b．由噁唑啉转化得来。β-羟基胺与羰基缩合过程中会产生噁唑啉中间体，且

b. Converted from oxazoline. <br>Oxazoline intermediates are produced during the condensation of β-hydroxyamine with carbonyl groups, and some of these intermediates are usually relatively stable, especially carbonyl compounds with relatively large steric hindrance, such as sterically hindered aldehydes and ketones, which contribute to This second type of reaction intermediate is produced. <br>c. Obtained from cyano compounds.

B. It's converted from a pickle.<br>β-hydroxyamine and niobium-based contraction process will produce niobium intermediates, and some of these intermediates are usually relatively stable, especially the position resistance of larger niobium-based compounds, such as large-bit resistance of aldehyde and ketones, which contributes to the reaction of the intermediate's second type of production.<br>C. Obtained from cyanide compounds.

b. It is obtained from oxazoline.<br>Oxazoline intermediates are produced during the condensation of β - hydroxyamine with carbonyl group, and some of these intermediates are usually relatively stable, especially carbonyl compounds with high steric hindrance, such as aldehydes and ketones with high steric hindrance, which contributes to the second generation mode of intermediates.<br>c. From cyano compounds.<br>