Bis -butylthio benzene

Submitted by Rogee Adams, Walter Reieschneider, and Aldo Ferretti.  

Checked by William E. Parham, Wavland E. Noland, and James R. Throckmorton. 

Cuprous n-butylmercaptide. A mixture of 42.9 g. (0.30 mole) of freshly prepared cuprous oxide (Note 1), 61.3 g. (0.68 mole) of 1-butanethiol, and 750 ml. of 95% ethanol is heated under reflux with mechanical stirring (Note 2) until the orange or red color of the cuprous oxide is completely changed to the white color of the cuprous n-butylmercaptide (Note 3). The product is collected by filtration, washed several times with 95% 

2-Bis n-butylthio)benzem. In a 1-1., round-bottomed, three-necked flask fitted with a reflux condenser, a mechanical stirrer, and a thermometer which reaches into the reaction mixture is placed a solution of 59.0 g. (0.25 mole) of o-dibromobenzene in a mixture of 250 ml. of quinoline and 80 ml. of pyridine. To this solution is added 84.0 g. (0.55 mole) of cuprous -butylmer-captide, and the mixture is stirred and heated under reflux (Note 5) for 3.5 hours (Note 6). Heating is stopped and the reaction mixture is allowed to cool to about 100°. It is then poured into a stirred mixture of 1500 g. of ice and 400 ml. of concentrated hydrochloric acid occasional stirring is continued for about 2 hours. The aqueous part is then decanted from the dark brown, gummy residue and is extracted twice with 400 ml. portions of ether. The ether extract is added to the residue, and the resulting mixture is stirred for about 5 minutes. The ether solution is then decanted from the residue and is filtered. The residue is extracted twice more with 400-ml. portions of ether (Note 7). The combined ether extract is washed twice with 100-ml. portions of 10% hydrochloric acid, once with water, and twice with 100-ml. portions of concentrated ammonia (Note 8). After a final wash with water, the ether solution is dried over anhydrous potassium carbonate. The potassium carbonate is collected on a filter, and the ether is removed from the filtrate by distillation. The remaining brown oil is distilled in vacuum, giving a pale orange oil, b.p. 123-124°/0.3 mm., d 1.5684. The yield is 46.5-56.0 g. (73-87%) (Note 9). 

Cuprous oxide was prepared according to the procedure of King. A good grade of commercial cuprous oxide may also be used, but the time required to complete the conversion into mer-captide may be considerably longer (see Note 3). 

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The present procedure has also been used by the submitters to prepare the following thioethers l,4-bis-( -butylthio)benzene, pale yellow oil, b.p. 142°/0.S mm., Mq 1.5726, from -dibromo-benzene and cuprous -butylmercaptide (yield 68-74%) 1,2-bis(phenylthio)benzene, white ciystals, m.p. 42.5-44.5°, b.p. 190°/1 mm., from o-dibromobenzene and cuprous phenylmer-captide (see below) (yield 79-83%), or from i>-dichlorobenzene (see below) and cuprous phenylmercaptide (yield 58-71%) l,4-bis(phenylthio)benzene, white crystals, m.p. 82-83°, from / -dibromobenzene and cuprous phenylmercaptide (yield 80-84%), or from -dichlorobenzene (see below) and cuprous phenylmercaptide (yield 59-72%). The same method can be applied to the preparation of many other thioethers. 

The preparation of l,2-bis( -butylthio)benzene is described elsewhere in this volume. ... 

A 200-ml. two-necked flask is fitted with an efficient Dry Ice-isopropyl alcohol condenser connected to a soda-lime tube, a magnetic stirrer, and a gas inlet tube. Isopropyl alcohol and Dry Ice are added to the condenser while the flask and condenser are flushed with dry nitrogen. The flask is immersed in a Dry Ice-isopropyl alcohol bath, and a vigorous stream of dry ammonia is introduced into the system. When about 80 ml. of liquid ammonia is condensed, the gas inlet tube is replaced with a ground-glass stopper. The cooling bath is removed, stirring is started, and 5.1 g. (0.020 mole) of l,2-bis( -butylthio)benzene (Note 1) is quickly introduced (Note 2). 

B is( -butylthio)benzene and 1,4-bis( -butylthio)benzene have been prepared from the corresponding dibromobenzene and cuprous w-butylmercaptide, using a mixture of quinoline and pyridine as solvent.6, l,2-Bis(phenylthio)benzene and 1,4-bis(phenylthio)benzenehave been prepared from the corresponding dichloro- or dibromobenzenes and cuprous phenylmercaptide, using a mixture of quinoline and pyridine as solvent.5 1,4-Bis(phenylthio)benzene has also been prepared from -dibromo-benzene or -bromophenyl phenyl sulfide and lead phenylmercaptide 7 and from diazotized 4-aminophenyl phenyl sulfide and sodium phenylmercaptide.8... 

Further examples of this procedure are the preparation of variously substituted diphenyl sulfides, such as methyl-, methoxy-, and nitro-phenyl phenyl sulfide and o-bis(butylthio)-benzene.305... 

Bis(K-butylthio)benzene, 42,24 4,4 -Bis(diethy amino)benzil, 41, 3 4,4 -Bis(dimethylamino)benzil, 41, 1 Bis(dimethylamino)methane, reaction... 

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