Hypervalent Iodine in the Synthesis of Bridgehead Heterocycles: A Facile Route to the Synthesis of 6‐Arylimidazo[2,1‐b]thiazoles Using [Hydroxy(tosyloxy)iodo]benzene

α‐Tosyloxyketones (2), readily accessible through hypervalent iodine oxidation of enolizable ketones (1) using [hydroxy(tosyloxy)iodo]benzene (HTIB) in acetonitrile, exclusively generates the 6‐arylimidazo[2,1‐b]thiazoles (4) on treatment with commercially available 2‐aminothiazole (3).     

Transfer Hydrogenation of Nitriles with 2-Propanol and Raney® Nickel

Abstract

Raney nickel in refluxing 2-propanol containing 2% KOH is an effective catalytic system for reducing nitriles to amines.     

Simplified Approach to the Uncatalyzed Knoevenagel Condensation and Michael Addition Reactions in Water using Microwave Irradiation

Use of microwave irradiation in the synthesis of arylidenemalononitrile and benzopyran derivatives in water without catalyst is a clean method with high yield.     

Synthesis of Novel Spiro[indol-2,2′-pyrroles] Using Isocyanide-Based Multicomponent Reaction

An efficient and facile method for the synthesis of novel spiro[indole-2,2′-pyrroles] from N-methyl-3-isatin imines, t-butyl isocyanide, and dialkyl acetylenedicarboxylate has been achieved by [3 + 2] cyclo addition reaction. All the products were purified by column chromatography as yellow solids and confirmed with ¹H NMR, ¹³C NMR, fast atom bombardment, mass, and infrared. Compound 11 was further confirmed with x-ray analysis.     

Lanthanide Triflate Catalyzed One-Pot Synthesis of Dihydropyrimidin-2(1H)-thiones by a Three-Component of 1,3-Dicarbonyl Compounds,Aldehydes, and Thiourea Using a Solvent-Free Biginelli Condensation

Abstract

Novel one-pot Biginelli-type reaction has been developed. Aromatic and aliphatic aldehydes with β-dicarbonyl compounds and thiourea in the presence of catalytic amount 5 mol% of Yb(OTf)₃ at 100° C for 60–90 min under solvent-free conditions proceeded smoothly to afford corresponding dihydropyrimidin-thiones. The yields of the classical Biginelli reaction can be increased from 20–50% to 81–91% while the reaction time was shortened from 18–48 h to 60–90 min. In addition the catalyst can be easily recovered and reused.     

Alkylation of 3‐Phenyl‐1H‐pyrazolo[4,3‐c] quinoline: Theoretical Analysis of Regioselectivity

The interaction of 3‐phenyl‐1H‐pyrazolo[4.3‐c]quinoline with alkylating agents in the presence of NaH leads mainly to N1‐substituted derivatives. The regioselectivity of the reaction has been studied using AM1 semi‐empirical calculations in the isolated molecule approximation.     

The Palladium Catalyzed Hydrostannation of 1-Alkenylphosphonates: A New Approach to Stereodefined α,β-Disubstituted Vinylphosphonates

Abstract

The palladium catalyzed hydrostannation of 1-alkenylphosphonates gives the (E)-α-stannyl 1-alkenylphosphonates 2 stereospecifically. 2 can be transferred to α,β-disubstituted vinylphosphonates with the retention of the configuration.     

Synthesis of Metal‐Free Phthalocyanines in Functionalized Ammonium Ionic Liquids

A convenient, fast, efficient, and ecofriendly synthesis of metal‐free phthalocyanines from various substituted phthalonitriles in different hydroxyalkylammonium ionic liquids in the presence of 1,8‐diazabicyclo‐[5,4,0]‐undec‐7‐ene (DBU) is reported in moderate yields. The effect of concentration of DBU and temperature on the synthesis of phthalocyanine in N‐(2‐hydroxyethyl)‐N,N‐dimethylbutylammonium bromide ionic liquid has been examined, and the ionic liquid has been recovered and reused conveniently.     

Synthesis of an o-Nitrobenzyl Attached A1 Adenosine Receptor Antagonist,a Prodrug Approach

Abstract

The o-nitrobenzyl group, possessing distinct advantage of being photolabile under mild conditions, was successfully connected to 8-(5,6-epoxynorbornan-2-yl)-1,3-dipropylxanthine (5), a high specific A₁ adenosine receptor antagonist. The resulting compound 4 would have potential use as a prodrug.     

Chemoselective Removal of Acyloxy in 1-(Benzotriazole-1-yl)alkyl Esters and Its Application in the Preparation of β-(Benzotriazole-1-yl)alcohols

Mediated by samarium diiodide, 1-(benzotriazole-1-yl)alkyl esters 1 underwent cross-coupling with aldehydes or ketones to afford β-(benzotriazole-1-yl)alcohols 2 exclusively with the selective removal of acyloxy over benzotriazolyl.