreb amide 13 acylated heterosubstituted methyllithiums. This led to aryl “methyl” ketones whose sp3-carbon was substituted by Cl+OMe (in 14 a), 2×Cl (in 14 b), OtBu (in 17 a), SPh (in 17 b) or SO2Ph (in 17 c). The enolates of these ketones were C-allylated. This furnished the benzene-fused nona-1,8-dienones 7 a–b and 9 a–c, respectively. Ring-closing metatheses provided the corresponding benzocycloheptadienones 8 a-b and 10 a–c. Their ketone moieties were α,α-disubstituted (in 8 a–b) or α-monosubstituted (in 10 a–c). Each substitution pattern allowed to generate the hydroxyenone motif of the corresponding benzocycloheptatrienone—or 6,7-benzotropolone—6 a: The MeO- and PhS-containing benzocycloheptadienone 8 a gave 6,7-benzotropolone methyl ether (15) by sulfoxide formation and pyrolysis; 15 was demethylated with BCl3. The same intermediate resulted from the dichlorobenzocycloheptadienone 8 b and NaOMe. The benzocycloheptadienone 10 a was de(tert-butylated) with formic acid; a subsequent Pfitzner-Moffatt oxidation completed 6,7-benzotropolone (6 a) once more. The PhS-containing benzocycloheptadienone 10 b was α-acetoxylated with Pb(OAc)4; the resulting O,S-acetal gave 6,7-benzotropolone (6 a) by hydrolysis. The PhSO2-containing substrate 10 c was deprotonated whereupon an oxidation with Me3Si?O?O?SiMe3 gave 6,7-benzotropolone (6 a).
- Brückner, Reinhard,Koblischek, Philip
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- Synthesis of Isoindolinones through Intramolecular Amidation of ortho-Vinyl Benzamides
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A synthetic approach of isoindolinones through intramolecular amidation of ortho-vinyl benzamides was reported. A variety of N-aryl isoindolinone derivatives were prepared in moderate to excellent yields using perfluorobutyl iodide as oxidant. (Figure pre
- Wei, Wen-tao,Chen, Zhen-yu,Lin, Yong-lu,Chen, Ri-xing,Wang, Qi,Wu, Qing-guang,Liu, Si-jun,Yan, Ming,Zhang, Xue-jing
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supporting information
p. 1972 - 1976
(2020/04/20)
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- Study on the ArI-catalyzed intramolecularoxy-cyclization of 2-alkenylbenzamides to benzoiminolactones
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A new intramolecularoxy-cyclization of 2-alkenylbenzamides catalyzed by ArI has been developed. This protocol is highlighted by its metal-free catalytic system and extremely short reaction time, providing efficient and straightforward access to various benzoiminolactones in good to excellent yields. Interestingly, a regioselective transformation occurred when using two different reaction systems. Mechanistic studies suggested thatmCPBA acts as both oxidant and ligand at the IIIIcenter, and the Lewis acid BF3accelerated ligand exchange and reductive elimination in the catalytic process.
- Deng, Xiaojun,He, Wei,Huang, Xie,Ji, Nan,Liu, Huixia
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p. 3654 - 3658
(2020/06/03)
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- Tandem Reaction Approaches to Isoquinolones from 2-Vinylbenzaldehydes and Anilines via Imine Formation-6π-Electrocyclization-Aerobic Oxidation Sequence
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Two distinctive transition-metal-promoted aerobic oxidation protocols have been developed for the synthesis of isoquinolones from 2-vinylbenzaldehydes and aniline derivatives. Thus, the one-pot tandem reaction sequence of imine formation, thermal 6π-electrocyclization, followed by either Cu(OAc)2-mediated or Pd(OAc)2-catalyzed aerobic oxidation protocol allowed the ready access to isoquinolone derivatives. The control experiments revealed that the 1,2-dihydroisoquinoline intermediates from the 6π-electrocyclization of 1-azatrienes were aerobically oxidized to isoquinolones in the presence of either Cu(OAc)2 or Pd(OAc)2 catalyst.
