sentences:  It was also observed that increasing the bulk of the R group on the diketone and using methoxy-substituted anilines leads to the formation of 2-CF3-quinolines.If chloro- or fluoroanilines are used, the major product would be the 4-CF3 regioisomer.The study concludes that the interaction of steric and electronic effects leads to the preferred formation of 2-CF3-quinolines, which provides us with some information on how to manipulate the Combes quinoline synthesis to form a desired regioisomer as the product.