7260-07-3Relevant academic research and scientific papers
Zn(OTf)2-promoted chemoselective esterification of hydroxyl group bearing carboxylic acids
Mamidi, Narsimha,Manna, Debasis
, p. 2386 - 2396 (2013/05/21)
Selective esterification of aliphatic and aromatic carboxylic acids with various alcohols is studied using triphenylphosphine, I2, and a catalytic amount of Zn(OTf)2. Use of this catalyst allows the formation of esters at a faster rate with good to excellent yield by activating the in situ generated acyloxyphosphonium ion intermediate. During the esterification process, both their aromatic and aliphatic hydroxyl groups are fully preserved from transesterification. The results show that the bulkiness and the reactivity of this doubly activated intermediate III control the selectivity and the rate of the reaction, respectively. The method is also useful for direct amidation reactions.
Direct synthesis of esters and amides from unprotected hydroxyaromatic and -aliphatic carboxylic acids
Katritzky, Alan R.,Singh, Sanjay K.,Cai, Chunming,Bobrov, Sergey
, p. 3364 - 3374 (2007/10/03)
A facile method for the activation of hydroxy-substituted carboxylic acids using benzotriazole chemistry without prior protection of the hydroxy substituents is presented. The N-acylbenzotriazole intermediates 2a-g, 6a-d, and 9a-c have been used for high-yielding synthesis of both aliphatic (3a-1) and aromatic (7a-h, 10a-f) hydroxy carboxamides. High yields of aromatic hydroxy esters 12a-h and 13a-i were obtained using either neat alcohols in neutral microwave conditions or nucleophilic alkoxides and the intermediate N-(arylacyl)benzotriazoles. Moderate yields were obtained in the case of aliphatic hydroxy esters 11a,b and thiolesters 11e-g from the intermediates 2a-c.
The oxidative cross-coupling of substituted 2-naphthols. Part I: The scope and limitations
Hovorka,Scigel,Gunterova,Tichy,Zavada
, p. 9503 - 9516 (2007/10/02)
Highly selective oxidative cross-coupling of differently substituted 2-naphthols mediated by Cu(II)-tert-butyl amine complexes is described. The 'cross'-products are obtained in good to excellent yields and the selectivity up to >90% is observed depending on the substitution of naphthol nuclei. The alternative procedures - the cross-coupling of free naphthols with CuCl(OMe) as well as the coupling of sodium naphtholates with anhydrous copper(II) chloride - were also studied. All these methods enable a simple and high-yield access to the unsymmetrically substituted binaphthols. A successful optical resolution of methyl 2,2'-dihydroxy-1,1'-binaphthalene-3-carboxylate by means of liquid chromatography on triacetylcellulose and the subsequent configurational correlation with a binaphthol derivative of known absolute configuration is reported.