- Lee, Jiyeon,Kim, Hun Young,Oh, Kyungsoo
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supporting information
p. 474 - 478
(2020/01/21)
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- SMALL MOLECULE INHIBITORS OF A PROTEIN COMPLEX
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Compositions and methods for treating thrombosis, inflammation, and atherosclerosis by administration of a compound that binds to KRIT1 to inhibit binding with HEG1.
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Paragraph 00159
(2020/12/29)
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- Preparation of cyclic imides from alkene-tethered amides: Application of homogeneous Cu(ii) catalytic systems
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A Cu-based homogeneous catalytic system was proposed for the preparation of imides from alkene-tethered amides. Here, O2 acted as a terminal oxidant and a cheap and easily available oxygen source. The cleavage of CC bonds and the formation of C
- Chen, Suqing,Liu, Zhenghui,Mu, Tiancheng,Ou, Hualin,Tan, Xingxing,Wang, Peng,Yan, Zhenzhong,Yu, Dongkun,Zhao, Xinhui
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p. 7698 - 7707
(2020/03/13)
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- Palladium-catalyzed: Ortho -halogen-induced deoxygenative approach of alkyl aryl ketones to 2-vinylbenzoic acids
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The 2-vinylbenzoic acids have wide applications in the field of polymer chemistry and are key precursors for the synthesis of important bioactive molecules. Herein, an ortho-halogen-induced deoxygenative approach for the generation of 2-vinylbenzoic acids from alkyl aryl ketones by palladium catalysis is discovered and explored. This approach requires no base or stoichiometric additives and can be carried out through a simple one-step process. Furthermore, the present reaction is scalable up to one-gram scale. The commercially available palladium on carbon (5 wt%) was used as a heterogeneous catalyst and showed excellent recyclability (5 times) without significant loss in catalytic activity. Pleasingly, under our optimized conditions, the alpha alkyl substituted 2-iodoacetophenones exhibit good diastereoselectivity and predominantly (E)-2-vinylbenzoic acids were obtained with good to excellent yields.
- Ram, Shankar,Sharma, Ajay Kumar,Chauhan, Arvind Singh,Das, Pralay
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supporting information
p. 10674 - 10677
(2020/10/02)
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- Benzyl piperazine compound with anti-inflammatory activity as well as preparation method and medical application thereof
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The invention relates to the field of medicinal chemistry, in particular to a benzylpiperazine compound (I) with anti-inflammatory activity and a preparation method thereof; pharmacodynamic tests prove that the compound provided by the invention has a COX
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Paragraph 0076-0079
(2020/01/08)
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- Copper(II)-Catalyzed Alkene Aminosulfonylation with Sodium Sulfinates for the Synthesis of Sulfonylated Pyrrolidones
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A copper-catalyzed direct aminosulfonylation of unactivated alkenes with sodium sulfinates for the efficient synthesis of sulfonylated pyrrolidones is described. This reaction features good functional group tolerance and wide substrate scope, providing an efficient and straightforward protocol to access this kind of pyrrolidones. Moreover, preliminary mechanistic investigations disclosed that a free-radical pathway might be invovled in the process.
- Rao, Wei-Hao,Jiang, Li-Li,Liu, Xiao-Meng,Chen, Mei-Jun,Chen, Fang-Yuan,Jiang, Xin,Zhao, Jin-Xiao,Zou, Guo-Dong,Zhou, Yu-Qiang,Tang, Lin
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supporting information
p. 2890 - 2893
(2019/04/30)
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- Copper-Catalyzed Modular Amino Oxygenation of Alkenes: Access to Diverse 1,2-Amino Oxygen-Containing Skeletons
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Copper-catalyzed alkene amino oxygenation reactions using O-acylhydroxylamines have been achieved for a rapid and modular access to diverse 1,2-amino oxygen-containing molecules. This transformation is applicable to the use of alcohols, carbonyls, oximes, and thio-carboxylic acids as nucleophiles on both terminal and internal alkenes. Mild reaction conditions tolerate a wide range of functional groups, including ether, ester, amide, carbamate, and halide. The reaction protocol allows for starting with free amines as the precursor of O-benzoylhydroxylamines to eliminate their isolation and purification, contributing to broader synthetic utilities. Mechanistic investigations reveal the amino oxygenation reactions may involve distinct pathways, depending on different oxygen nucleophiles.
