5,6-dichloro-1H-indole-2-carbaldehyde

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 5,6-dichloroindole-2-methanol (43 g, 199 mmol) in diethyl ether (1.3 l) was treated with activated MnO2 (64 g, 730 mmol) and stirred for 15 hours at room temperature. Additional MnO2 (20 g, 230 mmol) was added and stirring continued for 5 h. The suspension was filtered on a Celite pad, then the pad was washed with diethyl ether and warm acetone. The pooled organic phases were concentrated to give 38.5 g of the title compound (180 mmol, yield 90.4%) that was used as such in the next step, m.p.=207-208° C. stirring continued for 5 h The suspension was filtered on a Celite pad the pad was washed with diethyl ether warm acetone The pooled organic phases were concentrated

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: ethyl 3-(5,6-dichloro-2indolyl)-2-propenoate (16.23 g, 57.1 mmol) was dissolved under nitrogen in dry THF (300 ml) cooled at -20° and 1M DIBAL in hexanes (115 ml, 115 ml) was added dropwise at -20° C. The reaction mixture was maintained at this temperature for 1 hour and then quenched with H2O. The mixture was warmed to RT, diluted with Et2O (200 ml) and filtered on a Celite pad, washing with 300 ml of Et2O. The dark-red solution was dried over MgSO4 and evaporated under vacuum to give pure title compound (13.8 g, 57.0 mmol, yield 99.8%). cooled at -20° The reaction mixture was maintained at this temperature for 1 hour quenched with H2O diluted with Et2O (200 ml) filtered on a Celite pad washing with 300 ml of Et2O The dark-red solution was dried over MgSO4 evaporated under vacuum

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5,6-Dichloro-1H-indole-2-carboxaldehyde (35 g, 164 mmol) and (ethoxycarbonylmethylene)triphenylphosphorane (60 g, 176 mmol) were dissolved in toluene and refluxed for three hours. The solvent was evaporated under reduced pressure and the reaction mixture was purified by chromatography on silicagel (n-hexane/AcOEt, 8/2) obtaining pure title compound (28 g, 98.5 mmol, yield 60.1%). refluxed for three hours The solvent was evaporated under reduced pressure the reaction mixture was purified by chromatography on silicagel (n-hexane/AcOEt, 8/2)

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl 5,6-dichloro-1H-indole-2-carboxylate (77.5 g, 301 mmol) dissolved in dry THF (70 ml) was added dropwise to an ice cold solution of LiAlH4 (19.17 g, 505 mmol) in anhydrous THF (1000 ml) under nitrogen. The mixture was stirred for 45 min at 0° C. and then quenched by the sequential addition of water (20 ml), 15% aqueous NaOH (20 ml) and water (60 ml). The mixture was filtered through-a Celite pad and then washed with THF (2×500 ml). The filtrate dried over Na2SO4 and evaporated at reduced pressure yielded an orange raw solid. This was dissolved in CH2Cl2 (1500 ml) and activated MnO2 (150 g, 1.73 mol) was added. The mixture was stirred at RT for 12 hours and then filtered through a Celite pad which was washed with warm acetone (4×750 ml), and the combined filtrates were evaporated to dryness, yielding pure title compound (42.1 g, 197 mmol, yield 65.4%), mp=207-208° C. quenched by the sequential addition of water (20 ml), 15% aqueous NaOH (20 ml) and water (60 ml) The mixture was filtered through-a Celite pad washed with THF (2×500 ml) The filtrate dried over Na2SO4 evaporated at reduced pressure yielded an orange raw solid The mixture was stirred at RT for 12 hours filtered through a Celite pad which was washed with warm acetone (4×750 ml) the combined filtrates were evaporated to dryness

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 5,6-dichloroindole-2-methanol (43 g, 199 mmol) in diethyl ether (1.3 l) was treated with activated MnO2 (64 g, 730 mmol) and stirred for 15 hours at room temperature. Additional MnO2 (20 g, 230 mmol) was added and stirring continued for 5 h. The suspension was filtered on a Celite pad, then the pad was washed with diethyl ether and warm acetone. The pooled organic phases were concentrated to give 38.5 g of the title compound (180 mmol, yield 90.4%) that was used as such in the next step, m.p.=207-208° C. stirring continued for 5 h The suspension was filtered on a Celite pad the pad was washed with diethyl ether warm acetone The pooled organic phases were concentrated