Alkaloids is one family of N-containing natural prodcuts, which display a wide range of biological activities. In the following entries, which one belongs to anticancer alkaloids?
A.
B.
C.
D.
A.
B.
C.
D.
A、a team player is someone who can work within a group of people.
B、a team player is someone who can score goals.
C、a team player is someone who can play a role in the team, to achieve and support the goals set and agreed upon by the team.
D、all of the above.
A、Warfarin
B、Etoposide
C、Bifendate
D、Aspirin
A、黄酮类化合物分子中-吡喃酮环上的1-位氧原子,因有未共用的电子对,故表现微弱的碱性,可与强无机酸,如浓硫酸、盐酸等生成钅羊盐,但生成的钅羊盐不稳定,加水可分解。
B、黄酮的色原酮部分无色,在2-位上引入苯环后,即形成交叉共轭体系,使共轭链延长,因而呈现出颜色。
C、黄酮类化合物多为晶状固体,少数(如黄酮甙类)为无定形粉末。
D、黄酮类化合物的生源合成主要经过途径:一种为桂皮酸途径生成肉桂酸辅酶A;一种通过丙二酸途径生产丙二酸辅酶A两者再经过环化生成对应的色原酮结构。
A、生物碱盐类往往易于结晶,可加入有机酸或者无机酸先使其成盐后再用分步结晶法加以分离
B、水溶性的季铵碱,或者生物碱的酸水提取液可加雷氏铵盐等使成沉淀析出;沉淀溶解丙酮中,再加入饱和的硫酸银溶液可除去雷氏铵盐负离子,溶液中得到生物碱硫酸盐
C、麻黄碱和伪麻黄碱可采用硅胶柱层析的方式实现二者的分离
D、生物碱一般可用乙醚,氯仿进行萃取,对于有些酚性的生物碱,可利用pH梯度萃取法进行分离纯化
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