Impact of Geometric Parameters,Charge, and Lipophilicity on Bioactivity of Armed Quinoxaline,Benzothiaole, and Benzothiazine: Pom Analyses of Antibacterial and Antifungal Activity

Abstract

A series of four different armed heterocyclic candidates; 1-(2-methyl-2,3-dihydro-1,3-benzothiazol-2-yl)acetone (2), 1-(3-methyl-4H-1,4-benzothiazin-2-yl)ethanone (3), 2-[(2-aminophenyl)dithio]aniline (4), and 3-hydroxy-3-methyl-4-(3-methyl-2-quinoxalinyl)-2-butanone (5) have been prepared and their microbial activities were evaluated. A correlation of the structure and activities relationships of these compounds with respect to molecular modeling, Lipinski Rule of Five, drug likeness, toxicity profiles, and other physico-chemical properties of drugs are described and verified experimentally.     

Synthesis and Characterization of Two New Compounds: N(C2H4NH3)3(H2TO4)(HTO4)·2H2O (T = P,As)

The synthesis and structures of two new compounds with the general formula N(C₂H₄NH₃)₃(H₂TO₄)(HTO₄)·2H₂O (T = P, As) are reported. They crystallize with triclinic unit cells and are isotropic. We determined the structure of phosphate salt. The following unit cell parameters were found: a = 9.886(4), b = 9.308(2), c = 10.140(3) Å, α = 109.38(2), β = 108.83(3), γ = 74.40(3)°, V = 819.2(5) ų, and ρ_cal. = 1.537 g · cm^?3. The crystal structure was solved with a final R = 0.042 for 3748 with I > 3σ I). The space group is P-1 and Z = 2. The atomic arrangement can be described as a three-dimensional network of hydrogen bonds made up from H_nPO₄ ^3?n (n = 1, 2) anions and H ₂ O molecules between which are trapped the tris(2-ammoniumethyl)amine cations. Solid-state ¹³C and ³¹P MAS-NMR spectroscopies are in agreement with X-ray structure. Ab initio calculations allow the attribution of the phosphorus signals to the independent crystallographic sites.     

Melting of pentaerythritol tetranitrate (PETN) nanoconfined in controlled pore glasses (CPG)

The melting temperature depression of pentaerythritol tetranitrate, nanoconfined in controlled pore glasses (CPG), was systematically studied by differential scanning calorimetry (DSC). The solid–liquid interfacial energy σ _sl was obtained from the Gibbs–Thomson equation fit to melting temperature vs. reciprocal pore diameter. The pore size distribution of the CPG pores was also estimated from the DSC data. Pore sizes obtained from the manufacturer by BET are compared with those determined from the DSC curves using either the curves directly or by assuming spherical shaped confining cavities. The thermal mass vales are in better agreement with the BET estimation.     

Synthesis of bis N-heterocyclic carbenes,derivatives and metal complexes

A method for the synthesis and isolation of 1,1′-methylene-bis-(3-aryl-imidazol-2-ylidene) ligands, aryl = 2,6-diisopropyl-phenyl (DiPP), L^DiPP, mesityl (mes), L^mes, is reported, which provides synthetically useful quantities of high purity. Derivatisation of L^DiPP with chalcogenides gave the adducts L^DiPPE₂, E = S, Se, Te. Reaction of L^DiPP with [Pd(tmeda)Me₂], [Pt(μ-SMe₂)Me₂]₂, [Ir(1,5-COD)(μ-Cl)]₂/KPF₆ and [NiBr₂(dme)] gave [Pd(L^DiPP)Me₂] (1), [Pt(L^DiPP)Me₂] (2), [Ir(L^DiPP)(1,5-COD)](PF₆) (3) and [Ni(L^DiPP)Br₂] (4), respectively. The latter was reduced in the presence of CO to [Ni(L^DiPP)(CO)₂] (5). The structures of L^mes, L^DiPPTe₂, and 1–5 are also reported.     

Stereoselective Synthesis of Some Dialkyl (E)-2-Bromomethylene Glutarates

Reaction of 2-bromo-2-bromomethyl glutaric acid esters with tetraalkylammonium fluoride in HMPA, conveniently provides the corresponding dialkyl (E)-2-bromomethylene derivatives in good yields.     

Acid-Promoted Oxygen-Atom Transfer from a Novel Dihydroisoquinoline-Derived Oxaziridine Substituted at Position 1

N-Alkyl-oxaziridines react in the presence of a nucleophile as an oxygenating agent; in the absence of a nucleophile, an isomerization reaction is observed. This study describes the synthesis of two new dihydroisoquinoline oxaziridines and their reactivity in an acid-promoted reaction in the presence and absence of sulfides.     

γ-Keto Esters and γ-Butyrolactones From the Reaction of Dialkoxydihydrofurans With Trimethylsilyl Iodide

Dimethoxydihydrofurans are converted into γ-keto esters and γ-butyrolactones by a new procedure using an equimolar quantity and an excess of trimethylsilyl iodide, respectively.     

A Facile Ester Homologation of Carbonyl Compounds Via Ketene-O,S-Acetals

A usefull extension of the available methods for the conversion of carbonyl compounds into ketene-O,S-acetals^1,2,3 has been found in the Peterson olefination with methoxyphenylthiotrimethylsilyl-methyllithium 1 of aldehydes and ketones. The starting material for this reagent 1 was prepared by reaction of methoxyphenylthio-methyllithium^4,5 with chlorotrimethylsilane at -80°C in THF. Deprotonation of the obtained methoxyphenylthiotrimethylsilyl-methane with n-butyllithium at -80°C in THF gave 1 and subsequent addition of the carbonyl compound at -80°C gave mixtures of Z and E ketene-O,S-acetals 2.     

Application of a Chitosan-Immobilized Talaromyces thermophilus Lipase to a Batch Biodiesel Production from Waste Frying Oils

Waste frying oil, which not only harms people’s health but also causes environmental pollution, can be a good alternative to partially substitute petroleum diesel through transesterification reaction. This oil contained 8.8 % of free fatty acids, which cause a problem in a base-catalyzed process. In this study, synthesis of biodiesel was efficiently catalyzed by the covalently immobilized Talaromyces thermophilus lipase and allowed bioconversion yield up to 92 % after 24 h of reaction time. The optimal molar ratio was four to six parts of methanol to one part of oil with a biocatalyst loaded of 25 wt.% of oil. Further, experiments revealed that T. thermophilus lipase, immobilized by a multipoint covalent liaison onto activated chitosan via a short spacer (glutaraldehyde), was sufficiently tolerant to methanol. In fact, using the stepwise addition of methanol, no significant difference was observed from the one-step whole addition at the start of reaction. The batch biodiesel synthesis was performed in a fixed bed reactor with a lipase loaded of 10 g. The bioconversion yield of 98 % was attained after a 5-h reaction time. The bioreactor was operated successfully for almost 150 h without any changes in the initial conversion yield. Most of the chemical and physical properties of the produced biodiesel meet the European and USA standard specifications of biodiesel fuels.