Improved procedure for the synthesis of thiazolium-type peptide coupling reagents: BMTB as a new efficient reagent

Amide bond formation: beyond the myth of coupling reagents

“…reagent, BMTB 95, was proposed by Wischnat (Scheme 9). 90 BMTB 95 performed better than HATU 28a in coupling Boc-N(Me)-Ile to N(Me)-Ile-OBn. However BMTB 95 was not compared to BEMT 94.…”

Peptide Synthesis

“…The imidazolium reagent BOI 74 and its precursor CIP 75 were developed by Kisos group [331]. In contrast to the latter, BMTB 78 [334] is a crystalline and non-hygroscopic compound. The benzene ring-fused derivate of CIP, termed CMBI 76, is also an efficient coupling reagent [332] as is the thiazolium-type reagent BEMT 77 [333].…”

α-Selective C(sp3)–H Thio/Selenocyanation of Ketones with Elemental Chalcogen

“…(E)-1-Thiocyanato-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3en-2-one (28). The general procedure was followed (70 °C, 12 h), and 20/1 petroleum ether/EtOAc was used as the eluant to obtain a yellow oil (31.4 mg, 42% yield).…”

“…1 H NMR (500 MHz, CDCl 3 ): δ 6.85−6.79 (m, 1H), 6.20−6.17 (m, 1H), 5.55 (s, 1H), 4.25 (s, 2H), 2.34 (d, J = 9.6 Hz, 1H), 2.14−2.01 (m, 2H), 1.57 (s, 3H), 1.45−1.43 (m, 1H), 1.26−1.24 (m, 1H), 0.94 (s, 3H), 0.87 (s, 3H); 13 C{ 1 1-Thiocyanatopropan-2-one (29). 28 The general procedure was followed (70 °C, 12 h), and 5/1 petroleum ether/EtOAc was used as the eluant to obtain a yellow oil (13.8 mg, 40% yield). 1 H NMR (400 MHz, CDCl 3 ): δ 4.06 (s, 2H), 2.36 (s, 3H); 13 C{ 1 H} NMR (125 MHz, CDCl 3 ) (δ, ppm): δ 198.7, 111.3, 44.4, 28.4.…”