- Phosphate tricyclic coumarin analogs as steroid sulfatase inhibitors: Synthesis and biological activity
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In the present work, we report convenient methods for the synthesis and biological evaluation of phosphate tricyclic coumarin derivatives as potential steroid sulfatase inhibitors. The described synthesis includes the straightforward preparation of 7-hydroxy-2,3-dihydro-1H-cyclopenta[c]chromen-4-one, 3-hydroxy-7,8,9,10-tetrahydro-6H-benzo[c]chromen-6-one and 3-hydroxy-8,9,10,11-tetrahydro-7H-cyclohepta[c]chromen-6-one modified with various phosphate moieties. The inhibitory effects of the synthesized compounds were tested on STS isolated from human placenta as well as the MCF-7, MDA-MB-231 and MDA-MB-435S cancer cell lines. Most of the new STS inhibitors possessed IC50 values between 21 to 159 μM. In the course of our investigation, the largest inhibitory effects in the STS enzyme assays were observed for the three compounds 9p, 9r and 9s, with IC50 values of 36.4, 37.8 and 21.5 μM, respectively (IC50 value of 1.0 μM for the 665-COUMATE used as a reference). The compound 9r, exhibited the highest potency against MCF-7, an estrogen receptor positive (ER+) cell line, with a GI50 value of 24.7 μM. The structure-activity relationships of the synthesized coumarin derivatives with the STS enzyme are discussed.
- Kozak, Witold,Dasko, Mateusz,Maslyk, Maciej,Pieczykolan, Jerzy S.,Gielniewski, Bartlomiej,Rachon, Janusz,Demkowicz, Sebastian
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Read Online
- Solvent-free Dieckmann condensation reactions of diethyl adipate and pimelate
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Dieckmann condensation reactions of diethyl adipate and pimelate proceeded efficiently in the absence of solvent, and the reaction products were collected by a direct distillation from the solvent-free reaction mixture.
- Toda, Fumio,Suzuki, Takaaki,Higa, Satoru
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Read Online
- Enantioselective α-Amination of Acyclic 1,3-Dicarbonyls Catalyzed by N-Heterocyclic Carbene
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Herein, we describe a method for the catalytic enantioselective α-amination of α-substituted acyclic 1,3-ketoamides and 1,3-amidoesters that affords the products possessing N-substituted quaternary stereocenters with a chiral N-heterocyclic carbene (NHC). The reaction is based on the utilization of an intrinsic Br?nsted base characteristic of NHC that enables the catalytic formation of a chiral ion pair comprising the enolate and the azolium ion. A series of challenging open-chain α-substituted 1,3-dicarbonyls are aminated via this method with ee's of ≤99%.
- Santra, Surojit,Maji, Ujjwal,Guin, Joyram
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supporting information
p. 468 - 473
(2020/02/04)
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- Radical Aza-Cyclization of α-Imino-oxy Acids for Synthesis of Alkene-Containing N-Heterocycles via Dual Cobaloxime and Photoredox Catalysis
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Nitrogen-containing heterocycles are prevalent in both naturally and synthetically bioactive molecules. We report herein an unprecedented protocol for radical aza-cyclization of α-imino-oxy acids with pendant alkenes via synergistic photoredox and cobaloxime catalysis. With or without alkenes as the intermolecular cross-coupling partners, the transformation provides a variety of corresponding alkene-containing dihydropyrrole products in satisfactory yields. In the presence of external alkenes, the tandem reaction generates E-selective coupling products with excellent chemo- and stereoselectivity.
