Synthesis and Fungitoxicity of 1-[N-Benzoyl-3-(21-Substituted-31-Sulphonyl-51-Methoxyindol-31-Yl)-2-Pyrazolines and 1-(N-Phenylsulphonyl)-3-(21-Substituted-31-Sulphonyl)-51-Methoxyindol-31-Yl)-2-PyrazolinesAuthor(s): Rishi Pratap Singh, D. V. Singh, Chavi Raj Singh and Shailendra Singh
Starting material 2-substituted-3-vinylsulphonyl-5-methoxyindols (1a-g) have been synthesized from easily available 2-substituted-5-methoxyindols in 1, 4-dioxane and chlorosulphonyl chloride. Compound (1a-g) reacts with triethyl amine in dry tetrahydrofuran and treated with diazomethane to form 3-(21-substituted-3-sulphonyl-51-methoxyindol-31-yl)-2- pyrazolines (2a-g). Compound (2a-g) reacts with benzoyl choride, potassium hydroxide and methanol to give 1-[N-Benzoyl- 3-(21-substituted-31-sulphonyl-51-methoxyindol-31-yld-2-pyrazolines (3a-g) and again reacts with benzenesulphonyl chloride in pyridine and neutralize with dilute HCl to formed 1-(N-phenylsulphonyl)-3-(21-substituted-31-sulphonyl)-51-methoxyindl- 31-yl)-2-pyrozalines (4a-g). Antifungal activity has been compaired with dithane M-45, a commercial fungicide, for their fungitoxic action against Phytophthora infestance and Collectotricum fulcatium, and the result correlated with their structural features.