Asian Coordinating Group for Chemistry, Chemical Research Communications, Volume 21 (2007)


table of contents

Author(s): Viwat Hahnvajanawong; Karunarak Kaewchulsri; Parinya Theramongkol
Title: Ring opening of benzoxazole caused by alkyl and aryl Grignard reagent
ACGC Chem. Res. Commun. Vol. 21, p. 1-3 (2007)
keywords: benzoxazole; ring opening; Grignard reagents
Ring opening reactions of benzoxazole with alkyl and aryl Grignard reagents are reported, possible mechanisms are presented.

Author(s): Chalev Pachthong; Dumrat Supyen; Duang Buddhasukh; Araya Jatisatien
Title: Isolation and characterization of brassinolide and castasterone from mature seeds of smooth loofah (Luffa cylindrica (L.) M.J. Roem.)
ACGC Chem. Res. Commun. Vol. 21, p. 4-8 (2007)
keywords: brassinolide; brassinosteroids; castasterone; Luffa cylindrical; rice lamina inclination
From the mature seeds of smooth loofah (Luffa cylindrica (L.) M.J. Roem.), two brassinosteroids i.e. brassinolide and castasterone were identified by GC-MS-SIM and GC-MS. The brassinolide and castasterone contents were 41 ng/kg and 312 ng/kg (dried weight), respectively. This study provides the first evidence for the occurrence of brassinolide and castasterone in the mature seeds of smooth loofah.

Author(s): Theeraphan Machan; John Korth; Boonsom Liawruangrath; Saisunee Liawruangrath; Apiwat Baramee; Stephen G. Pyne
Title: Free fatty acids from the crude hexane extract of the aerial parts of Heliotropium indicum Linn. growing in Phitsanulok, Thailand
ACGC Chem. Res. Commun. Vol. 21, p. 9-12 (2007)
keywords: fatty acid; Heliotropium indicum; methylation; fatty acid methyl ester; GC-FID; GC-MS
Sixteen free fatty acids from the crude hexane extract of the aerial parts of Heliotropium indicum Linn, growing in Phitsanulok, Thailand, have been identified after conversion to their methyl esters with boron trifluoride-methanol followed by quantification by GC-FID and identification by GC-MS analysis. They accounted for 95% of the chromatographable components, with 9,12-octadecadienoic acid, (39.7%), 9-octadecenoic acid (32.4%), hexadecanoic acid (14.2%) and octadecanoic acid (5.1%), as the major constituents. A small amount of 6,10,14-trimethyl-2-pentadecanone and 3,7,11,15-tetramethyl-2-hexadecen-l-ol as well as a homologous series of n-alkanes present at trace level and ranging from C25 to C31 was also found (see Table 1). The crude hexane extract has been shown to have modest antituberculosis activity (MIC of 100 μg/ml) against Mycobacterium tuberculosis H37Ra.

Author(s): Intan S. Ismail; Hideyuki Ito; Takashi Yoshida
Title: An ichthyotoxic procyanidin oligomer and four new hydroxy acid conjugates from the leaves of Sandoricum koetjape
ACGC Chem. Res. Commun. Vol. 21, p. 13-19 (2007)
keywords: Sandoricum koetjape; Meliaceae; ichthyotoxicity; procyanidin oligomer, hydroxy acid conjugates
Beside previously isolated new modified limonoids, sandrapins A-E, an ichthyotoxic procyanidin oligomer (1) and four new hydroxy acid conjugates, 5-O-(E)-caffeoyl-D-galactaric acid (2), 2-O-syringoyl-L-malic acid (3), 2-O-syringoyl-DL-tartaric acid (4), and 2-O-vanilloyl-DL-tartaric acid (5), were isolated along with thirteen known compounds from the leaves of Sandoricum koetjape (Meliaceae). The structures of the new compounds were elucidated with the aid of NMR spectral data and chemical evidence.

Author(s): Katheryn S. Mandap; Roland V. Marcelo; Allan Patrick G. Macabeo; Tatsuo Yamauchi; Fumiko Abe; Scott G. Franzblau; Alicia M. Aguinaldo
Title: Antitubercular phenyldecanoids from the Philippine ginger (Zingiber officinale)
ACGC Chem. Res. Commun. Vol. 21, p. 20-22 (2007)
keywords: phenyldecanoids; Zingiber officinale, antitubercular activity
In vitro anti-TB susceptibility assay using the radiorespirometric method shows that a crude alcoholic extract of the rhizome of Zingiber officinale inhibited the growth of Mycobacterium tuberculosis H37Rv by 100% at 1000 μg/mL. Bioassay-guided isolation of the constituents present in the bioactive hexane fraction afforded two phenyldecanoids namely, 6-shogaol (1) and 6-gingerol (2). The identities of these two phenolic metabolites were established thru spectroscopic techniques such as positive-ion FABMS and NMR. Compounds 1 and 2 exhibited 100% inhibitory activity at 64 and 32 μg/ml, respectively.

