- Stepwise benzylic oxygenation via uranyl-photocatalysis
-
Stepwise oxygenation at the benzylic position (1°, 2°, 3°) of aromatic molecules was comprehensively established under ambient conditions via uranyl photocatalysis to produce carboxylic acids, ketones, and alcohols, respectively. The accuracy of the stepwise oxygenation was ensured by the tunability of catalytic activity in uranyl photocatalysis, which was adjusted by solvents and additives demonstrated through Stern–Volmer analysis. Hydrogen atom transfer between the benzylic position and the uranyl catalyst facilitated oxygenation, further confirmed by kinetic studies. Considerably improved efficiency of flow operation demonstrated the potential for industrial synthetic application.
- Hu, Deqing,Jiang, Xuefeng
-
supporting information
p. 124 - 129
(2022/01/19)
-
- Synthesis of α,β-dibromo ketones by photolysis of α-bromo ketones with N-bromosuccinimide: Photoinduced β-bromination of α-bromo ketones
-
Irradiation of α-bromopropiophenones in the presence of NBS results in the formation of α,β-dibromopropiophenones, which can be viewed as β-bromination of α-bromopropiophenones. The reaction is believed to go through a series of reactions; photoinduced C–Br bond cleavage, elimination of HBr to give α,β-unsaturated ketone intermediates, and addition of Br2, which are formed by the reaction between HBr and NBS. From mechanistic studies of the reaction, we have also found a very convenient method for α-debromination of the α,β-dibromopropiophenones which is by simple irradiation of the dibromo ketones in acetone or 2-propanol without the use of any additives. Our results demonstrate that bromine can be added into or eliminated from the alpha, beta, or both positions to the carbonyl group by photochemical methods, which make synthetic options of bromine containing carbonyl compounds versatile.
- Moon, Da Yoon,An, Sejin,Park, Bong Ser
-
-
- 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)
-
- A gold-catalyzed 1,2-acyloxy migration/intramolecular cyclopropanation/ring enlargement cascade: Syntheses of medium-sized heterocycles
-
The synthesis of medium-sized heterocycles possessing a trans double bond is still a challenge. Herein, gold(I)-catalyzed 1,2-acyloxy migration/intramolecular cyclopropanation/ring enlargement cascade reaction of furans has been developed, providing highly efficient access to ten- and eleven-membered heterocycles with a broad substrate scope under mild reaction conditions. The reaction outcome features high chemoselectivity at the C5-position of furan. Moreover, a trans-double bond was embodied in the medium ring system.
- Sun, Yin-Wei,Tang, Xiang-Ying,Shi, Min
-
supporting information
p. 13937 - 13940
(2015/09/07)
-
- Anodic cyclization of dimethyl 2-(3-Oxo-3-arylpropyl) malonates into the corresponding dimethyl 2-aroylcyclopropane-1,1-dicarboxylates
-
A variety of dimethyl 2-(3-oxo-3-arylpropyl)malonates were electrooxidized in methanol, in the presence of potassium iodide and a base or a neutral salt, to give the corresponding cyclized dimethyl 2-aroylcyclopropane-1,1- dicarboxylates in moderate to good yields. The reactions were carried out under extremely mild reaction conditions, in which the optimal amount of electrolytic current varied from 2.12-2.41 F·mol-1 depending on the substrates. The reaction presumably proceeds via a two-electron oxidation process, in which iodide ions play an important role as the electron carrier between the anode and the substrate. Georg Thieme Verlag Stuttgart. New York.
- Okimoto, Mitsuhiro,Yamamori, Haruki,Ohashi, Kousuke,Hoshi, Masayuki,Yoshida, Takashi
-
p. 1568 - 1572
(2013/08/23)
-
- Azido carbonyl compounds as DNA cleaving agents
-
Irradiation of azido carbonyl compounds using UV light (≥310 nm) produced triplet alkyl nitrenes and aroyl radicals, which resulted in efficient cleavage of single strand DNA at pH 7.0. DNA cleaving ability of azido carbonyl compounds was found to be dependent on its concentration and substituents on its aromatic ring. Further, newly synthesized naphthalene based azido carbonyl compounds showed DNA cleavage ability at longer wavelength of UV light (≥350 nm) and also binding studies revealed that they bind to ct-DNA by weak intercalation mode.
- Chowdhury, Nilanjana,Dutta, Sansa,Karthick,Anoop, Anakuthil,Dasgupta, Swagata,Pradeep Singh
-
-
- Enantioselective synthesis of quinolizidines and indolizidines via a catalytic asymmetric hydrogenation cascade
-
A catalytic enantioselective synthesis of a new class of quinolizidines and indolizidines is presented. An asymmetric Bronsted acid catalyzed hydrogenation cascade as well as a sequential Bronsted acid/metal catalyzed hydrogenation protocol of 2-substituted quinolines yields benzofused quinolizidines and indolizidines in good yields with high diastereo- and enantioselectivities. Georg Thieme Verlag Stuttgart - New York.
