Novel Synthesis Of N-substituted 1, 2, 3, 9 4H-carbazol-4-one

With the increased understanding of exist tetrohydrocarbazolone derivatives’application and the continuous discovery of new tetrohydrocarbazolone compounds in natural products, there is a demand to develop novel methods for the construction of tetrohydrocarbazolone compounds. This thesis launched an investigation on the synthetic methodology of N-substituted-1,2, 3, 9-tetrohydrocarbazol-4-one derivatives and covered the following aspects:According to the process already reported, various 3-(N-substitutedamino)- cyclohex-2-enones were prepared. Then they were used to react with hypervalent iodine reagents to make 3-(N-disbstitutedamino)-2-iodocyclohex-2-enones which were used as substrates to make N-substituted tetrohydrocarbazolones via intro- molecular cyclization. After trying many different reaction conditions, we finally successfully affording 18 final products by employing Pd(OAc)2 as catalyst in DMF. All the products were characterized by NMR spectra and LC-MS. The results of experiments indicated that types and position of substituents on the aromatic ring did not significantly affect the reactions, but only affect the yields and regional selectivity. The characteristic of this method is that the benzene ring of the tetrohydrocarbazolone comes from hypervalent iodine reagents.This thesis also find another new method to make N-substituted-1,2,3,9 -tetrohydrocarbazol-4-one by using 3-(N-substituedaniline)-cyclohex-2-enones as substrates. First, according to the process already reported, a series of 3-(N- substitutedamino)-cyclohex-2-enones were prepared. Then we introduced another substituent at the nitrogen atom of substrates by using sodium hydride and alkyl halide. 14 kinds of N-substituted-1,2,3,9-tetrohydrocarbazol-4-ones were afforded by using 0.1 equiv Pd(OAc)2 as catalyst and through the oxygen flow in acetic acid. All the products were characterized by NMR spectra and LC-MS. Furthermore, this reaction condition is mild and the work up procedure is very simple.The routes and the mechanisms of these two methods are different and have their own advantages. The suitable method can be chosen according to the structure of the target products.