- Dual aminoquinolate diarylboron and nickel catalysed metallaphotoredox platform for carbon-oxygen bond construction
-
Herein, aminoquinolate diarylboron complexes are utilized as photocatalysts in dual Ni/photoredox catalyzed carbon-oxygen construction reactions. Via this unified metallaphotoredox platform, diverse (hetero)aryl halides can be conveniently coupled with acids, alcohols and water. This method features operational simplicity, broad substrate scope and good compatibility with functional groups. This journal is
- Day, Craig,Jia, Xin,Wei, Lanfeng,Xu, Liang,Zu, Weisai
-
supporting information
p. 8273 - 8276
(2020/08/17)
-
- A molybdenum based metallomicellar catalyst for controlled and chemoselective oxidation of activated alcohols in aqueous medium
-
A surfactant based oxodiperoxo molybdenum complex, which could activate molecular oxygen, has been employed as a catalyst for controlled oxidation of benzylic alcohols to corresponding carbonyls. The oxidation reactions were carried out under aqueous environment, however, in the absence of any extraneous base or co-catalyst. Sensitive/oxidizable functional groups like cyano, sulfide, hydroxyl, aryl-hydroxyl, alkene (internal/terminal), alkyne (internal/terminal), and acetal were tolerated during the transformations. Such selectivity is attributed to the mild nature of the catalyst. The methodology could also be scaled-up for multi-gram synthesis and the protocol is likely to find practical use since it requires an inexpensive recyclable-catalyst and easily available oxidant (under green conditions). A plausible mechanism is proposed with the help of preliminary computational study.
- Thiruvengetam, Prabaharan,Chakravarthy, Rajan Deepan,Chand, Dillip Kumar
-
p. 123 - 133
(2019/07/19)
-
- BETA-HYDROXYETHYLAMINES FOR USE IN THE TREATMENT OR PREVENTION OF NON-ALCOHOLIC FATTY LIVER DISEASES
-
There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, for use in the treatment of a non-alcoholic fatty liver disease (NAFLD), such as non-alcoholic steatohepatitis (NASH), wherein X, R1, R2, R3 and n have meanings as provided in the description.
- -
-
-
- Solvent free, light induced 1,2-bromine shift reaction of α-bromo ketones
-
Photolysis of α-bromopropiophenones in acetonitrile results in formation of β-bromopropiophenones with good product selectivity, which can be coined as 1,2-Br shift reaction. The product selectivity increases when the reaction is done in neat or solid state, where only the 1,2-Br shift product is formed in some cases. The reaction is suggested to proceed by C–Br bond homolysis to give a radical pair, followed by disproportionation and conjugate addition of HBr to the α,β-unsaturated ketone intermediate. When the unsaturated intermediate is stabilized by an extra conjugation, the reaction stops at the stage, in which the unsaturated ketone becomes a major product. The synthetic method described in this research fits in a category of eco-friendly organic synthesis nicely since the reaction does not use volatile organic solvents and any other additives such as acid, base or metal catalysts, etc. Besides, the method fits into perfect atom economy, which does not give any side products. The synthetic method should find much advantage over other alternative methods to obtain β-bromo carbonyl compounds.
- An, Sejin,Moon, Da Yoon,Park, Bong Ser
-
p. 6922 - 6928
(2018/10/24)
-
- COMPOUNDS FOR THE TREATMENT OF HYPERGLYCAEMIA
-
There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, for use in the treatment of hyperglycaemia or a disorder characterized by hyperglycaemia, such as type 2 diabetes, wherein X, R1, R2, R3 and n have meanings as provided in the description.
- -
-
-
- Selective oxidation of aliphatic C-H bonds in alkylphenols by a chemomimetic biocatalytic system
-
Selective oxidation of aliphatic C-H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum. The system consisting of CreHI (for installation of a phosphate directing/ anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C-H bonds of p-And m-Alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity.
