A SYNTHETIC STUDY FOR OPTICALLY ACTIVE 2H-CHROMENE TRIMERS

天然conconurvone是一种具有光学活性的吡萘醌三聚体，而conconurvone的有效合成，包括以吡萘四酮为关键化合物的有效制备，分别将吡萘四酮转化为相应的氢萘醌和萘醌，然后将两个单体萘醌三聚化，得到2摩尔的羟基萘醌和1摩尔的萘醌。在第一年，通过一些2h -铬烯与氢琥珀酸甲酯酰化，然后还原和水解制备2h -铬烯-6-丁酸的分子内环化，发现对制备关键的吡诺四酮没有效果。在第二年，发现7-羟基-1-四酮的丙炔醚的热环化对关键化合物最有效。一些具有萘[2,1 -b]吡喃结构的四氯酮，通过相应的丙炔醚的区域选择性热环化制备。但是，一个类似的手性吡喃四酮的制备，由于丙炔醚化过程中的外消旋作用而失败了，因此热环化得到了外消旋的吡喃四酮。侧链为戊烯基的吡诺四酮及其二甲类似物分别转化为相应的羟基萘醌和萘醌。由此得到的羟基甲醌和萘醌均具有烯丙基侧链，从而制备出与天然萜烯叶酮B及其脱氧衍生物相同的化合物。二摩尔二甲基萘醌和一摩尔二甲基萘醌的三甲基化反应得到了康曲酮的二甲基类似物。核磁共振结果表明，该化合物存在atrop异构体。二甲基类三聚体的结构研究和手性吡诺四酮的制备有待进一步研究。

Natural conocurvone is an optically active pyranonaphthoquinone trimer, and the effective synthesis of conocurvone, consist of the effective preparation of a pyranotetralone as the key compond, the respective conversions of the pyranotetralone to the corresponding hydronaphthoquinone and naphthoquinone, and followed by trimerization of both monomeric naphthoquinones, two moles of the hydroxynaphthoquinone and one mole of the naphthoquinone. In the first year, the intramolecular cyclization of 2H-chromene-6-butanoic acids, prepared by acylation of some 2H-chromene with methyl hydrogensuccinate followed by reduction and hydrolysis, was found not to be effective for the preparation of the key pyranotetralone. In the second year, the thermal cyclization of the propargyl ether of 7-hydroxy-1-tetralone was found to be most effective for the key compound. Some tetralones having a naphtho[2, 1-b] pyran structure, were preprared by the regioselective thermal cyclization of the corresponding propargyl ethers. But, a similar preparation of the chiral pyranotetralone, having the prenyl side-chain was falied, because of racemization in the the propargyl etherification, and so the thermal cyclization gave the racemic pyranotetralone. The pyranotetralone, having a prenyl side-chain, and its dimethyl analog were converted respectively to the corresponding hydroxynaphthoquinones and naphthoquinones. Thus obtained hydroxyraphthoquinone and naphthoquinone, having the prenyl side-chain, thus prepared were identical with natural teretifolione B and its deoxy derivative. Trimerization of two mole of dimethylhydroxynaphthoquinone and one mole of dimethylnaphthoquinone gave the dimethyl analog of conocurvone. The ^1H NMR showed the existence of atrop isomerism.The structural investigation for the dimethylanalogous trimer and the preparation of the chiral pyranotetralone are left to study.