Author(s): M. A. Affan; Y. Z. Liew; Fasihuddin B. Ahmad; Bohari M. Yamin; Mustaffa B. Shamsuddin
Title: Synthesis, structural characterization and biological studies of organotin(IV) derivatives with carbohydrazone-bis(salicylaldehyde) (H4CBS): X-ray crystal structure of t-Bu2Sn(H2CBS)
ACGC Chem. Res. Commun. Vol. 21, p. 23-29 (2007)
keywords: organotin(IV) complexes; carbohydrazone ligand; crystal structure; antibacterial activity
An interesting series of new organotin (IV) complexes has been synthesized by the reaction of RnSnCl4-n (n = 1, 2) with carbohydrazone-bis(salicylaldehyde) (H4CBS) ligand in the presence of base and refluxing in 1:2:1 mole ratio (metal:base:ligand). All organotin(IV) complexes (2-7) have been characterized by the different physico-chemical techniques of molar conductivity measurements, elemental analysis, UV-visible, IR and 1H NMR spectral studies. All origanotin (IV) complexes (2-7) are non electrolytic in nature. Among them, di-tert-butyltin(IV) complex (4) is also characterized by X-ray crystallography diffraction analyses. In the solid state, the carbohydrazone ligand (1) exists as the keto tautomer but in solution in the presence of base and organotin(IV) chloride(s), it is converted to the enol tautomer and coordinated to the tin(IV) atom in its deprotonated enolate form. X-ray crystallographic analysis shows that the di-tert-butyltin(IV) complex tert-Bu2Sn(H2CBS) (4), is five-coordinated and has a distorted trigonal-bipyramidal geometry with the ligand coordinated to the tin(IV) as a tridentate dinegative fashion through its phenolic-O, enolic-O and imine-N atoms. The general bond length order is oxo < phenolato < enolato. The Sn-O (enolato) bond is longer than Sn-O (phenolato) bond by ca. 0.08 Å and is identical with Sn-O (carboxylate) bond. The crystal structure of tert-Bu2Sn(H2CBS) (4) is monoclinic with space group C2/c with a = 34.365(8) Å, b = 8.7304(19) Å, c = 17.183(4) Å, α = 90.011(4) °, β = 108.168(5) °, γ = 89.889(6) °, V = 4898.2(19) ų, Z = 8 and D(calc.) = 1.435 Mg/m³. The IR and 1H NMR data are consistent with all the organotin(IV) derivatives having similar geometry. The ligand [H4CBS, (1)] and its organotin(IV) complexes were tested against several bacteria and found to show a certain degree of biological activity.

Author(s): Wan Aini Wan Ibrahim; Sharain Liew Yen Ling; Mohd. Marsin Sanagi
Title: Sample matrix effect on the separation of 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzo-p-furan using micellar electrokinetic chromatography
ACGC Chem. Res. Commun. Vol. 21, p. 30-33 (2007)
keywords: MEKC; tetrachlorodibenzo-p-dioxin; tetrachlorodibenzo-p-furan; sample matrix
The effect of sample matrix on the separation of two selected dioxin-related compounds i.e. 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2378-TCDF) and 2,3,7,8-tetrachlorodibenzo-p-furan (2378-TCDF) using micellar electro-kinetic chromatography (MEKC) was investigated. The samples were prepared in aqueous and non-aqueous media at equal concentrations. The non-aqueous media used is ethanol while the aqueous media are water and buffer matrix. The best separation efficiency for these two dioxin-related compounds was obtained with the analytes dissolved in the sample buffer matrix (280,000 plates for 2378-TCDF and 180,000 plates for 2378-TCDD) but the analytes dissolved in water matrix produced the highest peak area and peak height. Sensitivity enhancement for both analytes in water increased 3 fold for 2378-TCDF and 5 fold for 2378-TCDD, respectively compared to analytes dissolved in buffer matrix. The separation efficiency for these two analytes in water matrix were 200,000 plates for 2378-TCDF and 100,000 plates for 2378-TCDD and a more stable baseline was obtained as compared to non-aqueous media.

Author(s): B. Y. Kamaruzzaman; M. C. Ong
Title: Spatial distribution of organic carbon in estuarine Mangrove forests in Terengganu, Malaysia
ACGC Chem. Res. Commun. Vol. 21, p. 34-37 (2007)
keywords: organic carbon; mangroves; spatial distribution; Terengganu
The distribution of organic carbon in the surficial sediment collected from seven estuarine mangrove forests (100 sampling points) of Terengganu region was analyzed. The organic carbon concentrations were determined by the wet dichromate oxidation method. The overall average organic carbon content was 4.07% and ranged from 3.61% to 4.67%. Generally, southern mangrove areas are characterized by higher organic carbon content while the northern mangrove area has lower organic carbon content. In this study, the statistical analysis of Pearson correlation matrix proved that there was a significant relationship between the organic carbon content and the grain size with the organic carbon content decrease with the increase of grain size.

Author(s): Hasan Ahmad; M. Amran Hossain; A. H. M. Tarikul Islam; M. A. Jalil Miah
Title: Erratum to "Preparation kinetics of monosized cyano functionalized copolymer particles by dispersion co-polymerization and adsorption behavior of biomolecules" [ACGC Chem. Res. Comm. 20: 24-31 (2006)]
ACGC Chem. Res. Commun. Vol. 21, p. 38 (2007)

The publishers regret that Figure 10 referred to on page 29 of the manuscript was unintentionally left out. A corected figure is presented.