- Tu, Jia-Lin,Liu, Jia-Li,Tang, Wan,Su, Ma,Liu, Feng
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supporting information
p. 1222 - 1226
(2020/02/15)
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- Coumarin-dithiocarbamate hybrids as novel multitarget AChE and MAO-B inhibitors against Alzheimer's disease: Design, synthesis and biological evaluation
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A series of new coumarin-dithiocarbamate hybrids were designed and synthesized as multitarget agents for the treatment of Alzheimer's disease. Most of them showed potent and clearly selective inhibition towards AChE and MAO-B. Among these compounds, compound 8f demonstrated the most potent inhibition to AChE with IC50 values of 0.0068 μM and 0.0089 μM for eeAChE and hAChE, respectively. Compound 8g was identified as the most potent inhibitor to hMAO-B, and it is also a good and balanced inhibitor to both hAChE and hMAO-B (0.114 μM for hAChE; 0.101 μM for hMAO-B). Kinetic and molecular modeling studies revealed that 8g was a dual binding site inhibitor for AChE and a competitive inhibitor for MAO-B. Further studies indicated that 8g could penetrate the BBB and exhibit no toxicity on SH-SY5Y neuroblastoma cells. More importantly, 8g did not display any acute toxicity in mice at doses up to 2500 mg/kg and could reverse the cognitive dysfunction of scopolamine-induced AD mice. Overall, these results highlighted 8g as a potential multitarget agent for AD treatment and offered a starting point for design of new multitarget AChE/MAO-B inhibitors based on dithiocarbamate scaffold.
- He, Qi,Liu, Jing,Lan, Jin-Shuai,Ding, Jiaoli,Sun, Yongbing,Fang, Yuanying,Jiang, Neng,Yang, Zunhua,Sun, Liyuan,Jin, Yi,Xie, Sai-Sai
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supporting information
p. 512 - 528
(2018/09/29)
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- Cobalt-Catalyzed Cross-Couplings between Alkenyl Acetates and Aryl or Alkenyl Zinc Pivalates
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CoBr2 (5 mol %) in the presence of 2,2′-bipyridyl (5 mol %) enables electrophilic alkenylations between easily accessible alkenyl acetates or tosylates and various functionalized aryl zinc pivalates at ambient temperature. This cobalt-catalyzed
- Li, Jie,Knochel, Paul
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supporting information
p. 11436 - 11440
(2018/08/11)
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- Regioselective catalytic asymmetric C-alkylation of isoxazolinones by a base-free palladacycle-catalyzed direct 1,4-addition
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Isoxazolinones constitute a class of heterocycles utilized for the development of novel drug candidates. The cyclic oxime ester motif is also synthetically useful as it contains functional handles which have previously been used to provide access to an assortment of valuable compound classes not easily accessible by alternative approaches. However, asymmetric methods towards isoxazolinones are notoriously scarce. Herein we report the first catalytic asymmetric alkylations of isoxazolinones forming all-C-substituted quaternary stereocenters. The present studies were driven by the question of how to control the regioselectivity in the competition of different nucleophilic positions. The investigation of a direct 1,4-addition uncovered that a sterically demanding palladacycle catalyst directs the reactivity in the absence of a base nearly exclusively to the nucleophilic C atom, while at the same time it allows for high enantioselectivity and TONs up to 1900.
- Hellmuth, Tina,Frey, Wolfgang,Peters, Ren
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supporting information
p. 2788 - 2791
(2015/03/04)
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- 1-(Arylmethyl)-5,6,7,8-tetrahydroquinazolline-2,4-diones and Analogs and the Use Thereof
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Disclosed are novel 1-(arylmethyl)-5,6,7,8-tetrahydroquinazoline-2,4-diones and analogs thereof, represented by the Formula I, wherein Ar, A, B, R3-R6 are defined herein. Compounds having Formula I are PARP inhibitors. Therefore, compounds of the invention may be used to treat clinical conditions that are responsive to the inhibition of PARP activity, such as cancer.
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Paragraph 0149
(2014/09/30)
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- Selective transformations of carbonyl functions in the presence of α,β-unsaturated ketones: Concise asymmetric total synthesis of decytospolides A and B
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Enones selectively react with a combination of PPh3 and TMSOTf to produce phosphonium silyl enol ethers, which work as protective groups of enones during the reduction of other carbonyl functions and can be easily deprotected to regenerate parent enones at workup. Furthermore, the first ketone selective alkylations in the presence of enones were also accomplished. This in situ protection method was applied to concise asymmetric total syntheses of decytospolides A and B.
