- An upconverting nanotheranostic agent activated by hypoxia combined with NIR irradiation for selective hypoxia imaging and tumour therapy
-
A novel upconverting nanotheranostic agent, UCNP-CAE-FDU/NO2, activated by both hypoxia (internal stimuli) and NIR irradiation (external stimuli) was designed and synthesized for simultaneous imaging and chemotherapy of solid tumours
- Li, Hongliang,Lei, Weiyan,Wu, Jianong,Li, Shenghui,Zhou, Guoqiang,Liu, Dandan,Yang, Xinjian,Wang, Shuxiang,Li, Zhenhua,Zhang, Jinchao
-
-
Read Online
- Domino condensation/aza-Michael/O→N acyl migration of carbodiimides with activated α,β-unsaturated carboxylic acids to form hydantoins
-
Activated α,β-unsaturated carboxylic acids undergo an unexpected domino condensation/aza-Michael/O→N acyl migration with carbodiimides, producing N,N-disubstituted hydantoins in good yields. An array of structurally varied aspartic acid-derived hydantoins
- Volonterio, Alessandro,Zanda, Matteo
-
-
Read Online
- DMAP Mediated Efficient Construction of Functionalized Chromenes through One-Pot Reaction of para-Quinone Methides with Allenoates
-
A novel DMAP-mediated Rauhut-Currier/oxa-Michael addition cascade reaction of hydroxylphenyl-substituted para-quinone methide with allenoate was reported for the first time. A series of functionalized chromenes were successfully obtained with moderate to
- Song, Zefeng,Jia, Yuping,Zhang, Daizhou,Wang, De
-
p. 1942 - 1948
(2021/04/05)
-
- Enantioselective Rauhut–Currier Reaction with β-Substituted Acrylamides Catalyzed by N-Heterocyclic Carbenes
-
β-Substituted acrylamides have low electrophilicity and are yet to be exploited in the enantioselective Rauhut–Currier reaction. By exploiting electron-withdrawing protection of the amide and moderate nucleophilicity N-heterocyclic carbenes, such substrates have been converted to enantioenriched quinolones. The reaction proceeds with complete diastereoselectivity, good yield, and modest enantioselectivity. Derivatizations are reported, as are computational studies, supporting decreased amide bond character with electron-withdrawing protection of the nitrogen.
- Pitchumani, Venkatachalam,Breugst, Martin,Lupton, David W.
-
p. 9413 - 9418
(2021/12/09)
-
- Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers
-
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
- De Bruin, Bas,De Zwart, Felix J.,Li, Zirui,Mathew, Simon,Wolzak, Lukas A.,Zhou, Minghui
-
supporting information
p. 20501 - 20512
(2021/12/03)
-
- Catalytic asymmetric [3+2] cycloaddition of isomünchnones with methyleneindolinones
-
An efficient enantioselective [3+2] cycloaddition of isomünchnones with methyleneindolinones that are generated by anin situintramolecular addition of the carbonyl group to rhodium carbenes is realized with a chiralN,N′-dioxide/Zn(ii) complex as a Lewis acid. A series of chiral oxa-bridged 3-spiropiperidines are obtained in high yields with excellent dr and excellent ee values.
- Feng, Xiaoming,Hu, Xinyue,Lin, Lili,Wang, Kaixuan,Xu, Chaoran,Zhou, Yuqiao
-
p. 8917 - 8920
(2021/09/10)
-
- Ring-closing metathesis approaches towards the total synthesis of rhizoxins
-
Efforts are described towards the total synthesis of the bacterial macrolide rhizoxin F, which is a potent tubulin assembly and cancer cell growth inhibitor. A significant amount of work was expanded on the construction of the rhizoxin core macrocycle by ring-closing olefin metathesis (RCM) between C(9) and C(10), either directly or by using relay substrates, but in no case was ringclosure achieved. Macrocycle formation was possible by ring-closing alkyne metathesis (RCAM) at the C(9)/C(10) site. The requisite diyne was obtained from advanced intermediates that had been prepared as part of the synthesis of the RCM substrates. While the direct conversion of the triple bond formed in the ring-closing step into the C(9)-C(10) E double bond of the rhizoxin macrocycle proved to be elusive, the corresponding Z isomer was accessible with high selectivity by reductive decomplexation of the biscobalt hexacarbonyl complex of the triple bond with ethylpiperidinium hypophosphite. Radical-induced double bond isomerization, full elaboration of the C(15) side chain, and directed epoxidation of the C(11)-C(12) double bond completed the total synthesis of rhizoxin F.
