Table 5 Optimization of reaction conditions in the oxidation of 1,4-DHPs.

Entry	Solvent	Time (min)	Amount of catalyst (mg)	Temperature	Yield^a (%)
1	Dichloromethane	1080	117	Reflux	0
2	Chloroform	1080	117	Reflux	0
3	Ethanol	1080	117	Reflux	0
4	Water	1080	117	Reflux	0
5	Acetonitrile	1080	117	Reflux	0
6	Formic acid	1080	117	Reflux	0
7	Tetrahydrofuran	1080	117	Reflux	0
8	Acetic acid	10	117	Reflux	96
9	Acetic acid	120	117	r. t	85
10	Acetic acid	10	117	Reflux	96^b
11	Acetic acid	10	117	Reflux	96^c
12	Acetic acid	60	58	Reflux	73
13	Acetic acid	60	88	Reflux	85
14	Acetic acid	60	116	Reflux	90
15	Acetic acid	10	120	Reflux	96
16	Acetic acid	10	180	Reflux	96

Reaction conditions: 1,4-DHPs (1.0 mmol), solvent (3.0 mL). ^aIsolated yields. ^bUnder N₂ atmosphere. ^cUnder O₂ atmosphere.

Quick links

Search