A New Aluminium Hydroxide Coating on Fused Silica Fiber for the Determination of 1,4-Dioxane in Surfactants and Detergents Using HS-SPME-GC

This paper presents a simple and convenient analytical method for determination of 1,4-dioxane in surfactants and detergents by using a novel SPME fiber. For the preparation of the fiber, the surface of a fused silica capillary tubing was modified by means of aluminium tri-tert-butoxide in a straightforward grafting process. The surface of our proposed fiber provides a Lewis acid–base interaction with analyte functional groups. The main factors affecting the extraction were optimized by using a central composite design method, which leads to the following optimum conditions: extraction temperature of 34?°C, extraction time of 4?min, equilibrium time of 13?min, and salt content of 25% (w/v). The optimum conditions showed a linear range from 0.005 to 60?μg?g^?1. LOD and LOQ of the proposed method were estimated to be 0.0015 and 0.005?μg?g^?1, respectively. This method was also applied for the analysis of some real samples including ethoxylated fatty alcohol, sodium lauryl ether sulfate, dish-washing agents, and shampoos by using the standard addition method.     

Scope and Limitation of the Reactions of 3-Imino Derivatives of Pentane-2,4-Diones with Organophosphorus Reagents

Abstract

3-(Hydroxyimino)pentane-2,4-dione reacts with phosphonium ylides, Wittig–Horner reagents, trialkyl phosphites, and Lawesson's reagents to give the olefinic and cyclic products, the phosphonate adducts, the dialkyl phosphate products, the phosphinodithioic acid, and 2,4-dithione products, respectively. Furthermore, the reaction of 3-(phenylimino)pentane-2,4-dione with Wittig, Wittig–Horner reagents and trialkyl phosphite resulted in the formation of 2,5-diendioate, diethoxy phosphoryl hexanoate and the phosphate products. Possible reaction mechanisms are considered and the structural assignments are based on analytical and spectroscopic results. The antibacterial and antifungal activities for some of the new compounds are also reported.     

An efficient one‐pot synthesis of pyridazinones and phthalazinones using HY‐zeolite

The first one‐pot synthesis of pyridazinones and phthalazinones from arenes, cyclic anhydrides, and ArNHNH₂ in the presence of efficient recyclable heterogeneous catalyst, HY‐zeolite, in high yield and short reaction time is reported. J. Heterocyclic Chem., (2011).     

Melamine–formaldehyde resin supported H a mild and inexpensive reagent for synthesis of coumarins under mild conditions

Melamine-formaldehyde resin supported H~+ is used as an efficient catalyst in the Pechmann condensation reaction of phenols withβ-ketoesters,in solvent-free media leading to the formation of coumarin derivatives using conventional heating and microwave irradiation in excellent yields with good purity.     

The behavior of 2‐thioxo‐4‐thiazolidinones toward organophosphorus reagents

The reaction of 2‐thioxo‐4‐thiazolidinone ( 1a ) with phosphorus ylides 2a and 2b afforded compounds 5 and 6. On the other hand, formylmethylenetriphenylphosphorane (2c) reacts with 1a and its N‐methyl derivative 1b to give the new complicated phosphonium ylides 7a,b, respectively. Reactions of 1b with ylides 2a and 2d gave rise to the olefinic compound 8 and the new phosphorane product 9. Moreover, dialkyl phosphites 3a,b and trialkyl phosphites 4a–c react with 1a to give both the alkylated products 10a–c and the dimeric compounds 11,12. A mechanism is proposed to explain the formation of the new products.© 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 337–341, 1999