4122-57-0Relevant articles and documents
Bismuth(III) triflate: A safe and easily handled precursor for triflic acid: Application to the esterification reaction
Kwie, Franciane Ho A.,Baudoin-Dehoux, Cecile,Blonski, Casimir,Lherbet, Christian
experimental part, p. 1082 - 1087 (2010/05/01)
A series of carboxylic acids were converted into their corresponding methyl esters using bismuth(III) triflate as a catalyst in methanol. Good to excellent yields were obtained for different aliphatic or aromatic starting materials. In the reaction, bismuth triflate acts as a precursor that, upon hydrolysis, liberates sufficient triflic acid to catalyze the esterification.
Assignment of the absolute configuration of concentricolide - absolute configuration determination of its bioactive analogs using DFT methods
Ren, Jie,Jiang, Ju-Xing,Li, Ang-Bo,Liao, Tou-Geng,Tian, Ren-Rong,Chen, Xu-Lin,Jiang, Si-Ping,Pittman Jr., Charles U.,Zhu, Hua-Jie
supporting information; experimental part, p. 3987 - 3991 (2010/02/27)
The configuration of concentricolide was assigned as (S). The configuration of its three analogs, which have anti-HIV-1 activity, were predicted by optical rotation values obtained by the B3LYP/aug-cc-pVDZ//B3LYP/6-31+G(d) and B3LYP/ aug-cc-pVDZ//MP2/6-31
Synthons for biologically active compounds on the basis of naphthalene ozonolysis products
Kukovinets,Kislitsyn,Zainullin,Abdullin,Galin
, p. 396 - 402 (2007/10/03)
Ozonolysis of naphthalene in aqueous methanol, followed by the reduction of peroxy compounds thus formed with potassium iodide in the presence of acetic acid, gave 3-methoxy-2-benzofuran-1(3H)-one. In the absence of water, the product was methyl o-formylbenzoate. The latter was used as a synthon for the preparation of aromatic analogs of (2E)-2,6-dimethyloct-2-ene-1,8-diol ethers which are effective juvenoids. Pleiades Publishing, Inc., 2006.
Preparation and cycloaddition reactions of novel heterocyclic mesomeric betaines
Morgan, David O.,David Ollis,Stanforth, Stephen P.
, p. 5523 - 5534 (2007/10/03)
The heterocyclic mesomeric betaines 6a-c reacted with dimethyl acetylenedicarboxylate and ethyl propiolate giving the 1,3-dipolar cycloaddition products 7a-c and 8a-c, respectively. With esters of maleic, fumaric, acrylic and methacrylic acids, mesomeric betaines 6a and 6b gave substituted tetralone derivatives. (C) 2000 Elsevier Science Ltd.
NOVEL OXIDATIVE CLEAVAGE OF CARBON-CARBON BOND IN HYDRAZONES BY OXYGENATION WITH COBALT SCHIFF BASE COMPLEX
Nishinaga, Akira,Yamazaki, Shigekazu,Matsuura, Teruo
, p. 2649 - 2652 (2007/10/02)
Oxygenation of aromatic ketone hydrazones with Co(salen) in methanol resulted unexpectedly in oxidative degradation to give methyl benzoate derivatives.A mechanism involving nucleophilic attack by methanol on a diazo intermediate is discussed.
Reaction of (Acyloxy)alkyl α-Halides with Phenols: Effect of Nucleofugicity and Nucleophilicity on Product Distribution
Sloan, Kenneth B.,Koch, Suzanne A. M.
, p. 3777 - 3783 (2007/10/02)
The product distribution obtained from the reaction of (acyloxy)alkyl α-halides (1 or 5) with phenols was found to depend on the nucleophilicity of the phenol, the nucleofugicity of the leaving group, and the ability of the electrophile to stabilize a carbenium ion.More nucleophilic phenols tended to give more acylation while better leaving groups and more stable incipient carbenium ions in the electrophile tended to favor the formation of alkylated products.In addition, the reaction of methanol with 1a was found to give a mixture of acylated and alkylated products (40 : 60).Thus, a general trend for all the nucleophiles for which information is available suggests that better nucleophiles undergo relatively more acylation and that poorer nucleophiles undergo more alkylation.These results are suggested to be consistent with the observations of Westaway on the effect of leaving group nucleofugicity and nucleophilicity of the nucleophile on bond lengths in the SN2 transition state.Facile rearrangements of acylated to alkylated products and of one alkylated product to another caused by the phenolate anion were also observed in the 3-phenoxy-1(3H)-isobenzofuranone-phenyl 2-formylbenzoate series.
Intramolecular Electrostatic and General Acid Catalysis in the Hydrolysis of O,S-Thioacetals
Fife, Thomas H.,Przystas, Theodore J.
, p. 292 - 299 (2007/10/02)
The pH-independent release of thiophenolate ion from phthalaldehydic acid O-methyl S-phenyl thioacetal in H2O at 50 deg C and at pH values where the carboxyl group is ionized is 22 times faster than the corresponding reaction in hydrolysis of the terephthalaldehydic acid derivative.This rate difference arises becouse of electrostatic stabilization of the developing carbanium ion by the neighboring carboxylate ion.In the view of the large amount of C-S bond breaking in the transition state the rate enhancement due to electrostatic effects must be near maximal in water for reactions in which a methoxybenzyl carbonium ion is produced.The plot of log kobsd vs. pH for release of thiosalicylic acid from phthalaldehydic acid O-methyl S-(o-carboxyphenyl) thioacetal at 50 deg C in 50percent dioxane-H2O shows hydronium ion catalysis at low pH, and from pH 3 to 7 the profile is bell shaped.The value of the rate constant k2 for hydronium ion catalyzed reaction of the dianionic species is 6*106 greater than the second-order rate constant kH for hydronium ion catalyzed hydrolysis of the dimethyl ester and is 360-fold greater than the corresponding rate constant of terephthalaldehydic acid O-methyl S-(o-carboxyphenyl) thioacetal.The hydronium ion catalyzed neutral species reaction of phthaladehydic acid O-methyl S-(o-carboxyphenyl) thioacetal is retarded in 50percent dioxane-H2O as compared with H2O, but k2 is accelerated 50-fold.Both carboxyl groups are participating in hydrolysis of the monoanionic species, i.e., intramolecular general acid catalysis is occurring in conjunction with electrostatic stabilization effects.It is likely that intramolecular general acid catalysis also occurs in hydrolysis of benzaldehyde O-methyl S-(o-carboxyphenyl) thioacetal and terephthalaldehydic acid O-methyl S-(o-carboxyphenyl) thioacetal, but rate enhancements are small in comparison with corresponding O,O-acetals.The significant electrostatic stabilization effects in the general-acid-catalyzed reaction of phthalaldehydic acid O-methyl S-(o-carboxyphenyl) thioacetal in contrast with the absence of such effects in the intramolecular general-acid-catalyzed reaction of phthalaldehydic acid O-methyl O-salicyl acetal shows that much more bond breaking is required in the transition state in reaction of the thioacetal.The factors influencing concerted bifunctional catalysis are discussed.