- Yahata, Kenzo,Minami, Masaki,Watanabe, Kei,Fujioka, Hiromichi
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supporting information
p. 3680 - 3683
(2014/08/05)
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- Synthesis of five-and six-membered 1,3,3-trimethyl-2-(trimethylsilyl) cycloalkenes: A novel preparation of alkyl/alkenyl/aryl 2,5,5-trimethyl-1- cyclopentenyl ketones
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1,3,3-trimethyl-2-(trimethylsilyl)cyclopentene and 1,3,3-trimethyl-2- -(trimethylsilyl)cyclohexene were prepared in good yields by the Wurtz-Fittig coupling reaction of the corresponding 2-iodo-1,3,3-trimethylcyclopentene and 2-chloro-1,3,3-trimethylcyclohexene with metallic sodium and chlorotrimethylsilane in anhydrous ether solvent. The Friedel-Crafts acylation reaction of 1,3,3-trimethyl-2-(trimethylsilyl)cyclopentene with six different acid chlorides and the novel preparation of six alkyl/alkenyl/aryl 2,5,5-trimethyl-1-cyclopentenyl ketones are reported.
- Venkatesha, Manjunatha A.,Suresh, Hariprasad
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p. 759-768+S57-S61
(2013/07/26)
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- 1-(ARYLMETHYL)-5,6,7,8-TETRAHYDROQUINAZOLINE-2,4-DIONES AND ANALOGS AND THE USE THEREOF
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Disclosed are novel 1-(arylmethyl)-5,6,7,8-tetrahydroquinazoline-2,4-diones and analogs thereof, represented by the Formula I, wherein Ar, A, B, R3-R6 are defined herein. Compounds having Formula I are PARP inhibitors. Therefore, compounds of the invention may be used to treat clinical conditions that are responsive to the inhibition of PARP activity, such as cancer.
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Page/Page column 23
(2013/05/22)
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- Pd-catalyzed coupling of β-hydroxy α-diazocarbonyl compounds with aryl iodides: A migratory insertion/β-hydroxy elimination sequence
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The coupling of β-hydroxy α-diazocarbonyl compounds with aryl halides is described, which proceeds through a Pd-catalyzed migratory insertion/β-OH elimination sequence. This reaction provides a new route to the synthesis of tetrasubstituted olefins.
- Zhou, Lei,Liu, Yizhou,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 3622 - 3624
(2011/05/02)
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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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- Gold-catalyzed synthesis of carbon-bridged medium-sized rings
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Bicyclo[m.n.1]alkenone frameworks possessing quaternary carbon centers adjacent to a bridged ketone are frequently found in bioactive natural products. Although several methods have been developed to construct such frameworks, most of them are specific to a particular scaffold. Herein, we report a mild and highly efficient method to generate carbon-bridged frameworks of various sizes using phosphlno gold(I) catalysts.
- Barabe, Francis,Betournay, Genevieve,Bellavance, Gabriel,Barriault, Louis
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supporting information; experimental part
p. 4236 - 4238
(2009/12/31)
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- Total synthesis of (±)-dihydroactinidiolide using selenium-stabilized carbenium ion
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A new, short total synthesis of dihydroactinidiolide 1 is described using selenium carbenium ion-promoted carbon-carbon bond formation as the key step. Our synthetic strategy starts with a lactonization reaction between 1,3,3-trimethylcyclohexene 13 and α-chloro-α-phenylseleno ethyl acetate 14, affording the key intermediate, α-phenylseleno-γ-butyro lactone 15, which reacted via a selenoxide elimination to the target compound 1.
- Dabdoub, Miguel J.,Silveira, Claudio C.,Lenard?o, Eder J.,Guerrero Jr., Palimécio G.,Viana, Luiz H.,Kawasoko, Cristiane Y.,Baroni, Adriano C.M.
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scheme or table
p. 5569 - 5571
(2011/02/24)
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- Hydride-promoted ring expansion of 2-azaspiropyrrolinium salts: An approach towards the synthesis of (-)-nitramine
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An enantioselective approach toward the synthesis of the spiroalkaloid (-)-nitramine was achieved by electrophile-induced cyclization of a suitably substituted and protected chiral α-allylcyclohexanecarboxaldimine. Its hydride-promoted ring expansion after spirocyclization gave rise to the competitive formation of isomeric spiropyrrolidines and a spiropiperidine, the latter being further transformed into (-)-nitramine. Georg Thieme Verlag Stuttgart.
