Yamamoto esterification

H. Kita, S. Sasaki, K. Tanaka, K. Okamoto and M. Yamamoto, Esterification of carboxylic acid with ethanol accompanied by pervaporation, Chem. Lett., 1988, 2025. 

Kiguchi, M. and Yamamoto, K. (1992). Chemical modification of wood snrfaces by esterification III. Some properties of self-bonded benzylated particleboard. Mokuzai Gakkaishi, 38(2), 150-158. 

Yamamoto and co-workers reported the use of scandium(lll) triflate as an esterification catalyst when acetic anhydride was used as the acetate source.5 6 While they only reported on monoalcohols (1°, 2°, and 3°) on a small scale, the submitters modified the Yamamoto procedure to suit the submitters reaction with the 1,1,2-triphenyl-1,2-ethanediol. As detailed above, the current procedure provides a yield of the HYTRA acetate that is comparable to the procedure reported by Braun and coworkers,2 1 but via simple, direct filtration for the reaction mixture. 

Ishihara and Yamamoto et al. investigated the catalytic activities of various metal salts for esterification of equimolar aliphatic carboxylic acid and... 

Ishihara and Yamamoto and coworkers [150] reported the use of 1 mol% of Zr0Cl2 8H20 and Hf0Cl2-8SH20 as water-tolerant, reusable homogeneous catalysts for esterification. 

Okamoto K, Yamamoto M, Noda S, Semoto T, Otoshi Y, Tanaka K, and Kita H. Vapor-permeation-aided esterification of oleic-acid. 

Polymer supported pyridinium salts, such as Mukaiyama reagent, have proven very useful synthetic tools in the preparation of 2-oxazoline libraries 05JC0688> and in automatable esterification reactions <05TL2817>. Yamamoto et al. have examined the use of polymer supported boronopyridinium salts for the preparation of amides and esters in good to excellent yield <050L5043,05TL5047>. 

In 1981 Meyers and Yamamoto reported the use of an external reagent in the construction of a 2,3-anti unit. The boron azaenolate (85), prepared from the chiral boron reagent (86 diisopinocampheylbotyl triflate lpc2BOTf) and the achiral oxazoline derivative (87), reacts with aldehydes in ether at -78 C (Scheme 36). The direct products (88) are converted, after hydrolysis and esterification, to the corresponding a-methyl-P-hydroxycarboxyl derivatives (89), which are rich in the anti isomer (antiisyn... 

K. Okamoto, M. Yamamoto, S. Noda, T. Semoto, Y. Otsushi, K. Tanaka and H. Kita, Vapor-permeation-aided esterification of oleic acid, Ind. Eng. Chem., Res., 1994, 33, 849-853 B. Chemseddine and R. Audinos, Use of ion-exchange membranes in a reactor for esterification of oleic acid and methanol at room temperature, J. Membr. Sci., 1996, 115, 77-84. 

Watanabe, Y., Yamauchi-Sato, Y., Nagao, T., Yamamoto, T., Ogita, K., and Shimada, Y. 2004. Production of monoacylglycerol of conjugated linoleic acid by esterification followed by dehydration at low temperature using Penicillium camembertii lipase. J. Mol. Catal. B Enzym. 27 249-254. 

Alkoxycarbonylation followed by esterification provides an attractive alternative derivatization method for amino acid quantitation (Yamamoto et al., 1982 Makita et al., 1982). N-Alkoxycarbonyl methyl esters are prepared by a two-step procedure involving the use of an alkyl chloroformate in aqueous medium, followed by esterification with diazomethane. (Fig. 5) Alk-oxycarbonylahon is performed at room temperature for 10 min, whereas esterification is complete in 3 min at room temperature. 

Kita, H., Tanaka, K., Okamoto, K.-L, Yamamoto, M. (1987). The esterification of oleic acid with ethanol accompanied by membrane separation. Chemistry Letters, 2053—2056. 

Ferrous ion-induced Hpid peroxidation of rat liver mitochondria was accelerated by phosphate (Yamamoto et al. 1974). Preincubation of rat liver microsomes with iron (Fe)/ascorbate (50 pM/ 200 pM), known to induce peroxidation, resulted in a significant inhibition of (i) the rate-limiting enzyme in cholesterol biosynthesis, HMG-CoA reductase (46 %, P <0.01, (ii) the crucial enzyme control-Hng the conversion of cholesterol in bile acids, cholesterol 7a-hydroxylase (48%, P <0.001), and (iii) the central enzyme for cholesterol esterification, acyl-CoAxholesterol acyltransferase (ACAT, 80%, P <0.0001) (Brunet etal. 2000). The disturbances of these key enzymes coincided with a high rate of malondialdehyde production (350%, P <0.007) and the loss of polyunsaturated fatty adds (36.19 1.06% vs. 44.24 0.41% in controls, P <0.0008). While a-tocopherol simultaneously neutrahsed lipid peroxidation, preserved microsomal fatty acid status, and restored ACAT activity, it was not effective in preventing Fe/ascorbate-induced inactivation of both HMG-CoA reductase (44%, P <0.01) and cholesterol 7a-hydroxylase (71%, P< 0.0001). 

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