DD222021A1 - PROCESS FOR THE PREPARATION OF 5-AMINO-4-ALKYL (BZW. ARYL) THIO-2-ARYL-THIAZOLENE - Google Patents

Abstract

The invention relates to a process for preparing 5-amino-4-alkyl (or -aryl) thio-2-aryl-thiazoles by reacting 4-alkyl (or aryl) thio-2-aryl-5-benzylidene- amino-thiazoles with hydrazine in lower alcohols. The previously unknown 5-amino-thiazoles are of interest as intermediates as well as potentially biologically active compounds.

Description

Title of the invention

Process for the preparation of 5-Jimino-4-alkyl (or -aryl) thio-2-aryl-thiazoles.

Field of application of the invention

The invention relates to a process for the preparation of 5-amino-4 ~ alkyl (or -aryl) thio-2 ~ aryl-thiazoles by. Reaction of 4-alkyl (or -aryl) thio-2-aryl-5-benzylideneamino-thiazoles with hydrazine,

5-amino-4-alkyl (or aryl) thio-2-aryl-thiazoles is of great importance as organic intermediates and potentially biologically active compounds.

Characteristic of the known technical solutions

\ ·

The preparation of 5 - ^ iB-O-4 - al.kyl (or -aryl) thio-2-aryl thiazoles has not been previously known.

Aim of the invention

The aim of the invention is to find a process for the preparation of 5-amino-4-alkyl (or aryl) thio-2-arylthiazoles in a simple way from industrially readily available starting materials.

Explanation of the essence of the invention

The task is solved by 4-alkyl (or -aryl)

Thio-2-aryl ~ 5 ~ benzylidenamino-thiaaole of the general formula I in which R is unsubstituted and in various positions mono- or polysubstituted by halogen atoms, lower alkyl and alkoxy, nitro groups substituted aryl groups or heteroaryl groups and R for branched or unbranched alkyl groups , aralkyl groups which may also be substituted in different positions by halogen atoms, alkyl, alkoxy or nitro groups, or aryl groups which may in particular be monosubstituted or polysubstituted by nitro groups, is in molar excess of hydrazine the title compounds of the general

1 2

my formula II, in which R and R have the above meaning, be implemented.

The thiazoles of the formula I are heated with about 50 % hydrazine solution in lower alcohols, such as methanol or ethanol for 1 to 2 hours to boiling. The reaction solutions are mixed with excess water and placed cool. The precipitated 5-amino-thiazoles of formula II are filtered off with suction, dried and can be purified by recrystallization from organic solvents. The aldehyde hydrazones formed in the reaction remain in the solution. The advantage of the invention consists in a simple process which provides the 5-amino-thiazoles of the formula II which are important as intermediates for the synthesis of biologically active thiazole derivatives in high yields.

embodiments

The invention is further illustrated by the following general example and the table of the table, without being limited thereto.

0.05 mol of 4-alkyl (or -aryl) thio-2-aryl-5-benzylidenaminothiazol be with 0.05 to 0.2 moles of about 50 % Hydrazine solution in 200 ml of methanol or ethanol for 1 to 2 hours under

Reflux heated »Ate Lösunp; is poured into 1 liter of water and placed cool. Bs crystallize colorless crystals, which is sucks abge, washed with water and dried at 80 °. The products are for further reactions can sufficiently pure _f but by Uaikristallisieren of ethanol, may be further purified dimethylformamide with the addition of water or.

ι + N ₂ H ₄

Table: 5'-Mino-4-alkyl (b2, w of the formula (II) -aryl) thio-2-aryl-thiazoles

(Solvent)

Yield (%)

° 6 ^H 5

° 6 ^H 5

4-Cl-C ₆ H ₄

4-Cl-C ₆ H ₄

4-CH ₃ -C ₆ H ₄ 4-CH ₃ -C ₆ H ₄ 4-CH ₃ -C ₆ H ₄ pyrid-3-yl pyrid-3-yl

CH ₃

G ₂ H ₅

4-NO ₂ -C ₆ H ₄ CH ₃

⁰ Z = S

4-NO ₂ -C ₆ H ₄ 2 -NO ₂ -C ₆ H ₄

4-CH ₃ -C ₆ H ₄ -CH ₂

C ₆ H ₅ -CH ₂ CH ₃

C ₆ H ₅ -CH ₂

C ₆ H-CH ₂ (EtOH) 84- 86 (EtOH) 62 159- (DMF) 172- 75 (DMF) 106-110 (EtOH) 141-144 (EtOH) 200 (dec ·) (EtOH) 112-117 (DMF) 123-25 (DMF) 122-23 (EtOH ZH PO) 115-116 (EtOH ZH ₂ O) 111-114 (EtOH ZH ₂ O) (EtOH ZH ₂ O) 104-106 (EtOH ZH ₂ O) 99-100 (EtOHZH ₂ O) (EtOHZH ₂ O) 114-115 (EtOHZH ₂ O) .105-107 (EtOHZH ₅ O)

80 80 60

55 82

87 61

91 58

95 82

87 87 86

75 63 94

Claims (1)

invention claim \. A process for the preparation of 5-, Äiiiino-4-alkyl (or -aryl) thio-2-aryl-thiazoles of general formula II, in which R is unsubstituted or in various positions singly or multiply by halogen atoms, alkyl or Alko: xy- or nitro-substituted aryl groups or heteroaryl groups and R for branched or unbranched alkyl groups, aralkyl groups which may also be substituted in different positions by halogen atoms, alkyl, alkoxy or nitro groups, or aryl groups which are also mono- or polysubstituted in different positions be substituted by halogen atoms, alkyl, alkoxy or nitro groups, are, characterized in that 4-alkyl (or -aryl) thio-2-aryl-5-benzylidenamino-thiazoles of the general formula I, 1 2
in which R and R have the above meaning, be heated with hydrazine in lower alcohols to boiling temperature.