- Rueping, Magnus,Hubener, Lukas
-
supporting information; experimental part
p. 1243 - 1246
(2011/07/31)
-
- Direct asymmetrie catalytic thienylaluminum addition to ketones: A concise approach to the synthesis of (S)-tiemonium iodide
-
A direct asymmetric addition of a (2-thienyl)aluminum reagent to ketones catalyzed by a titanium catalyst of (S)-BINOL to afford chiral tertiary 2-thienyl alcohols is reported. The catalytic system works excellently for aromatic ketones and for 1-acetylcyclohexene, furnishing products in excellent enantioselectivities of up to 97% ee. However, the additions to dialkyl ketones afford products in low enantioselectivities of 8-17% ee. Importantly, a concise 3-step synthesis of (S)-tiemonium iodide with an 84% yield is demonstrated.
- Biradar, Deepak B.,Zhou, Shuangliu,Gau, Han-Mou
-
supporting information; experimental part
p. 3386 - 3389
(2009/12/01)
-
- An efficient and general approach to β-functionalized ketones
-
Figure presented The oxidation of selected anlons (N3 -, SCN-, I-, and Br-) by eeric ammonium nitrate (CAN) in the presence of substituted cyclopropyl alcohols provides a novel approach to β-functionalized ketones. The protocol has a number of advantages including short reaction times, ease of reagent handling, and mild, neutral reaction conditions. Overall, this method provides an alternative pathway to important starting materials and intermediates in organic synthesis.
- Jingliang, Jiao,Nguyen, Larry X.,Patterson, Dennis R.,Flowers II, Robert A.
-
p. 1323 - 1326
(2008/01/01)
-
- Synthesis and pharmacological properties of benzamide derivatives as selective serotonin 4 receptor agonists
-
A series of 4-amino-5-chloro-2-methoxy-N-(piperidin-4-ylmethyl)benzamides with a polar substituent group at the 1-position of the piperidine ring was synthesized and evaluated for its effect on gastrointestinal motility. The benzoyl, phenylsulfonyl, and benzylsulfonyl derivatives accelerated gastric emptying and increased the frequency of defecation. One of them, 4-amino-N-[1-[3-(benzylsulfonyl)propyl]piperidin-4-ylmethyl]-5-chloro-2- methoxybenzamide (13a, Y-36912), was a selective 5-HT4 receptor agonist offering potential as a novel prokinetic with reduced side effects derived from 5-HT3- and dopamine D2 receptor-binding affinity. In the oral route of administration, this compound enhanced gastric emptying and defecation in mice, and has a possibility as a prokinetic agent, which is effective on both the upper and the lower gastrointestinal tract.
- Sonda, Shuji,Katayama, Kenichi,Kawahara, Toshio,Sato, Noriko,Asano, Kiyoshi
-
p. 2737 - 2747
(2007/10/03)
-
- BENZOIC ACID COMPOUNDS AND USE THEREOF AS MEDICAMENTS
-
Benzoic acid compounds of the formula STR1 wherein each symbol is as defined in the specification, optical isomers thereof and pharmaceutically acceptable salts thereof; pharmaceutical composition comprising this compound and pharmaceutically acceptable additive; and serotonin 4 receptor agonists, gastrointestinal prokinetic agents and therapeutic agents for various gastrointestinal diseases, which comprise this compound as active ingredient. The compounds of the present invention have high and selective affinity for serotonin 4 receptor, and show agonistic effects thereon. Accordingly, they are useful medications for the prophylaxis and treatment of various gastrointestinal diseases, central nervous disorders, cardiac function disorders, urinary diseases, and the like, as well as useful anti-nociceptors for analgesic use which increase threshold of pain.
- -
-
-
- BENZOIC ACID COMPOUNDS AND MEDICINAL USE THEREOF
-
A benzoic acid compound of the formula wherein each symbol is as defined in the specification, an optical isomer thereof and a pharmaceutically acceptable salt thereof. A pharmaceutical composition comprising this compound and a pharmaceutically acceptable additive, a serotonin 4 receptor agonist comprising this compound as an active ingredient, a gastrointestinal prokinetic agent and a therapeutic agent for gastrointestinal diseases. The compound of the present invention shows selective and high affinity for serotonin 4 receptors, activates same, is useful as a pharmaceutical agent for the prophylaxis and treatment of gastrointestinal diseases (e.g., reflux esophagitis; gastroesophageal reflux such as that accompanying cystic fibrosis; Barrett syndrome; intestinal pseudoileus; acute or chronic gastritis; gastric or duodenal ulcer; Crohn's disease; non-ulcer dyspepsia; ulcerative colitis; postgastrectomy syndrome; postoperative digestive function failure; delayed gastric emptying caused by gastric neurosis, gastroptosis, diabetes, and the like; gastrointestinal disorders such as indigestion, meteorism, abdominal indefinite complaint, and the like; constipation such as atonic constipation, chronic constipation, and that caused by spinal cord injury, pelvic diaphragm failure and the like; and irritable bowel syndrome), central nervous disorders (e.g., schizophrenia, depression, anxiety, disturbance of memory and dementia), cardiac function disorders (e.g., cardiac failure and myocardial ischemia), urinary diseases (e.g., dysuria caused by urinary obstruction, ureterolith, prostatomegaly, spinal cord injury, pelvic diaphragm failure, etc.), and shows superior absorption.
