| 摘要 |
Described is a process for preparing 2,2'-disubstituted-1,3-dioxolane-4-methanol compounds having the formula <IMAGE> wherein R1 and R2 are each independently hydrogen, alkyl, cycloalkyl or R1 and R2 together with the carbon atom form a 3 to 6 member cycloalkyl group, or aryl, the process comprising: reacting D- or L-serine with a nitrosating agent in an aqueous solution in the presence of formic acid, acetic acid, or propanoic acid to prepare 2,3-dihydroxypropanoic acid (D- or L-glyceric acid), the aqueous solution comprising from about 0.1 to 0.5 liter of water per mole of the serine starting material; reacting the glyceric acid so formed with 2,2-dimethoxypropane in the presence of a loweralkyl alcohol to prepare the D- or L-glyceric acid alkyl ester which is reacted with a selected aldehyde or ketone or the acetal or ketal derivative to prepare the corresponding 1,3-dioxolane derivative. Reacting the 1,3-dioxolane derivative with lithium aluminum hydride provides the desired 2,2'-disubstituted-1,3-dioxolane-4-methanol derivative. If an alcohol is not used as described above, then the 2,3-dihydroxypropanoic acid is reacted with a selected aldehyde or ketone or the acetal or ketal derivative to prepare the 1,3-dioxolane derivative. The dioxolane derivative is then reacted with lithium aluminum hydride to provide the desired 2,2'-disubstituted-1,3-dioxolane-4-methanol derivative. The compounds so prepared are intermediates in the preparation of optically active beta-agonists or antagonists.
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