| 摘要 |
<p>A process for the preparation of a compound of the formula II wherein R is lower n-alkyl, R' is tertiary lower alkyl or a group of the formula wherein R2 is hydrogen or lower n-alkyl, R3 and R4 each taken independently is lower n-alkyl, and R3 and R4 taken together is lower alkylene of from 3 to 6 carbon atoms, and R" is lower n-alkyl, tertiary lower alkyl, benzyl, diphenylmethyl or trityl, which comprises contacting a compound of the formula I wherein R and R' are as above, with a compound of the formula wherein R" is as above and M is magnesium halide, lithium or copper, in an inert organic solvent and, where M is magnesium halide or lithium, in the presence of cuprous ion, and hydrolyzing the product in an aqueous medium.</p> |
