It is well known that chitosan degradation by nitrous acid leads to oligochitosan (oligoCHIt–ahm) bearing reactive 2,5-anhydromannose (3,4-dihydroxy-5-hydroxymethyl-tetrahydrofuran-2-aldehyde) units at the new reducing ends of macromolecules. Standard protocol requires reduction of oligoCHIt–a...

A protein toxic to mice was isolated from the venom of the Mexican beaded lizard Heloderma horridum horridum by a combination of gel filtration (Sephadex G-75) and ion exchange chromatography (both diethylaminoethyl-cellulose [DE-cellulose] and carboxymethyl-cellulose [CM-cellulose]). The purifi...

Helothermine, a protein from the venom of the Mexican beaded lizard (Heloderma horridum horridum), was found to inhibit [3H]ryanodine binding to cardiac and skeletal sarcoplasmic reticulum, to block cardiac and skeletal ryanodine receptor channels incorporated into planar bilayers, and to block ...

Substituted imidazoles (substituents are Me, Et, i-Bu, n-Hexyl, (CH2)2S–Bu-n, Ph, Bn) react smoothly (room temperature, without catalyst and solvent) with cyanoacetylenes (3-phenyl-2-propynenitrile and 4-(1-butoxyethoxy)-4-methyl-2-pentynenitrile) and aromatic or heteroaromatic aldehydes (benza...

O-linked methylation of sugar substituents is a common modification in the biosynthesis of many natural products and is catalyzed by multiple families of S-adenosyl-l-methionine (SAM or AdoMet)-dependent methyltransferases (MTs). Mycinamicins, potent antibiotics from Micromonospora griseorubida,...

SummaryMacrolides are a class of valuable antibiotics that include a macrolactone ring, at least one appended sugar unit, and, in most cases, additional hydroxyl or epoxide groups installed by cytochrome P450 enzymes. These functional groups contribute to structural diversification and serve to ...

Fungal infections are a growing health threat to mankind. The development of novel potent antifungal agents is a challenge to overcome the resistance to the available antifungal medications. The current report focuses on the synthesis and spectroscopic characterization of a new imidazole-bearing...

In this work, (E)-2-((2-butyl-4-chloro-1H-imidazol-5-yl)methylene)-N-methylhydrazine-carbothioamide (L) and its Cu(II), Ni(II) and Mn(II) complexes were synthesized. The ligand (L) characterized by 1H, 13C NMR, IR, HRMS and UV-Visible techniques and theoretical calculations have been performed a...

Two new imidazole salts, namely, [HIMT]+ X (X = NO3–) (1), ClO4– (2) [IMT = 4-((1H-imidazol-1-yl)methyl)benzonitrile], were grown through reacting IMT and two different inorganic acids by slow evaporation method, respectively. Salts 1 and 2 have been characterized by single–crystal X–ray dif...

The design, synthesis, and SAR study of a new series of HIV-1 protease inhibitors incorporating stereochemically defined tetrahydrofuran-tertiary amine-acetamide P2-ligand are described. Various substituent effects on the tertiary amine P2-ligand and phenylsulfonamide P2′-ligand were investigat...

Various 6-methoxytetrahydro-β-carboline derivatives, namely BEN (6-methoxy-1-phenyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole), ANI (6-methoxy-1-(4-methoxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole), ACE (6-methoxy-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole) and VAN (2-methoxy-4-...

Various diseases are related to epigenetic modifications. Histone deacetylases (HDACs) and histone acetyl transferases (HATs) determine the pattern of histone acetylation, and thus are involved in the regulation of gene expression. First generation histone deacetylase inhibitors (HDACi) are unse...

The acid-catalyzed Pictet–Spengler reaction of d-tryptophan methyl ester with piperonal in acetic acid has been reported, the best stereoselectivity (cis/trans = 92:8) was obtained with benzoic acid as the catalyst. The Pictet–Spengler reaction of d-tryptophan methyl ester hydrochloride with p...

Five new coordination compounds based on edtza or (datza)2− ligands [edtza = ethyl-[N2(N3),N2′-di(tetrazol-5-yl) amine] acetate and (datza)2− = [di(tetrazol-5-yl)] amine-N2(N3),N2′-diacetato anion] [Scheme 1], namely, binuclear cluster [Cd2(edtza)4(H2O)2]·2H2O (1) and 2-D polymers, [Ca(datza)...

The dinuclear nickel(II) complex [Ni2LCl]+, where L2− represents a 24-membered macrocyclic hexamine-dithiophenolate ligand, reacts with 5,5′-(1,3-phenylene)bis-1H-tetrazole and N,N-bis(tetrazol-5-yl)amine to give the tetranuclear complexes [(Ni2L)2(N4C–X–CN4)]+, where X = 1,3-C6H4 (1) and NH ...

New monometallic bis-bipyridyl Ru(II) and Os(II) complexes bonded with high nitrogen content five membered aromatic dianionic ligands 5,5′-bis-tetrazolate (bt) and N,N-bis(tetrazol-5-yl)-amine (bta) have been prepared. NMR results presented are consistent with N1-N1 bidentate chelate bonding to...

Aldol reaction of aldehydes with difluoroketene ethyl trimethylsilyl acetal (1) in the presence of a substoichiometric amount of chiral Lewis acid 2 or 3 provides the corresponding α,α-difluoro β-hydroxy esters 4–12 with high enantioselectivities (up to 98% ee). Reaction temperature has a gr...

In the presence of Lewis acids, η3-crotyltitanocene reagents react with acetals to give homoallylic ethers in moderate to good yields. In all cases the reactions proceed with total γ-regioselectivity. The diastereoselectivity for aliphatic acetals is no longer observed in comparison with the t...

The synthesis of (RS)-2- or (RS)-3-methoxy-2,3-dihydro-5H-1,4-benzodioxepins and (RS)-5- or (RS)-3-methoxy-2,3,5,6-tetrahydro-8H-benzo-[1,4,7]-trioxecins has been developed. The mechanism of such a reaction via the boron trifluoride etherate-promoted transformation of 2-(methoxyethoxymethoxy)ben...

Angiogenesis, a process by which new vascular networks are formed from pre-existing capillaries, is required for tumors to grow, invade, and metastasize. Vascular endothelial growth factor (VEGF), a specific mitogen to endothelial cells, is a crucial factor for tumor angiogenesis. In this study,...