Claims
- 1. A method for producing N-protected β-amino-α-hydroxycarboxylic acids or their esters of the formula (VII): wherein R1 represents an unsubstituted or substituted, linear, branched or cyclic alkanoyl group having from 2 to 18 carbon atoms, an unsubstituted or substituted, linear, branched or cyclic alkoxycarbonyl group having from 2 to 18 carbon atoms, an aralkyloxy carbonyl group having from 7 to 18 carbon atoms, or an unsubstituted or substituted benzyl group, or represents, together with R2, a residue of a dibasic acid having from 8 to 1 8 carbon atoms;R2 represents a hydrogen atom or an unsubstituted or substituted benzyl group, or represents, together with R1, a residue of a dibasic acid having from 8 to 18 carbon atoms; R3 represents an unsubstituted or substituted, linear, branched or cyclic alkyl group having from 1 to 18 carbon atoms, an aralkyl group having from 7 to 18 carbon atoms, or an aryl group having from 6 to 18 carbon atoms; R7 represents a hydrogen atom, an alkyl group having from 1 to 8 carbon atoms, an aryl group having from 6 to 18 carbon atoms, or an aralkyl group having from 7 to 18 carbon atoms, which comprises rearranging, in the presence of a base, an α-keto-hemimercaptal-carboxylate of the formula (I): wherein R1, R2 and R3 are as defined above,R4 represents an unsubstituted or substituted, linear, branched or cyclic alkanoyl group having from 7 to 18 carbon atoms; and R5 represents an alkyl group having 1 or 2 carbon atoms, an aryl group having from 6 to 18 carbon atoms, or an aralkyl group having from 7 to 18 carbon atoms, to provide an x-acyloxy-thioester of the formula(Il): wherein R1, R2, R3, R4 and R5 are as defined above, and then hydrolyzing or alcoholyzing the a-acyloxy-thioester.
Priority Claims (1)
Number |
Date |
Country |
Kind |
7-257497 |
Oct 1995 |
JP |
|
Parent Case Info
This application is a division of U.S. application Ser. No. 09/186,272, filed on Nov. 5, 1998, now U.S. Pat. No. 6,169,200, which is a division of application Ser. No. 09/098,538, filed Jun. 17, 1998, now U.S. Pat. No. 5,883,284; which is a division of application Ser. No. 08/878,079, filed Jun. 18, 1997, now U.S. Pat. No. 5,817,859; which is a division of application Ser. No. 08/725,714, filed Oct. 4, 1996, now U.S. Pat. No. 5,705,671.
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