- Altmann, Karl-Heinz,Liniger, Marc,Neuhaus, Christian M.
-
supporting information
(2020/10/18)
-
- Phosphinative cyclopropanation of allyl phosphates with lithium phosphides
-
A new cyclopropanation reaction of allyl phosphates with lithium phosphides has been developed to give cyclopropylphosphines through the formation of both a C-P bond and a cyclopropane ring at the same time, and high selectivity toward cyclopropanation over allylic substitution has been realized by conducting the reaction in the presence of HMPA.
- Shintani, Ryo,Ohzono, Ayase,Shirota, Kentaro
-
supporting information
p. 11851 - 11854
(2020/10/13)
-
- Asymmetric Catalytic Diverse Ring Opening/Cycloadditions of Cyclobutenones with (E)-Alkenyloxindoles and (E)-Dioxopyrrolidines
-
Highly enantioselective ring-opening/cycloaddition reactions of cyclobutenones were achieved by employing chiral N,N′-dioxide/metal complexes as the catalysts. The Diels-Alder type cycloaddition with (E)-alkenyloxindoles yielded spirocyclohexaneoxindoles with excellent results. Meanwhile, a hetero-Diels-Alder process occurred with (E)-dioxopyrrolidines to afford spiropyrrolidinone-dihydropyranone derivatives.
- Luo, Yao,Zhang, Hang,Wang, Siyuan,Zhou, Yuqiao,Dong, Shunxi,Feng, Xiaoming
-
p. 2645 - 2650
(2020/04/02)
-
- Phosphine-catalyzed dearomative [3+2] annulation of 3-nitroindoles and allenoates
-
The efficient phosphine-catalyzed dearomative [3+2] annulation of 3-nitroindoles with allenoates has been successfully developed, providing a facile access to cyclopenta[b]indolines with good to excellent yields and high diastereoselectivities. This strategy features mild reaction conditions, high functional group tolerance, and scalability. Additionally, the 2-nitrobenzofuran and 2-nitrobenzothiophene were good dearomative [3+2] annulation partners.
- Liu, Kui,Wang, Gang,Cheng, Shao-Jie,Jiang, Wen-Feng,He, Cheng,Ye, Zhi-Shi
-
p. 1885 - 1890
(2019/06/21)
-
- A Ba/Pd Catalytic System Enables Dehydrative Cross-Coupling and Excellent E-Selective Wittig Reactions
-
A Ba/Pd cooperative catalysis system was developed to enable the dehydrative cross-coupling of allylic alcohols with P-ylides to occur directly and promote a subsequent Wittig reaction in one pot. A variety of multisubstituted 1,4-dienes were isolated in good to excellent yields with broad P-ylides (stabilized by both ester and ketone carbonyl groups) and aldehyde (aliphatic and aromatic) substrates with excellent E selectivity.
- Xie, Peizhong,Fu, Weishan,Cai, Xinying,Sun, Zuolian,Wu, Ying,Li, Shuangshuang,Gao, Cuiqing,Yang, Xiaobo,Loh, Teck-Peng
-
p. 7055 - 7059
(2019/09/12)
-
- Synthesis of (-)-mitrephorone A via a bioinspired late stage C-H oxidation of (-)-mitrephorone B
-
We present a bioinspired late-stage C-H oxidation of the ent-trachylobane natural product mitrephorone B to mitrephorone A. The realization of this unprecedented transformation was accomplished by either an iron-catalyzed or electrochemical oxidation and enabled access to the densely substituted oxetane in one step. Formation of mitrephorone C, which is lacking the central oxetane unit but features a keto-function at C2, was not formed under these conditions.