- Alonso, Erick Rosas,Tehrani, Kourosch Abbaspour,Boelens, Mark,De Kimpe, Norbert
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p. 1726 - 1730
(2007/10/03)
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- Studies on diastereoselective reduction of cyclic β-ketoesters with boron hydrides. Part 4: The reductive profile of functionalized cyclohexanone derivatives
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Reduction of 2-allyl-2-carboalkoxycyclohexanones (3d-f), 2-propyl-2-carboethoxycyclohexanone (3g) and 2-benzyl-2- carboethoxycyclohexanone (3h) with boron hydrides in the presence and absence of several chelating agents were studied. Molecular modeling studies using semiempirical PM3 method were performed in order to find a suitable explanation of the diastereoselection of ketone carbonyl faces during the reductive process, which yielded trans-2-allyl-2-carboethoxycyclohexanol (6e) and cis-2-allyl-2-carboethoxycyclohexanol (7e) in good diastereomeric excess by using inexpensive sodium and tetrabutylammonium borohydrides.
- Fraga, Carlos A.M.,Teixeira, Lis Helena P.,Menezes, Carla Maria De S.,Sant'Anna, Carlos Mauricio R.,Ramos, Maria Da Concei??o K.V.,De Aquino Neto, Francisco R.,Barreiro, Eliezer J.
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p. 2745 - 2755
(2007/10/03)
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- Method for preparing chiral diphosphines
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The invention concerns a method for preparing a compound of formula (1) wherein: A represents naphthyl or phenyl optionally substituted; and Ar1, Ar2independently represent a saturated or aromatic carbocyclic group, optionally substituted.
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- Palladium-catalyzed cyclization of alkenyl β-keto esters in the presence of chlorotrimethylsilane
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PdCl2(CH3CN)2 catalyzed the cyclization of alkenyl β-keto esters in the presence of a stoichiometric amount of SiMe3Cl to form 2-carboalkoxycyclohexanones in good yield with excellent regioselectivity.
- Pei, Tao,Widenhoefer, Ross A.
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p. 650 - 651
(2007/10/03)
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- Preparation of cycloalkanone oxime ethers via a free radical acylation approach
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Abstract: Radical-mediated annulation approaches for the formation of cycloalkanone oxime ethers are described. Based on radical acylation approaches, α-functionalized cycloalkanone oxime ethers, 1,3- and 1,4-cyclohexanedione oxime ethers are prepared.
- Kim,Kim,Yoon,Oh
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p. 1148 - 1150
(2007/10/03)
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- Preparation of fluorinated dicarbonyls
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PCT No. PCT/GB94/02547 Sec. 371 Date Feb. 21, 1997 Sec. 102(e) Date Feb. 21, 1997 PCT Filed Nov. 18, 1994 PCT Pub. No. WO95/14646 PCT Pub. Date Jun. 1, 1995A method for the fluorination of 1,3-diketones and 1,3-ketoesters is disclosed.
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- Asymmetric hydrogenation method of a ketonic compound and derivative
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The present invention relates to a process for the asymmetric hydrogenation of a ketonic compound and derivative. The invention relates to the use of optically active metal complexes as catalysts for the asymmetric hydrogenation of a ketonic compound and derivative. The process for the asymmetric hydrogenation of a ketonic compound and derivative is characterized in that the asymmetric hydrogenation of said compound is carried out in the presence of an effective amount of a metal complex comprising as ligand an optically active diphosphine corresponding to one of the following formulae: STR1
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- InCl3: A new Lewis acid catalyst for reactions with α-diazocarbonyl compounds
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The use of InCl3 as a Lewis acid catalyst in diazocarbonyl S-H insertion reactions, nitrile cyclizations and addition reactions to aldehydes and ketones is described.
