[H2-Cryptand 222]2+(Br3 –)2 as a Tribromide-Type Catalyst for the Trimethylsilylation/Tetrahydropyranylation of Alcohols

A stable organic tribromide, [H2-cryptand 222]2+(Br3–)2 was utilized as an active catalyst for the trimethylsilylation/tetrahydropyranylation of alcohols. The method is general for the preparation of OH-protected aliphatic (acyclic and cyclic), aromatic, primary, secondary and tertiary alcohols.Keywords: [H2-cryptand 222]2+(Br3–)2, trimethylsilylation, tetrahydropyranylation, alcohols, tribromide, TMS-ether, THP-ethe

Synthesis, Structural Studies, and α-Glucosidase Inhibitory, Antidiabetic, and Antioxidant Activities of 2,3-Dihydroquinazolin-4(1 H)-ones Derived from Pyrazol-4-carbaldehyde and Anilines

A series of new quinazoline derivatives were designed and synthesized via a one-pot condensation reaction between isatoic anhydride and aromatic aldehydes with anilines using aluminum sulfate as a catalyst in refluxing ethanol. Their structures were confirmed by their physical, IR, 1H NMR, 13C NMR, and mass spectroscopy data and evaluated for some biological effects, including the antioxidant and α-glucosidase inhibitory activities as well as some in vivo hematological parameters. The ability of synthesized compounds in the inhibition of α-glucosidase was also investigated through the in silico study. The significant and important changes in some hematological tests were perceived. Notably, compound 4h showed more reducing effects on cholesterol and triglyceride levels. This molecule certainly has the potential to be developed as the antihyperlipemic compound. The tested compounds, in particular, compounds 4j and 4l, were found to be uniquely reducing blood sugar levels. The entire synthesized compounds showed the potent α-glucosidase inhibitory activity compared with acarbose as a standard material. Amongst, the compounds 4h and 4i showed the strongest enzyme inhibitory potentials than the standard drug acarbose. There was a good correlation between in vitro and in silico studies for ligands 4i and 4l. The majority of compounds presented a good radical scavenging activity, though the compound 4j exhibited the strongest activity, even to the standard of ascorbic acid. Further studies are required to determine whether these main compounds could be a potential treatment for diabetes and hyperlipidemia diseases

First report of an entomopathogenic nematode, Steinernema kraussei (Rhabditida, Steinernematidae) from Iran

During conduction a survey of entomopathogenic nematodes throughout Arasbaran forests and rangelands, north west of Iran in 2007-2008, an entomopathogenic nematode was isolated using Galleria baiting method from soil samples collected from rangelands, near Chichakloo, Varzeghan, East Azarbaijan. It was identified as Steinernema kraussei (Steiner, 1923) Travassos, 1927 based on morphology and morphometric characters, cross breeding test, as well as molecular data. This species can be separated from other members of the genus by medium body length of infective juvenile (818 μm), lateral field with eight ridges in which the central pair is less distinct than others, head smooth, long cephalic papillae, secretory-excretory pore located at the level of middle of esophagus and anterior to the nerve ring; broad, slightly yellowish and short spicules, low D% value and tail with fine mucron in males. The analysis of ITS-rDNA sequence placed Iranian population of S. kraussei in the âfeltiae - kraussei - oregonenseâ group in the clade that containing different isolates of the species. It has some morphological and morphometric differences such as long cephalic papillae of IJ, more curvature of spicules and absence of mucron in some males as compared with type species. The mentioned differences are considered as intraspecific variations, and the described population from Iran is another isolate of S. kraussei. This is the first record of S. kraussei from Iran

A survey on the response of the last instar larvae of acorn weevil, Curculio glandium (Col.: Curculionidae), to entomopathogenic nematodes Steinernema bicornutum and Heterorhabditis bacteriophora in the laboratory

