- A secure and convenient synthesis of 5-amino-1, 2, 3-thiadiazole by diazoacetonitrile
-
A new synthesis of 5-amino-1,2,3-thiadiazole (3) by diazoacetonitrile (2) and H2S in the presence of a base is described. The compound (2) is undoubtedly explosive but with our method we found it could be used for industrial purposes.
- Harada, Katsumasa,Mori, Yoshikatsu,Nakai, Mamoru
-
-
Read Online
- Method for synthesizing 5-amino-1,2,3-thiadiazole
-
The invention discloses a method for synthesizing an intermediate 5-amino-1,2,3-thiadiazole. The intermediate 5-amino-1,2,3-thiadiazole is prepared from anhydrous chloroform, thionyl chloride, 2-chloroethyl hydrazono methyl formate, boron trifluoride diethyl ether, dichloroethane, epichlorohydrin and N-methylimidazole; according to the synthesis process, the 2-chloroethyl hydrazono methyl formateand the thionyl chloride are subjected to cyclized substitution reaction under the action of a catalyst [HOOC-PECH-MIM]Cl to obtain the 5-amino-1,2,3-thiadiazole; the reaction operation is simple, and the main operation process includes stirring at room temperature, steam distillation and crystallization, so that the equipment requirements are simple, special equipment requirements are avoided, the intermediate product can be subjected to the next step without purification, the synthesis process is smooth, and the reaction yield is high.
- -
-
Paragraph 0009-0031
(2019/01/15)
-
- Process for preparing 5-amino-1,2,3-thiadiazoles
-
There is provided a process for preparing a 5-amino-1,2,3-thiadiazole represented by the formula STR1 wherein R represents a hydrogen atom, a lower alkyl group or an aryl group, which comprises bringing a diazoacetonitrile represented by the formula STR2 wherein R has the same meaning as defined above, into contact with hydrogen sulfide in the presence of a base or with a salt of hydrogen sulfide, in a solvent.
- -
-
-
- Process for making 5-amino-1,2,3-thiadiazoles
-
5-amino-1,2,3-thiadiazoles of the formula STR1 are made by reacting halogenoacetaldehydes of the formula with hydrazine derivatives of the formula preferably in an aqueous medium or in a mixture of an aqueous medium with organic solvents so as to form acylhydrazones of the formula whereupon the latter are reacted with thionylchloride of the formula whereby 5-halogeno-1,2,3-thiadiazoles are formed which are then reacted with ammonia preferably in the presence of a catalyst such as a mineral acid or Lewis acid whereby the desired product is obtained. The products are useful in making plant protection agents and herbicides such as the 1,2,3-thiadiazolyl-urea derivatives.
- -
-
-