- Du, Lei,Dong, Sheng,Zhang, Xingwang,Jiang, Chengying,Chen, Jingfei,Yao, Lishan,Wang, Xiao,Wan, Xiaobo,Liu, Xi,Wangi, Xinquan,Huang, Shaohua,Cui, Qiu,Feng, Yingang,Liu, Shuang-Jiang,Li, Shengying
-
p. E5129 - E5137
(2017/07/04)
-
- Unambiguous Identification of β-Tubulin as the Direct Cellular Target Responsible for the Cytotoxicity of Chalcone by Photoaffinity Labeling
-
Chalcone is a simple and potentially privileged structure in medicinal chemistry with a diverse repertoire of biological activities, among which cytotoxicity is of particular interest. The sharp structure–activity relationship (SAR) for chalcone's cytotoxicity suggests structure-specific target interactions. Despite the numerous putative targets proposed, evidence for direct target interactions in cells is unavailable. In this study, guided by the sharp cytotoxic SAR, we developed a cytotoxic chalcone-based photoaffinity labeling (PAL) probe, (E)-3-(3-azidophenyl)-1-[3,5-dimethoxy-4-(prop-2-yn-1-yloxy)phenyl]-2-methylprop-2-en-1-one (C95; IC50: 0.38±0.01 μm), along with two structurally similar non-cytotoxic probes. These probes were used to search for the direct cellular target responsible for chalcone's cytotoxicity through intact cell-based PAL experiments, in which β-tubulin was identified to specifically interact with the cytotoxic probe (i.e., C95) but not the non-cytotoxic probes. A set of phenotypical and biochemical assays further reinforced β-tubulin as the cytotoxic target of chalcones. Peptide mass quantitation by mass spectrometric analysis revealed one peptide potentially labeled by C95, providing information on chalcone's binding site on β-tubulin.
- Zhou, Bo,Yu, Xingxin,Zhuang, Chunlin,Villalta, Peter,Lin, Yong,Lu, Junxuan,Xing, Chengguo
-
p. 1436 - 1445
(2016/07/16)
-
- PHOTOLABILE PRO-FRAGRANCES
-
Fragrances that provide a scent of freshness tend to be volatile and are therefore not very economical when used in typical applications such as washing or cleaning processes, so they have to be used in relatively large quantities to be able to produce adequate effects. The disclosed photolabile pro-fragrances provide a much longer-lasting sense of fragrance, in particular with a scent of freshness, when used in typical applications, thus allowing said fragrances to be used economically.
- -
-
Paragraph 0094-0100
(2015/04/15)
-
- A novel chemoselective cleavage of (tert-butyl)(dimethyl)silyl (TBS) ethers catalyzed by Ce(SO4)2·4 H2O
-
(tert-Butyl)(dimethyl)silyl (tBuMe2Si; TBS) phenyl/alkyl ethers were efficiently cleaved to the corresponding parent hydroxy compounds in good yields using catalytic amounts of Ce(SO4) 2·4 H2O by microwave-assisted or conventional heating in MeOH. Intramolecular and competitive experiments demonstrated the chemoselective deprotection of TBS ethers in the presence of triisopropylsilyl (iPr3Si; TIPS) and (tert-butyl)(diphenyl)silyl ( tBuPh2Si; TBDPS) ethers. Copyright
- González-Calderón, Davir,González-González, Carlos A.,Fuentes-Benítez, Aydeé,Cuevas-Yá?ez, Erick,Corona-Becerril, David,González-Romero, Carlos
-
p. 965 - 972
(2014/08/05)
-
- DMF as carbon source: Rh-catalyzed α-methylation of ketones
-
An unprecedented Rh-catalyzed direct methylation of ketones with N,N-dimethylformamide (DMF) is disclosed. The reaction shows a broad substrate scope, tolerating both aryl and alkyl ketones with various substituents. Mechanistic studies suggest that DMF delivers a methylene fragment followed by a hydride in the methylation process.
- Li, Yang,Xue, Dong,Lu, Wei,Wang, Chao,Liu, Zhao-Tie,Xiao, Jianliang
-
supporting information
p. 66 - 69
(2014/01/23)
-
- Ethacrynic acid as a lead structure for the development of potent urease inhibitors
-
Ethacrynic acid and a series of its analogues were synthesized and subsequently evaluated for their inhibitory effect on jack bean urease. Ethacrynic acid showed, even at low concentrations, very potent inhibitory activity against the enzyme. For ethacrynic acid, the inhibition potential increased with increasing preincubation time of ethacrynic acid and enzyme, whereas for some other compounds a higher preincubation time lead to a significant reduction of their activity. We could demonstrate that the α,β-unsaturated carbonyl unit of our compounds is mandatory to inhibit the enzyme, possibly due to its ability to bind to cysteine residues in the active site of the jack bean urease.
