... 5-Methylthiazole Ring (Nt) Derivative. The Boc-protected 2-amino-5-methylthia- zole acid 10 (Boc-Nt-OH) was synthesized on a multi-gram scale by brominating 2- Helvetica Chimica Acta ± Vol. 85 (2002) 4493 Scheme 3 N H COCCl3 N H COCCl3 O2N ... 23 24 25 2 26 12 i) ii) iii) ...