- Wein, Lukas Anton,Wurst, Klaus,Angyal, Peter,Weisheit, Lara,Magauer, Thomas
-
supporting information
p. 19589 - 19593
(2019/12/25)
-
- Nickel-catalyzed, ligand-free, diastereoselective synthesis of 3-methyleneindan-1-ols
-
Nickel-catalyzed, highly diastereoselective annulations between activated allenes and 2-acetylarylboronic acid or 2-formylarylboronic acids are reported. No ligand for nickel is required, and the reactions proceed efficiently at room temperature to give a broad range of substituted 3-methyleneindan-1-ols. Preliminary results of an enantioselective variant are also described.
- Panchal, Heena,Clarke, Christopher,Bell, Charles,Karad, Somnath Narayan,Lewis, William,Lam, Hon Wai
-
supporting information
p. 12389 - 12392
(2018/11/20)
-
- A Tunable Route to Prepare α,β-Unsaturated Esters and α,β-Unsaturated-γ-Keto Esters through Copper-Catalyzed Coupling of Alkenyl Boronic Acids with Phosphorus Ylides
-
A tunable strategy to prepare α,β-unsaturated esters and α,β-unsaturated-γ-keto esters in good to excellent yields was developed through copper-catalyzed oxidative coupling of phosphorus ylides with alkenyl boronic acids under mild conditions. The reaction without water afforded α,β-unsaturated esters, ketones, and amides while α,β-unsaturated-γ-keto esters, 1,4-α,β-unsaturated diketones and α,β-unsaturated-γ-keto amides were obtained when using 5.0 equiv. of water. H2O18 labeling experiments showed that water played an important role in the formation of α,β-unsaturated-γ-keto esters. A plausible formation mechanism for α,β-unsaturated esters and α,β-unsaturated-γ-keto esters was proposed based on mechanistic studies. Phosphonium salts could also be used directly as coupling partners instead of phosphorus ylides. The reaction exhibited a broad substrate scope, good functional group tolerance, good regioselectivity, and diverse coupling products. (Figure presented.).
- Bi, Hong-Yan,Liu, Feng-Ping,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
-
supporting information
p. 1510 - 1516
(2018/03/05)
-
- Cycloaddition of Fluorenone N-Aryl Nitrones with Methylenecyclopropanes and Sequential 1,3-Rearrangement: An Entry to Synthesis of Spirofluorenylpiperidin-4-ones
-
A facile synthesis of various spirofluorenylpiperidin-4-ones has been achieved in good yields from fluorenone N-aryl nitrones and methylenecyclopropanes. This method involved an initial cycloaddition to form a 5-spirocyclopropane-isoxazoline, which underwent a highly selective 1,3-rearrangement to give the desired product. The stereochemistry of the spirofluorenylpiperidin-4-one could be controlled by the cycloaddition and sequential rearrangement strategy. Furthermore, the spirofluorenylpiperidin-4-ones could be not only prepared in one-pot procedure but also converted to useful scaffolds by reduction or oxidation conditions.
- Ma, Xiao-Pan,Zhu, Jie-Feng,Wu, Si-Yi,Chen, Chun-Hua,Zou, Ning,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
-
p. 502 - 511
(2017/04/26)
-
- Phosphine-Catalyzed Domino β/γ-Additions of Benzofuranones with Allenoates: A Method for Unsymmetrical 3,3-Disubstituted Benzofuranones
-
A phosphine-catalyzed domino process of benzofuranones with allenoates has been developed which furnishes highly functionalized unsymmetrical 3,3-disubstituted benzofuranones in synthetically useful yields. The mechanism for the transformation is a tandem β-umpolung/γ-umpolung process.
- Huang, Zhusheng,Yang, Xiuqin,Yang, Fulai,Lu, Tao,Zhou, Qingfa
-
supporting information
p. 3524 - 3527
(2017/07/17)
-
- Photoinduced Intermolecular [4+2] Cycloaddition Reaction for Construction of Benzobicyclo[2.2.2]octane Skeletons
-
A novel and efficient method for the synthesis of highly substituted benzobicyclo[2.2.2]octane skeletons has been explored. Under UV-light irradiation, o-divinylbenzenes underwent a pericyclic reaction to form the cyclic o-quinodimethane intermediates which were subsequently reacted with olefins through [4+2] addition to construct the benzobicyclo[2.2.2]octane skeletons in mild conditions. Gram scale reactions demonstrated the synthetic potential application of this protocol.
