作者howard8674 (Frog)
標題[轉錄][交流] 分辨(D, L)(d, l)(R, S)三種命名方式
時間Wed Sep 22 21:32:18 2010
※ [本文轉錄自 howard8674 信箱]
作者: mauvaisvie.bbs@ptt2.cc (mauvaisvie.bbs@ptt2.cc)
標題: [交流] 分辨(D, L)(d, l)(R, S)三種命名方式
時間: Wed Sep 22 21:20:43 2010
作者: vulture24 () 看板: godblessmyBC
標題: (D, L) vs (d, l) vs (R, S)
時間: Mon Sep 28 23:06:00 2009
Q:如何辨別(D, L)(d, l)(R, S)三種命名方式?
以及如何辨別 amino acid 為 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.
---有機課本 p.177
簡單來說，就是需要用polarimeter才能測出來的東西(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.)
---生化課本 p.74
辨別方法: 把 amino acid 的 α-C 放中間，H 放到最後面，然後依據剩下三組
functional groups 的 order of precedence 排序，看是順時針還是逆時
針，
順時針為 D ，逆時針為 L 。
order of precedence of functional groups:
carboxylic acid > anhydride > ester > alkanoyl halide > amide > nitrile >
aldehyde > ketone > alcohol > thiol > amine
---有機課本 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.
---有機課本 p.206
sequence rules: 看
原子量 (忘記了就回去翻有機課本p.178-180)
順時針是R，逆時針是S
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→ mauvaisvie:如果需要中文解釋再推文跟我說 我自己都懶的看英文XD推 09/28 23:13
→ vulture24:哈 其實很多是廢話推 09/28 23:17
→ vulture24:我研究一下怎麼變色後把重點標出來好了推 09/28 23:18
→ howard8674:辛苦了推 09/29 19:50
※ milkhuang:轉錄至看板 KerkerSpongy 10/21 14:18
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