The present invention relates to a process for converting lutein and/or lutein esters to β-cryptoxanthin and α-cryptoxanthin, suitable for human consumption as dietary supplements, by employing safe and environmentally friendly reagents. In the first synthetic step, commercially available lutein and/or lutein esters are transformed into a mixture of dehydration products of lutein (anhydroluteins) in the presence of a catalytic amount of an acid. The resulting anhydroluteins are then converted to β-cryptoxanthin (major product) and α-cryptoxanthin (minor product) by heterogeneous catalytic hydrogenation employing transition elements of group VIII in a variety of organic solvents under atmospheric pressure of hydrogen. A novel feature of this invention is the regioselective hydrogenation of anhydroluteins while the highly conjugated polyene chain of these carotenoids remains intact.
本发明涉及一种将
叶黄素和/或
叶黄素酯转化为β-隐子黄质和α-隐子黄质的过程,适合作为膳食补充剂供人类消费,采用安全和环保的试剂。在第一合成步骤中,利用商业上可获得的
叶黄素和/或
叶黄素酯在少量酸的存在下转化为
叶黄素的脱
水产物混合物(脱
水叶黄素)。然后,利用过渡元素群VIII在各种有机溶剂中,在
氢气大气压下进行异质催化加氢,将所得的脱
水叶黄素转化为β-隐子黄质(主要产物)和α-隐子黄质(次要产物)。本发明的一个新特点是在保持这些类
胡萝卜素高度共轭多烯链完整的情况下,对脱
水叶黄素进行区域选择性加氢。