3-(1,4-Dioxaspiro[4.5]dec-7-en-8-yl)-1H-indole → 3-(1,4-dioxaspiro[4.5]decan-8-yl)-1H-indole

Participants

Reaction Steps

To a 2-L PAAR hydrogenation bottle was charged Pd/C (10%, 11.06 g) and part of THF (1.11 L). Solid 3-(1,4-dioxaspiro[4.5]dec-7-en-8-yl)-1H-indole (as prepared in the previous step, 221.1 g) was added along with the rest of the THF. The bottle was connected to the PAAR shaker, cycled through vacuum/nitrogen (3×), vacuum/hydrogen (3×) and the 45 psi hydrogen was applied with shaking Over the course of 4 hrs, the pressure dropped and was recharged until 45 psi was maintained. The reaction was complete by LCMS. The catalyst was filtered using celite/glass fiber filter, and the reaction was evaporated, but not to complete dryness. Denatured EtOH (250 mL) was added, the reaction concentrated, but again not to dryness. EtOH (1050 mL) was added, the contents heated to boiling, which dissolved nearly all the material. The mixture was allowed to come to ambient temperature with stirring and the product precipitated. After coming to ambient temperature, the suspension was chilled in a refrigerator for 3 hrs, and the product was filtered, and washed with ice-cold EtOH (250 mL) to obtain the title compound. 1H NMR (400 MHz, CHLOROFORM-d) δ: 7.79-8.04 (m, 1H), 7.66 (d, J=7.3 Hz, 1H), 7.36 (d, J=8.1 Hz, 1H), 7.18 (s, 1H), 7.12 (d, J=6.8 Hz, 1H), 6.99 (d, J=2.2 Hz, 1H), 4.00 (s, 4H), 2.74-3.03 (m, 1H), 2.09 (br. s., 2H), 1.66-1.96 (m, 6H). 13C NMR (101 MHz, CHLOROFORM-d): 136.4, 126.8, 121.9, 119.3, 111.1, 108.9, 77.2, 64.3, 35.1, 34.1, 31.0.

Provenance & Evidence