A Modified Method Of The Synthesis Of 2-(Ethoxycarbonyl)-3,4-dimethylpyrrole And The Synthesis Of A Series Of Substituted 2-Ethoxycarbonyl-pyrrole

substituted 2-Ethoxy carbonxyl pyrrole is an very important intermediate of the synthesis of porphyrins.. Since 1955,these pyrroles have most conveniently been prepared,where possible,by the method of Kleinspehn. This reaction was initially used with 2,4-Pentanedione and its 3-alkyl devivatives. and then extended to the use unsymmetrically substituted diketones and oxide sodium salt.The procedure is very easy to handle and doesnt use expensive raw material. Howe ver,the Kleinspehn proceduce using this diethyl oximinomalonate Gave disappointingly low yields of the substituted 2-Ethoxy carbonyl pyrrole(10-20%).2-(Ethoxy carbonyl )-3,4-dimethylpyrrole is an very important substituted 2-Ethoxy carbonxyl pyrrole.Untill now,it has been prepared by the method of Kleinspehn,a dissolving Zinc reduction of diethyl oximinomalonate in the presence of 2-methyl-3-oxo-1-butene-1-oxide salt in acetic acid.The yield of product is 18%. The synthesis of 2-(Ethoxycarbonyl) -3, 4-dimethylpyrrole was studied, Anew method for the sysnthesis of 2-(Ethoxy carbonyl )-3,4-dimethylpyrrole was introduced. A series of substituted 2- (Emoxycarbonyl) pyrrole was prepared by means of reacting oxo alfin salt with diethyl aminomalonate in the argon atmosphere.In comparison with the process reported in literature,the new process not only increased the yield of the product, but also simplified the after-treatment. The crude pyrrole wasnt chromatographed on silica.The high purity product was gotten by recrystallization. The special merit of this method is that it is economic, operationally simple, and suitable for large scale preparations. When combined with porphyrin, the expensive porphyrin can be obtainedreadily with a minimum cost.We have composed 2 new compounds which haven t been reported so far. Some fanctors influencing on synthetc reactions were discussed. The new procedure gave satisfactory yield of the substituted 2-Ethoxy carbonyl pyrroles(30-45%).This article has six parts:1. introduction2. experiments3. discussion4. results5. summary6. reference...