- Liu, Qiang,Wang, Junlei,Li, Dazhi,Yang, Chao,Xia, Wujiong
-
p. 1389 - 1402
(2017/02/10)
-
- A novel anticancer theranostic pro-prodrug based on hypoxia and photo sequential control
-
A novel anticancer pro-prodrug (GMC-CAE-NO2) with diagnosis and therapy functions based on hypoxia and photo sequential control was designed. It provides a platform for constructing theranostic pro-prodrugs to release active drugs controlled by hypoxic status and UV illumination.
- Feng, Weipei,Gao, Chunyue,Liu, Wei,Ren, Huihui,Wang, Chao,Ge, Kun,Li, Shenghui,Zhou, Guoqiang,Li, Hongyan,Wang, Shuxiang,Jia, Guang,Li, Zhenhua,Zhang, Jinchao
-
supporting information
p. 9434 - 9437
(2016/07/29)
-
- Copper-catalyzed asymmetric synthesis and comparative aldose reductase inhibition activity of (+)/(-)-1,2-benzothiazine-1,1-dioxide acetic acid derivatives
-
A copper catalyst system for the asymmetric 1,4-hydrosilylation of the α,β-unsaturated carboxylate class was developed by which synthesis of (+)- and (-)-enantiomers of 1,2-benzothiazine-1,1-dioxide acetates has been achieved with a good yield and an excellent level of enantioselectivity. A comparative structure-activity relationship study yielded the following order of aldose reductase inhibition activity: (-)-enantiomers > racemic > (+)-enantiomers. Further, a molecular docking study suggested that the (-)-enantiomer had significant binding affinity and thus increased inhibition activity.
- Parveen, Shagufta,Hussain, Saghir,Qin, Xiangyu,Hao, Xin,Zhu, Shaojuan,Rui, Miao,Zhang, Shuzhen,Fu, Fengyan,Ma, Bing,Yu, Qun,Zhu, Changjin
-
p. 4963 - 4972
(2014/06/23)
-
- Catalytic enantioselective carboannulation with allylsilanes
-
The first catalytic asymmetric carboannulation with allylsilanes is presented. The enantioselective [3+2] annulation is catalyzed using a scandium(III)/indapybox complex with tetrakis-[3,5-bis(trifluoromethyl)phenyl]- borate (BArF) to enhance catalytic activity and control stereoselectivity. Functionalized cyclopentanes containing a quaternary carbon center are derived from alkylidene oxindole, coumarin, and malonate substrates with high stereoselectivity. The enantioselective 1,4-conjugate addition and enantioselective lactone formation (by trapping of the β-silyl carbocation) is also described. It's a trap: The catalytic asymmetric carboannulation of alkylidene oxindole, coumarin, and malonate substrates with allylsilanes in the presence of a ScIII/BArF/indapybox catalyst affords functionalized cyclopentanes containing a quaternary carbon center with high stereoselectivity. Enantioselective allylation and asymmetric lactone formation by trapping of the β-silyl carbocation are also presented.
- Ball-Jones, Nicolas R.,Badillo, Joseph J.,Tran, Ngon T.,Franz, Annaliese K.
-
supporting information
p. 9462 - 9465
(2015/02/05)
-
- Structure-activity relationship of brominated 3-alkyl-5-methylene-2(5H)- furanones and alkylmaleic anhydrides as inhibitors of Salmonella biofilm formation and quorum sensing regulated bioluminescence in Vibrio harveyi
-
A library of 25 1′-unsubstituted and 1′-bromo or 1′-acetoxy 3-alkyl-5-methylene-2(5H)-furanones and two 3-alkylmaleic anhydrides was synthesized using existing and new methods. This library was tested for the antagonistic effect against the biofilm format
- Steenackers, Hans P.,Levin, Jeremy,Janssens, Joost C.,Weerdt, Ami De,Balzarini, Jan,Vanderleyden, Jos,De Vos, Dirk E.,De Keersmaecker, Sigrid C.
