Research in the field of synthesis of new indole containing heterocyclic systems and their derivatives

Author: Ioseb Chikvaidze
Keywords: indole, quinoxaline, pyrroloindole
Annotation:

Alternative pathways through the synthesis of isomeric pyrroloindoloquinoxalines have been analyzed. Two different ways are selected among the different alternatives: first, framing tetracyclic system of indoloquinoxaline and then building pyrrole ring on it according to the classical mechanism of Fischer reaction, and second, synthesis of pyrrole izatinering at the initial stage and then building ring of quinoxaline. Condensation of izatine with o-phenylendiamine results synthesis of 6H-indolo[2,3-b]quinoxaline. N-(6)-alkylation and nitration of last synthesized compound gives N(6)-ethyl-9–nitro–6H-indolo-[2,3-b]quinoxaline, in which reduction N(6)-ethyl-9–nitro–6H-indolo[2,3-b]quinoxaline has been obtained. Its diazotization and azo-conjunction with Ethyl 2-methylacetoace-tate was formed N(6)-ethyl–6H-indolo[2,3-b]quinoxaline-9-ylhydrazone Ethylpyruvate in which cyclization was conducted in polyphosphoric acid esters (PPAE) (100-110˚C). Currently, the separation of pure compounds from produced complex mixture is taking place. The attempts of synthesis of above mentioned hydrazine from the initially step synthesized 9-bromo-6H-indolo[2,3-b]quinoxalinehas been failed. By transformations of 7-aminoindole derivative is produced 2-Ethoxycarbolyl-3-methyl-6,7-dihydro-1H,8H-pyrrolo[3,2-g]indole-6,7-dion. In which condensation with o-phenylendiamine is synthesized 3-Methyl-2-ethoxycarbonyl-1H,12H-pyrrolo[3’,2’:6,7]indolo[2,3-b]quinoxaline, one more isomer of whole aromatic pentacyclic systems containing 4 nitrogen atoms. 5-substituted derivatives by interaction of 2-phenylindole with 2-Etoxycarbonylindole in polyphosphoric acid (PPA) or PPEA is obtained. The derivatives of pyrroleindole and noncondensed symmetric bisindoles in PPAE also are synthesized. According to the Manich reaction is conducted aminomethylation of 2,7-diethoxycarbonyl-1H,6H-pyrrolo[2,3-e]indole, 2,2’-diethoxycarbonyl-bis(indol-5-yl)methane and 2,2’-diethoxycarbonyl-bis(indol-5-il)oxide. It is obtained corresponding Gramine bisanalog compounds, in which alkylation in ethanol area by using methyliodide bis-cyanomethyl derivatives are produced. These compounds are accumulated for further transformations. According to Manich reaction aminomethylation of some derivatives of 2-ethoxycarbonylindole are carried out. Similarly are produced 2-ethoxycarbonylindole, 3-dimethylaminomethyl- and 3-cyanomethyl- derivatives. These compounds are accumulated for further transformations.