Use of enantio-, chemo- and regioselectivity of acylase I. Resolution of polycarboxylic acid esters
Acylase I was used to catalyze the enantioselective butanolysis of trimethyl 2-[(carboxymethyl)oxy]succinate (E=30) and N-carboxymethylaspartate (E=9) exclusively at the most sterically hindered of the three ester groups (the position α to the asymmetric centre). Gram-scale resolution allowed the preparation of the less reactive trimethyl (S)-2-[(carboxymethyl)oxy]succinate (96% e.e.), that of the (R)-butyldimethyl regioisomer (78% e.e.) at 55% conversion and finally the preparation of the corresponding trisodium carboxylate by saponification. Acylase I was shown to transform (±)-methyl N-acetylmethionine and (±)-valine to the corresponding (S)-amino acids through ester hydrolysis-N-acetyl transfer sequence with absolute chemo- and enantioselectivity. Butanolysis of methyl N-acetylmethionine stopped in the formation of the butyl ester (E=12), the valine derivative being totally unreactive.
Liljeblad, Arto,Aksela, Reijo,Kanerva, Liisa T.
p. 2059 - 2066
(2007/10/03)
Prostaglandin I2 ester and fat emulsion containing the same
There is provided a new ester of prostaglandin of the formula STR1 wherein R1 denotes an alkyl group having 1 to 20 carbon atoms; R2 denotes a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms; and X denotes a group represented by the formula STR2 The new ester dissolves in oil easier than prostaglandin I2 itself and can easily be emulsified in the form of particles of solution in a vegetable oil. The ester in the fat emulsion is more stable than prostaglandin I2 and its physiological acts which are the same as prostaglandin I2 are prolonged.
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(2008/06/13)
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