- Janser, Ingo,Vortolomei, Caitlyn M.,Meka, Ranjith K.,Walsh, Courtney A.,Janser, Romy F.J.
-
p. 660 - 664
(2013/08/15)
-
- Cerium(IV) sulfate tetrahydrate: A catalytic and highly chemoselective deprotection of THP, MOM, and BOM ethers
-
Tetrahydropyranyl (THP), methoxymethyl (MOM), and benzyloxymethyl (BOM) phenyl/alkyl ethers were efficiently cleaved to the corresponding parent hydroxyl compounds in good yields using catalytic amounts of Ce(SO 4)2·4H2O by microwave-assisted or conventional heating in methanol solution. Intramolecular and competitive experiments demonstrated the chemoselective deprotection of THP ethers in the presence of triisopropylsilyl (TIPS) and tert-butyldiphenylsilyl (TBDPS) phenyl ethers.
- González-Calderón, Davir,González-González, Carlos A.,Fuentes-Benítez, Aydeé,Cuevas-Yá?ez, Erick,Corona-Becerril, David,González-Romero, Carlos
-
p. 7164 - 7166
(2013/12/04)
-
- Synthesis, biochemical evaluation and rationalisation of a series of 3,5- dibromo derivatives of 4-hydroxyphenyl ketone-based compounds as probes of the active site of type 3 of 17β-hydroxysteroid dehydrogenase (17β-hsd3) and the role of hydrogen bonding interaction in the inhibition of 17β-HSD3
-
We report the synthesis, evaluation and rationalisation of the inhibitory activity of a series of 3,5-dibromo derivatives of 4-hydroxyphenyl ketone as probes of the active site of the type 3 of 17β-hydroxysteroid dehydrogenase (17β-HSD3). The results support the important role of hydrogen bonding interaction in the inhibition of 17β-HSD3.
- Olusanjo, Moniola S.,Mashru, Shreena N.,Cartledge, Timothy,Ahmed, Sabbir
-
scheme or table
p. 604 - 610
(2012/08/28)
-
- Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
-
Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
- Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
-
experimental part
p. 641 - 649
(2011/03/19)
-
- Inhibitory effects of ethacrynic acid analogues lacking the α,β-unsaturated carbonyl unit and para-acylated phenols on human cancer cells
-
A series of ethacrynic acid analogues, lacking the α,β- unsaturated carbonyl unit, was synthesized and subsequently evaluated for their ability to inhibit the migration of human breast cancer cells, Hs578Ts(i)8 as well as of human prostate cancer cells, C4-2B. These cell lines provide a good model system to study migration and invasion, since they represent metastatic cancer. Our studies show that ethacrynic acid analogues with methyl substituents at the aromatic ring demonstrate no inhibitory effect on the migration of both cancer cell lines, whereas a precursor in the synthesis of these ethacrynic acid analogues (II-1, a para-acylated m-cresol) is an excellent inhibitor of the migration of both cancer cell lines.
- Bryant, Zack E.,Janser, Romy F.J.,Jabarkhail, Medina,Candelaria-Lyons, Melissa S.,Romero, Brittni B.,Slambrouck, Severine Van,Steelant, Wim F.A.,Janser, Ingo
-
scheme or table
p. 912 - 915
(2011/03/21)
-
- Synthesis and biochemical evaluation of a series of trifluoromethanesulfonate derivatives of 4 hydroxyphenyl ketones - Probes of the active site of type 1 and 3 of the 17β-hydroxysteroid dehydrogenase family of enzymes
-
In an effort to aid the design of 'dual-inhibitors' of types 1 and 3 of the 17β-hydroxysteroid dehydrogenase (17β-HSD), we report the synthesis, biochemical evaluation and rationalisation of the inhibitory activity of trifluoromethanesulfonate derivatives of 4-hydroxyphenyl ketone-based compounds which were found to be weak inhibitors of types 1 and 3.
