Preparative separation of α- and β-santalenes and (Z)-α- and (Z)-β-santalols using silver nitrate-impregnated silica gel medium pressure liquid chromatography and analysis of sandalwood oil

The major sesquiterpene constituents of East-Indian sandalwood oil (Z)-α- and (Z)-β-santalols have shown to be responsible for most of the biological activities and organoleptic properties of sandalwood oil. The work reported here describes the strategic use of medium pressure liquid chromatography (MPLC) for the separation of both α- and β-santalenes and (Z)-α- and (Z)-β-santalols. Silver nitrate impregnated silica gel was used as the stationary phase in MPLC for quantitative separation of α- and β-santalenes and (Z)-α- and (Z)-β-santalols with mobile phases hexane and dichloromethane, respectively. The purities of α-santalene and (Z)-α-santalol obtained were >96%; however, β-santalene and (Z)-β-santalol were obtained with their respective inseparable epi-isomers. Limits of quantification (LoQ) relative to the FID detector were measured for important sesquiterpene alcohols of heartwood oil of S. album using serial dilutions of the standard stock solutions and demonstrated that the quality of the commercial sandalwood oil can be assessed for the content of individual sesquiterpene alcohols regulated by Australian Standard (AS2112-2003), International Organization for Standardization ISO 3518:2002 (E) and European Union (E. U.).     

Fungi mediated production and practical purification of (R)-(−)-3-quinuclidinol

A fungal system belonging to Mucoraceae family (Mucor piriformis) was explored for the asymmetric reduction of a prochiral ketone, 3-quinuclidinone (I) in an efficient manner to produce an important pharmaceutical precursor (R)-(−)-3-quinuclidinol (II) with ∼96% enantiomeric excess. The efficiency of the process was improved by developing a cation exchange resin (Amberlite IR-120) which assisted the purification of water soluble metabolite II from fermentation media.     

A Reversible Dual Mode Chemodosimeter for the Detection of Cyanide Ions in Natural Sources

Herein, we report the synthesis of two indolium probes 1 and 2 based on anthracene and pyrene derivatives and their interactions with various anions. Of these probes, the pyrene conjugate 2 acts as a dual colorimetric and fluorescent chemodosimeter for the selective and sensitive detection of cyanide ions. The detection limit of probe 2 for CN^? ions was found to be 10 ppb (30 nM ). The nature of interaction has been thoroughly studied through various techniques such as ¹H NMR and IR spectroscopy, HRMS, and isothermal calorimetric (ITC) studies. These studies confirm that probe 2 forms a 1,2‐adduct in the presence of CN^? ions. Kinetic studies using probe 2 showed the completion of the reaction within 15 s with a rate constant of k′=0.522±0.063 s^?1_. This probe can be coated on a solid surface (dipstick) and a polymer matrix for the on‐site analysis and quantification of endogenous cyanide ions in natural sources such as Indian almonds.     

Synthesis and anti-inflammatory activity of 2,3-diaryl-4(3H)-quinazolinones

2,3-Diaryl-4(3H)-quinazolinones containing various substituents on diaryl rings have been synthesized and evaluated for their cyclooxygenase-2 inhibitory activity by the colorimetric COX (ovine) inhibitor screening assay and anti-inflammatory activity by the carrageenan-induced rat paw edema assay. 2-(4-Nitrophenyl)-3-(4-tolyl)-4(3H)-quinazolinone showed a maximum COX-2 inhibition of 27.72% at 22 μM concentration in the present series and exhibited a mild anti-inflammatory activity at a dose of 50 mg/kg in carrageenan-induced rat paw edema assay. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1198–1205, August, 2006.     

Formation of Coaxial Nanocables with Amplified Supramolecular Chirality through an Interaction between Carbon Nanotubes and a Chiral π‐Gelator

In an attempt to gather experimental evidence for the influence of carbon allotropes on supramolecular chirality, we found that carbon nanotubes (CNTs) facilitate amplification of the molecular chirality of a π‐gelator ( MC‐OPV ) to supramolecular helicity at a concentration much lower than that required for intermolecular interaction. For example, at a concentration 1.8×10^?4 m , MC‐OPV did not exhibit a CD signal; however, the addition of 0–0.6 mg of SWNTs resulted in amplified chirality as evident from the CD spectrum. Surprisingly, AFM analysis revealed the formation of thick helical fibers with a width of more than 100 nm. High‐resolution TEM analysis and solid‐state UV/Vis/NIR spectroscopy revealed that the thick helical fibers were cylindrical cables composed of individually wrapped and coaxially aligned SWNTs. Such an impressive effect of CNTs on supramolecular chirality and cylindrical‐cable formation has not been reported previously.