2.4- Dichloro-6-alkylamino-1,3,5-triazine

Cyanuric chloride is first reacted with an aliphatic amine in the presence of an acid acceptor, and 2,4-dichloro-6-alkylamino-jr- triazine, obtained as an intermediate product, is then converted with alkylmercaptan (in the presence of an acid acceptor, or with the alkaline-metal salt of alkylmercaptan) to 2-alkylmercapto-4-chloro-6-alkylamino- -triazine. The end-product is then obtained by the coupling of this intermediate with alkylamine. 

The preparation of 2,4-dichloro-6-alkylamino-i-triazines is an important intermediate step in the synthesis of bisalkylamino-j-triazines. The selective realisation of this substitution step determines whether the asymmetrically substituted bis(alkylamino)-5-triazines can be prepared in the required purity, that is, free of homologues. This is of decisive importance from the point of view of practical weed control. 

Dichloro-6-alkylamino-i-triazines can be prepared in the temperature range - 20 — 0°C from cyanuric chloride and the corresponding aikylamine in an absolute solvent (Diels, 1899) or in an aqueous solvent medium (Pearlman and Banks, 1948 Thurston et ai, 1951), according to the following reaction scheme ... 

Dichloro-6-alkylamino-j-triazines are unstable compounds with skin-irritating properties. They are quickly hydrolysed to the hydroxy compound, by the action of atmospheric moisture. Therefore, they are not isolated during the industrial manufacture of 2-chloro-4,6-bis(alkylamino)-j-triazines. It is interesting that... 

However, 2,4-dichloro-6-alkylamino-.r-triazines, 2,4-dichloro-6-dialkylamino-s-triazines, 2,4-dichloro-6-alkoxy-j-triazines and 2,4-dichloro-6-alkylmercapto-i-triazines have a considerable contact herbicidal effect (Koopman et al., 1957 Gysin and Kniisli, 1956). 

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