The acorn weevil, Curculio glandium Marsham, is an important forest pest of oak trees in most of countries as well as Iran. The pest disturbs regeneration of host trees by feeding on their acorn. The necessitate to control the pest as well as limitations of chemical pesticide application in natural resources, different indigenous entomopathogenic nematodes (EPNs): Heterorhabditis bacteriophora and Steinernema bicornutum were tested under laboratory conditions upon the fifth instar larvae of acorn weevil collected from Arasbaran forest. In the first experiment, penetration assay was conducted using a suspension of 4000 IJs of the EPNs per 1 ml distilled water in multi-well plates. The plates were incubated for 40 h at 25ºC and dead larvae were dissected. Penetration percentage was %1.6 for H. bacteriophora and %0.55 for S. bicornutum. In the second experiment, H. bacteriophora and S. bicornutum were applied at different concentrations (0, 150, 250, 500, 1000 and 2000 IJs per 1ml of distilled water) in the 9 cm Petri plates lined with filter papers in order to test their capability of parasitization of the fifth instar larvae of C. glandium. The experiments were conducted at two temperature ranges (21-24ºC and 25-28ºC). Maximum mortality caused by H. bacteriophora and S. bicornutum were %58.3, %25 (at 21-24ºC) and %63.5, %30.5 (at 25-28ºC), respectively. Therefore, H. bacteriophora caused higher larval mortality comparing to S. bicornutum at both temperature ranges. Analysis of variance revealed significant nematode species and concentration as well as temperature effects on larval mortality. By increasing of concentration of nematode and temperature, larval mortality was raised. The highest penetration in larva and the highest mortality of fifth instar larvae of C. glandium was observed for H. bacteriophora under the both temperature ranges. Based on probit analysis, the LC50 of H. bacteriophora at two temperature ranges of 21-24ºC and 25-28ºC were determined 1331 and 1037 IJs/ml, respectively. Regression analysis showed significant relationship between concentrations and larval mortality in both nematodes and both temperature ranges. Therefore, H. bacteriophora comparing to S. bicornutum is more effective and can be suggested for complementary studies toward finding a suitable biocontrol agent of the pest

Morphology and molecular study of an entomopathogenic nematode, Steinernema bicornutum (Nematoda, Rhabditida, Steinernematidae) from Iran

An entomopathogenic nematode was isolated by Galleria baiting technique from soil samples collected near Marand, East Azarbaijan province, North-west of Iran during 2003. Based on morphological and morphometric characters, as well as molecular data it was identified as Steinernema bicornutum Tallosi, Peters & Ehlers, 1995. Morphometrics comparison of the isolate with the type species showed no obvious differences between them. Differences in ITS-rDNA PCR-RFLP were found between the Iranian isolate, i.e. IRA7, with the type (Yugoslavian) isolate. The RFLP analysis was able to distinguish Iranian isolate from the type population of S. bicornutum in the HinfI (four restriction sites in the type vs three restriction sites in the IRA7), Hin6I (550, 250 and 250 bp in the studied isolate vs 541 and 474 in the type isolate) and AluI profiles (715, 177 and 123 in the type and 710 and 220 in the IRA7). These molecular differences are considered as intraspecific variations, and the described population from Iran is another isolate of S. bicornutum

Comparative study between wear of uncoated and TiAlN-coated carbide tools in milling of Ti6Al4V

As is recognized widely, tool wear is a major problem in the machining of difficult-to-cut titanium alloys. Therefore, it is of significant interest and importance to understand and determine quantitatively and qualitatively tool wear evolution and the underlying wear mechanisms. The main aim of this paper is to investigate and analyse wear, wear mechanisms and surface and chip generation of uncoated and TiAlN-coated carbide tools in a dry milling of Ti6Al4V alloys. The quantitative flank wear and roughness were measured and recorded. Optical and scanning electron microscopy (SEM) observations of the tool cutting edge, machined surface and chips were conducted. The results show that the TiAlN-coated tool exhibits an approximately 44% longer tool life than the uncoated tool at a cutting distance of 16 m. A more regular progressive abrasion between the flank face of the tool and the workpiece is found to be the underlying wear mechanism. The TiAlN-coated tool generates a smooth machined surface with 31% lower roughness than the uncoated tool. As is expected, both tools generate serrated chips. However, the burnt chips with blue color are noticed for the uncoated tool as the cutting continues further. The results are shown to be consistent with observation of other researchers, and further imply that coated tools with appropriate combinations of cutting parameters would be able to increase the tool life in cutting of titanium alloys