- Hemric, Brett N.,Chen, Andy W.,Wang, Qiu
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supporting information
p. 1468 - 1488
(2019/01/25)
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- PdII-Catalyzed Oxidative Tandem aza-Wacker/Heck Cyclization for the Construction of Fused 5,6-Bicyclic N,O-Heterocycles
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A PdII-catalyzed oxidative tandem cyclization was developed for the construction of fused 5,6-bicyclic N, O-heterocycles. This reaction was enabled by the combined use of a 3-methylpyridine ligand and pentafluorobenzoic acid additive. A range of heterocyclic products with different substituents could be prepared in moderate to good yields via this methodology. Several transformations, including a scaled-up preparation of product 2 a, were also carried out showing the good applicability of our methodology.
- Ye, Chenghao,Kou, Xuezhen,Xia, Jingzhao,Yang, Guoqiang,Kong, Li,Wei, Quhao,Zhang, Wanbin
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supporting information
p. 1897 - 1901
(2018/07/31)
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- Intramolecular Hydroamidation of ortho-Vinyl Benzamides Promoted by Potassium tert-Butoxide/N,N-Dimethylformamide
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An intramolecular hydroamidation of ortho-vinyl benzamides had been developed. The reaction was promoted efficiently by potassium tert-butoxide and N,N-dimethylformamide without the need for strong oxidants or transition-metal catalysts. A series of dihyd
- Chen, Zhen-Yu,Wu, Liang-Yu,Fang, Hai-Sheng,Zhang, Ting,Mao, Zhi-Feng,Zou, Yong,Zhang, Xue-Jing,Yan, Ming
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supporting information
p. 3894 - 3899
(2017/10/07)
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- Photoredox-Catalyzed Hydroacylation of Olefins Employing Carboxylic Acids and Hydrosilanes
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A hydroacylation reaction of alkenes has been achieved employing readily available carboxylic acids as the acyl source and hydrosilanes as a hydrogen source via photoredox catalysis. The combination of both single electron transfer and hydrogen atom transfer steps has dramatically expanded new applications of carboxylic acids in organic synthesis. The protocol also features extremely mild conditions, broad substrate scope, and good functional group tolerance, affording a novel and convenient approach to hydroacylation of alkenes.
- Zhang, Muliang,Ruzi, Rehanguli,Xi, Junwei,Li, Nan,Wu, Zhongkai,Li, Weipeng,Yu, Shouyun,Zhu, Chengjian
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supporting information
p. 3430 - 3433
(2017/07/15)
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- Photoredox-Catalyzed Cascade Difluoroalkylation and Intramolecular Cyclization for Construction of Fluorinated γ-Butyrolactones
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A cascade visible-light photocatalytic difluoroalkylation and intramolecular cyclization reaction has been developed for the synthesis of difluoroalkylated oxygen heterocycles. The reaction was carried out under very mild conditions, affording fluorinated
- Sha, Wanxing,Zhang, Wenzhong,Ni, Shengyang,Mei, Haibo,Han, Jianlin,Pan, Yi
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p. 9824 - 9831
(2017/09/23)
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- Visible-Light-Mediated Synthesis of Amidyl Radicals: Transition-Metal-Free Hydroamination and N-Arylation Reactions
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The development of photoredox reactions of aryloxy-amides for the generation of amidyl radicals and their use in hydroamination-cyclization and N-arylation reactions is reported. Owing to the ease of single-electron-transfer reduction of the aryloxy-amides, the organic dye eosin Y was used as the photoredox catalyst, which results in fully transition-metal-free processes. These transformations exhibit a broad scope, are tolerant to several important functionalities, and have been used in the late-stage modification of complex and high-value N-containing molecules.
