Microencapsulated Cu(acac)2: a recoverable and reusable polymer-supported copper catalyst for aziridination of olefins

Microencapsulated copper(II) acetylacetonate was prepared and used in the aziridination of alkenes employing [N-(p-tolylsulfonyl)imino]phenyliodinane (PhINTs) as the nitrogen source. Microencapsulated copper(II) acetylacetonate [MC-Cu(acac)₂] catalyst was reused for several cycles with consistent activity.     

Synthesis of cetyltrimethylammonium tribromide (CTMATB) and its application in the selective oxidation of sulfides to sulfoxides

The bright yellow crystalline cetyltrimethylammonium tribromide (CTMATB) reagent has been synthesized from the reaction of CTMAB and KBr with H₂MoO₄·H₂O, H₂O₂ and H₂SO₄ in the molar ratio 1:2:0.01:4:0.93. CTMATB selectively oxidizes a variety of dialkyl and alkyl aryl sulfides to the corresponding sulfoxides in high yields under mild conditions.     

Barbier coupling in water: SnCl2-mediated and Co(acac)2-catalyzed allylation of carbonyls

Co(acac)₂·2H₂O efficiently catalyzes SnCl₂-mediated Barbier coupling in water between carbonyls, including aromatic, aliphatic and α,β-unsaturated aldehydes, ketones, sugars and allyl bromide to afford the corresponding homoallylic alcohols in high yields. The catalyst was reused for several cycles with consistent activity.     

Coumarin derivatives as promising antibacterial agent(s)

Nowadays, bacterial infections epitomize significant health threats globally with an increased morbidity and mortality. Most contemporary antibacterial agents are resisted by pathogenic bacteria - the multidrug resistant (MDR) bacterial strains arising from cross resistances operative in natural bacterial consortia inside human body and in environments. Consequently, the development of newer potential drug candidate(s) is required against the broad spectrum of MDR bacteria. Indeed, the phytochemical coumarin and its derivatives had been reported with broad biological inhibitory properties, including antibacterial activities. In this review, several methods of synthetic strategies of coumarin derivatives as antibacterials were considered with individual schematic compounds by structure-activity relationship (SAR) studies as essential corollaries. Overall, substituents at positions C-3 and C-4 of coumarin are coveted for the development of newer antibacterial agents.     

X-Ray Crystal Structure and Photo Chemistry of N-Methyl-N-(1-phenylvinyl)benzamide

Abstract  

N-methyl-N-(1-phenylvinyl)benzamide (I) has empirical formula C₁₆H₁₅NO, crystallizes in the monoclinic space group, P21/n, with unit cell parameters a = 8.9101(2) ?, b = 15.1416(4) ?, c = 9.7737(2) ?, α = 90°, β = 109.3320(10)°, γ = 90°, Z = 4. Interestingly, the Compound (I) undergoes photocyclization upon irradiation of light to give two cyclic lactams (A and B) below 3100 ?. Compound (I) can be cyclized at either of two equivalent ortho positions. The mechanism for formation of lactam A may involve electrocyclic ring closure reaction upon irradiation of light to give six-membered cyclic zwitterionic intermediate. The ring proton rearranges via [1, 5]-H shift to give isomerized product A. The minor photoproduct B is supposed to be formed via photocyclization process followed by a loss of proton and the tautomerized product undergoes oxidation for the revival of aromaticity.     

Synthesis,X-ray Structure and Photo Chemistry of 2-(Methyl(1-Phenylvinyl)Carbamoyl)Phenyl Acetate

Abstract  

2-(Methyl(1-phenylvinyl)carbamoyl)phenyl acetate (SM), empirical formula C₁₈H₁₇NO₃, crystallizes in the triclinic space group, P−1, with unit cell parameters a = 9.10870(10) ?, b = 10.56940(10) ?, c = 16.1340(2) ?, α = 78.0590(10)°, β = 89.5080(10)°, γ = 86.6830(10)°, Z = 4. The 2-(methyl(1-phenylvinyl)carbamoyl)phenyl acetate (SM) molecule, upon irradiation of UV-light below 3,000 ?, releases acetate group to give six membered cyclic lactam 1 as the major product. The quantum yield for the lactam 1 was found to be 0.053. An alternate conrotatory 6-pi electron photochemically allowed electrocyclic ring closure reaction also occurs upon irradiation to give a six-membered cyclic zwitterionic intermediate which retains acetate as leaving group. A [1,5]-H shift would then give the isomerized product 2. The quantum yield for the lactam 2 was found to be 0.026. A minor oxidation product lactam 3 that retains the leaving group also formed, likely from loss of a proton and tautomerization of enol. The loss of one hydrogen molecule is the driving force for revival of aromaticity in the minor product 3. The quantum yield for the lactam 3 was found to be 0.012. The low value of total quantum yield (0.091) for photocyclization of SM can be explained as the photoproducts absorb light in competition with the photoreactant.