DD270072A1 - PROCESS FOR THE PREPARATION OF 5-ARYLIDENE-HIGH 2-THIAZOLIN-4-ONEN - Google Patents

Abstract

The invention relates to a process for the preparation of 5-arylidene-D2-thiazolin-4-ones of the general formula I. They can be used as intermediates for organic syntheses and for the production of biologically active substances. According to the invention Arylpropiolsaeurechloride be first reacted with Kaliumrhodanid in a polar aprotic solvent, preferably acetonitrile, and then with a thiol R2SH or amine R2R3NH. formula

Description

For this 1 page formulas

Field of application of the invention

The invention relates to a process for the preparation of 5-arylidene-A ² -thiazolin-4-ones of the general formula I in which R ^{1 is} an aryl group and X is the group R ² S or R ² R ³ N and R ^{2 is} a Alkyl · or aryl group and R * are alkyl, aryl or hydrogen. 5-Arylidene-A ² -thiazolin-4-ones are intermediates for organic syntheses. They can be used for the production of biologically active substances both in the pharmaceutical sector and in the field of phytopharmaceuticals.

Characteristic of the known technical solutions

It is known that various methods exist for the preparation of 5-arylidene-A ² -thlazolin-4-ones. Thus, 2-alkylthio-5-benzylidene-A ² -thiazolin-4-ones are prepared by reaction of the 2-thioxo-A ^r -thiazolidin-4-one with an alkylating agent in the presence of alcoholic potassium hydroxide solution and subsequent condensation with benzaldehyde (Bull. Soc.Chim.Fr. 1968,3461). Reaction of diazomethane with 5-benzylidenetrhodanine in the presence of triethylamine or aniline gives 2-methylthio-5-benzyliddn-A ² -thiazolin-4-one (Zh.Org.Khim., 14, 1065 [1978]). Disadvantages of these processes are that as by-products N-alkylated compounds are formed. The 2-amino-5-benzylidene-Ä ² -thiazolin-4-ones are obtained from the 2-methylthio compounds by reaction with primary or secondary aromatic amines (Zh. Org. Khim. 11, 1755 [1975]).

Object of the invention The aim of the invention is the simple preparation of these compounds based on readily available starting materials. Explanation of the essence of the invention

The object of the invention is to provide 5-arylidene-A ² -thiazolin-4-ones by a novel simple process. According to the invention, 5-arylidene-A ² -thiazolin-4-ones of the general formula I are prepared by arylpropiolic acid chlorides of the general formula II, in which R ^{1 has} the same meaning as in formula I, with potassium thiocyanate in a polar aprotic solvent, preferably Acetonitrile, be reacted with gentle warming. It is then cooled and the relevant thiol R ² SH or amine R ² R ³ NH is introduced or added dropwise. After 5-12 hours, dilute with water. Equation 1 illustrates the process according to the invention, according to which, for example, the compounds of Table 1 are prepared. The process according to the invention is a novel reaction in which arylpropiolic acid chlorides react surprisingly with potassium thiocyanate and a thiol or amine to give the 5-arylidene-A ² -thiazolin-4-ones.

embodiments Example 1:

5-Benzylidene-2-methylthio-A ² -thiazolin-4-one

3,3g Phenylpropiolsäurechlorid be heated with 1,94g Kaliumrhodanid in 25rrl dry acetonitrile for 1 hour at 40 ⁰ C.

After cooling to ⁰ ° C., 1.2 g of methylthiol are slowly introduced. After 12 hours, poured into 300 ml of water and the Sucked down precipitate. Example 2:

2-Anilino-5-benzylidene-A ² -thiazolin-4-one.

3.3 g Phenylpropiolsäurechlorid and 1.94 g of potassium thiocyanate in 25 mL of dry acetonitrile are heated for 1 hour at 4O ⁰ C.

The mixture is allowed to cool to room temperature and added dropwise 1.86 g of aniline in 5 ml of acetonitrile. After 12 hours, the The reaction mixture is poured into 300 ml of water and the precipitate is filtered off with suction. Table 1 5 ~ Benzylidone-A-thiazolin-4-ones I IR ¹ X Removal Mis. [ ⁰ CJ

(ridden out)

a C-H-SCH- 50 147-149

^{65 3} (methanol)

b CH- SC ₀ H- 55 103-105

^{65 2 5} (ethanol)

c C-H-SCH-C-H- 47 126-128

^{65 2 6 5} (ethanol)

d C-H-NHC-H- 65 261-263

^{65 6 5} (ethanol)

θ CH- N ^ ³ 60 200-202

^{ϋ D} CH- (n-butanol)

Equation 1

, 1 r * -

C = C coct

'1st + KSCN 2nd + XH

O _v

Vn

R ¹ -

/ 'ι ο, λ

Γη j , · i JiJj Uj

Claims (2)

1. A process for the preparation of 5-aryl-A ² -thiazolin-4-ones of the general formula I ₁ in which R ^{1 is} an aryl group and X is the group R ² S or R ² S ³ N and R ^{2 is} an alkyl radical or aryl group and R ^{3 are} alkyl, aryl or hydrogen, characterized in that Arylpropiolsäurechloride the general formula II, in which R ^{1 has the} same meaning as in formula I, first with potassium thiocyanate and then with a thiol R ² SH or amine R ² R ³ NH are reacted. 2. The method according to item 1, characterized in that the reaction is carried out in a dipolar aprotic solvent, preferably acetonitrile.