- Davies, Jacob,Svejstrup, Thomas D.,Fernandez Reina, Daniel,Sheikh, Nadeem S.,Leonori, Daniele
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supporting information
p. 8092 - 8095
(2016/07/16)
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- Rhodium-Catalyzed Hydrocarboxylation of Olefins with Carbon Dioxide
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The catalytic hydrocarboxylation of styrenes derivatives and α,β-unsaturated carbonyl compounds with CO2(101.3 kPa) in the presence of an air-stable rhodium catalyst was explored. The combination of [RhCl(cod)]2(cod = cyclooctadiene) as a catalyst and diethylzinc as a hydride source allowed for effective hydrocarboxylation and provided the corresponding α-aryl carboxylic acids in moderate to excellent yields. In this catalytic process with carbon dioxide, intervention of the RhI–H species, which could be generated from the RhIcatalyst and diethylzinc, was clarified. Significantly, the catalytic asymmetric hydrocarboxylation of α,β-unsaturated esters with carbon dioxide was also performed by employing a cationic rhodium complex possessing (S)-(–)-4,4′-bi-1,3-benzodioxole-5,5′-diylbis(diphenylphosphine) [(S)-SEGPHOS] as a chiral diphosphine ligand. A plausible model for asymmetric induction was proposed by determination of the absolute configuration of the product.
- Kawashima, Shingo,Aikawa, Kohsuke,Mikami, Koichi
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supporting information
p. 3166 - 3170
(2016/07/19)
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- Copper-Catalyzed Amino Lactonization and Amino Oxygenation of Alkenes Using O-Benzoylhydroxylamines
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A copper-catalyzed amino lactonization of unsaturated carboxylic acids has been achieved as well as the analogous intermolecular three-component amino oxygenation of olefins. The transformation features mild conditions and a remarkably broad substrate sco
- Hemric, Brett N.,Shen, Kun,Wang, Qiu
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supporting information
p. 5813 - 5816
(2016/06/09)
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- CuX2-mediated oxybromination/aminochlorination of unsaturated amides: Synthesis of iminolactones and lactams
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We report herein a CuX2-mediated halocyclization of γ,δ-unsaturated amides for the synthesis of functionalized iminolactones and lactams respectively under mild reaction conditions. Mechanism studies indicated that N-attack cyclization was via a radical route while oxycyclization was via a nucleophilic attack on the activated CC bond.
- Zhang, Zhi-Qiang,Liu, Feng
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supporting information
p. 6690 - 6693
(2015/06/25)
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- Copper-mediated/catalyzed oxyalkylation of alkenes with alkylnitriles
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A copper-promoted oxyalkylation of alkenes with alkylnitriles has been developed. The protocol provides rapid access to phthalides (γ-lactones) or isochromanones (d-lactones) via the formation of a C(sp3)-C(sp3) and a C(sp3)-O bond with the generation of up to two quaternary carbon atoms. Mechanistic studies suggest that this reaction is initiated by the formation of the C(sp3)-C(sp3) bond rather than the C(sp3)-O bond. Catalytic conditions were subsequently developed using carboxylic acid as an internal nucleophile.