- Olusanjo, Moniola S.,Cartledge, Timothy,Shah, Kruti,Ahmed, Sabbir
-
p. 253 - 259
(2013/01/10)
-
- Effect of structurally constrained oxime-ether linker on PPAR subtype selectivity: Discovery of a novel and potent series of PPAR-pan agonists
-
A novel series of thaizole and oxazole containing phenoxy acetic acid derivatives is reported as PPAR-pan agonists. Incorporation of structurally constrained oxime-ether based linker in the chemotype of a potent PPARδ selective agonist GW-501516 was adapted as designing strategy. In vitro, selected test compounds 12a, 12c, 17a and 18a showed PPAR-pan agonists activities and among these four compounds tested, 12a emerged as highly potent and efficacious compound, while 17a exhibited moderate and balanced PPAR-pan agonistic activity. In vivo, selected test compounds 12a and 17a exhibited significant anti-hyperglycemic and anti-hyperlipidemic activities in relevant animal models. These results support our hypothesis that the introduction of structurally constrained oxime-ether linker between lipophilic tail and acidic head plays an important role in modulating subtype selectivity and subsequently led to the discovery of potent PPAR-pan agonists.
- Makadia, Pankaj,Shah, Shailesh R.,Pingali, Harikishore,Zaware, Pandurang,Patel, Darshit,Pola, Suresh,Thube, Baban,Priyadarshini, Priyanka,Suthar, Dinesh,Shah, Maanan,Giri, Suresh,Trivedi, Chitrang,Jain, Mukul,Patel, Pankaj,Bahekar, Rajesh
-
experimental part
p. 771 - 782
(2011/03/18)
-
- Ethacrynic acid analogues lacking the α,β-unsaturated carbonyl unit-Potential anti-metastatic drugs
-
A series of ethacrynic acid analogues, lacking the α,β-unsaturated carbonyl unit, was synthesized and subsequently evaluated for their ability to inhibit the migration of human breast cancer cells, MCF-7/AZ. Several of the analogues were already active in the low micromolar range, whereas ethacrynic acid itself shows no potential to inhibit the migration of these cancer cells. Preliminary studies show that the presence of one or more methoxy groups at the phenyl ring of ethacrynic acid is important in order for the ethacrynic acid analogues to demonstrate an inhibitory effect on the migration.
- Janser, Romy F.J.,Meka, Ranjith K.,Bryant, Zack E.,Adogla, Enoch A.,Vogel, Elizabeth K.,Wharton, Jaimie L.,Tilley, Cynthia M.,Kaminski, Catherine N.,Ferrey, Seth L.,Van slambrouck, Severine,Steelant, Wim F.A.,Janser, Ingo
-
experimental part
p. 1848 - 1850
(2010/07/06)
-
- Thermal retro-aldol reaction using fluorous ether F-626 as a reaction medium
-
A high-boiling, fluorous-organic hybrid ether, F-626, was tested for use in thermal retro-aldol reactions and found to be an excellent reaction medium in view of the ease of separation from the product by fluorous/organic biphasic treatment. The recovered F-626 can be readily reused for subsequent runs.
- Fukuyama, Takahide,Kawamoto, Takuji,Okamura, Takahiro,Denichoux, Aurelien,Ryu, Ilhyong
-
experimental part
p. 2193 - 2196
(2010/10/21)
-
- Pyridizinone derivatives
-
The present invention provides compounds of formula (I*): their use as H3 inhibitors, processes for their preparation, and pharmaceutical compositions thereof.
- -
-
Page/Page column 108
(2008/06/13)
-
- Synthesis, biochemical evaluation and rationalisation of the inhibitory activity of a series of 4-hydroxyphenyl ketones as potential inhibitors of 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3)
-
We report the preliminary results of the synthesis and biochemical evaluation of a number of 4-hydroxyphenyl ketones as inhibitors of the isozyme of the enzyme 17β-hydroxysteroid dehydrogenase (17β-HSD) responsible for the conversion of androstenedione (AD) to testosterone (T), more specifically type 3 (17β-HSD3). The results of our study suggest that we have synthesised compounds which are, in general, potent inhibitors of 17β-HSD3, in particular, we discovered that 1-(4-hydroxy-phenyl)-nonan-1-one (8) was the most potent (IC50 = 2.86 ± 0.03 μM). We have therefore provided good lead compounds in the synthesis of novel non-steroidal inhibitors of 17β-HSD3.
