作者howard8674 (Frog)
标题[转录][交流] 分辨(D, L)(d, l)(R, S)三种命名方式
时间Wed Sep 22 21:32:18 2010
※ [本文转录自 howard8674 信箱]
作者:
[email protected] (
[email protected])
标题: [交流] 分辨(D, L)(d, l)(R, S)三种命名方式
时间: Wed Sep 22 21:20:43 2010
作者: vulture24 () 看板: godblessmyBC
标题: (D, L) vs (d, l) vs (R, S)
时间: Mon Sep 28 23:06:00 2009
Q:如何辨别(D, L)(d, l)(R, S)三种命名方式?
以及如何辨别 amino acid 为 L (or D) form?
A:
d,l system:
Two enantiomers can be distinguished by their
optical activity; that is,
their interaction with plane-polarized light as measured in a
polarimeter.
One enantiomer always rotates such light clockwise (dextrorotatory), the
other counterclockwise (levorotatory) by the same amount.
---有机课本 p.177
简单来说，就是需要用polarimeter才能测出来的东西(optical rotation,α)
D,L system
based on the absolute configuration of the three-carbon sugar
glyceraldehyde. For all chiral cpds, stereoisomers having a configuration
related to that of L-glyceraldehyde are designated L, and stereoisomers
related to D-glyceraldehyde are designated D.
(Historically, the similar L and D designations were used for levorotatory
and dextrorotatory. However, not all L-amino acids are levorotatory.)
---生化课本 p.74
辨别方法: 把 amino acid 的 α-C 放中间，H 放到最後面，然後依据剩下三组
functional groups 的 order of precedence 排序，看是顺时针还是逆时
针，
顺时针为 D ，逆时针为 L 。
order of precedence of functional groups:
carboxylic acid > anhydride > ester > alkanoyl halide > amide > nitrile >
aldehyde > ketone > alcohol > thiol > amine
---有机课本 p.857
R,S system
The "handedness" of stereocenter is revealed by
X-ray diffraction and can
be assigned as R or S by using the sequence rules.
---有机课本 p.206
sequence rules: 看
原子量 (忘记了就回去翻有机课本p.178-180)
顺时针是R，逆时针是S
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1F：→ mauvaisvie:如果需要中文解释再推文跟我说 我自己都懒的看英文XD推 09/28 23:13
2F：→ vulture24:哈 其实很多是废话推 09/28 23:17
3F：→ vulture24:我研究一下怎麽变色後把重点标出来好了推 09/28 23:18
4F：→ howard8674:辛苦了推 09/29 19:50
※ milkhuang:转录至看板 KerkerSpongy 10/21 14:18
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