| 摘要 |
In a new process for the prepn. of 2-aminobenzothiazole derivs. of formula (I): (where R and R1 are H or lower alkyl residues which may be linked so as to form a 5- to 7-membered ring system which, if 6-membered, may contain O,S or lower alkyl-substd. N as a further hetero atom), 2-mercaptobenzthiazole (II) is reacted with at least the stoichiometric amt. of an amine of formula HNRR1 (III) in the presence of at least the stoichiometric amount of a cpd. of the formula A2S2On (IV) (where n is 3-5; and A is an alkali metal or ammonium) at 60-250 degrees C under elevated pressure.(I) are intermediates for dyes and plant protection agents.Process avoids the use of gaseous SO2. (I) are obtd. in high purity in almost quantitative yield. Specific cpds. (I) include 2-methylaminobenzthiazole. In an example, this is prepd. in 98.2% yield by heating 27.8g (II), 62.7g Na2S2O5 and 54g 40% methylamine solution 4 hours at 160 degrees/8-10 atm. (gauge).
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