195616-19-4Relevant academic research and scientific papers
A catalytic asymmetric synthesis of chiral glycidic acid derivatives through chiral dioxirane-mediated catalytic asymmetric epoxidation of cinnamic acid derivatives
Imashiro, Ritsuo,Seki, Masahiko
, p. 4216 - 4226 (2007/10/03)
A novel and practical asymmetric synthesis of chiral glycidic acid derivatives involving methyl (2R,3S)-3-(4-methoxyphenyl)glycidate ((2R,3S)-2a), a key intermediate for diltiazem hydrochloride (1), was developed. Treatment of methyl (E)-4-methoxycinnamate ((E)-3a) with chiral dioxirane, generated in situ from a catalytic amount (5 mol %) of an 11-membered C2-symmetric binaphthyl ketone (R)-7a, provided (2R,3S)-2a in 92% yield and 80% ee. Other cinnamic acid esters and amides were epoxidized by the use of the same procedure to give the corresponding chiral glycidic acid derivatives with up to 95% yield and 92% ee. Higher enantioselectivities in the asymmetric epoxidation of (E)-cinnamates than that of (E)-stilbene derivatives were observed and were proposed to be attributed to a dipole-dipole repulsion between oxygen atoms of an ester group in the cinnamates and those of the lactone moieties in the binaphthyl dioxirane.
Process for preparing 1,5-benzothiazepine derivative
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, (2008/06/13)
A novel process for preparing 1,5-benzothiazepine derivative ?II!: STR1 wherein Ring A and Ring B are substituted or unsubstituted benzene ring, and R3 is H, (di-lower alkylamino)-lower alkyl or substituted or unsubstituted piperazinyl-lower alkyl, or a salt thereof, in high yield and in a single step from a novel 3-(2-amino-substituted or unsubstituted phenylthio)-2-hydroxy-3-substituted or unsubstituted phenylpropionamide compound. Said 1,5-benzothiazepine derivative ?II! is useful as an intermediate for preparing medicaments such as diltiazem hydrochloride.
