Amino groups were covalently introduced onto a polycaprolactone (PCL) surface by the reaction between 1,6-hexanediamine and the ester groups of PCL. The occurrence of the aminolysis and the introduction of free NH(2) groups were verified qualitatively by fluorescence spectroscopy, where rhodamine B isothiocyanate was employed to label NH(2) groups, and quantitatively by absorbance spectroscopy,...

IpaH enzymes are secreted bacterial effectors that function within host cells as E3 ubiquitin (Ub) ligases. Catalytic activity is imparted by a conserved novel E3 ligase (NEL) domain that is unique to Gram-negative pathogens and whose activity is repressed by a flanking substrate-binding leucine-rich repeat (LRR) domain when substrate is absent. How the NEL domain catalyzes the conjugation of U...

B3LYP calculations have been carried out to study the reaction mechanism of the aminolysis of Fischer carbene complexes of the type (CO)(5)Cr=C(XMe)R (X = O and S; R = Me and Ph). We have explored different possible reaction mechanisms either through neutral or zwitterionic intermediates as well as a general base catalysis assisted by an ammonia molecule. Our results show that the most favorabl...

A novel series of indole and quinoline tricarboxamides were synthesized using simple and efficient one-pot pseudo-five-component reactions of 2-formylindole or 2-chloro-3-formyl quinolines, isocyanides, amines, and Meldrum’s acid as a CH-acid in CH2Cl2 at room temperature. This conversion has been achieved via the construction of new bonds including two C-C bonds, two ...

Reactions of the cyclic systems (NPC12)2NS0X and NPC12(NS0X)2 (X = F, Cl, Ph) with NH3 in diethyl ether or acetonitrile at low temperature provide convincing evidence that the P-bonded chlorine atoms are replaced by NH2 groups along a geminal pathway. No disruption of the S-F and S-Ph bonds occurs. Aminolysis of NPC12(NS0C1)2 proceeds to NP(NH2)2(NS0C1)2, followed by decomposition, (NPC12)2NS0C...

A versatile method for the synthesis of chiral 1,4-disubstituted-1,2,3-triazole derivatives starting from easily accessible naturally occurring D-or L-amino acids as chiral synthons is described. The amino acids were converted into azido alcohols, followed by copper catalyzed [3+2] cycloaddition reactions between the azido alcohols and methyl propiolate and subsequent ester aminolysis with prim...

Hydrozirconation of 1-hexyne, the addition to in situ prepared N-acyliminium species, and ring-closing metathesis (RCM) were key steps in the preparation of a tricyclic isoindolinone scaffold. An unusual alkene isomerization process during the RCM was identified and studied in some detail. Chemical diversification for library synthesis was achieved by a subsequent alkene epoxidation and zinc-me...

Because of the importance of developing stereoselective syntheses for single enantiomers, a selected panel of racemic biologically active 1-aryl- and 1-heteroarylpropan-2-amines has been prepared, followed by a study of their behavior in enzymatic kinetic resolution (KR) processes. For this purpose, lipase B from Candida antarctica (CAL-B) proved to be an ideal biocatalyst allowing the preparat...

The mixed anhydrides with N-acyl carbamic acid (IV) were prepared by the reaction of carboxylic acids (Ill) with N-chlorocarbonyl lactams (Ila) or sec. amides (lib). Decarboxylation of IV yielded N-acyl lactams (VI), while symmetrical anhydrides (VII) were obtained by the side reaction of IV with carboxylic acids (III). Aminolysis of IV yielded carboxylic acid amides (IX) in high yield and puri...