Simple and Efficient Cleavage Reaction of the Boc Group in Heterocyclic Compounds.

Abstract

pounds. -The preparation of chiral cyclosulfamides (VII) is performed starting from amino esters (I). Benzoylation of (I), followed by reduction and chlorination yield the chiral 1-substituted N-benzyl chloroethylamine hydrochlorides (V). Sulfonylation of (V) by N-Boc sulfamoyl chloride (VI) under alkaline conditions causes spontaneous cyclization into chiral thiadiazolidine dioxides (VII). Regioselective deprotection of the five-membered cyclosulfamides (VII) is achieved by using the fusion method, consisting of heating (VII) in the presence of a catalytic quantity of iodine under reduced pressure. -(NADIA, K.; MALIKA, B.; NAWEL, K.; MEDYAZID, B.; ZINE, R.; AOUF*, N.-E.; J.

Synthesis of β-Hydroxy-α,α-difluorosulfonamides from Carbanions of Difluoromethanesulfonamides

“…1 H NMR data of this material was identical to previously reported spectra. 53 N-(9-Phenyl-9-fluorenyl)N-benzyl Valinol (28). Compound 27 (1.88 g, 9.74 mmol, 1 equiv) was dissolved in 50 mL of CH 3 CN, and bis(trimethylsilyl)acetamide (BSA, 2.85 mL, 11.6 mmol, 1.20 equiv) was added; the mixture was heated to reflux for 20 min and then cooled to 0 °C.…”

Iodine‐Mediated Neutral and Selective N‐Boc Deprotection

“…Thus, N-Boc deprotection has been carried out successfully using mild acidic conditions [7] such as trifluoroacetic acid (TFA), HCl, H 2 SO 4 , aqueous phosphoric acid [8], or Lewis acids such as BF 3 ⋅OEt 2 , TMSI, TMSOTf, TiCl 4 , SnCl 4 , AlCl 3 , Sn(OTf) 2 , and ZnBr 2 [9]. The use of montmorillonite K10 clay catalyst [10] and silica gel [11] or thermolytic conditions at high temperature [12,13] have also shown to work. Cleavage of the Boc group can be achieved in some cases under basic conditions, where the amine is activated, such as pyrroles [14][15][16].…”

N-tert-Butoxycarbonylation of Structurally Diverse Amines and Sulfamides under Water-Mediated Catalyst-Free Conditions

“…N -Boc deprotection is generally achieved under mild acidic conditions such as trifluroacetic acid (TFA), aqueous phosphoric acid in THF [4], or Lewis acid [5]. The deprotection can be carried out with montmorillonite K.10 clay [6], silica gel at low pressure [7], and by thermolytic cleavage although at high temperature [8, 9]. …”