DE1493187B1 - Process for the preparation of 1-butyl-3-tosylurea - Google Patents

Description

The invention relates to a method of production. In the case of the inventive precipitation of the process

of l-butyl-3-tosylurea by reacting product is crucial that the latter from a p-Tosylurea with an n-butylammonium salt. very dilute (1:20) solution is precipitated; because

The production of l-butyl-3-tosylurea from less dilute solutions falls to l-butyl-3-tosyl so far The methods used are for the technique 5 urea as a contaminated oil, if you have that not very suitable, since they give small yields, cooling continues for a long time.

or unproductive and costly intermediate steps. In one embodiment of the method, from

require. Sodium salt of p-tosylurea, which can be obtained by simple

From those used for the production of l-butyl-3-tosylharn- fusing p-tosylamide with urea and The most frequently used processes are the production of sodium hydroxide or carbonate, Reactions of tosyl isocyanate with n-butylamine started and after the addition of concentrated or of n-butyl isocyanate with p-toluenesulfonamide sulfuric acid, the reaction according to the invention in best known. However, these processes have the disadvantage of one move up to the intermediate complex of tosyl, that the tendency to polymerize of iso- urea and butylammonium sulfate is carried out, cyanates and their partial sensitivity to moisture. 15 Under these conditions a better homo occurs Difficulty leads. genization of the reaction mixture; because the

The production of 1-butyl-converting phases which are heterogeneous is also known as a result 3-tosylurea by converting p-tosylurea - a shortening of the reaction time, an increase substance with n-butylamine in a ketone as a solution of the yield and an improvement of the product means, initially a gel-like complex quality is achieved.

connection between n-butylamine and p-tosyl instead of n-butylammonium sulfate can also be used

forms urea. The work-up of the reaction immediately from the reaction mixture of n-butylamine mixture is carried out in such a way that one goes out after using concentrated sulfuric acid,
thin with dilute sodium hydroxide solution and phase In the following examples mean the

Separation of the separated solvent layer in two quantities, unless otherwise stated, times extracted with water and missing from the combined, parts by weight,
aqueous solutions after adjusting to pH

8.5 to 9.0 and filter by running into an example 1

Mixture of methanol and dilute sulfuric acid
the reaction product crystallizes out. 30 50 parts of concentrated sulfuric acid are added dropwise

Finally, it is known to modify the aforementioned production method to a solution of 73 parts of n-butylamine in the treatment process in such a way that 1000 parts of dry chlorobenzene and the erp-tosylurea containing n-butylammonium hydrochloride suspension of n-butylammonium sulfate or - acetate or a mixture of n-butylamine 234 parts of p-tosylurea are added, whereupon the acetic acid and the mixture are ^{heated at 110 °} C. for 4 hours at temperatures between 90 and 35 with stirring. 130 ⁰ C are reacted, from the diluted with water After completion of the reaction, the chlorobenzene reaction mixture the precipitated product is filtered off at 30 to 50 Torr distilled off and recrystallized after addition of and from aqueous ethanol. 450 parts of a 10% aqueous sodium hydroxide

Surprisingly, it was found that 1-butyl solution and 2000 parts of water to the residue, the 3-tosylurea stirred in high yields of 80 to 85% 4 ° mixture for 2 hours, then at 20 to 25 ° C, if p-tosylurea is available cooled with η-butyl and adjusted by dropwise addition of a 10% strength hydrochloric acid ammonium sulfate in a polar, easily distilled off to the pH value 9.3. The precipitated cash organic solvent at temperatures of p-toluenesulfonamide was filtered off, the filtrate is reacted with from 85 to 120 ⁰ C. In spite of its simplicity, twice the amount of water is diluted and the reaction is complicated and leads to 45 l-butyl-3-tosylurea by acidification with 10% by-products, which are obtained with the usual cleaning method hydrochloric acid at pH 4.5 pleases. The filtered off the, z. B. by recrystallization from aqueous crystalline product is washed with water and methanol, are not to be separated. The contamination dried at 6O ⁰ C. Yield: 210 parts (78 ° / o> impulses consist essentially of p-tosyl ureas, coated on n-butylamine). M.p. 127 to p-toluenesulfonamide and tarry products. 50 129 ⁰ C.

If the implementation takes place at lower temperatures,

less p-toluenesulfonamide and example 2 are obtained

tarry products, but the implementation is not going well

Completely. A mixture of 68 parts of p-tosylamide, 17 dough against the formation of p-toluenesulfonamide, which only 55 len sodium hydroxide, 25 parts urea and 6 to difficult by recrystallization from aqueous 8 parts water is on 4 to 5 hours 155 ⁰ C methanol can be separated from the main product. heated, kept this temperature for 15 minutes and

The present invention avoids the pre- then slowly lowered. The 90 parts obtained named disadvantages. The sodium salt of p-tosylurea is dissolved in 300 vol.

The process according to the invention for the production of 60 parts by volume of chlorobenzene entered; then sets of l-butyl-3-tosyl ureas is marked by constant stirring at 50 ⁰ C 21.2 parts of concentrate is characterized in that p-tosyl ureas at 85 to 12O ⁰ C centrated sulfuric acid and the mixture is stirred with n-butylammonium reacting, the solvent is 2 hours while cooling to 25 ⁰ C. Then it is distilled off, the residue is diluted in portionwise 21 parts of n-butylamine at 55 ⁰ C to, aqueous sodium hydroxide or ammonia solution 65 the mixture is cooled with stirring to 40 ⁰ C and takes up and while diluting with water up to the gelatinous suspension of tosylurea at least 1:20 and acidifying to a pH value butylamine complex 14 parts concentrated sulfur below 5.5 the reaction product precipitates fractionally, acid. The mixture is then

Heated flow condenser for 3 to 4 hours at 100 to 110 ° C and then the chlorobenzene is distilled off in vacuo. 500 parts of water containing 14 parts of sodium hydroxide are then added, the mixture is stirred for 1 hour at 40 to 50 ° C., the pH is adjusted to 9.0 to 10.0 with 10% sodium hydroxide solution and, after cooling, it is adjusted 2O ⁰ C by means of a 10 ° / cent hydrochloric acid to pH 8.8 to 9.3. After filtering off the precipitated 22 parts of p-toluenesulfonamide is the filtrate is treated with activated charcoal, then diluted with 800 parts of water with 10 ° / _o hydrochloric acid to pH 4.5 acidified. The crystalline product which has separated off is washed with water and dried at 60.degree. Yield: 45 parts (64%, based on the p-toluenesulfonamide used). Mp. 127 to 129 ⁰ C.

Claims (1)

Claim: Process for the preparation of l-butyl-3-tosylurea by reacting p-tosylurea with an n-butylammonium salt in a polar organic solvent with heating and working up of the reaction mixture by fractional precipitation in an aqueous alkaline and in an acid medium, characterized in that one o-tosyl ureas reacting at 85 and 120 ⁰ C and n-butylammonium sulfate, distilling off the solvent, taking up the residue in dilute aqueous sodium hydroxide or ammonia solution and diluting with water up to at least 1:20, and acidifying to a pH below 5 , 5 the reaction product precipitates fractionally.