A New Method Based On Alcohol Dehydrogenation Ester And Quinoline Synthesis

Dehydrogenation reactions could not only realize the oxidation of organic compounds, but also activate organic moleculars for further transformation. For examples, alcohols could be dehydrogenated to form carbonyl compounds, which could be used in a series of tandem reactions. This thesis describes two novel methods for prepration of esters and quinolines respectively based on the stratege of alcohol dehydrogenation.Esters are a very important class of organic compounds, which can be widely used in pharmaceutical and fine chemical industries. Traditional synthetic methods for ester preparation invovle the coupling of carboxylic acids and their derivatives with alcohols. However, such methods often generate a large amount of waste. The acceptorless dehydrogenative coupling of two alcohols to form esters is green alternative, which produces hydrogen gas as the only by-product. Although the reaction is green, it faces selectivity issues. The cross-coupling of two different alcohols has been a challenge task for acceptorless dehydrogenative coupling. And we are unaware of any example of cross-coupling of two different primary alcohols. In this thesis we achieved the acceptorless dehydrogenative cross-coupling of two different alcohols with a simple RhCl3-tpy catalyst. The method is operationally simple and performed under mild conditions, providing a green alternative method for ester preparation.Quinoline compounds have found broad applications in parmaceutical, agrochemical and dye industries.2-Aminobenzyl alcohol is often used starting material for quinoline synthesis. However,2-aminobenzyl alcohol is an expensive and difficult to prepare.2-Nitrobenzyl alcohol is a cheap and readily available alternative. We have sussessfully developed a transition-metal free method for the synthesis of quinolines using 2-nitrobenzyl alcohol as substrate in water.2-Nitrobenzyl alcohol was converted 2-amino-benzaldehyde through a dehydrogenation-reduction process, promoted by a strong base.2-Aminobenzaldehyde serve as a key intermediate for the formation of quinolines. The reaction provides a simple and practical method for the synthesis of quinolines.