- Bunescu, Ala,Wang, Qian,Zhu, Jieping
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p. 14633 - 14636
(2015/01/09)
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- C3-symmetric cinchonine-squaramide-catalyzed asymmetric chlorolactonization of styrene-type carboxylic acids with 1,3-dichloro-5,5- dimethylhydantoin: An efficient method to chiral isochroman-1-ones
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A more practical and efficient catalytic asymmetric chlorolactonization of styrene-type carboxylic acids with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) using C3-symmetric cinchonine-squaramide (CSCS) as organocatalyst has been developed. A series of chiral chloro-substituted isochroman-1-ones was obtained in excellent yields (up to 95%) and enantioselectivities (up to 99% ee), whwereby the results for chloro-substituted isochroman-1-ones are the best ever achieved. The catalyst can be recovered and reused for six cycles. Moreover, the chlorolactonization product 3b was further transformed to optically active bicyclic isochroman-1-one derivatives in high yield without losing the enantioselectivity. Furthermore, compounds 3e and 2n proved to be highly potent inhibitors of the HIV-1 in TZM-bl cells.
- Han, Xin,Dong, Chune,Zhou, Hai-Bing
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supporting information
p. 1275 - 1280
(2014/05/06)
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- Reductive electrochemical formation of 6H-dibenzo[b,d]pyran-6-one and 2-benzopyran-1(1H)-one
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In the present Letter several carbolactones (oxidative products) are obtained under aprotic cathodic conditions in the preparative scaled electrolysis of 1,2-quinones in a divided electrochemical cell and in the presence of oxygen. When 9,10-phenanthrenequinone is reduced 6H-dibenzo[b,d]pyran-6-one and [1,1′-biphenyl]-2,2′-dicarboxylic acid are obtained as major products. In the reduction of 1,2-naphthoquinone, 2-benzopyran-1(1H)-one, and 2-(2-carboxyethenyl)-benzoic acid were formed as main products. The proposed mechanism to explain the formation of these and other products, that involves an electron-transfer reaction to the oxygen in air, is now discussed.
- Batanero, Belen,Barba, Fructuoso,Barba, Isidoro,Elinson, Michail N.
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- A rapid and convergent synthesis of the integrastatin core
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The tetracyclic core of the integrastatin natural products has been prepared in a convergent and rapid manner. Our strategy relies upon a palladium(ii)-catalyzed oxidative cyclization to form the central [3.3.1]-dioxabicycle of the natural product core. Overall, the core has been completed in only 4 linear steps from known compounds.
- Tadross, Pamela M.,Bugga, Pradeep,Stoltz, Brian M.
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scheme or table
p. 5354 - 5357
(2011/09/13)
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- Acyloxylactonisations mediated by lead tetracarboxylates
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The reaction of lead(IV) tetracarboxylates with carboxylic acids containing unsaturated side chains has been found to give acyloxy lactone products in a diastereoselective process; the reaction can be extended to lead(IV) tetrazolates to give the analogous outcome. Mechanistic implications of these results are discussed.
- Cottrell, Ian F.,Cowley, Andrew R.,Croft, Laura J.,Hymns, Lauren,Moloney, Mark G.,Nettleton, Ewan J.,Kirsty Smithies,Thompson, Amber L.
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supporting information; experimental part
p. 2537 - 2550
(2009/08/07)
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- Synthesis of macrolide-saccharide hybrids by ring-closing metathesis of precursors derived from glycitols and benzoic acids
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The benzomacrolactone structural motif is a privileged or evolutionarily selected scaffold that codes properties required for binding to proteins and novel analogues thereof may provide a source of new bioactive compounds. Saccharides are also privileged structures, with (amino)sugars, imino-sugars, and sugar amino acids being applied as scaffolds for the development of nonpeptidal peptidomimetics. The syntheses of novel polyhydroxylated oxamacrolides, structural analogues of natural polyketide derived macrolides, are described herein, providing a basis for their development as scaffolds. The syntheses were carried out from benzoic acids and appropriately protected D-mannitol or D-sorbitol (D-glucitol). Ring-closing metathesis was applied in the macrocyclization step with high E-alkene selectivities being observed. X-ray crystal structures, for two polyhydroxylated derivatives, show that the macrocyclic rings display similar conformations. In addition, intermolecular hydrogen-bonding networks are observed in the lattices.
- Matos, Marie-Christine,Murphy, Paul V.