- Lota, Rupinder K.,Dhanani, Sachin,Owen, Caroline P.,Ahmed, Sabbir
-
p. 4519 - 4522
(2007/10/03)
-
- NOVEL BENZAMIDINE DERIVATIVES, PROCESS FOR THE PREPARATION THEREOF AND PHARMACEUTICAL COMPOSITION COMPRISING THE SAME
-
The present invention relates to novel benzamidine derivatives, process for the preparation thereof and pharmaceutical composition comprising the same. The novel benzamidine derivatives of the present invention are useful for the prevention and treatment of osteoporosis, bone fractures and allergic inflammatory diseases .
- -
-
Page/Page column 67
(2010/10/19)
-
- Synthesis and evaluation of uterine relaxant activity for a novel series of substituted p-hydroxyphenylethanolamines
-
Novel racemic 1-(4-hydroxyphenyl)-2-[3-(substituted phenoxy)-2-hydroxy-1-propyl]aminopropan-1-ol hydrochlorides (9a-h) were synthesized by condensing racemic 1-(p-hydroxyphenyl)-2-aminopropan-1-ol hydrochloride (6) with substituted aryloxymethyloxiranes (8a-h) in DMF in presence of anhydrous potassium carbonate and then reacting with dry hydrogen chloride gas. They were evaluated for uterine relaxant activity in vitro on isolated rat uterus and in vivo in pregnant rats. Their cAMP releasing potential was studied using rat uterus tissue homogenates by cAMP [3H] assay and cardiac stimulant potential was evaluated in dog. All compounds exhibited potent uterine relaxant activity in vitro and produced a significant delay in the onset of labour in pregnant rats; their cAMP releasing potential was higher than isoxsuprine hydrochloride except for 9b and 9c. Finally insignificant cardiac stimulant potential was noted for these compounds when compared to isoxsuprine hydrochloride.
- Viswanathan,Chaudhari
-
p. 6581 - 6585
(2007/10/03)
-
- Design, synthesis and evaluation of racemic 1-(4-hydroxyphenyl)-2-[3- (substituted phenoxy)-2-hydroxy-1-propyl]amino-1-propanol hydrochlorides as novel uterine relaxants
-
Novel 1-(4-hydroxyphenyl)-2-[3-(substituted phenoxy)-2-hydroxy-1-propyl] amino-1-propanol hydrochlorides were designed based on the pharmacophore for potent uterine relaxant activity and by utilizing the principles of structural hybridization. The designed molecules were synthesized as racemates by a novel route and were evaluated for uterine relaxant activity in vitro on isolated rat uterus and in vivo in pregnant rats. Their cAMP-releasing potential was studied using rat uterus tissue homogenates by the cAMP [3H] assay, and cardiac stimulant potential was evaluated on isolated guinea pig right atrium. All compounds exhibited potent uterine relaxant activity in vitro and produced a significant delay in the onset of labour in pregnant rats; their cAMP-releasing potential was slightly less, while their cardiac stimulant potential was insignificant as compared to isoxsuprine hydrochloride.
- Viswanathan,Kodgule,Chaudhari
-
p. 3532 - 3535
(2007/10/03)
-
- Palladium-catalyzed cleavage of O/N-propargyl protecting groups in aqueous media under a copper-free condition
-
(Figure presented) A copper-free palladium-mediated cleavage of O/N-propargyl bonds in aqueous media has been investigated, affording a mild and convenient method for the deprotection of phenols and anilines. The methodology could be utilized for the selective removal of propargyl groups from aryl ethers and amines without affecting a variety of unprotected functional groups present in the substrates. The mechanism and scope of the reaction is discussed.
- Pal, Manojit,Parasuraman, Karuppasamy,Yeleswarapu, Koteswar Rao
-
p. 349 - 352
(2007/10/03)
-
- Structure - Activity relationships of non-imidazole H3 receptor ligands. Part 1
-
SAR studies for novel non-imidazole containing H3 receptor antagonists with high potency and selectivity for rat H3 receptors are described. A high throughput screening lead, A-923, was further elaborated in a systematic manner to clarify a pharmacophore for this class of aryloxyalkyl piperazine based compounds.