- Sengupta, Saumitra,Mondal, Somnath
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p. 8685 - 8688
(2007/10/03)
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- Benzopyranones, a method for producing them and uses therefor
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Novel 2H-1-benzopyran-2-ones (coumarin derivatives) of the general formula (I) are provided: STR1 wherein R1, R2, R3, R4, X and Y are defined as in the specification, and the addition compounds thereof with physiologically compatible acids, intermediates and methods for the preparation thereof. The coumarin compounds possess a neuroprotective and anti-allergic action.
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- Photoinduced Molecular Transformations. Part 144. One-Carbon Intercalation of γ- and δ-Lactones involving the β-Scission of Alkoxyl Radicals as the Key Step: Synthesis of δ- and ε-Lactones with α-Substituents
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A new general method of a one-carbon intercalation of γ-lactones to δ-lactones and δ-lactones to ε-lactones in three steps involving a selective β-scission of the alkoxyl racicals as the key step is described.The reactions of γ- and δ-lactones with lithioalkyl acetate gave an equilibrium mixture of alkyl (2-hydroxytetrahydrofuran-2-yl)acetates and alkyl (2-hydroxytetrahydropyran-2-yl)acetates, as well as their ring-opened isomers in 62-95percent yields, respectively.The photolysis of the hypoiodites of these lactols in benzene containing mercury(II) oxide and iodine with Pyrex-filtered light resulted in a selective endocyclic β-scission of the corresponding alkoxyl radicals to give alkyl iodoalkyl propanedioates in 33-70percent yields.Treatment of the iodoalkyl propanedioates with tetraethylammonium bromide and sodium hydride gave alkyl 3,4,5,6-tetrahydro-2-oxo-2H-pyran-3-carboxylates or alkyl 2,3,4,5,5a,6,7,8,9,9a-decahydro-2-oxobenzoxepine-3-carboxylate in 61-81percent yields.On the other hand, succesive treatment of ω-iodoalkyl propanedioates with tetraethylammonium bromide-sodium hydride and then benzyl bromide gave a α-disubstituted δ-lactone, which gave a α-monosubstituted δ-lactone upon heating in trifluoroacetic acid under reflux.Cyclopentanone can similarly be transformed into 2-substituted cyclohexanone via a three-step procedure.
- Kobayashi, Kazuhiro,Minakawa, Hiroki,Sakurai, Hideo,Kujime, Sachiko,Suginome, Hiroshi
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p. 3007 - 3010
(2007/10/02)
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- Mechanism of hydrolysis and structure-stability relationship of enaminones as potential prodrugs of model primary amines
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The objective of this work was to investigate the chemistry and the structure-stability relationship of enaminones (a class of enamines formed between a primary amine and a 1,3-dicarbonyl compound) and to evaluate their potential usefulness as prodrugs of primary amines. The acid-catalyzed degradation of the enaminones was found to be very sensitive to minor differences in the structure of the 1,3-dicarbonyl compound used to form the enaminone, but relatively insensitive to changes in the amine portion of the enaminones. A correlation was found between the rate of enaminone hydrolysis and the pK(a) of the 1,3-dicarbonyl compound, suggesting that the rate-controlling step in the hydrolysis of the enaminones was the proton addition to the vinyl carbon of the enaminone. Enaminones formed with cyclic 1,3-dicarbonyl compounds were significantly more stable than those formed with structurally similar acyclic compounds. Based on chemical stability considerations alone, enaminones do not appear to be good candidates as prodrugs of primary amines. Evidence is presented, however, that enaminones formed between amines and 1,3-ketoesters or lactones may be subject to enzyme-catalyzed degradation. Further research on the design of enaminones destabilized by a triggering enzymatic event that results in the loss of conjugation (e.g., ester or lactone hydrolysis or an oxidation/reduction event) may prove worth pursuing.
