Abstract: Provided are an intermediate for synthesizing a camptothecin derivative, a preparation method therefor, and the use thereof. An intermediate A can be obtained from 3-fluoro-4-methylaniline by means of acylation, bromination, and cross-coupling reactions. The intermediate A can be used for preparing an intermediate B to further prepare exatecan mesylate. The intermediate compound B can be obtained from the intermediate A by means of a rearrangement reaction, and exatecan mesylate can be obtained from the intermediate compound B by means of deprotection for acetamido and amino at the a site, a condensation reaction, and a hydrolysis reaction. The reaction starting materials have a low price, the reaction conditions of each step are moderate, the operation is simple, and the yield is high, such that the intermediate is suitable for industrial production.

Abstract: A semiconductor device includes a substrate; an active layer disposed over the substrate and having a source region and a drain region; a contact region disposed over the substrate; a gate structure disposed over the active layer, wherein the gate structure includes a middle portion and a lateral portion connecting to the middle portion, and the lateral portion has a snake shape.