Sulfonamide synthesis using N-hydroxybenzotriazole sulfonate: an alternative to pentafluorophenyl (PFP) and trichlorophenyl (TCP) esters of sulfonic acids

New 1,1’-Ferrocene Bis(sulfonyl) Reagents

“…[18][19][20][21][22][23] This unit has been successfully used for the activation of carbonyl functionalized ferrocenes for the formation of amino acid conjugates. [22,24] HOBt has been used occasionally to activate sulfonic acid derivatives [25,26] and we hypothesized that a similarly structured sulfonyl group would allow for the rapid generation of ferrocene bis(sulfonamides). Thus, we prepared compound 4, 1,1'-bis(sulfonyl-N-hydroxybenzotriazole)ferrocene, which is produced from the reaction of compound 1 with 1-hydroxybenzotriazole hydrate.…”

Sulfonamide Synthesis via Oxyma‐O‐sulfonates – Compatibility to Acid Sensitive Groups and Solid‐Phase Peptide Synthesis

“…This methodology is applicable to a wide variety of amines that include primary amines (Table 2, Entries 1–7), protected hydroxylamines (Table 2, Entries 8 & 9), secondary amines (Table 2, Entries 10–13), and amino acid esters including those with sterically hindered side chains (Table 2, Entries 14–19). This methodology is also sensitive electronic and steric factors as its previous counterpart (HOBt) 12. For example, in the case of Table 2, Entries 4 and 6, in which a sterically hindered amine is subjected to the reaction conditions, the yield was found to be lower than that of its sterically less hindered analogue.…”

“…Thus, it is important to develop a method in which the sulfonic acid moiety is activated and undergoes amidation under ambient conditions such that there will be no HCl production; such a method would be compatible with all acid‐labile groups and resins for Fmoc‐based SPPS (Solid Phase Peptide Synthesis). We recently reported a method in which the sulfonic acid is activated as the corresponding N ‐hydroxybenzotriazole ester 12. However, this methodology has the limitation that triazoles are explosive on heating,13 although it serves the purpose well.…”

Synthesis, structure, theoretical calculations and biological activity of sulfonate active ester new derivatives

“…1) and 7-aza-1-hydroxy benzotriazole, abbreviated afterwards as HOAt (6-10 in Fig. 1) [4]. The reactivity of such sulfonate esters was shown to be directly related to the presence of electron withdrawing substituents in both benzotriazole and sulfonate moieties [5].…”