- Naringrekar,Stella
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p. 138 - 146
(2007/10/02)
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- Reaction of Carbonyl Compounds with Ethyl Lithiodiazoacetate. Studies Dealing with the Rhodium(II)-Catalyzed Behavior of the Resulting Adducts
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The carbenoid intermediate derived by treating ethyl 2-diazo-4-phthalimidobutyrate with rhodium(II) octanoate undergoes transannular cyclization onto the adjacent imido carbonyl group.The resulting cyclic carbonyl ylide diploe was trapped with several dipolarophiles.In an attempt to prepare related substrates for cyclization studies, the reaction of ethyl lithiodiazoacetate with various aldehydes and ketones was studied.Treatment of the α-diazo-β-hydroxy ester derived from acetone or cyclopentanone with rhodium(II) octanoate gave rise to a β-keto ester.The exclusive phenyl shift encountered with acetophenone is in keeping with migration to an electron-deficient center.The reaction works well with acrolein, leading to high yields of 3-oxo-4-pentenoate.The 1,2-hydrogen shift pathway was found to proceed much faster than intramolecular cyclopropanation.Dehydration of the α-diazo-β-hydroxy esters generates vinyl diazo esters, which readily cyclize to 1H-pyrazoles on thermolysis.
- Padwa, Albert,Kulkarni, Yashwant S.,Zhang, Zhijia
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p. 4144 - 4153
(2007/10/02)
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- C/O-Alkylation Ratios in the Ring-Closures of 7-Halo-3-oxo Esters
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Four acyclic 7-halo-3-oxo esters have been treated with bases under various conditions to obtain six-membered ring compounds.These halo keto esters give more O-alkylation (C/O = 0.18-3.2) than do the analogous halo ketones.
- Brandaenge, Svante,Lindquist, Bo
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p. 807 - 810
(2007/10/02)
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- Kinetics and Equilibria of Keto-Enol Conversion in Aqueous Solution. Rate and Equilibrium Constants Determined from a Single Experiment
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The zero-order bromination of 2-carbethoxycyclohexanone in aqueous solution, followed spectrophotometrically at 267 nm, transforms near the end of the reaction quite suddenly into an opposing first-order process, representing a restoration of the perturbed keto-enol equilibrium.This is partly due to a (coincidental) overlap of the spectra for bromine and the substrate (enol) in the range 250-280 nm.Rate constants and the equilibrium constant for the keto-enol conversion can be determined (in principle) from a single kinetic experiment.The keto-enol conversion studied here is catalyzed only by bases, although a small component of catalysis by the hydronium ion is also found.Catalytic data for twelve bases, including water and the hydroxide ion, are correlated with pKA in a Broensted plot.Carboxylates form a linear correlation with a Broensted slope of β=0.67, in accordance with earlier observations.Phosphates exhibit moderately negative deviations, presumably due to electrostatic effects.Stronger bases show large negative deviations, undoubtedly relating to strong solvation of these ions.Kinetic experiments by stopped-flow in aqueous hydroxide provide a basis for determining the acidity constants for the substrate.
- Groth-Andersen, Henrik,Soerensen, Poul E.
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- SYNTHESIS OF STABLE ANALOGUES OF TXA2
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Intramolecular aldol condensations and intramolecular Lewis acid-catalysed alkylations are used in approaches to substituted bicyclononanes and bicyclooctanes, specifically the oxo esters ( 7 ), ( 8 ), and ( 9 ).A ring expansion to a cycloheptane derivative is observed on treatment of the cyclopentyl derivative ( 18 ) with acid, and the bicyclodecane and bicyclononane derivatives ( 34 ) and ( 36 ) are obtained from the prenyl derivatives ( 30 ) and ( 35 ) respectively.The oxo esters ( 7 ), (8 ), and ( 9 ) are converted into the stable TXA2 analogues ( 10 ), ( 11 ), and ( 12 ) respectively, by a series of reactions which involve stereospecific functionalisation of their ketone and ester groups.
- Evans, Elizabeth H.,Hewson, Alan T.,March, Lorraine A.,Nowell, Ian W.,Wadsworth, Alan H.
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p. 137 - 150
(2007/10/02)
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- One-pot Synthesis of 2-Substituted Cyclohexanones
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The one-pot synthesis of 2-substituted cyclohexanones involves alkylation of 2-hydroxymethylenecyclohexanone (1) in the presence of solid KOH
- Ravikumar, V. T.,Sathyamoorthi, G.,Thangaraj, K.,Rajagopalan, K.