- Faghih, Ramin,Dwight, Wesley,Gentles, Robert,Phelan, Kathleen,Esbenshade, Timothy A,Ireland, Lynne,Miller, Thomas R,Kang, Chae-Hee,Fox, Gerard B,Gopalakrishnan, Sujatha M,Hancock, Arthur A,Bennani, Youssef L
-
p. 2031 - 2034
(2007/10/03)
-
- A convenient synthesis of an unsymmetrical biphenyl ether and its elaboration for the synthesis of Illicium neolignan - Isomagnolone
-
A facile synthesis of isomagnolone, a (3-O-4′)-neolignan isolated from Illicium simonsii is reported via the synthesis of the appropriate biphenyl ether as an alternative to conventional oxidative coupling route.
- Panda, Atulya Kumar
-
p. 181 - 183
(2007/10/03)
-
- Fries rearrangement at atmospheric pressure using microwave irradiation
-
A very safe, fast and practical Fries rearrangement with conventional AlCl3 catalyst, carried out in a modified domestic microwave oven at atmospheric pressure is reported.
- Khadilkar, Bhushan M.,Madyar, Virendra R.
-
p. 1195 - 1200
(2007/10/03)
-
- Selective deprotection of propargyl ethers using tetrathiomolybdate
-
Benzyltriethylammonium tetrathiomolybdate, [PhCH2NEt3]2MoS4, 1 deprotects propargyl ethers of alcohols and phenols in a selective manner in high yields. Easily reducible groups like nitro, aldehyde, keto and allyl are not affected.
- Swamy,Ilankumaran, Palanichamy,Chandrasekaran, Srinivasan
-
p. 513 - 514
(2007/10/03)
-
- Novel applications of Raney nickel/isopropanol: Efficient system for the reduction of organic compounds
-
Catalytic hydrogenation of various organic substrates with Raney nickle in isopropanol proceeds under mild conditions of temperature and pressure. Comparison with other catalysts systems evidenced the superiority of Raney nickel/isopropanol.
- Regla, Ignacio,Reyes, Adelfo,Koerber, Claudia,Demare, Patricia,Estrada, Osvaldo,Juaristi, Eusebio
-
p. 817 - 823
(2007/10/03)
-
- Selective removal of phenolic and alcoholic silyl ethers
-
Potassium carbonate/Kriptofix 222 and pyridinium p-toluenesulfonate or BF3-etherate have been found to remove the tert-butyldimethylsilyl group from phenolic and alcoholic silyl ethers, respectively. This methodology should find wide applicability in complex organic synthesis.
- Prakash, Chandra,Saleh, Samir,Blair, Lan A.
-
p. 7565 - 7568
(2007/10/02)
-
- β-Cyclodextrin Effects on the Photo-Fries Rearrangement of Aromatic Alkyl Esters
-
The photolysis of phenyl propionate (1a) and phenyl valerate (1b) in water and in solutions containing β-cyclodextrin (CD) leads to the corresponding p-hydroxyphenyl alkyl ketone 2, o-hydroxyphenyl alkyl ketone 3, and phenol 4.When the reactions are carried out in the presence of oxygen there is a decrease in the total amount of rearrangement products, but the inhibition is less marked in the presence of CD.The / ratio for 1b increases when CD concentration changes from 0 to 10 mM.These changes are due to the increase in the quantum yield for the formation of 3 and a decrease in the quantum yield for 2 in the solutions containing CD.The / ratio for 1a decreases in the presence of CD although both quantum yields increase with CD concentrations.Under the conditions used in this study, the substrate reacted in the bulk solution and in the cavity of CD.The quantum yields for the formation of 3 and 4, ΦCD3 and ΦCD4, are higher for the included substrate than the corresponding values for the free substrate while ΦCD2 is higher than Φw2 for 1a but lower for 1b.This effect is attributed to the different orientation of the substrates in the cavity of CD.Besides, ΦCD4 also increases due to the availability of hydrogens bonded to secondary carbons in the cavity of the cyclodextrin.
