The activities of tobramycin derivatives acetylated and ethylated on the 6'-N,2'-N and 3-N positions were examined. The MICs of these derivatives against tobramycin sensitive strains indicated that 2'-N-ethylated and 6'-N-ethylated derivatives have a fairly good activity, and confirmed that the 3-N position is the most important one for antibiotic activity since 3-N derivatives were less active...

Previously it was reported that activation of (t)Bu2Zn by [(TMEDA)Na(μ-dpa)]2 led to tert-butylation of benzophenone at the challenging para-position, where the sodium amide functions as a metalloligand towards (t)Bu2Zn manifested in crystalline [{(TMEDA)Na(dpa)}2Zn(t)Bu2] (TMEDA is N,N,N',N'-tetramethylethylenediamine, dpa is 2,2'-dipyridylamide). Here we find altering the Lewis donor or alkal...

A systematic study of the stoichiometric alkylation reactions of 2,2,2-trifluoroacetophenone 1 with [ZnR(2)(TMEDA)] (R= Me, Et, (t)Bu, CH(2)SiMe(3); TMEDA= N,N,N',N'-tetramethylethylenediamine) monitored by (1)H and (19)F NMR spectroscopy is presented. For R = Me, Et the alkylation products alkyl(alkoxides) [(TMEDA)Zn(R){OC(CF(3))(R)Ph}] (R = Me, 2: Et, 3) are obtained as the single products of...

2,6-diaminopyridine is extensively used as a pharmaceutical intermediate and a hair dye coupler as oxidation formulations. It is soluble in protic solvents. Primary and secondary amines are N-methylated by various methods such as direct alkylation of amines with Hofmann mechanism, but in many of these methods due to overalkylations, we earn a mixture of amino products. Consequently, they aren't...

Investigating how a test drug alters the reaction of a site-directed electrophile with a receptor is a powerful method for determining whether the drug acts competitively or allosterically, provided that the binding site of the electrophile is known. In this study, therefore, we mutated nucleophilic residues near and within the orthosteric pockets of M(1) and M(2) muscarinic receptors to identi...

BACKGROUND 1,2,4-Triazole3-thiones are good scaffolds for preparation of new lead compounds. Their derivatives attracted the attention of chemists due to their wide spectrum of biological activities. Alkylsulfanyl-1,2,4-triazoles have three nucleophilic sites (nitrogens) ready for reaction with electrophiles. Herein, new regioselective isomers were synthesized by the reaction of benzylsulfanyl-...

2,6-diaminopyridine is extensively used as a pharmaceutical intermediate and a hair dye coupler as oxidation formulations. it is soluble in protic solvents. primary and secondary amines are n-methylated by various methods such as direct alkylation of amines with hofmann mechanism, but in many of these methods due to overalkylations, we earn a mixture of amino products. consequently, they aren't...

N -carboxyanhydrides ring-opening polymerization (ROP) showed that electron-donating groups of the -alkylation enhanced ROP kinetic rates through an inductive effect could counterbalance steric hindrance during propagation.