- -
-
-
- Synthesis, X-ray structure, thermal stability and reactions of triaryl(3-oxoalkyl)bismuthonium salts
-
Treatment of triarylbismuth difluorides 2 with siloxycyclopropanes 3 in the presence of trimethylsilyl trifluoromethanesulfonate (triflate) or boron trifluoride-diethyl ether gave the corresponding triaryl(3-oxoalkyl)bismuthonium salts 4 as crystals.X-ray crystallographic analysis of the triflate 4a showed that the central bismuth atom has a distorted tetrahedral geometry with weak intramolecular coordination by the oxygen atoms of the carbonyl group and triflate anion.Whilst all onium salts 4 are thermally stable in a solid state, the triflate 4a slowly decomposed in chloroform to give triphenylbismuthane 6 and an ester 7 quantitatively.In nucleophilic solvents such as MeOH, DMSO and DMF, both triflate 4a and tetrafluoroborate 4d underwent decomposition in a complicated way to afford the bismuthane 6, 3-methoxypropanoyl compounds 8a,b, α,β-unsaturated carbonyl compounds 9a,b, diphenylbismuth triflate 10a or tetrafluoroborate 10b and alkoxysulfonium salts 11a,b.The formate 12 was an additional product from 4d in DMF.The bismuthonium salt 4d reacted with dimethyl sulfide 13 and sodium benzenesulfinate 15 to afford the sulfonium salt 14 and the sulfonyl ketone 16, respectively.Reaction of the salt 4d with potassium halides 17 in DMF gave the enone 9b, formate 12 and halogeno ketone 18 in varying yields depending on the nucleophilic nature of the halogen anions employed.When treated with KOBut, the salt 4d underwent facile β-elimination to yield the enone 9b.In all of these reactions, the triphenylbismuthane moiety behaved as a good leaving group.
- Matano, Yoshihiro,Azuma, Nagao,Suzuki, Hitomi
-
p. 2543 - 2550
(2007/10/02)
-
- Synthesis and biological activity of 3-aryloxy-3-phenylpropanamines
-
Some new 3-aryloxy-3-phenylpropanmaines (6-12) have been synthesized.Their strucrures have been elucidated by mass, IR and 1H-NMR spectra and by elemental analysis.These compounds and thirteen other compounds (13-25) (synthesized earlier) have been tested for antidepressant, anorexigeniv and hypotensive activities.SAR is discussed in this note.
- Sharma, V. L.,Bhandari, Kalpana,Singh, C. M.,Dua, P. R.
-
p. 1000 - 1003
(2007/10/03)
-
- REACTION OF ALKYLMAGNESIUM HALIDES WITH CARBOXYLIC ESTERS IN THE PRESENCE OF TETRAISOPROPOXYTITANIUM
-
The reaction of carboxylic esters with a threefold molar excess of ethylmagnesium bromide in the presence of an equimolar amount of tetraisopropoxytitanium leads to the formation of the corresponding 1-substituted 1-cyclopropanols.Propyl-, butyl-,and 2-phenylethylmagnesium bromides enter into a similar reaction, leading to 1,2-disubstituted 1-cyclopropanols.
- Kulinkovich, O.G.,Sviridov, S.V.,Vasilevskii, D.A.,Savchenko, A.I.,Pritytskaya, T.S.
-
p. 250 - 253
(2007/10/02)
-
- An Efficient and Convenient Method for the Preparation of α-Methylenated Ketones from Silyl Enol Ethers
-
In the presence of a catalytic amount of stannous halide, silyl enol ethers react with bromomethyl methyl ether to give the corresponding α-bromoethyl ketones, which are smoothly converted to α-methylenated ketones on the successive addition of tertiary amine by one-pot procedure.This method is successfully applied to a synthesis of sarkomycin intermediate.
- Hayashi, Masaji,Mukaiyama, Teruaki
-
p. 1283 - 1286
(2007/10/02)
-
- Intramolecular Charge-Transfer Interactions in Triplet Keto Sulfides
-
The photochemistry of β-,γ-and δ-phenacyl sulfides, sulfoxides, and sulfones has been studied.The first group undergoes no irreversible reaction.The other two undergo type II photoelimination but in low quantum efficiency.Analysis of triplet lifetimes and product quantum yields indicates that all undergo rapid internal quenching, which is ascribed to a charge-transfer (CT) process.The positional dependence of rate constants for this CT reaction is β > γ > α >> δ > ε .Some rate constants (units of 1E8 s-1) for PhCO(CH2)nSBu are as follows: n = 1, 16; n = 2, 55; n = 3, 29; n = 4 ,1.7; n = 5, PhS BuS(O) >> BuS, BuSO2, CH3CO-S and range from 1E9-3*1E5 s-1.Rate constants for triplet state γ-hydrogen abstraction were found to correlate well with the ?1 values of the various sulfur groups, except for δ-sulfinyl, which apparently participates in the reaction.
- Wagner, Peter J.,Lindstrom, Michael J.
-
p. 3057 - 3062
(2007/10/02)
-