-
experimental part
p. 5224 - 5233
(2010/09/11)
-
- Asymmetrie hydrogenation of α,ss-unsaturated esterphosphonates
-
The rhodium-catalyzed asymmetric hydrogenation of readily available α,ss-unsaturated esterphosphonates affords the corresponding α-chiral phosphonates in excellent yield and ee. The resulting products are useful multifunctional building blocks applied in
- Huang, Yange,Berthiol, Florian,Stegink, Bart,Pollard, Michael M.,Minnaard, Adriaan J.
-
experimental part
p. 1423 - 1430
(2009/12/24)
-
- Kinetic and mechanistic study on the thermal reactivity of stabilized phosphorus ylides, part 3: [(Acetyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and [(alkoxy-carbonyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and their thiocarbamoyl analogues
-
A series of five [(acety])(arylcarbabmoyl)methylene]triphenyl-phosphoranes 1a-e and their thiocarbamoyl analogues 2a-e, |(alkoxycarbonyl)(arylcarbamoyl) methylene]triphenylphosphoranes 3a-e and thiocarbamoyl analogues 4a-e were prepared and fully characterized. All ylides are found under conditions of flash vacuum pyrolysis to fragment giving arylisocyanate or isothiocyanate and acetyl ylides or alkoxy ylides which undergo thermal extrusion of Ph3PO. A kinetic study shows that these reactions are unimolecular and are of first-order nature with no significant substituent effect. The thiocarbamoyl ylides 2 react from 4.6 to 42 times faster than their carbamoyl ylides 1, while the thiocarbamoyl ylides 4 react from 6.6 to 20.9 times faster than their carbamoyl ylides 3.
- Aitken, R. Alan,Al-Awadi, Nouria A.,Dawson, Graham,El-Dusouqui, Osman,Kaul, Kamini,Kumar, Ajith
-
-
- Antibiotic-Bound Poly(Caprolactone) Polymer
-
This invention is the design and synthesis of a caprolactone monomer which bears a pendant protected carboxyl group. This monomer has been copolymerized with caprolactone in varying ratios. After polymerization, the protecting group can be removed and an antibiotic can be attached as a new pendant group. The bioactivity of the antibiotic-bound poly(caprolactone) polymer is described.
- -
-
Page/Page column 4
(2008/06/13)
-
- Rapid and efficient access to meso-2,5-cis-disubstituted pyrrolidines by double aza-Michael reactions of chiral primary amines
-
The double aza-Michael reaction of enantiopure primary amines on bis α,β-unsaturated diesters has been studied under various activating conditions. High pressure allowed a rapid and efficient access to meso-2,5-disubstituted pyrrolidines.
- Cabral dos Santos, Leila,Bahlaouan, Zineb,El Kassimi, Khadija,Troufflard, Claire,Hendra, Frederic,Delarue-Cochin, Sandrine,Zahouily, Mohamed,Cave, Christian,Joseph, Delphine
-
experimental part
p. 751 - 768
(2009/09/25)
-
- A facile one-pot synthesis of α-fluoro-α,β-unsaturated esters from alkoxycarbonylmethyltriphenylphosphonium bromides
-
A convenient one-pot synthesis of α-fluoro-α, β-unsaturated esters from ethoxy- and tert- butoxycarbonylmethyltriphenylphosphonium bromide was developed. The fluorinated phosphoranes, generated in situ from alkoxycarbonylmethyltriphenylphosphonium bromides and 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor), undergo a Wittig reaction with aldehydes to yield α-fluoro-α,β-unsaturated esters with (Z)-selectivity.
