Step 1:
1. 4.00 g of oxalyl chloride were added dropwise to a suspension of 1.00 g of 2-iodobenzoic acid in 30 ml of dichloromethane at 0 *C.
2. The reaction mixture was warmed to room temperature and stirred for 2 h.
3. After cooling, the solvent and excess oxalyl chloride were removed in vacuo to give a brown residue (0.90 g), which was used in the next step without further purification.
4. 1.40 g of indole in 5.0 ml of ether was added dropwise to a stirred solution of 3.17 ml of 2.5M ethylmagnesium bromide in ether, diluted with 1.1 ml of ether, at 0 *C.
5. The solution was stirred for 0.5 h at room temperature, and a solution of 0.90 g of 2-iodobenzoyl chloride in 5 ml of ether was added dropwise.
6. The reaction mixture was stirred for 1.5 h, quenched with saturated aqueous ammonium chloride, and stirred until the solid was broken up into a fine suspension.
7. The residue was washed with water and ether, then suspended in 20 ml of methanol, to which was added 4 g of sodium hydroxide and 10 ml of water.
8. The mixture was stirred at room temperature for 18 h, the solid was filtered off and washed with successive portions of methanol, water, and ether.
9. Drying in vacuo at 100 *C turned 1.06 g (70%) of 3-(2-iodobenzoyl)indole a viscous oil, which was used in the next step without further purification.
Step 2:
1. 0.5 g of sodium hydrate was added to a solution of 1.06 g of 3-(2-iodobenzoyl)indole in 10.0 ml of N, N-dimethylformamide.
2. The reaction mixture was stirred at room temperature and 1.03 g of 1-bromo-5-fluoropentane were added slowly.
3. The solution was stirred at 120 *C for 1 h.
4. After cooling, the reaction mixture was diluted with water and extracted with three portions of ethylacetate.
5. The extracts were washed with brine and dried, and the solvent was removed in vacuo.
6. Yield 0.60 g (30%) of 1-(heptyl-7-carboxylate)-3-(2-iodobenzoyl)indole as a yellow solid.
1. 4.00 g of oxalyl chloride were added dropwise to a suspension of 1.00 g of 2-iodobenzoic acid in 30 ml of dichloromethane at 0 *C.
2. The reaction mixture was warmed to room temperature and stirred for 2 h.
3. After cooling, the solvent and excess oxalyl chloride were removed in vacuo to give a brown residue (0.90 g), which was used in the next step without further purification.
4. 1.40 g of indole in 5.0 ml of ether was added dropwise to a stirred solution of 3.17 ml of 2.5M ethylmagnesium bromide in ether, diluted with 1.1 ml of ether, at 0 *C.
5. The solution was stirred for 0.5 h at room temperature, and a solution of 0.90 g of 2-iodobenzoyl chloride in 5 ml of ether was added dropwise.
6. The reaction mixture was stirred for 1.5 h, quenched with saturated aqueous ammonium chloride, and stirred until the solid was broken up into a fine suspension.
7. The residue was washed with water and ether, then suspended in 20 ml of methanol, to which was added 4 g of sodium hydroxide and 10 ml of water.
8. The mixture was stirred at room temperature for 18 h, the solid was filtered off and washed with successive portions of methanol, water, and ether.
9. Drying in vacuo at 100 *C turned 1.06 g (70%) of 3-(2-iodobenzoyl)indole a viscous oil, which was used in the next step without further purification.
Step 2:
1. 0.5 g of sodium hydrate was added to a solution of 1.06 g of 3-(2-iodobenzoyl)indole in 10.0 ml of N, N-dimethylformamide.
2. The reaction mixture was stirred at room temperature and 1.03 g of 1-bromo-5-fluoropentane were added slowly.
3. The solution was stirred at 120 *C for 1 h.
4. After cooling, the reaction mixture was diluted with water and extracted with three portions of ethylacetate.
5. The extracts were washed with brine and dried, and the solvent was removed in vacuo.
6. Yield 0.60 g (30%) of 1-(heptyl-7-carboxylate)-3-(2-iodobenzoyl)indole as a yellow solid.
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