Introduction of substituents into the benzene ring of indole. IV. Preparation of bromo-, nitro-, and aminoindoles and indolines was written by Terent’ev, A. P.;Preobrazhenskaya, M. N.;Bobkov, A. S.;Sorokina, G. M.. And the article was included in Zhurnal Obshchei Khimii in 1959.SDS of cas: 3484-23-9 This article mentions the following:
To 100 ml. concentrated H2SO4 was added dropwise at 5° 11.9 g. indoline, followed by 4.4 ml. HNO3 (d. 1.5) in 100 ml. concentrated H2SO4 added at below 0°; after 1 hr. the mixture was quenched on ice to yield 100% 6-nitroindoline (I), m. 66.5-7.5° (ligroine); refluxing with Ac2O gave the 1-Ac derivative, m. 154.5-5.0°. Refluxing 6.1 g. I and 9.1 g. chloranil in 300 ml. xylene 5 hrs. gave after treatment with aqueous NaOH 82% 6-nitroindole (II), m. 141-2°. Similarly, 6-nitro-2-methylindoline gave 81% 6-nitro-2-methylindole (III), m. 113.5-14.5°. Heating 1.3 g. II in 100 AcOH with 1.5 g. CrO3 in 10 ml. H2O 0.5 hr. on a steam bath gave 45% 6-nitroisatin, decomposing 300°; phenylhydrazone decomposed 265-6°. Similarly, III was oxidized in 1 hr. to 33% 4-nitro-2-acetamidobenzoic acid, m. 225-6°. Nitration of 5-bromo-1-methylindoline with HNO3-H2SO4 at below 0° in 1 hr. gave 100% red 6-nitro-5-bromo-1-methylindoline, m. 73-4°, which heated with chloranil as above gave 54% yellow 6-nitro-5-bromo-1-methylindole, m. 167-8°. Nitration of indoline in Ac2O with fuming HNO3 at 10-12° gave a solid acetyl derivative of 5-nitroindoline which refluxed 0.5 hr. with concentrated HCl gave yellow 5-nitroindoline (IV), 74%, m. 91-1.5°, and a little less soluble dinitroindoline, m. 243-4°. Similarly, 2-methylindoline gave 63% 5-nitro-2-methylindoline, m. 78-9°. IV with chloranil as above gave in 10 hrs. 68% 5-nitroindole, m. 135-7°. 5-Nitro-2-methylindoline similarly gave 65% 5-nitro-2-methylindole, m. 171.5-2.5°. Oxidation of 5-nitroindole in AcOH with CrO3-H2O 1 hr. gave 5-nitro-2-aminobenzoic acid, decomposing 275.2-6.0°, which refluxed 1 hr. with 50% H2SO4 gave p-nitroaniline. To 5.4 g. 5-nitroindole in 50 ml. EtOH was added a little Raney Ni followed by dropwise addition of 100 ml. N2H4.H2O over several hrs. at reflux; the filtered solution gave 82% 5-aminoindole, b6 190°, decomposing 129-30°; Bz derivative m. 166-7°. Similar reduction of 5-nitro-2-methylindole gave 76% 5-amino-2-methylindole, m. 156-6.5°; Bz derivative m. 192-2.5°. Similarly, 6-nitro-2-methylindole gave 43% 6-amino-2-methylindole, b4 170-7°, m. 84-5°; Bz derivative m. 210°. 6-Nitroindole gave 77% 6-aminoindole, b1 138°, m. 67-8°; Ac derivative m. 269-71°. Heating 6-nitro-1-acetylindoline (3.8 g.) with 30 g. SnCl2 in 20 ml. concentrated HCl 25 min. on a steam bath gave after addition of NaOH 89% 6-amino-1-acetylindoline, m. 179-9.5°. Reduction of 6-nitro-2-methylindoline with N2H4 as above gave 91% yellow 6-amino-2-methylindoline, b17 175-80°, m. 61-2°; HCl salt, decomposed 230-5°. Similarly, 5-nitroindoline gave 97% 5-aminoindoline, m. 678.5°, whose diacetyl derivative, m. 211-12.5°. Similarly was prepared 93% 5-amino-2-methylindoline, b9 155-8°, m. 92°. Bromination of 2-methylindoline with Br in AcOH in the presence of H2SO4 gave in 1 hr. 63.5% 5-bromo-2-methylindoline (V), b3 130-45° (some decomposition) crude, b3 132-3.5°, d20 1.4550, nD20 1.6085; Bz derivative m. 157°. Similarly, indoline gave 72.7% 5-bromoindoline, b2 114-14.5°, 1.5240, 1.6311; Ac derivative m. 119-19.5°. V and chloranil, as above, gave 54% 5-bromo-2-methylindole, b4 155-62° (some decomposition), m. 97-8°; this with formalin and aqueous Me2NH in AcOH gave 5-bromo-2-methylskatyldimethylamine, m. 145-7°. 5-Bromoindoline and chloranil gave 47% 5-bromoindole, m. 92-3°. Cf. Colo, et al., C.A. 49, 14733a. In the experiment, the researchers used many compounds, for example, 2-Methyl-6-nitro-1H-indole (cas: 3484-23-9SDS of cas: 3484-23-9).
2-Methyl-6-nitro-1H-indole (cas: 3484-23-9) belongs to indole derivatives. Indole, first isolated in 1866, and it is commonly synthesized from phenylhydrazine and pyruvic acid, although several other procedures have been discovered. They are capable of binding to a variety of receptors with high affinity and thus have applications in a wide range of therapeutic areas.SDS of cas: 3484-23-9
Referemce:
Indole alkaloid derivatives as building blocks of natural products from Bacillus thuringiensis and Bacillus velezensis and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles