An efficient and highly selective cleavage of N-tert-butoxycarbonyl group under microwave irradiation

Protection Reactions

“…The last example can be used for simultaneous deprotection and purification of Boc-protected peptides. AlCl 3 -mediated cleavage can be carried out in short duration under microwave irradiation [111]. When nonprotic acids are used for cleavage, the free amino peptide can be converted into its salt by the addition of HCl or HBr solutions in anhydrous Et 2 O/EtOAc/dioxane to facilitate isolation, given there is no other acid-labile group.…”

“…The unprotected d, v 0 , and v-nitrogens can be involved in the formation of d-lactams (110), cycloheptane derivatives (111), and deguanidilation of Arg to Orn (112), respectively (Figure 1.43). However, an ideal protection represented by N d ,N v ,N v0 -per derivatized guanidino group has not yet been devised (except Trt-Arg(Trt) 3 -OMe, but its utility in peptide synthesis is yet to be established).…”

Organic Synthesis Using Microwaves and Supported Reagents

“…6.2.1.6 Selective Cleavage of the N-tert-butoxycarbonyl Group This approach may find application in peptide bond formation that would eliminate the use of irritating and corrosive chemicals such as trifluoroacetic acid and piperidine as has been demonstrated recently for the deprotection of N-boc groups (Scheme 6.7); a solvent-free deprotection of N-tert-butoxycarbonyl group occurs upon exposure to microwave irradiation in the presence of neutral alumina ªdopedº with aluminum chloride (Scheme 6.7) [41].…”

Solvent-Free Mechanochemical Deprotection of <i>N</i>-Boc Group

“…These include grinding in a mortar with iodine [5], thermolysis at 180˚C -185˚C [6], or by thermolysis on silica gel at mild temperature (50˚C) at reduced pressure [7] [8]. Microwave-assisted thermolytic deprotection was achieved on silicagel within 1 min [9] or by MW heating on neutral alumina with AlCl 3 in 1 min [10]. For deprotecion at low temperatures (rt to 40˚C), Lewis acid, YbTf 3 was added on silicagel [11].…”