(N)-Sulphonyl chloral azo-methine derivs. - useful as intermediates for pharmaceuticals, pesticides, reactive dyes and amino acids

摘要

In a new process for the prepn. of azomethine derivs. of formula R1SO2-N=CH-CCl3 (I) (where R1 is F, Cl or an opt. substd. organic residue), chloral is reacted with a sulphonyl isocyanate of the formula R1-SO2-N=C=O (II) in the presence of >=1 tert. amine and/or at least one quat. ammonium base at ca -20 to +120 degrees C. Cpds. of formula (I) in which R1 is F or Cl are new and claimed. Partic. useful is intermediates for amino acids are (I; R1 = F) and (I; R1 = Cl); reaction with isobutylene, catalytic hydrogenation and boiling with dil. HCl gives leucine hydrochloride. The new process enables previously unobtainable cpds. to be produced, and considerably facilitates the prodn. of known cpds. (I). In an example, a mixt. of fluorosulphonyl isocyanate (687 g) and triethylamine (20.6 g) is treated dropwise over 3 hrs. at 30 degrees with chloral (736 g). Distn. of the reaction mixt. gives (I; R1 = F) (920 g).