Protic Ionic Liquids: Properties and Applications

Transition-Metal-Catalyzed C−S, C−Se, and C−Te Bond Formation via Cross-Coupling and Atom-Economic Addition Reactions

Organic Chemistry By Dr. I. L. Finar. Vol. 2: Stereochemistry and the Chemistry of Natural Products. Pp. xi + 733. (London and New York: Longmans, Green and Co., Ltd., 1956.) 40s. net.

Advanced Organic Chemistry

The copper(I)-catalyzed 1,2,3-triazole-forming reaction between azides and terminal alkynes has become the gold standard of 'click chemistry' due to its reliability, specificity, and biocompatibility. Applications of click chemistry are increasingly found in all aspects of drug discovery; they range from lead finding through combinatorial chemistry and target-templated in vitro chemistry, to proteomics and DNA research by using bioconjugation reactions. The triazole products are more than just passive linkers; they readily associate with biological targets, through hydrogen-bonding and dipole interactions. The present review will focus mainly on the recent literature for applications of this reaction in the field of medicinal chemistry, in particular on use of the 1,2,3-triazole moiety as pharmacophore.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/asia.201100432

Click Chemistry: 1,2,3‐Triazoles as Pharmacophores

3.1.2. Huisgen [3 + 2] Cycloaddition Reaction 6313 3.1.3. Claisen Rearrangement 6315 3.2. Multicomponent Reactions 6316 3.3. Nucleophilic Ring-Opening Reactions 6316 3.4. Wittig Reaction 6318 3.5. Bioorthogonal Reactions 6318 4. Catalyzed Reactions 6319 4.1. Metal-Catalyzed Reactions 6319 4.1.1. Pericyclic Reactions 6320 4.1.2. Arylation Reactions 6321 4.1.3. Olefin Metathesis 6323 4.1.4. Mizoroki-Heck Reaction 6324 4.1.5. Suzuki Reaction 6325 4.1.6. Sonogashira Reaction 6327 4.1.7. Transfer Hydrogenation 6327 4.1.8. Lewis Acid Catalysis 6328 4.2. Organocatalyzed Reactions 6330 4.2.1. Pericyclic Reactions 6330 4.2.2. Michael Reaction 6331 4.2.3. Mannich Reaction 6332 4.2.4. Aldol Reaction 6333 5. Conclusion 6334 6. Supporting Information Available 6335 7. References 6335

Water: Nature’s Reaction Enforcer—Comparative Effects for Organic Synthesis “In-Water” and “On-Water”

Natural Kaolinitic Clay and EPZG®: Efficient Solid Catalysts for Selective Regeneration of Carboxylic Acids from Their Corresponding Allyl or Cinnamyl Esters.

Substituted chroman-4-ones, a class of oxygen heterocycles are common among the natural products and are extensively used as synthetic intermediates I. They have been used to prepare various fused heterocyclic ring systems and have been used for a wide range of pharmacological activitl. Some chroman-4ones with medical use are khellin , a coronary vasodilator,4, chroman-4-one-2-carboxylic acids, a spasmolytic agent and disodium chromoglycate, and an antiallergenic drug 5. On the other hand, it is well known that a number of heterocyclic compounds containing nitrogen and sulfur exhibit a wide variety of biological activities. However, reports about selenium containing heterocycles are relatively Iess-, although some of them are used as chemotherapeutic agents; also some 1, 3, 4 and 1, 2, 3selenalthiadiazoles were found to possess significant antibacterial and antiviral activities. lo . The fused ring systems of chroman-4-ones are found to posses enhanced biological activities and the synthesis of the title heterocycles (selenadiazoles and thiadiazoles) is of growing interest, say, 1,2,3-selenal thiadiazole rings, worked out by Bhaskar Reddy el t ll -19 f db· a . use to car ocyclJc/heterocychc rings. Therefore, as a part of continuation of our work2o on chromone nucleus, it was thought to synthesize 1,2,3 selenalthiadiazoles fused to chroman-4-one.s.

Synthesis of Newer Selenadiazoles (II) and Thiadiazoles (III) from Their Chroman-4-one Precursors (I).

Microwave Induced Synthesis of 3-Methyl-4-[(chromon-3-yl)methylene]-1-phenylpyrazolin-5-(4H)-ones with Alumina Support and in Solvent-Free Conditions.

The described multicomponent cyclocondensation can be considered as green chemistry, since water is used as solvent.

Facile and Rapid Access to Poly Functionalized Pyridine Derivatives.

A thin layer chromatographic method with densitometric detection has been developed for determination of nicorandil, in the presence of its degradation products and impurities, in tablet formulations. Nicorandil tablet solution was subjected to stress tests under thermal, photolytic, hydrolytic, and oxidative conditions, to induce degradation of the drug. Nicorandil was separated from the degradation products on RP18 TLC plates by isocratic elution and was determined densitometrically. To assess the specificity of the method two dimensional chromatography was performed with a second mobile phase of different selectivity. Because no interference from degradation products was observed in the assay of nicorandil by the described method, it can be regarded as a stability-indicating method and can be used for analysis of stability study samples and routine quality-control samples. The method requires no sample pretreatment and is accurate (recovery = 100.20%), reproducible, rugged (intermediate precision, %RSD = 1.73; n = 18), and selective. The calibration plot for nicorandil was linear in the range 35 to 65 μg (70 to 130% of assay concentration).

Murlidhar S. Shingare

Papers

Natural Kaolinitic Clay and EPZG®: Efficient Solid Catalysts for Selective Regeneration of Carboxylic Acids from Their Corresponding Allyl or Cinnamyl Esters.

Synthesis of Newer Selenadiazoles (II) and Thiadiazoles (III) from Their Chroman-4-one Precursors (I).

Microwave Induced Synthesis of 3-Methyl-4-[(chromon-3-yl)methylene]-1-phenylpyrazolin-5-(4H)-ones with Alumina Support and in Solvent-Free Conditions.

Facile and Rapid Access to Poly Functionalized Pyridine Derivatives.

A stability-indicating thin-layer chromatographic and densitometric method for determination of nicorandil in tablet formulations