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The methods for the separation of racemic compounds [(RS)-1-bromo-3-chloro-2-propanol, (RS)-1-bromo-3-chloropropan-2-yl acetate] into the corresponding enantiomers were tried to develop in high performance liquid chromatography in a single injection mode. In the case of HPLC, both the reversed (Phenomenex Lux 5u cellulose-1, Lux 5u cellulose-2, Lux 5u amylose-1) and normal phase (Chiralcel OJH, ODH, ADH) chiral columns were used for this purpose. HPLC methods could not resolute the desired enantiomers. However, phenoxy derivatives of (RS)-1-bromo-3-chloro-2-propanol and (RS)-1-bromo-3-chloropropan-2-yl acetate were separated by normal phase (ODH) column using a mobile phase consisting of n-hexane and isopropanol (80 : 20) at a flow rate of 0.5 mL/min (25°C) and detected at 254 nm. The method was validated for linearity, range, accuracy and precision. The developed method was applied for monitoring the progress of lipase catalyzed enantioselective synthesis of (S)-1-bromo-3-chloropropan-2-yl acetate from (RS)-1-bromo-3-chloro-2-propanol. All the analytes were synthesized chemically. Keywords: (RS)-1-bromo-3-chloro-2-propanol, (RS)-1-bromo-3-chloropropan-2-yl acetate, chiral HPLC, ODH column DOI: 10.1134/S1061934815010098, Aryloxypropanolamines are extensively used as precursors for the synthesis of a varieties of cardiovascular drugs used in the treatment of hypertension, myocardial infarction, arrhythmias, angina pectoris and ischemic heart disease [...]

The catalytic potential of various metal Lewis acid catalysts have been assessed to derive a high‐yielding, multi‐component domino synthesis of functionalized pyridines from (E)‐3‐(dimethylamino)‐1‐aryl/heteroaryl‐prop‐2‐en‐1‐ones, 1,3‐dicarbonyl compounds, and an ammonium salt (as the nitrogen precursor). Amongst the various metal halides, tetrafluoroborates, perchlorates, and triflates used as the catalyst, GaI3 proved to be the most effective. The mechanistic course of the most plausible pathway has been outlined as the intermediate formation of imine/enamine by the reaction of the 1,3‐dicarbonyl compound with ammonia (liberated in situ from the ammonium salt used as the nitrogen source), which participates in the domino nucleophilic Michael reaction to the (2E)‐3‐(dimethylamino)‐1‐aryl/hetroarylprop‐2‐en‐1‐one by its active methylene carbon through its enamine form followed by intramolecular cyclization and aromatization. The effect of different ammonium salts as the nitrogen source has been investigated and NH4OAc was found to be best. The influence of the acetate counter anion of NH4OAc on the progress of the reaction was studied and its specific role in the cyclization and subsequent aromatization has been revealed. This work offers distinct advantages compared to the literature reported methodologies on the count of several green index parameters. [ABSTRACT FROM AUTHOR]

The articles describes the properties of zinc(II) perchlorate hexahydrate, which is found to be an extremely efficient catalyst for opening of the epoxide rings by amines in alcohols under various solvent free conditions. The methodology described can be effectively used for the synthesis of various cardiovascular drugs, like propranolol and naftopidil as raccmates and optically active enantiomers.

Commercially available anhydrous Mg[(Cl[O.sub.4]).sub.2] is described as a new and extremely efficient catalyst for synthesis of [alpha]-aminophosphonate by a three-component, one pot reaction. The observation of Mg[(Cl[O.sub.4]).sub.2]-catalyzed [alpha]-aminophosphonate synthesis indicates the simultaneous involvement of the carbonyl compound, the amine, and phosphite in the transition state.

Acetaminophen (paracetamol), one of the most widely used analgesics, is toxic under conditions of overdose or in certain disease conditions, but the mechanism of acetaminophen toxicity is still not entirely understood. To obtain fresh insights into acetaminophen toxicity, this phenomenon was investigated in yeast. Acetaminophen was found to be toxic to yeast cells, with erg mutants displaying hypersensitivity. Yeast cells grown in the presence of acetaminophen were found to accumulate intracellular acetaminophen, but no metabolic products of acetaminophen could be detected in these extracts. The toxicity response did not lead to an oxidative stress response, although it did involve Yap1p. The cytochrome P450 enzymes of yeast, Erg5p and Erg11p, did not appear to participate in this process, unlike the mammalian systems. Furthermore, we could not establish a central role for glutathione depletion or the cellular glutathione redox status in acetaminophen toxicity, suggesting differences from mammalian systems in the pathways causing toxicity. Investigations of the resistance mechanisms revealed that deletion of the glutathione-conjugate pumps Ycf1p (a target of Yap1p) and Bpt1p, surprisingly, led to acetaminophen resistance, while overexpression of the multidrug resistance pumps Snq2p and Flr1p (also targets of Yap1p) led to acetaminophen resistance. The Yap1p-dependent resistance to acetaminophen required a functional Pdr1p or Pdr3p protein, but not a functional Yrr1p. In contrast, resistance mediated by Pdr1p/Pdr3p did not require a functional Yap1p, and revealed a distinct hierarchy in the resistance to acetaminophen. Abbreviations: MDR, multidrug resistance protein; MRP, multidrug resistance associated protein; NAPQI, N-acetyl-[rho]-benzoquinone imine; ROS, reactive oxygen species.

Research has been conducted on thiolate anions. These anions have been generated for the chemoselective deprotection of aryl alkyl ethers under neutral conditions and the role of steric and electronic factors in this deprotection during intra-and intermolecular competitions has been investigated and discussed.

Research has been conducted on the arenethiols' nucleophilicity. The methods for the chemoselective cleavage of aryl ethers, aryl esters and aryl ester selective deprotection in the presence of alkyl esters and alkyl ethers are described.

In situ production of thiolate anion is described. The thiolate anions are deprotecting agnets for alkyl and aryl esters as well as aryl sulfonates in the order of aryl ester to alkyl ester to aryl sulfonates. Data indicate that an aryl acetate/benzoate is selectively deprotected.

A study concerning stereoselective protection of carboxylic acids under mild conditions is presented. The replacement of toxic diazomethane by LiOH.H (sub)2 O-Me (sub)2-SO (sub)4 has been discussed.