Application Of 7-methyl(Ethyl)isatin Skeleton For The Synthesis Of Novel Heterocyclic Compounds

Isatin and substituted isatin were widely present in plants and animals as one important nitrogen-containing organic compounds. With the rapid development of fine chemicals, isatin and substituted isatin were widely applied in medicine, fuel, pesticides, high-performance materials. In light of these findings, this thesis described the syntheses of novel heterocyclic compounds using 7-methyl(ethyl)isatins as raw materials. this thesis is mainly divided into five parts.In the first part, reviewed the synthesis and application of the compounds of isatin, substituted isatin and indoles.In the second part, 2-methyl(ethyl)aniline a, b were first underwent the Sandmeyer reaction to give 7-methyl(ethyl)isatins 1a, 1b. The resulting 1a, 1b were then subjected to the bromination reaction with NBS using eco-friendly PEG-400 as solvent at room temperature to afford 5-bromo-7-methyl(ethyl) indoline-2,3-diones(2a, 2b). Compounds 1a, 1b, 2a, 2b were further alkylated at the nitrogen atom to give the corresponding 1-alkylation-7-methyl(ethyl) indoline-2,3-diones(3a~3j), and 1-alkylation-5-bromo- 7-methyl(ethyl) indoline-2,3-diones(4a~4j). Finally, 1a, 1b, 2a, 2b, 3a~3j, 4a~4j were subjected to the condensation reaction with thiosemicarbazide using dioxane as solvent and potassium carbonate as alkali to successfully synthesize 24 kinds of 5H-[1,2,4]triazine[5,6-b]indole-3-thiol derivatives 5a~5x.In the third part, 7-methyl(ethyl)indoline-2,3-diones 1a, 1b as the raw materals were first alkylated to give the corresponding N-alkyl-7-methyl(ethyl indoline-2, 3-diones(3a-3j). Compounds 1a-1b,3a-3j were then underwent the condensation reaction with 1,2-diaminobenzene in the presence of acetic acid or water as solvent and tetrabutyl ammonium bromide(TBAB) as phase transfer catalyst to afford a series of new 6H-indolo[2,3-b]quinoxaline derivatives 2a-2b,4a-4j with good yields of 70.0%-85.8%. Fluorescence spectroscopy showed that compounds 2a-2b,4a-4j have good fluorescence properties.In the fourth part, 7-methyl(ethyl)indoline-2,3-diones 1a, 1b as the raw materals were then subjected to the reduction reaction with hydrazine hydrate to give the corresponding 7-methyl(ethyl)indolines(2a, 2b). 2a, 2b were treated with Vilsmeier reagent, prepared from N,N-dimethylacetamide with POCl3 to afford the structurally 3-acetyl-2-choloro-7- methyl(ethyl)-indole(3a, 3b), then the product 3a, 3b were further alkylated to give the corresponding 3-acetyl-N-methyl-2-chloro-7-methyl(ethyl)indoles(4a, 4b). Subsequently, the obtained product 4a, 4b were ethoxylated to give the corresponding 3-acetyl-N-methyl-2-ethoxylate-7-methyl(ethyl)indoles(5a, 5b). Finally, 4a, 4b, 5a, 5b were subjected to the condensation reaction with substituted isatin using 20% ethanol-water as solvent to successfully synthesize 20 kinds of alkaloid analogues derivatives(6a-6t).In the fifth part, a facile synthesis of a series of novel indole-based pyrimidines derivatives(6a-6h, 7a-7h) are described, 2-chloro-7-methyl(ethyl)-1-substituted-indole-3-carbaldehyde(4a-4j), 1-(2-chloro-7- methyl(ethyl)-1-substituted-indol-3-yl) ethanone(5a-5j) were underwent the condensation reaction with guanidine nitrate in ethanol as solvent with the presence of potassium hydroxide as catalyst. Under the same conditions, we get no closed-loop products, when using the substrates(4a-4j, 5a-5j) reacted with aminoguanidine.All of the structures of synthesized compounds were confirmed by IR, 1H and 13 C NMR, MS spectra.