- Veglia, Alicia V.,Rossi, Rita H. de
-
p. 4941 - 4944
(2007/10/02)
-
- A REEXAMINATION OF THE RETRO-FRIES REARRANGEMENT OF SOME o-HYDROXYKETONES
-
The retro-Fries rearrangement, catalyzed by protic and Lewis acids, was studied for some o-hydroxyketones.The results are consistent with the mechanism of an heterolytic cleavage and rearrangement.It appears that, in general, Lewis acids do not induce the retro-Fries rearrangement of o-hydroxyketones.However, in certain cases, it may be brought about the presence of a protic acid generated in situ, from a solvent-catalyst interaction.
- Martin, Robert,Lafrance, Jean Ronald,Demerseman, Pierre
-
p. 539 - 548
(2007/10/02)
-
- Synthesis of (aryloxy)alkylamines. 1. Novel antisecretory agents with H+K+-ATPase inhibitory activity
-
A series of heterocyclic (aryloxy)alkylamines of structures II and III were prepared and found to possess gastric antisecretory activity. Of the variety of substituted thiazoles, benzoxazoles, and benzothiazoles prepared, thiazole 18, benzoxazole 32, and benzothiazole 47 exhibited gastric antisecretory potency comparable to that of ranitidine in vivo in the pylorous ligated rat model. In an isolated rabbit parietal system, the series of thiazoles, benzoxazoles, and benzothiazoles also demonstrated similar potency to that of ranitidine toward the inhibition of both histamine-stimulated and dcAMP-stimulated uptake of amino[14C]pyrine. These compounds inhibited the H+K+-sensitive ATPase enzyme in isolated gastric microsomes. A direct correlation existed between inhibition of 14C uptake, in vivo antisecretory activity, and inhibition of the H+K+-ATPase enzyme. The more potent antisecretory compounds 18, 32 and 47 were also the more potent enzyme inhibitors. These data suggest that the mechanism responsible for the observed in vitro and in vivo gastric antisecretory activity, in these series of compounds, is a consequence of the inhibition of the H+K+-sensitive ATPase enzyme.
- Sanfilippo,Urbanski,Press,Hajos,Shriver,Scott
-
p. 1778 - 1785
(2007/10/02)
-
- FACILE SELECTIVE AMINOLYSIS OF PHENOLIC BENZOATES WITH 1-BUTANAMINE IN BENZENE
-
1-Butanamine in benzene at room temperature effects selective aminolysis of phenolic benzoates without affecting aliphatic benzoates
- Bell, Kevin H.
-
p. 2263 - 2264
(2007/10/02)
-
- RECHERCHES SUR LES SUBSTANCES MESOGENES-VIII; PREPARATION ET PROPERTIES MESOMORPHES DE SERIES ISOMETRIQUES
-
The synthesis and the mesomorphic properties of various series of isometric mesogenic compounds are described.It is confirmed that isometric mesogenic molecules may be nematogenic and/or smectogenic according to the position of the polar rigid core.
- Malthete, Jacques,Canceill, Josette,Gabard, Jacqueline,Jacques, Jean
-
p. 2815 - 2821
(2007/10/02)
-
- BETA-ADRENERGIC BLOCKING AGENTS IN THE 1,2,3-THIADIAZOLE SERIES
-
Novel 4-2,3 or 4(3-amino-2-hydroxypropoxy) phenyl!-and 5-2, 3 or 4(3-amino-2-hydroxypropoxy) phenyl!-1,2,3-thiadiazole derivatives which may be further substituted at the C-5 or C-4 position of the thiadiazole ring, respectively, by a lower alkyl, phenyl, trifluoromethyl, carboxy, alkoxycarbonyl, cyano or an aminocarbonyl group, and the pharmaceutically acceptable acid addition salts thereof and processes for the production of such compounds; 4-4(3-t-butylamino-2-hydroxypropoxy) phenyl!-1,2,3-thiadiazole and 5-4(3-t-butylamino-2-hydroxypropoxy) phenyl!-1,2,3-thiadiazole are representative of the class. These compounds possess cardiovascular activity and are useful for the treatment of abnormal heart conditions in mammals.
- -
-
-