The new tripeptide reported here is composed of (R)-2-(3-aminophenoxy)propionic acid and is a bowl-shaped receptor that simultaneously binds both cations and anions of acetylcholine chloride and benzyltrimethylammonium compounds. An intriguing conformational change of the host was observed in th...

Targeted carboxybetaine synthesis is an important process that one can apply to prepare polymeric materials with various unique properties or low molecular weight products, such as deep eutectic solvents based on acrylic acid formulated for the specific tasks. Analyzing the mechanism of carboxyb...

2-Amino-3-(purin-9-yl)propanoic acids substituted at position 6 of the purine base moiety by dimethylamino, cyclopropylamino, pyrrolidin-1-yl, hydroxy, and sulfanyl group as well as their 2-aminopurine analogues were prepared from corresponding 9-(2,2-diethoxyethyl)purines and 2-aminopurines, re...

We report the synthesis and fluorescence properties of two aromatic d-amino acids. The key step for the synthesis of (R)-2-amino-3-(4′-acetamido-[1,1′-biphenyl]-4-yl)propanoic acid was a Suzuki cross-coupling reaction between the pinacol diester of N-acetylphenylboronic acid and Fmoc-d-p-bromo...

Of the nine legitimate diagonal Conformational minima (αlαl, αdαd, βlβl, γlγl, γdγd, δlδl, δdδd, ϵlϵl and ϵdϵd) only six conformations (αdαd, βlβl, γlγl, γdγd, δdδd, and ϵdϵd) could be located by gradient optimization at the HF/3-21G level of theory. The Conformational an...

A complete conformational database is presented for For-Gly-NH2, For-l-Ala-NH2, Ac-l-Ala-NHMe and For-l-Val-NH2. This database has been obtained by a 'tight' optimization condition, using a 1.0 × 10−5 a.u. gradient length (r.m.s. force) criterion. The annihilation of the right-handed ...

This is the second paper which reports the results obtained from a systematic conformational analysis of the (R)-8-amino-pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8-carboxylic acid monopeptide (Cage monopeptide), using molecular mechanics and ab initio methods. The purpose of this paper is to hi...

Ab initio Molecular Orbital computations were carried out on the tripeptide models, N-Ac-d-Ala-Gly-l-Ala-NHMe and N-Ac-l-Ala-Gly-l-Ala-NHMe at the RHF/3-21G level of theory. The topologies of conformational Potential Energy Surfaces were explored and analyzed. In addition, global and local minim...

Using molecular simulation, we show how Ac-(Ala)10-NHMe adsorbed on a solid surface switches between three conformations at distinct surface energies. The first switch is from an α-helix to a 3.110-helix. The second involves further stretching to a 27-helix. This switching has several potential...

Quinoline, a hepatocarcinogen in rats and mutagen in Salmonella typhimurium, binds to RNA, DNA and certain polyribonucleotides in the presence of NADPH and rat liver microsomes. The binding was pronounced with the help of liver microsome preparations made from the rats pretreated with some induc...

Analysis of proton NMR spectra of N-methyl and O-acetyl derivatives of 4-hydroxyaminoquinoline 1-oxide (6) and 4-aminoquinoline 1-oxide revealed that the structure of carcinogenic 6 and its O-monoacetate are 1-hydroxy-4-hydroxyimino-1,4-dihydroquinoline and 1-hydroxy-4-acetoxyimino-1,4-dihydroqu...

Quinoline, 8-hydroxyquinoline, 8-nitroquinoline, and 8-aminoquinoline are mutagenic in Salmonella when assayed by histidine reversion. Metabolic activation is required for the maximal effect. Frameshift mutagenesis appears to be the mechanism with 8-nitro- and 8-aminoquinoline. Quinoline and 8-h...

The metabolism of 14C-labelled 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) was studied in suspensions of hepatocytes isolated from PCB-pretreated rats. The metabolites found after incubation of IQ/MeIQ (0.1 mM) with PCB-pretreated hepatocyt...

SummaryThe primary focus of this experiment was on the investigation of localizations of α 1 -antitrypsin (α 1-AT), α 1-antichymotrypsin (α 1-ACT), fibronectin (FN) and lysozyme (LY) in tumor cells of experimental malignant fibrous histiocytoma (MFH). The induction of MFH was conducted by in...

DNA binding in vitro was measured with 2-amino-3-methylimidazo(4,5-ƒ)[5-3H]quinoline (3H-IQ) in the presence of S9 and microsomes from Wistar rat liver. DNA binding of 3H-IQ was catalyzed by both microsomes and S9 and was increased 5-fold in Aroclor (PCB)-pretreated animals. DNA binding was redu...

Heterocyclic amines and inflammation have been implicated in the etiology of colon cancer. We have recently demonstrated that during autoxidation of the inflammatory mediator nitric oxide 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) undergoes nitrosation to form 2-nitrosoamino-3-methylimidazo[4,...

Previously, we reported the establishment of two transplantable osteosarcomas, one induced by local application of a carcinogen, 4-hydroxyamino quinoline 1-oxide(4-HAQO), and another which developed spontaneously in rats, and their subdivision into four lines with high and low metastatic potenti...

Thioureas react quantitatively with phenacyl bromide in ethanolic solution to give hydrobromides of aminothiazoles/iminodihydrothiazoles which can be titrated with sodium carbonate, Thymol Blue being used as indicator.

The rate constants have been measured for deprotonation reaction of substituted N-phenacyl-pyridinium bromides, in the pyridine ring, with 1,4-diazabicyclo[2,2,2]octane in water and DMSO, and some with 1,8-diazabicyclo[5,4,0]undec-7-ene. The dependence of the rate constant, k, on pKa of substitu...

New benzimidazole-2-ylidene palladium(II) complexes of PEPPSI type, having pyridine as a throw-away ligand were obtained in one step from phenacyl benzimidazolium bromides and PdCl2. Although the presence of phenacyl groups attached to the N3 could lead in basic medium either to the N-heterocycl...