- Suzuki, Yumiko,Sato, Masayuki
-
p. 1679 - 1681
(2007/10/03)
-
- A convenient route to higher sugars by two-carbon chain elongation using Wittig/dihydroxylation reactions
-
The combination of a Wittig olefination and a dihydroxylation reaction constitutes a facile synthetic protocol for the transformation of unprotected carbohydrates into higher sugars. The Wittig reaction is carried out with tert-butyl or diphenylmethyl ester stabilized phosphoranes to give (E)-configured α,β-unsaturated esters as the only products in most cases. These are dihydroxylated in a diastereoselective fashion using OsO4/NMO. The stereochemical outcome in the dihydroxylation follows Kishi's empirical rule and gives high diastereoselectivity (5:1-8:1) when starting from sugars with the 2,3-threo configuration. When starting from sugars with the 2,3-erythro configuration, the diastereoselectivity in the dihydroxylation is low (2:1-2.5:1). As a result, the Wittig/dihydroxylation protocol is most effective for producing higher sugars with the galacto configuration at the reducing end. The two steps can either be carried out individually or, more efficiently, as a one-pot procedure.
- Jorgensen,Iversen,Madsen
-
p. 4625 - 4629
(2007/10/03)
-
- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 15. Generation of alkoxycarbonyl(sulfenyl)carbenes and their intramolecular insertion to give alkenyl sulfides
-
A range of 18 alkoxycarbonyl sulfinyl phosphorus ylides 9 have been prepared and their behaviour upon flash vacuum pyrolysis (FVP) at 600 deg C examined. For R1 = H, Me and Et they lose Ph3PO and in some cases Ph3P to give mixtures of products including the alkenyl sulfides 10, the sulfides 11, the disulfides 12 and the thioesters 14. The alkenyl sulfides 10 most likely arise from intramolecular insertion of the alkoxycarbonyl sulfenyl carbenes resulting from loss off Ph3PO to produce β-lactones which then lose CO2 and this is supported by the results from 13C labelled ylides. Possible mechanisms for the formation of 11 and 14 are also presented and the feasibility of various steps has been examined by preparation and pyrolysis of the proposed intermediates. In contrast, pyrolysis of the ylides 9 where R1 = Ph and the tert-butoxycarbonyl ylides 30 leads mainly to complete fragmentation with loss of Ph3PO and benzyl alcohol or 2-methylpropan-2-ol and does not give any useful sulfur-containing products. Four alkoxy-carbonyl sulfonyl diazo compounds 33 have been prepared and in three cases they give the alkenyl sulfones 34 upon FVP at 400 deg C, probably by an intramolecular insertion and decarboxylation process analogous to the formation of 10 from 9. On the other hand the alkoxycarbonyl carbenes produced by FVP of the amino acid-derived diazo compounds 35 undergo alternative proocesses with no sign of β-lactone formation. Fully assigned 13C NMR data are presented for 13 of the ylides.
- Aitken, R. Alan,Armstrong, Jill M.,Drysdale, Martin J.,Ross, Fiona C.,Ryan, Bruce M.
-
p. 593 - 604
(2007/10/03)
-
- Wittig chain extension of unprotected carbohydrates: Formation of carbohydrate-derived α,β-unsaturated esters
-
Unprotected carbohydrates react with Wittig reagents 6 and 7 to give unsaturated esters. This homologation has been used to prepare an intermediate (18) previously employed in a synthesis of Kdo (19).
- Railton, Craig J.,Clive, Derrick L.J.
-
-
- SYNTHESIS AND CHARACTERIZATION OF PYRROLINONECARBOXYLATES FORMED BY REACTION OF VICINAL TRICARBONYL DERIVATIVES WITH ALDEHYDE SCHIFF BASES
-
A series of vicinal tricarbonyl derivatives undergo reaction with aldehyde Schiff bases forming pyrrolinone derivatives by benzilic acid-related rearrangements.The structures were established by X-ray analyses and, independently by the SESAMI NMR-based computer program.
- Wasserman, Harry H.,Ennis, David S.,Vu, Chi B.,Schulte, Gayle,Munk, Morton E.,et al.
-
p. 975 - 995
(2007/10/02)
-
- Oxidation of ylide precursors to vicinal tricarbonyls. Applications in vincamine alkaloid synthesis
-
Attachment of carbethoxyalkyl residues to an α,β-diketo ester provides dielectrophilic species applicable to the synthesis of the vincamine alkaloids, eburnamonine and tacamonine. The required vicinal tricarbonyl aggregates were formed by oxidation of suitable ylide precursors with ozone or singlet oxygen.
