Sulfonated polystyrene/montmorillonite nanocomposite (OMMT/PS-SO3H) was prepared and used as a novel, efficient and inexpensive heterogeneous acid catalyst in the one-pot reaction three-component Mannich reaction of ketones, aromatic aldehydes and amines under solvent-free conditions. The catalyst was characterized by XRD, SEM, TG, BET and FT-IR techniques. This method has advantages...

The transamidase subunit GAA1/GPAA1 is predicted to be the enzyme that catalyzes the attachment of the glycosylphosphatidyl (GPI) lipid anchor to the carbonyl intermediate of the substrate protein at the ω-site. Its ~300-amino acid residue lumenal domain is a M28 family metallo-peptide-synthetase with an α/β hydrolase fold, including a central 8-strand β-sheet and a single metal (most likely zi...

Herein we report the metal-free diastereoselective frustrated Lewis pair (FLP)-catalyzed hydrogenation of azaMorita−Baylis−Hillman (aza-MBH) adducts, accessing a diverse range of stereodefined β-amino acid derivatives in excellent isolated yields (28 examples, 89% average yield, up to 90:10 d.r.). Furthermore, sequential organo-FLP catalysis has been developed. An initial organocatalyzed aza-MB...

A hydrophilic phosphinobiphenyl amidosulfonate, 2′-(dicyclohexylphosphino)-2{[(sulfonatomethyl)amino]carbonyl}[1,1′-biphenyl], triethylammonium salt (L2), was prepared and, together with its isomer bearing the polar amido-sulfonate tag in the position 4 of the biphenyl scaffold (compound L1), evaluated as a supporting ligand in Pd-catalyzed cyanation of aryl bromides using K4[Fe(CN)6] as the no...

Theories of browning reactions, including carbonyl-amino, caramelization, and oxidative types, are integrated in review. A unified mechanism for browning in sugaramine systems is presented, wherein sugaramine condensation, the Amadori rearrangement, sugar dehydration by β-elimination reactions, and reductone formation are shown to be important intermediary reactions leading to the production of...

The title compound, C(7)H(6)BrN(3)O, was obtained from the reaction of 6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one with methyl iodide. All non-H atoms lie in a common plane [r.m.s deviation = 0.017 (1) Å]. The amino group is a hydrogen-bond donor to the carbonyl group of an inversion-related mol-ecule, the pair of hydrogen bonds giving rise to a hydrogen-bonded dimer.

Schiff bases are versatile ligands and known to be synthesized from the condensation of an amino compound with carbonyl compounds. These compounds along with their metal complexes are considered to be an important as catalysts in various biological processes. Also Schiff base complexes are gaining popularity among the various industries including polymers, dyes and pharmaceutical. This review s...

In the title compound, C(11)H(14)N(2)O(5)S, the amide O atom acts as a hydrogen-bond acceptor from a carboxyl-ate O atom and a secondary amino N atom. In addition, one of the sulfonyl O atoms and the carbonyl O atom of the carboxyl group also form hydrogen bonds with the primary amido N atom. These intermolecular hydrogen-bonding inter-actions give rise to a layer structure, with the layers par...

The bond distances and bond angles of the title compound, C(23)H(25)NO(6), are consistent with values typically found for fluoren-9-ylmethoxy-carbonyl-protected amino acids. The conformations of the backbone and the side chain are slightly different from those of l-aspartic acid. The crystal structure exhibits two inter-molecular hydrogen bonds, forming a two-dimensional sheet structure paralle...