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p. 1803 - 1806
(2007/10/03)
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- Intramolecular [3 + 2]-cycloaddition reaction of push-pull dipoles across heteroaromatic π-systems
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(Chemical Equation Presented) Push-pull dipoles generated from the Rh(II)-catalyzed reaction of diazo imides containing tethered heteroaromatic rings undergo successful [3 + 2]-cycloaddition across the 2,3-π-bond to provide novel pentacyclic compounds in
- Mejia-Oneto, Jose M.,Padwa, Albert
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p. 3241 - 3244
(2007/10/03)
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- Mascara comprising solid particles
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A composition for coating keratinous fibers, comprising, in a cosmetically acceptable medium comprising at least one volatile solvent, a nonvolatile fraction comprising: a) at least one polymer capable of adhering to the keratinous fibers, b) particles which are solid at 25° C. chosen from: i) solid particles of a crystalline or semicrystalline material, ii) solid particles of an amorphous material, iii) solid particles of at least one wax having a hardness of greater than or equal to 6.5 MPa iv) and mixtures thereof. The solid particles are present in the composition in an amount such that the volume fraction of the solid particles is less than or equal to 50% of the total volume of the said nonvolatile fraction. The composition can make it possible to obtain good curling of keratinous fibers, such as eyelashes.
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- Synthesis of β-phenylethylamines from styrene derivatives
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β-Phenylethylamines are prepared from the styrene derivatives; 4,4- dimethyl-2-(2-vinylphenyl)-2-oxazoline, 2-(3-methoxy-2-vinylpnenyl)-4,4- dimethyl-2-oxazoline, 2-vinylbenzoic acid, styrene, β-methylstyrene, and α- methylstyrene.
- Seijas, Julio A.,Vazquez-Tato, M. Pilar,Entenza, Cesar,Martinez, M. Montserrat,Onega, M. Gabriela,Veiga, Susana
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p. 5073 - 5076
(2007/10/03)
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- The stille cross coupling reactions on solid support. Link to solution phase directed ortho metalation. An ester linker approach to styryl, biaryl and heterobiaryl carboxylic acids
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The synthesis of the titled compounds by Stille cross coupling on Merrifield resin - linked halo benzoates with stannanes followed by LiOH hydrolysis is reported.
- Chamoin, Sylvie,Houldsworth, Stephen,Snieckus, Victor
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p. 4175 - 4178
(2007/10/03)
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- Nitrile Oxide Cycloaddtion Routes to 2-(Isoxazolyl)benzoates and 2-(1,2,4-Oxadiazol-3-yl)benzoates
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Cycloaddition of aromatic nitrile oxides to methyl o-vinylbenzoate produced methyl 2-(3-aryl-2-isoxazolin-5-yl)benzoates; the isoxazolines were converted to methyl 2-(3-arylisoxazol-5-yl)benzoates.Reaction of the nitrile oxide from o-methoxycarbonylbenzohydroximinoyl chloride (11) with phenylacetylene, styrenes, and aromatic nitriles resulted in methyl 2-(5-phenylisoxazol-3-yl)benzoate, methyl 2-(5-aryl-2-isoxazolin-3-yl)benzoates (15) and methyl 2-(5-aryl-1,2,4-oxadiazol-3-yl)benzoates, respectively.The isoxazolines 15 were converted to the corresponding isoxazoles 16.
- Howe, Robert K.,Schleppnik, Frances M.
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p. 721 - 726
(2007/10/02)
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- Trifluoromethylphenyl isoxazolyl benzoates
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The invention relates to 3-trifluoromethylphenylisoxazol-5-yl-benzoates and their use as herbicides or plant growth regulants.
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- 2-[3-Aryl-2-isoxazolin-5-yl]benzoates
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2-[3-aryl-2-isoxazolin-5-yl]benzoates and their use as intermediates for agricultural chemicals. The subject isoxazolines can be converted to the corresponding isoxazoles. The latter are useful as herbicides and as plant growth regulants.
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