PREPARATION AND REACTIONS OF ORTHO-HYDROXYCINNAMIC ACIDS AND ESTERS
PREPARATION AND REACTIONS OF ORTHO-HYDROXYCINNAMIC ACIDS AND ESTERS
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DOI：
10.1021/ja01141a038
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发表时间：
1952-01-01
影响因子：
15
通讯作者：
BOCKSTAHLER, TE
中科院分区：
文献类型：
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作者：
ADAMS, R;BOCKSTAHLER, TE
在丙二酸与邻羟基苯甲醛和+羟基苯甲醛的缩合反应中，苯胺吡啶作为溶剂和催化剂组合的优越性已被证明。亚硫酸氢钠水溶液用于3-羧基香豆素的脱羧基已被证明是普遍适用的。虽然邻羟基肉桂酸甲酯与异戊二烯以较低的产率缩合成吡喃酮，但后者的邻羟基和2，6-二羟基肉桂酸及其甲酯在类似的条件下不与异戊二烯反应，这些条件与类似化合物以乙氧基取代羟基是有效的。当羟基被缩醛键保护时，无论是乙基乙烯基醚还是二氢吡喃，都不会发生异戊二烯的加成反应。在Diels-Alder反应中，邻羟基肉桂酸或酯与异戊二烯的反应活性很低，这是以前在天然产物领域观察到的。现在已经尝试在可能的情况下确定可能更令人满意地产生所需加成的条件，并观察当一个或多个酚基被缩醛形成封闭时的反应性。对苯胺的使用进行了详细的研究
The superiority of aniline-pyridine as a solvent and catalyst combination for the condensation of malonic acid with o-and+ hydroxybenzaldehydes has been demonstrated. The use of aqueous sodium bisulfite for the decarboxylation of 3-carboxycoumarins has been shown to be of general application. Although methyl o-hydroxyeinnamate condenses with isoprene to form a pyrone in lowyield, o-hydroxy-and 2, 6-dihydroxycinnamic acids and themethyl ester of thelatter do not re-act with isoprene under conditions similar to those which are effective with the analogous compounds having inethoxy in place ofhydroxy groups. When thehydroxy groups are protected with acetal linkages, cither prepared from ethyl vinyl ether or dihydropyran, the addition of isoprene does not occur.The low reactivity of o-hydroxycinnamic acid or ester with isoprene in the Diels-Alder reaction has been observed by previous investigators2 in the field of natural products. An attempt has now been made to determine, if possible, conditions which might bring about the desired addition more satisfactorily and to observe the reactivity when the phenolic group or groups are blocked with acetal formation. A detailed study of the use of aniline2