Ring synthesis by stereoselective, methylene-free enyne cross metathesis

Tandem enyne metathesis between 1-alkynes and 1,5-cyclooctadiene or all-cis-1,4-polybutadiene resulted in a direct, one-step ring synthesis of cyclohexadienes by methylene-free metathesis. The use of methylene-free metathesis conditions provided apparent Z-selectivity in the intermolecular enyne metathesis step.     

B and collider physics: Working group report

This report summarises the work done during WHEPP-6 (Institute of Mathematical Sciences, Chennai, India, Jan 3–15, 2000) in Working group on ‘B and collider physics’.     

Bismuth Chloride–Sodium Nitrite: A Novel Reagent for Chemoselective N-Nitrosation

Bismuth(III) chloride–sodium nitrite was used as a mild and efficient reagent for N-nitrosation of various tetrazoles, secondary amines, and amides under ambient conditions. Nitrosation took place chemoselectively at the nitrogen atom, giving corresponding N-nitroso derivatives in good to excellent yield.     

Heteroaryl Hydroxycarbonylation: An Efficient,Robust, Practically Scalable Approach Using Formyl Acetate as the CO Source

A simple, efficient, regioselective, and scalable palladium-catalyzed hydroxycarbonylation of heteroaryl halides to corresponding carboxylic acids using acetic–formic anhydride in presence of Pd(OAc)₂, dppf, and diisopropylethyl amine in dimethyl formamide at 80–90 °C in excellent yields.     

A novel amino acid functionalized ionic liquid promoted one-pot solvent-free synthesis of 3,4-dihydropyrimidin-2-(1H)-thiones

An environmentally benign, cheap and reusable L-amino acid functionalized ionic liquid [L-AAIL]/AlCl₃ was found to be an effective catalyst for the synthesis of 3,4-dihydropyrimidine-2-(1H)-thione derivatives in good to excellent yield under solvent-free condition. Compared with the classical Biginelli reactions, this method consistently enjoys the advantages of mild reaction conditions, easy work-up, and short reaction time. These one-pot three-component Biginelli products could be separated easily from the catalyst–water system, and the catalyst could be reused at least five times without noticeably reducing catalytic activity.     

Mannich Reaction as a New Route for the Synthesis of Tetrahydro Pyrimido Benzimidazolyl Coumarins

Condensation of coumarin‐4‐acetic acids ( 1 ) with ortho‐phenylenediamine ( 2 ) in anhydrous phosphoric acid afforded 4‐((1H‐benzo[d]imidazol‐2‐yl)methyl)‐2H‐chromen‐2‐ones ( 3 ). Attempted Mannich reaction of 3 with formalin and primary amines resulted in 4‐(2‐phenyl‐1,2,3,4‐tetrahydrobenzo[4,5]imidazo[1,2‐c]pyrimidin‐4‐yl)‐2H‐chromen‐2‐ones ( 6 ). The structures of synthesized compounds were elucidated by analyses including 2D HETCOR and DEPT experiments. Synthesized compounds have been subjected for anti‐inflammatory activity. Compound 6j exhibited promising anti‐inflammatory activity.     

Sequential determination of fat- and water-soluble vitamins in Rhodiola imbricata root from trans-Himalaya with rapid resolution liquid chromatography/tandem mass spectrometry

A rapid method was developed to determine both types of vitamins in Rhodiola imbricata root for the accurate quantification of free vitamin forms. Rapid resolution liquid chromatography/tandem mass spectrometry (RRLC–MS/MS) with electrospray ionization (ESI) source operating in multiple reactions monitoring (MRM) mode was optimized for the sequential analysis of nine water-soluble vitamins (B₁, B₂, two B₃ vitamins, B₅, B₆, B₇, B₉, and B₁₂) and six fat-soluble vitamins (A, E, D₂, D₃, K₁, and K₂). Both types of vitamins were separated by ion-suppression reversed-phase liquid chromatography with gradient elution within 30 min and detected in positive ion mode. Deviations in the intra- and inter-day precision were always below 0.6% and 0.3% for recoveries and retention time. Intra- and inter-day relative standard deviation (RSD) values of retention time for water- and fat-soluble vitamin were ranged between 0.02–0.20% and 0.01–0.15%, respectively. The mean recoveries were ranged between 88.95 and 107.07%. Sensitivity and specificity of this method allowed the limits of detection (LOD) and limits of quantitation (LOQ) of the analytes at ppb levels. The linear range was achieved for fat- and water-soluble vitamins at 100–1000 ppb and 10–100 ppb. Vitamin B-complex and vitamin E were detected as the principle vitamins in the root of this adaptogen which would be of great interest to develop novel foods from the Indian trans-Himalaya.     

Ionic Liquid–Mediated Synthesis of Coumarin-3-carboxylic Acids via Knoevenagel Condensation of Meldrum's Acid with ortho-Hydroxyaryl Aldehydes

A simple, efficient, and green protocol for synthesis of coumarin-3-carboxylic acids is described via Knoevenagel condensation of Meldrum's acid with ortho-hydroxyaryl aldehydes in [Hmim]Tfa ionic liquid, which was found to give better results than other ionic liquids. Furthermore, ionic liquid is easily reused without any appreciable loss in activity.     

Working group report: Low energy and flavour physics

This is a report of the low energy and flavour physics working group at WHEPP-8, held at the Indian Institute of Technology, Mumbai, India, during 5–16 January 2004.