in this paper the synthesis of some new polyaromatic monocyclic β-lactams has been reported. these cycloadducts have been synthesized by the [2+2] ketene-imine cycloaddition reaction known as the staudinger reaction. all of the products have been fully characterized by ir, 1h-nmr, 13c-nmr, mass spectroscopy and elemental analyses. the x-ray crystal structure of a cis β-lactam has been also pres...

Imine chemistry represents an important category of chemical reactions involved in the biosynthesis plant natural products, ranging from newly discovered mobile defense hormone N-hydroxy-pipecolic acid to red-to-yellow tyrosine-derived betalain pigments. Spontaneous imine formation have also served as basis for evolution numerous metabolic enzymes, such specialized Pictet-Spenglerases that prod...

abstractpyrimidine nucleosides are constituents of fundamental structure of the cells. there has been considerable attentions in the chemistry of pyrimidine derivatives due to having a wide range of biological activities such as antiviral, anti-malarial agents, cytostatic, antithelemintic, antibacterial, adenosine receptor ligands, anti-cancer agents, compounds targeting delayed-type hypersensi...

Imine dynamic hydrogels are synthesized via dual-imine bond crosslinking from O-carboxymethyl chitosan (CMCS) and a water soluble dynamer using ‘green’ approach. Three dynamers prepared through reaction of benzene-1,3,5-tricarbaldehyde di-amino Jeffamine with molar mass 500, 800 1900, respectively. Hydrogels, namely H500, H800 H1900 then obtained by mixing CMCS aqueous solutions. FT-IR confirms...

Continuous-flow mass spectrometry (CFMS) was used to monitor the products formed during the initial 0.25-20 s of the reactions catalyzed by the flavoprotein N-acetylpolyamine oxidase (PAO) and the pterin-dependent enzymes phenylalanine hydroxylase (PheH) and tyrosine hydroxylase (TyrH). N,N'-Dibenzyl-1,4-diaminobutane (DBDB) is a substrate for PAO for which amine oxidation is rate-limiting. CFM...

Formation of carbinolamine, imine, and oxazolidines from the reactions of desisopropylpropranolol (5), its O-methyl ether (10), and 3-(1-naphthoxy)propylamine (11) with trifluoroacetone and trifluoroacetaldehyde methyl hemiacetal was investigated by F NMR and tandem mass spectrometry. Products from the metabolism of the related secondary amine substrates trifluoropropranolol (7), its O-methyl e...

We report a dynamic covalent approach to transmembrane transport of amino acids by the formation of a three-component assembly. A mixture of a squaramide and a lipophilic and electrophilic aldehyde is shown to synergistically transport highly polar glycine (Gly) across vesicle membranes. The transport was investigated by a (13)C NMR assay, an osmotic response assay, a newly developed fluorescen...

The occurrence of imine formation at the active site of acetoacetate decarboxylase and several aldolases prompted an attempt to demonstrate this mechanism in the formally similar isocitrate dehydrogenase reaction. Although treatment of isocitrate dehydrogenase with NaBH4 in the presence of cr-ketoglutarate resulted in inactivation of the enzyme, reduction in the presence of labeled a-ketoglutar...

The hydrolysis of iminohydantoins generates the same tetrahedral intermediate as that obtained in the cyclization of hydantoic acid amides to hydantoins. The ratio of the products of imine hydrolysis under kinetic control is determined by the relative height of the barriers of the breakdown of to amide or to hydantoin. Thus the partitioning of products unequivocally proves which is the rate det...