摘要:
A process for preparing trans-.beta.-benzoylacrylic acid ester having the general formula (I): ##STR1## wherein R is alkyl group or aralkyl group, which comprises dealcoholizing .beta.-benzoyl-.alpha.-alkoxypropionic acid ester having the general formula (II): ##STR2## wherein R is above, in the presence of an acid catalyst to give trans-.beta.-benzoylacrylic acid ester having the general formula (I).According to the process of the present invention, the by-product (II) produced in the esterification reaction of .beta.-benzoylacrylic acid (III) with the alcohol (V) by the dehydration reaction can be converted into the compound (I) by the dealcoholization reaction in the presence of the acid catalyst and thus trans-.beta.-benzoylacrylic acid ester (I) with a high purity can be produced in an industrially advantageous manner.
摘要:
A process for preparing optically active hydantoins having the general formula (II): ##STR1## wherein R.sup.1 and R.sup.2, which are different from each other, are independently alkyl group, aralkyl group, aryl group, substituted alkyl group, substituted aralkyl group, or substituted aryl group, or R.sup.1 and R.sup.2 form an asymmetric cyclic compound, characterized in that one configuration of racemic N-carbamoyl-.alpha.-amino acid having the general formula (I): ##STR2## wherein R.sup.1 and R.sup.2 are as above, is enzymatically converted into the corresponding hydantoins.The present invention provides a process for an optical resolution with a high efficiency which can be used for the synthesis of (S)-6-fluoro-spiro-[chroman-4,4'-imidazolidine]-2',5'-dione (USAN; Sorbinil), which is an optically active hydrantoins attracting public attention as a preventive or a remedy for the particular chronic symptoms of diabetes such as cataract and neuropathy, and (S)-.alpha.-methyl-3,4-dihydroxyphenylalanine (L-methyldopa), which is an optically active amino acid widely used as antihypertensives. Further, the present invention provides a novel finding that N-carbamoyl-.alpha.-amino acid having no hydrogen atom on its .alpha.-carbon atom can be biochemically converted into hydantoins by an enzymatic cyclization reaction.
摘要:
The present invention relates to 3-(4-fluorophenoxy)propionitrile having the formula (I): ##STR1## a process for preparing 3-(4-fluorophenoxy)propionitrile having the formula (I) which comprises reacting 4-fluorophenol and acrylonitrile in the presence of a tertiary amine, a process for preparing 6-fluoro-4-chromanone having the formula (II): ##STR2## which comprises reacting 3-(4-fluorophenoxy)propionitrile having the formula (I) with an acid, and a process for preparing 6-fluoro-4-chromanone having the formula (II) which comprises reacting 4-fluorophenol with acrylonitrile in the presence of a catalyst to give 3-(4-fluorophenoxy)propionitrile having the formula (I), which is then reacted with an acid. 6-Fluoro-4-chromanone is an important intermediate for the synthesis of (S)-2,3-dihydro-6-fluoro-spiro[4H-1-benzopyran-4,4'-imidazolidine]-2',5'dione (USAN: sorbinil).
摘要:
A process for preparing D-N-carbamoyl-.alpha.-amino acids by subjecting 5-substituted hydantoins to the action of a cultured broth, cells or treated cells of microorganisms having an ability in asymmetrically hydrolyzing the hydantoin ring in an aqueous medium of pH 7 to 10. The process is suited for the industrial manufacture of D-N-carbamoyl-.alpha.-amino acids which are useful intermediates for the preparation of medicines.
摘要:
A process for preparing L-methionine by subjecting DL- or L-N-carbamoylmethionine to the action of a cultured broth, cells or treated cells of microorganisms having a capability in asymmetrically hydrolyzing the carbamoyl group of N-carbamoylmethionine. The process is suited for large-scale economical manufacturing of L-methionine.