声音简介 A, ac, ai, an, am, ao, ap, at, au, ay A Ac Ai 短 i i ngắn An Am Ao Ap At Au Ay 长 y y dài 下载手机APP 7天免费畅听10万本会员专辑 当前评论用户 越南语小鱼 19543242 简介:愿为清晨的和风,愿化落日的余辉;我是跳出水面的小鱼要为中越青年交流荡出可爱的涟漪。 Xin ch...
The preparative value of the 1-(phenylsulfonyl)N-blocking and directing group for the synthesis of 3-acylpyrroles has been further evaluated. Acetylation and benzoylation are strongly regiospecific and give good yields. However, the regiospecificity is not general and other substitution reactions give...