Synthesis of natural polyprenols for the production of biological prenylquinones and tocochromanols

We elaborate the chemical synthesis of polyprenols by chain lengthening, which is considerably less time-consuming than the other previously described methods. Our method eliminates critical steps requiring low temperature and toxic chemicals, which are difficult to perform in ordinary laboratories. The critical step of acetylene addition in liquid ammonia was replaced by a new approach, namely, the use of sodium acetylide in dimethoxyethane at room temperature, where the reaction is completed within one hour. This method is of general significance as it can also be applied to the synthesis of any other acetylides. Our method provides reasonable yields and can be scaled depending on the requirements. All the reactions were followed by high-performance liquid chromatography, allowing the formation of undesired isomers and other side-products to be controlled. The resulting polyprenols were further used in the synthesis of plastoquinones, although a variety of biological prenylquinones can be synthesized this way. Moreover, we found a new method for the direct formation of tocochromanols (plastochromanols, tocochromanols) from polyprenols and aromatic head groups.

Automated summary

We describe a time-saving method for the chemical synthesis of polyprenols by chain lengthening. This method eliminates critical steps requiring low temperature and toxic chemicals, making it suitable for ordinary laboratories. A new approach using sodium acetylide in dimethoxyethane at room temperature was employed to replace the critical acetylene addition in liquid ammonia, resulting in the completion of the reaction within one hour. Our method offers reasonable yields and can be scaled as needed. High-performance liquid chromatography was used to monitor the reactions and control the formation of undesired isomers and side-products. The resulting polyprenols were successfully utilized in the synthesis of plastoquinones, and a new method for the direct formation of tocochromanols from polyprenols and aromatic head groups was discovered.