Easy Microwave Assisted Deprotection of N-Boc Derivatives

Abstract

A simple and efficient method for the cleavage of tertbutoxycarbonyl amides and amines is described, which takes place on silica gel under microwave irradiation.

Design and Synthesis of a Conformationally Rigid Mimic of the Dihydropyrimidine Calcium Channel Modulator SQ 32,926

“…115°). Finally, gentle removal of the BOC group in 12 was carried out by microwave-promoted deprotection following a recently reported protocol [25] to furnish the target compound 3 in 90% yield. Molecular models based on semiempirical calculations of pentacycle 3 demonstrate that the geometry of this conformationally rigid DHPM derivative is very similar to the receptor-bound conformation proposed in Figure 1 for DHP/DHPM calcium channel modulators (see Figure 3).…”

τ-Regioselective addition of (-)-Nα-tert-butoxycarbonyl-L-histidine methyl ester to diethyl fumarate

“…This is a remarkable and very convenient result because this is an unusual and not previously reported deprotection method for these funtional groups. Cleavage of tert-butoxycarbonyl groups (BOC) are normally carried out in stronger conditions, with CF 3 COOH, either neat or in combination with CH 2 Cl 2 10 Milder methods have been described with the assistance of microwaves 11 or solid-phase 12 methodologies. Additionally selective hydrolysis of methyl esters in the presence of ethyl esters can be conveniently achieved by treatment with LiI in pyridine 13 or with NaCN in HMPA 14 The results obtained by us can be interpreted as a cascade hydrolytic process.…”

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].…”