O-Aminothiolic acids

Isoamyl nitrite/trichloroacetic acid 3,4-Dihydro-3,l92-benzothiadiazin-4-ones from o-aminothiolic acids... 

Potassium hydroxide o-Aminothiolic acids from 3,l-benzoxazine-2,4-diones s. 27, 293 KOH c... 

An unusual construction of the thiazine nucleus is illustrated by the synthesis of a number of 5/ >o-indole derivatives (272). Here 3-thiopropanoic acid, which provides the sulfur and three carbon atoms, reacts with 3-iminoindolin-2-ones (273) to give aminothiols (274), which then lactamize (Scheme 52). The 3-iminoindolin-2-ones are formed in situ by the condensation of arylamines with isatins (275) <86H2479>. 

Peptide chemistry has made headlines this year with the publication of the first total synthesis of an enzyme. Ribonuclease A, a peptide or rather protein with 124 amino acid residues was prepared by two independent groups and by two quite different procedures, the now well-established Merrifield automated solid-state synthesis and a fragment condensation method with 19 preassembled parts. Regarding the Merrifield method, improved attachment and removal of the polymeric peptide support have been reported. A new peptide synthesis proceeds through sulfen-amides by an oxidation-reduction process . Peptides can also be obtained from N-protected aminothiolic aryl esters and sulfen-amino acids with selective removal of a protective o-nitrophenyl-sulfenyl group... 

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