2-nitro- and 2,4-dinitrobenzenesulfonamides as protecting groups for primary amines

Procedures for the deprotection of the 2-nitro- and 2,4-dinitrobenzenesulfonamides to give the corresponding primary amines were developed. The 2-Nitrobenzenesulfonyl group was effectively removed by HSCH2CH2OH/DBU or PhSH/Cs2CO3 in DMF under mild conditions to give the corresponding primary amines in high to excellent yield. For removal of the 2,4-dinitrobrnzenesulfonyl group, the use of thiol alone (HSCH2CH2OH or PhSH) was quite effective. Selective deprotection of 2,4-dinitrobenzene-sulfonamide in the presence of 2-nitrobznzenesulfonamide has also been achieved.

Synthesis and characterization of phosphorylcholine-substituted chitosans soluble in physiological pH conditions

A polymer analogous synthesis involving the reductive amination of phosphorylcholine (PC)-glyceraldehyde with primary amines of deacetylated chitosan (M-w approximate to 57000 g mol(-1)) was used to prepare phosphorylcholine-substituted chitosans (PC-CH) with a degree of substitution (DS) ranging from similar to 11 to similar to 53 mol% PC-substituted glucosamine residues. The PC-CH derivatives were characterized by H-1 NMR spectroscopy, FTIR spectroscopy, and multiangle laser light scattering gel permeation chromatography (MALLS-GPC). The pKa of the PC-substituted amine groups (pKa approximate to 7.20) was determined by H-1 NMR titration. The PC-CH samples (1.0 g L-1) were shown to be nontoxic using an MTT assay performed with human KB cells. Aqueous solutions of PC-CH samples (4.0 g L-(1)) of DS g 22 mol% PC-substituted glucosamine residues remained clear, independently of pH (4.0 < pH < 11.0). The remarkable water solubility and nontoxicity displayed by the new PC-CH samples open up new opportunities in the design of chitosan-based biomaterials and nanoparticles.

Aplicação de Neurospora crassa para avaliação da biosorção e biodegradação de corantes ácido, xanteno, diretos e reativo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sílica mesoporosa como suporte sólido para o ancoramento da molécula 4-amino-3-hidrazino-5-mercapto-1,2,4-triazole e aplicação na adsorção de Cu(II), Cd(II), Ni(II), Pb(II) e Co(II) em amostras aquosas

Pós-graduação em Química - IQ

Basicities of primary arylamines and calculated amine nitrogen electronic charges

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)