The Effects of Solvent and Added Bases on the Protection of Benzylamines with Carbon Dioxide

Abstract

Abstract:The introduction and removal of protecting groups is ubiquitous in multi-step synthetic schemes. From a green chemistry standpoint, however, alternative strategies that employ in situ and reversible protection and deprotection sequences would be attractive. The reversible reactions of CO2 with amines could provide a possible vehicle for realizing this strategy. Herein, we present (1) the products of reaction of benzylamines with CO2 in a variety of solvents with and without the presence of basic additives; (2) 498(4-aminomethyl)phenyl) methanol with isopropenyl acetate in acetonitrile containing DBU in the absence and presence of CO2.

Bioactive Diketopiperazines and Nucleoside Derivatives from a Sponge-Derived Streptomyces Species

“…The existence of the mercaptocarbamic acid moiety was supported by the presence of NMR signals at δ H/C 7.26 (1H, brs, N H ) and 10.90 (1H, hump, H-3′′)/158.1 (qC, C-3′′) (Table 3) and by MS/MS fragmentation ion peaks at m / z 316 [M − OH] + , 288 [M − COOH] + , 273 [M − NHCOOH] + and 242 [M − SNHCOOH + H] + (Figure 7 and Figure 8), completing the degrees of unsaturation and the molecular formula of 3 . The 13 C chemical shift of the carboxylic acid moiety of the carbamic acid is in good agreement with the literature [28]. The placement of the 2′-desoxyribose moiety at N -1 was supported by HMBC long-range correlations from H-1′ to C-2 and C-6 (Table 3 and Figure 2).…”

Mechanistic insights into carbamate formation from CO2and amines: the role of guanidine–CO2adducts

“…An overview of reactions involving CO 2 -capture by amines, including related nomenclature. 8,[11][12][13][14][15] Primary and secondary alkylamines (nitrogen bound to sp 3hybridized carbon) react rapidly with CO 2 at ambient pressure and temperature. A carbamic acid is the dominant species in polar aprotic solvents (Scheme 2A).…”

Carbon nanotube/PVA aerogels impregnated with PEI: solid adsorbents for CO2 capture

“…The materials synthesised from PVA/CNT mixtures reported here satisfy all these requirements: (i) crosslinked PVA forms stable hydrogels in aqueous solutions, (ii) PVA has a high melting temperature (185 o C) and (iii) PVA does not react with amines. Additionally, the presence of hydroxyl groups in the composite was considered to provide good wetting with amines and also could facilitate the reaction of amines with CO2 via formation of alkyl carbonate salts 45,46 or carbamate esters. 47 The lyophilisation technique makes it possible to tune the resultant density of the aerogel by varying the initial concentrations of CNT and PVA, i.e.…”