Indole-3-carbonitrile

A mixture of 1.44 g. (0.0099 mole) of indole-3-carboxaldehyde,2 7.0 g. (0.053 mole) of diammonium hydrogen phosphate, 30 g. (30 ml., 0.34 mole) of 1-nitropropane, and 10 ml. of glacial acetic acid is refluxed for 12.5 hours. During the reflux period the pale-yellow mixture becomes dark red. The volatile reactants and solvent are removed under reduced pressure, and an excess of water is then added to the dark residue. After a short time, crude indole-3-carbonitrile precipitates rapidly. It is separated by filtration and dried under reduced pressure weight 1.20-1.34 g. (85-95%). Crystallization from acetone-hexane, with decoloriza-tion by activated carbon, yields 0.68-0.89 g. (48-63%) of fairly pure indole-3-carbonitrile, m.p. 179.5-182.5° (Note 1). 

Indole-3-carbonitrile has been prepared by the dehydration of indole-3-carboxaldehyde oxime,8 5 indole-3-glyoxalic acid oxime,58 or indole-3-carboxamide 8 by the action of cyanogen... 

Indole, 1-methyl-, 40, 68 Indole-3-carbonttrile, 43, 58 Indoie-3-carboxaldehyde, conversion to indole-3-carbonitrile, 43, 58 Indole-2-carboxylic acid, ethyl ester, 43, 40... 

Indole-3-aldehyde, 879 Indole-3-carbonitrile, 745-746 Indole-3-carboxaldehyde, 745-746 Indole-2-carboxylic add, 839 Indoles, 642 Indolines, 642... 

The checkers obtained pure indole-3-carbonitrile, m.p. 182-184°, by subliming the product at a pressure of 1.5 mm. (bath temperature 165-170°) and recrystallizing the sublimate from a mixture of acetone and light petroleum ether. The recovery was 84%. 

Reaction with indoles. The reagent reacts with indole or 2-substituted indoles (1) to form the derivatives 2, which can be converted into indole-3-carboxamides (3) or into indole-3-carbonitriles (4). The compounds are versatile precursors to 3-substituted indoles. 

Indole alkaloids, 233 Indole-3-carbonitriles, 106 lndole-3-carboxamides, 106 Indolenine alkaloids, 232 Indoles. 293, 518 Indoline, 50 Indolines, 46 Iodine, 235, 256-260 lodine-Copper(lI) acetate, 260 lodine-Thalliumfl) acetate, 260 Iodine azide, 260-261 Iodine chloride, 261 (l-Iodo-l-alkenyl)silanes, 104 lodobenzene diacetate, 351 lodocyclization, 259 trans, vic-Iodohydrins, 258 a-lodo ketones, 260, 442 lodolactonization, 257, 258... 

Ethoxy-1-methylindole added to a soln. of triphenylphosphine carbethoximine and BFj-etherate in tetrahydrofuran, refluxed ca. 4hrs. 2-ethoxy-l-methyl-indole-3-carbonitrile. Y 96%. F. e. s. D. vor der Briick et al., Ang. Ch. 80, 397 (1968). 

Depending on the conditions, reducticm of a-(2-nitroaryl)acrylonitriles with carbon monoxide can give two products (Scheme 74) [194]. Thus, reduction with palladium acetate-triphenylphosphine complex (neutral conditions) leads to indole-3-carbonitriles, while in the presence of DBU or t-BuOK (basic conditions) 4-cyanoquinoline was formed. 

Zohuri et al. (2013) synthesized novel 2,9-dihydro-2-oxo-4-aryl-l//-pyrido[2,3-fc] indole-3-carbonitrile derivatives by condensation of substituted (triethoxymethyl) arene, l-methyl-lH-indol-2-ol, and cyanoacetamide using catalytic amounts of crosslinked poly(2-acrylamido-2-methyl propane sulfonic acid) (AMPS) as an efficient and heterogeneous catalyst (Scheme 2.10). This polymeric solid acid catalyst is stable and can be easily recovered and reused without significant change in its... 

The convenient formation of nitriles by dehydration of oximes using FVP over molecular sieves has been appHed to the synthesis of pyrrole-3-carbonitrile 43 and indole-3-carbonitrile 44 (Scheme 8 2015UP9). 

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