Synthesis Of Quinoline-2-carboxylic Acid Derivatives From Photodegradation Of Furfural

Quinoline-2-carboxylic acid is a kind of very important synthetic intermediate,mainly used in organic synthesis,medicine,pesticide,and other fields.In organic synthesis,quinoline-2-carboxylic acid is a raw material for the synthesis of fine chemicals such as quinoline-2-carbonitrile and quinoline-2-carboxylic acid methyl ester.In medicine,quinoline derivatives that have protective effects on cell tumors can be prepared from them and have higher activity.In the synthesis of pesticides,quinoline-2-carboxylic acid can be used as raw material for synthesizing organic tin carboxylate derivatives with insecticidal and bactericidal effects.Furfural derived from corncob and other agricultural and forest by-products are renewable,cheap and readily available.The use of furfural as a raw material for the synthesis of valuable chemicals meets the basic philosophy of green chemistry and therefore,will attract the attention of more and more chemical researchers.We have developed a method for the synthesis of quinoline-2-carboxylic acid from furfural.The reaction proceeded through the following four steps: In the first step,5-hydroxyfuran-2(5H)-one was generated from furfural through a photooxidation reaction in almost quantitative yield;In the second step,ethyl 4,4-diethoxy-2-butenoate was generated from acidolysis reaction of 5-hydroxyfuran-2(5H)-one;In the third step,ethyl quinoline-2-carboxylate was synthesized from the rection of ethyl 4,4-diethoxy-2-butenoate and aniline in acetic acid;In the final step,quinoline-2-carboxylic acid was obtained from the hydrolysis of ethyl quinoline-2-carboxylate.