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- ULTRASOUND IN ORGANIC SYNTHESIS 5. PREPARATION AND SOME REACTIONS OF COLLOIDAL POTASSIUM
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colloidal potassium is easily obtained by ultrasonic irradiation in toluene.Some of its reactions with organic substrates are given.
- Luche, J.L.,Petrier, C.,Dupuy, C.
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p. 753 - 756
(2007/10/02)
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- Epoxyannulation. 5. Reactions of 1-Butadienylsulfonium Salts
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Treatment of the lithium enolate from three aldehydes, cycloheptanone, and four unhindered cyclohexanones with (1,3-butadien-1-yl)dimethylsulfonium fluoborate (1) provides a 7-oxabicyclohept-4-ene stereoselectively in 30-58percent yield.These epoxides are accompanied by 2--3-butenyl>ketones.This alkylated ketone is the sole product from the enolates of three hindered cyclic ketones and three acyclic ketones.Five related sulfonium salts, 2, 21, 46, 50, and 63, and the enolate from cyclohexanone gave these alkylated ketones accompanied by 5-40percent yield of the epoxyannulated product.
- Garst, Michael E.,Arrhenius, Peter
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- The effect of crown ethers on the alkylation of a cyclic β-keto ester
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The effects of crown ethers (6 and 7) on the reactions of sodium (2a) and potassium enolates (2b) of 2-ethoxycarbonylcyclohexanone (1) with isopropyl iodide in dimethylsulfoxide and dimethoxyethane have been investigated. When the addition of crown ether promoted dissociation of ion pair 2 in either of the two solvents, the total rate of reaction (kt) increased and the ratio of carbon- (3) to oxygen-alkylation (4 and 5) products decreased. The results are consistent with the involvement of both the ion pair and more dissociated species in alkylation and with greater reactivity for the latter.
- Whitney, Richard R.,Jaeger, David A.
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p. 769 - 773
(2007/10/02)
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- 2,3-Polymethylene-4-oxo-4H-pyrido[1,2-a]pyrimidines
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Pharmaceutical intermediates, morphine potentiators and other compounds have the formula STR1 wherein R is hydrogen, halogen, C1-4 alkyl, hydroxy, nitro, amino, carboxy or a carboxylic acid derivate radical, R1 is hydrogen or a C1-4 alkyl, R2 is hydrogen or C1-4 alkyl, R3 is hydrogen, R4 is hydrogen or C1-4 alkyl, R5 is hydrogen R6 is hydrogen or R3 and R4 and/or R5 and R6 form a chemical bond, X is oxygen or imino, m is 1, 2, 3 or 4, n is 0, 1, 2 or 3, and if n is 1, then the dotted lines can stand for bonds, with the proviso that if m=1 and n=1 and if in the 2,3-, 6,7-, 8,9- and 1,10-positions double bonds are present, and R1 and R2 are hydrogen, then R is other than 9-hydroxy or 9-methyl; if m=2 and n=1 and R2 is hydrogen, then at least one of R and R1 is other than hydrogen; and if m=2 and n=2 and R2 is hydrogen and the molecule is a 2,3,4,6,7,8,9,10-octahydro derivative, then at least one of R and R1 is other than hydrogen or an acid-addition or quaternary salt thereof.
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- Cycloalkanapyrazole-3-carbonitrile herbicides
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Herbicidal cycloalkanapyrazoles of the formula: STR1 where N IS 3, 4 OR 5; R1 is hydrogen or methyl; X is fluorine, chlorine, bromine, iodine, cyano, or methoxy; Y is hydrogen, fluorine, or chlorine; Z is hydrogen or fluorine; and V is hydrogen, fluorine, chlorine or methoxy; provided that (a) when n is 3, R1 must be hydrogen; (b) when n is 5, R1 must be hydrogen, Y must be hydrogen or fluorine, Z and V must both be hydrogen, and X must be fluorine, chlorine or bromine; (c) when V is methoxy, X and Y must be chlorine, and Z must be hydrogen; and (d) when V is fluorine or chlorine, X must be fluorine, chlorine or bromine, and Z must be hydrogen.
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