A Facile Oxidation of Thiols to Disulfides Catalyzed by CoSalen

Figures & data

Scheme 1

Table 1 Oxidative coupling of 2-thiobenzothiazole under different conditions ^a

Entry	CoSalen (1a) (mmol)	Time (min)	Temperature (°C)	Yield ^b (%)
1	0.025	120	20	0
2	0.025	120	40	85
3	0.025	50	50	92
4	0.025	50	70	93
5	None	360	50	0
6	0.01	120	50	91
7	0.04	60	50	93
8	0.06	50	50	92
9	0.1	50	50	92

Table 2 Oxidative coupling of 2-thiobenzothiazole catalyzed by different CoSalens ^a

Entry	CoSalen	Time (min)	Temperature (°C)	Yield ^b (%)
1	1a	50	50	92
2	1b	50	50	97
3	1c	50	50	87
4	1d	50	50	90

Table 3 Aerobic oxidative coupling of thiols to disulfides catalyzed by CoSalen ^a

	Substrate	Time	Yield^b	Disulfides		mp (°C)
Entry	(2)	(min)	(%)	(3)	mp (°C)	(Literature)
1	2-Thiobenzothiazole	50	92	3a	174∼176	177∼179 ^28
2	Benzenethiol	60	90	3b	60∼61	61 ^20b
3	p-Methylbenzenethiol	60	91	3c	45	45 ^20b
4	p-Chlorobenzenethiol	50	92	3d	72∼73	72 ^20b
5	p-Methoxybenzenethiol	40	94	3e	39∼41	43 ^20b
6	p-Aminobenzenethiol	70	90	3f	74∼77	74∼76 ^29
7	m-Chlorobenzenethiol	50	91	3g	Oil	Oil ^20b
8	Thiosalicylic acid	60	90	3h	288∼289	288∼290 ^30
9	3,5-Bis(trifluoro-methyl)benzenethiol ^c	20	95	3i	71∼72	74∼75 ^31
10	3,4-difluorobenzenethiol	90	88	3j	Oil	Oil ^9
11	Propane-2-thiol	720	80	3k	Oil	Oil ^32

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