Usama Karama

An efficient synthesis of highly functionalized novel chromeno[4,3-b]pyrroles and indolizino[6,7-b]indoles as potent antimicrobial and antioxidant agents

A facile and efficient synthesis of novel chromeno[4,3-b]pyrroles has been accomplished by intramolecular 1,3-dipolar cycloaddition which on subsequent Pictet-Spengler cyclisation in presence of p-toluenesulfonic acid yielded indolizino[6,7-b]indoles. The synthesized chromenopyrroles and indolizinoindoles were evaluated for their antimicrobial and antioxidant activities. Compounds 7b, 7e, 7a and 7d exhibited respectively, good antibacterial and antifungal activities against tested pathogens when compared to reference control.

A Facile One-Pot Synthesis of α-Bromo-α,β-unsaturated Esters from Alcohols

Treatment of N-bromosuccinimide (NBS) with (carboethoxymethylene) triphenylphosphorane (1) in CH2Cl2 followed by the addition of an alcohol in the presence of manganese dioxide under ultrasonic irradiation constitutes a stereoselective one-pot procedure for the preparation of Z-configured α–bromo-α,β-unsaturated esters in good to excellent yield.

An Expedient Regio- and Diastereoselective Synthesis of Hybrid Frameworks with Embedded Spiro[9,10]dihydroanthracene [9,3′]-pyrrolidine and Spiro[oxindole-3,2′-pyrrolidine] Motifs via an Ionic Liquid-Mediated Multicomponent Reaction

A series of hitherto unreported anthracene-embedded dispirooxindoles has been synthesized via a one-pot three-component 1,3-dipolar cycloaddition reaction of an azomethine ylide, generated in situ from the reaction of isatin and sarcosine to 10-benzylideneanthracen-9(10H)-one as a dipolarophile in 1-butyl-3-methylimidazolium bromide([bmim]Br), an ionic liquid. This reaction proceeded regio- and diastereoselectively, in good to excellent yields.

One-Pot Approach to the Conversion of Alcohols into α-Iodo-α,β-unsaturated Esters

(Carboethoxymethylene)triphenylphosphorane 1 can undergo the tandem reaction of iodination–oxidation–Wittig reaction with alcohol in the presence of N-iodosuccinimide (NIS) and manganese dioxide. The reaction constitutes a stereoselective one-pot procedure for the preparation of Z-configured α-iodo-α,β-unsaturated esters in good to excellent yield.

Synthesis of 2-(9,10-Dihydro-9,10-propanoanthracen-9-yl)-N- methylethanamine via a (4+2) Cycloaddition

The synthesis of the tetracyclic molecule 2-(9,10-dihydro-9,10-propano-anthracen-9-yl)-N-methylethanamine (2) as a homologue of the antidepressant 1-(9,10-dihydro-9,10-ethanoanthracen-9-yl)-N-methylmethaneamine (1) was described. The key intermediate 9-(prop-2-en-1-yl)-9,10-dihydro-9,10-propanoanthracen-12-one (7) was successfully synthesized via a [4+2] cycloaddition of α-bromoacrolein and 9-allyl-anthracene, followed by ring expansion and samarium diiodide deoxygenation.

Synthesis of Chlorinated Tetracyclic Compounds and Testing for Their Potential Antidepressant Effect in Mice

The synthesis of the tetracyclic compounds 1-(4,5-dichloro-9,10-dihydro-9,10-ethanoanthracen-11-yl)-N-methylmethanamine (5) and 1-(1,8-dichloro-9,10-dihydro-9,10-ethanoanthracen-11-yl)-N-methylmethanamine (6) as a homologue of the anxiolytic and antidepressant drugs benzoctamine and maprotiline were described. The key intermediate aldehydes (3) and (4) were successfully synthesized via a [4 + 2] cycloaddition between acrolein and 1,8-dichloroanthracene. The synthesized compounds were investigated for antidepressant activity using the forced swimming test. Compounds (5), (6) and (3) showed significant reduction in the mice immobility indicating significant antidepressant effects. These compounds significantly reduced the immobility times at a dose 80 mg/kg by 84.0%, 86.7% and 71.1% respectively.

One-Pot Combination of the Wittig Olefination with Bromination and Oxidation Reactions

Abstract A simple one-pot process for in situ bromination of (ethoxycarbonylmethylene)-triphenylphosphorane 1 was carried out. This was followed by oxidation of alcohol using SO3. Pyridine complex as a mild oxidant and in situ trapping of the aldehyde. This process constitutes a stereoselective one-pot procedure for the preparation of Z-configured α-bromo-α, β-unsaturated esters in good yield. GRAPHICAL ABSTRACT

9-(Pent-4-en-yl)anthracene.

In the title compound, C19H18, the anthracene system is almost planar, with a maximum deviation of −0.039 (1) Å. The structure is stabilized by C—H⋯π interactions. The pentene moiety is not planar and is twisted away from the attached anthracene system with a maximum torsion angle of 91.2 (1)°.

One-pot synthesis of (E)-α-chloro-α,β-unsaturated esters

Chlorination of a phosphonate anion derived in situ from methyl bis(2,2,2-trifluoroethoxy)phosphonoacetate 2 followed by the addition of aldehydes constitutes a stereoselective single flask procedure for the preparation of E-configured α-chloro-α,β-unsaturated esters.

Synthesis of bishomobenzoctamine 2-19,10-dihydro-9,10-propanoanthracen-9-yl)-N-methylethanamine

Tetracyclic bishomobenzoctamine as a homologue of benzoctamine 1 was synthesised. The key intermediate 9-(prop-2-en-1-yl)-9,10-dihydro-9,10-propanoanthracen-12-one was successfully synthesised via [3+4] cycloaddition of tetrabromoacetone on 9-allylanthracene by using ultrasonication at 15–20 °C followed by debromination.