- Wasserman,Kuo
-
p. 7071 - 7082
(2007/10/02)
-
- Vinyl tricarbonyl compounds and methods of making the same
-
A vinyl tricarbonyl compound of the formula STR1 or its monohydrate of the formula STR2 wherein R1 is a hydrogen, halogen, unsubstituted or substituted C1 to C30 alkyl, unsubstituted or substituted aryl, arylalkyl, and cycloalkyl with 3 to 7 carbon atoms, R2 is hydrogen, halogen, unsubstituted or substituted C1 to C30 alkyl, unsubstituted or substituted aryl, arylalkyl, cycloalkyl with 3 to 7 carbon atoms, cyano, nitro, or a heterocyclic, R3 is hydrogen, halogen, unsubstituted or substituted C1 to C30 alkyl, unsubstituted or substituted aryl, arylalkyl, cycloalkyl with 3 to 7 carbon atoms, cyano, nitro, or a heterocyclic, and R4 is unsubstituted or substituted C1 to C30 alkyl, unsubstituted or substituted aryl, arylalkyl, cycloalkyl are 3 to 7 carbon atoms. Such vinyl tricarbonyl compound is effective against tumor cells.
- -
-
-
- Novel pesticides, preparation and use
-
The specification describes and claims methods of controlling acarine pests by application of a compound of Formula (I), methods of controlling arthropod pests by application of a compound of Formula (IA), compounds of Formula (IA) per se, pesticidal compositions comprising a compound of Formula (IA), and processes for preparing a compound of Formula (IA).
- -
-
-
- Chemistry of Cumulenes, 6. Syntheses and Reactions of 1-H-Allene-1,3-dicarboxylic Acid Monoesters
-
The title compounds 5a-e have been prepared.The carboxylation of allene monoesters 4 was successful with the phenyl derivative 4a only.The resulting extremely unstable halfester 5a as its benzylammonium salt was spontaneously transformed into the enamine ester 7.The alkyl-substituted allenes 5b-e are accessible via Wittig reaction of alkylmalonic monoester chlorides 11 with (alkoxycarbonyl)methylene ylides 12, which comprise the 2,2,2-trichloroethyl or the tert-butyl residues as selectively cleavable carboxylic protecting groups.Cleavage of the CCl3CH2 group with Zn succeeded for the tert-butylallenes 13a/b only.In the case of the methylallene 13c the cleavage was accompanied by hydrogenation of the allene.The mechanism of this reaction is discussed.Cleavage of the tert-butyl ester group in 13d and e was readily achieved with ether/sulfuric acid.
- Nader, Franz W.,Brecht, Angelika,Kreisz, Siegfried
-
p. 1196 - 1207
(2007/10/02)
-
- SYNTHESIS OF 1-SUBSTITUTED (S)-4-ACETOXY-1-PENTEN-3-ONES USING (S)-LACTIC ACID AS A CHIRAL SOURCE AND THEIR SYNTHETIC REACTIONS
-
Ylide reaction of (S)-3-acetoxy-1-triphenylphosphoranylidene-2-butanone, derived from (S)-lactic acid, with aldehydes gives 1-substituted (S)-4-acetoxy-1-penten-3-one derivatives, which are shown to be transformed into useful chiral compouds by stereosele
- Hiyama, Tamejiro,Kobayashi, Kumi,Fujita, Makoto
-
p. 4959 - 4962
(2007/10/02)
-
- Charge-Directed Conjugate Addition Reactions in the Preparation of Substituted Methyl Ketones
-
Charge-directed conjugated addition reactions of the tert-butyl esters of α,β-unsaturated acylphosphoranes 2 have been used to prepare a variety of substituted methyl ketones.Substituted ylides 6 are prepared by alkylating ylide anions 4 generated by the addition of nucleophiles to 2 and are converted under acidic conditions to substituted (acylmethylene)phosphoranes 12 which are hydrolyzed to methyl ketones.The utility of these unsaturated acylphosphoranes as methyl vinyl ketone equivalents in conjugate addition-alkylation reactions is demonstrated in a synthesis of the racemic form of the sex pheromone of the California red scale, 14.
- Cooke, Manning P.,Burman, Diana L.
-
p. 4955 - 4963
(2007/10/02)
-
