3077-13-2Relevant academic research and scientific papers
Fe(Cp)2BF4: An efficient lewis acid catalyst for the aminolysis of epoxides
Yadav, Geeta Devi,Chauhan, Manmohan Singh,Singh, Surendra
, p. 629 - 634 (2014/03/21)
Ferrocenium tetrafluoroborate [Fe(Cp)2BF4] is an efficient Lewis acid catalyst for the aminolysis of aromatic, aliphatic, and cyclic epoxides using aniline and substituted anilines as the nucleophile to provide regioselective β-amino alcohols in 61-97% yields under solvent-free conditions at room temperature. The ring opening of cyclohexene oxide with aliphatic amines gave 2-aminocyclohexanols in 33-98% yields at 60 °C under solvent-free conditions. Georg Thieme Verlag Stuttgart New York.
Zinc tetrafluoroborate hydrate as a mild catalyst for epoxide ring opening with amines: Scope and limitations of metal tetrafluoroborates and applications in the synthesis of antihypertensive drugs (RS)/(R)/(S)-metoprolols
Pujala, Brahmam,Rana, Shivani,Chakraborti, Asit K.
experimental part, p. 8768 - 8780 (2011/12/04)
The scope and limitations of metal tetrafluoroborates have been studied for epoxide ring-opening reaction with amines, and Zn(BF4) 2?xH2O has been found to be a mild and efficient catalyst affording high yields under solvent-free conditions at rt with excellent chemo-, regio-, and stereoselectivities. The catalytic efficiency followed the order Zn(BF4)2?xH2O ? Cu(BF4)2?xH2O > Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > LiBF4 for reactions with cyclohexene oxide and Zn(BF4)2?xH2O ? Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > Cu(BF4)2?xH2O for stilbene oxide, but AgBF4 was ineffective. For reaction of styrene oxide with aniline, the metal tetrafluoroborates exhibited comparable regioselectivity (1:99-7:93) with preferential reaction at the benzylic carbon of the epoxide ring. A reversal of regioselectivity (91:1-69:31) in favor of the reaction at the terminal carbon of the epoxide ring was observed for reaction with morpholine. The regioselectivity was dependent on the electronic and steric factors of the epoxide and the pKa of the amine and independent of amine nucleophilicity. The role of the metal tetrafluoroborates is envisaged as "electrophile nucleophile dual activation" through cooperativity of coordination, charge-charge interaction, and hydrogen-bond formation that rationalizes the catalytic efficiency, substrate reactivity, and regioselectivity. The methodology was used for synthesis of cardiovascular drug metoprolol as racemic and enriched enantiomeric forms.
The reaction of primary aromatic amines with alkylene carbonates for the selective synthesis of bis-N-(2-hydroxy)alkylanilines: The catalytic effect of phosphonium-based ionic liquids
Selva, Maurizio,Fabris, Massimo,Lucchini, Vittorio,Perosa, Alvise,Noe, Marco
experimental part, p. 5187 - 5198 (2010/12/25)
At T ≥ 140 °C, different primary aromatic amines (pX-C 6H4NH2; X = H, OCH3, CH3, Cl) react with both ethylene- and propylene-carbonates to yield a chemoselective N-alkylation process: bis-N-(2-hydroxyalkyl)anilines [pX-C 6H4N(CH2CH(R)OH)2; R = H, CH 3] are the major products and the competitive formation of carbamates is substantially ruled out. At 140 °C, under solventless conditions, the model reaction of aniline with ethylene carbonate goes to completion by simply mixing stoichiometric amounts of the reagents. However, a class of phosphonium ionic liquids (PILs) such as tetraalkylphosphonium halides and tosylates turn out to be active organocatalysts for both aniline and other primary aromatic amines. A kinetic analysis monitored by 13C NMR spectroscopy, shows that bromide exchanged PILs are the most efficient systems, able to impart a more than 8-fold acceleration to the reaction. The reactions of propylene carbonate take place at a higher temperature than those of ethylene carbonate, and only in the presence of PIL catalysts. A mechanism based on the Lewis acidity of tetraalkylphosphonium cations and the nucleophilicity of halide anions has been proposed to account for both the reaction chemoselectivity and the function of the catalysts.
Design and synthesis of novel dihydroquinoline-3-carboxylic acids as HIV-1 integrase inhibitors
Sechi, Mario,Rizzi, Giuseppe,Bacchi, Alessia,Carcelli, Mauro,Rogolino, Dominga,Pala, Nicolino,Sanchez, Tino W.,Taheri, Laleh,Dayam, Raveendra,Neamati, Nouri
experimental part, p. 2925 - 2935 (2009/09/05)
Previously, we discovered linomide analogues as novel HIV-1 integrase (IN) inhibitors. Here, to make possible structure-activity relationships, we report on the design and synthesis of a series of substituted dihydroquinoline-3-carboxylic acids. The crystal structure of the representative compound 2c has also been solved. Among the eight new analogues, 2e showed a potency in inhibiting IN strand transfer catalytic activity similar to the reference diketo acid inhibitor L-731,988 (IC50 = 0.9 μM vs. 0.54 μM, for 2e and L-731,988, respectively). Furthermore, none of the compounds showed significant cytotoxicity in two tested cancer cell lines. These compounds represent an interesting prototype of IN inhibitors, potentially involved in a metal chelating mechanism, and further optimization is warranted.
The Stereochemical Investigation of 8-Membered 1,3,6-Dioxazocines via NMR
Nishiyama, Tomihiro,Iwasaki, Yoshiaki,Nishikawa, Takeshi,Miyatake, Shinji,Yamada, Fukiko
, p. 1369 - 1372 (2007/10/02)
The stereochemical properties of 2-,4-,7-, and 8-methyl substituted 5,6,7,8-tetrahydro-1,3,6-dioxazocines have been investigated by their pmr and cmr spectroscopy.On the basis of the coupling constants and γ-effects, the stereochemical structures are discussed.
