DE1040531B - Process for the production of ª ‰ -Merkaptoaethylureas - Google Patents

Description

Process for the preparation of ß-mercaptoethylureas It was found that new mercaptans are obtained if one thiazolidin-one- (2) with compounds of the general formula H., N-R treated, wherein R 'is hydrogen, an aliphatic or araliphatic hydrocarbon radical, the amino group or the group N H - R 'means in which R' is an aliphatic, araliphatic or aromatic Represents hydrocarbon residue.

Surprisingly, the ring of the thiazolidin-one- (2) is cleaved on treatment with amines between the carbonyl group and the sulfur atom with the formation of β-mercaptoethanolurea derivatives according to the reaction scheme below. On the basis of previous experience, the person skilled in the art could count on such ring cleavage reactions. that the carbonyl group eliminated and corresponding side reactions would occur.

The thiazolidinone- (2) used as starting material can, for example by treating cysteamine with phosgene in the presence of acid binding agents be won.

Examples of compounds of the general formula H, N-R are Consideration: ammonia, primary amines, such as methylamine, ethylamine, propylamine, allylamine, Butylamine, benzylamine, cyclohexylamine. However, corresponding amines can also be used. the carry further substituents and functional groups. like cvsteamin, used, used will. There are also hydrazine and substituted hydrazine, such as methyl, ethyl. Propyl, benzyl and phenyl hydrazine into consideration.

You can use the two reaction components in the presence of solvents let act on each other, as such preferably @@ 'water or low molecular weight aliphatic alcohols used.

The implementation is advantageously carried out by melting the two together Components in an equivalent amount. One works expediently depending on the one used Components between 100 and 150 ° C. Pay attention to this. that the temperature is not chosen so high, since in this case slightly under rtop_nelter splitting de, ring of urea d --- r eingv @ etztii ami # nogruppenhaltigen component under simultaneous formation of cysteamine occurs.

The process products represent valuable intermediate products for pharmaceuticals Preparations are and can themselves be used, for example, as keratin-softening agents Find.

Example 1 N- (, 8-mercaptoethyl) -N'-benzylurea 1.03 parts by weight Thiazolidin-one- (2) are melted with 1.07 parts by weight of benzylamine and slowly heated in the bathroom. At 120 ° C, a reaction occurs, which occurs as the internal temperature rises makes noticeable compared to the bath temperature. After 5 minutes it is allowed to cool, whereby the melt solidifies. The reaction product is triturated with water, filtered off with suction and recrystallizes from methanol. In addition to small amounts of the symmetrical urea: of the benzylamine one obtains the N- (ß-1lerkaptoäthvl) -N'-lectzylurea from the melting point 88 to 89 ° C. The product shows a strong '-5, iccaptan reaction. -With death it becomes corresponding disulfide is oxidized.

Example 2 N.N'-bis (. (3-mercaptoethyl) urea 1.03 parts by weight Thiazolidin-one- (2) and 0.77 parts by weight of cysteamine are slowly raised to 125 ° in the bath C heated. The reaction mixture is kept at this temperature for 20 minutes and cooled the melt, which solidifies to a white mass. A titration of the crude product with iodine shows that 8001o of the ring have opened in the desired sense. the Melt is unicrystallized twice from Denzol. Fine white ladebi are obtained @ -om Schmelzpuiiht 113- C. The product thus obtained is, as the analysts Iysen values endure. N.N'-bis- (ß-inerkaptoiithyl) -urea and is easy in chloroform, in alcohol. Glacial acetic acid. Toluene. Cyclohexane, dioxane, butyl acetate soluble. utilöslicli in ether and petroleum ether.

Example 3 4- (ß-llerkaptoäthvl) -1-phenyl-semicarl) azide 1.03 parts by weight '1'hiazolidin-one- (2) and 1.08 parts by weight phenylhvdrazine are about 15 minutes heated to 150 ° C. After cooling down, the Schineize solidifies. By unicrystallizing acicular ones are obtained from a mixture of cyclohexane and butanol in a ratio of 3: 1 Crystals with a melting point of 152 ° C. 1.9 parts by weight (90% of theory) are obtained 4- (ß-llerkaptoethyl) -1-phenyl-semicarbazide. The product shows a strong mercaptan reaction and forms white to pale yellow complex salts with heavy metal salts. the Compound is easy in alcohol and glacial acetic acid, in water, chloroform, and benzene Toluene soluble and sparingly soluble in cyclohexane.

Example 4 4- (ß-llerkaptoäthyl) -semicarbazid 1.03 parts by weight of niazolidin-one- (2) and 0.67 parts by weight of 81% hydrazine hydrate are melted at 105 ° C. for about 20 minutes. A reaction occurs at this temperature. Then water and unreacted Hvdrazine are distilled off under reduced pressure. The melt solidifies as it cools. It shows a strong mercaptan content. The yield of 4- (ß-mercaptoethyl) semicarbazide is 92% of theory. Recrystallization from chloroform and cyclohexane in a ratio of 1: 1 gives colorless flakes with a melting point of 74 ° C. When treated with iodine, oxidation to disulfide occurs, and the amount of iodine consumed is correct. The product is easily soluble in alcohol and water and glacial acetic acid, soluble in benzene and chloroform, and sparingly soluble in gasoline. Example N-β-llerkaptoätliylurea 5 parts by weight of Tliiazolidin-on- (2) "earths with 15 parts by volume of 2511 / own Amrrioniaks for 2 hours in a pressure bottle on a water bath. Because "excess ammonia and the water" earths are distilled off to dryness under reduced pressure. The residue solidifies to a waxy mass. The N-ß-mercaptoethy # 1-urea is obtained from this in the form of white. needle-shaped crystals with the melting point 109 ' C. The compound is easily soluble in alcohol and water. sparingly soluble in cyclohexane and benzene.

The product obtained is very sensitive to oxidation. By exposure the corresponding disulfide is obtained from iodine. The amount of iodine consumed corresponds to the theoretically calculated amount.

Claims (1)

PATENT CLAIM: Process for the preparation of ß-mercaptoethylureas, characterized in that 2-thiazolidin-one is treated with compounds of the general formula H2N-R at an elevated temperature, in which R 'is hydrogen, an aliphatic or araliphatic hydrocarbon radical, the amino group or the NH group -R 'means. in which R 'represents an aliphatic, araliphatic or aromatic hydrocarbon radical. Considered publications: Deutsche Patentschriften \ Tr. 860 797, 890 340: Liebig's annals of chemistry. 176, p. 184; Helv. Chim. Acta. 36 (1953). Pp. 416 to 417.