. 2017 May 23;2(5):2238–2247. doi: 10.1021/acsomega.7b00201

Table 3. Screening of Solvents for the Synthesis of 3-Indolylquinone from Hydroquinone.

entry	solvent	yields^a^,^b^,^c, %	time, h
1	nil	9^a/15^c	10
2	water	12^a/67^c	15
3	MeOH	45^a/10^b/20^c	7
4	1,4-dioxane	10^a	9
5	DCM	18^a	8
6	acetonitrile (ACN)	68^a/24^c	8
7	THF	93^a	2

Reactions were performed with 1:1 2-methylhydroquinone/2-methylindole, 0.1 g Fe₃O₄/PVP–PWA (141), 20 mol % Ag₂O, 3 mmol H₂O₂, and 10 mL of solvent at RT; isolated yield of the 3-indolylquinone after column chromatography. Bold values represent maximum product yield under optimized reaction conditions.

The byproduct is 4-methoxy-hydroquinone (6).

The byproduct 2-methylbenzoquinone was formed.