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

Participants

Role	Name	HCID	Charge
Reactant	Indole	HCID 798	—
Reactant	Potassium Hydroxide	HCID 14797	—
Reactant	1,4-Dioxaspiro[4.5]decan-8-one	HCID 567415	—
Solvent	Methanol	HCID 887	—
Product	3-(1,4-Dioxaspiro[4.5]dec-7-en-8-yl)-1H-indole	HCID 2763857	89.1%

Reaction Steps

Indole (4.69, 40 mmol), 1,4-cyclohexanedione monoethylene ketal (6.3 g, 40 mmol) and potassium hydroxide (13.2 g, 200 mmol) were heated to reflux in 70 ml methanol for 6 hours. The reaction was cooled and the product was isolated by filtration and washed with water to give 9.1 g (89%) of product.

Provenance & Evidence

DOI	10.6084/m9.figshare.5104873.v1
Patent number	US06313126B1
Source dataset	uspto-grants-2001_11
ORD ID	ord-c231f3e905344f7da9cd7cae7f810718
Source note	uspto-grants-2001_11