69.Coumarin為下列何者形成之內酯(lactone)?
(A)o-hydroxycinnamic acid
(B)m-hydroxycinnamic acid
(C)p-hydroxycinnamic acid
(D)4-hydroxybutanoic acid
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統計: A(3781), B(567), C(2171), D(395), E(0) #1376284
統計: A(3781), B(567), C(2171), D(395), E(0) #1376284
詳解 (共 4 筆)
#1591937
1. 苯丙烯類(Phenylpropenes)-由對位羥基桂皮酸(P-Coumaric acid)還原生成對位羥基桂皮醇(P-Coumaryl alcohol)再脫水而成,有揮發性與脂溶性,常由萜類揮發油所分離,是植物的香味來源。EX:Anethole(茴香腦)Eugenol(丁香油酚)Myristicin(肉豆蔻素)
2. 對位羥基桂皮酸類(p-Hydroxycinnamic acids)
a. p-coumaric acid:自然界常以E-form形式存在,在分離過成產生異構化,呈現兩種形式(E-form,Z-form)共存
b. caffeic acid
c. ferulic acid
d. sinapic aci
3. 香豆素(Coumarins):
a. 鄰位羥基桂皮酸(o-Hydroxycinnamic acid)的內酯, 一般為結晶型,且味道芳香味苦
b. 結構為α-Pyrone
c. 夾迷皮、Psoralens、Methoxalen、Echinacea、Coumarin
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