Based on the regio and stereoselectivity of 1,3-dipolar cycloaddition reactions of nitrones to alkenes the book has focus on - regio and stereoselectivity synthesis of N-nucleosides by 1,3-dipolar cycloaddition of sugar-derived nitrones with N-arylmaleimides. - 1,3-Dipolar cycloaddition of N-ribosylnitrones and N-arylmalaimides affords anti-isoxazolidine. - A series of novel nitrones were prepared and isolated in a pure state, and they cycloadded to some allyl derivatives to give isoxazolidine derivatives and studied the stereoselectivity of their cycloaddition reactions. - Lewis acid (MgBr2.Et2O) was applied as a catalyst for 1,3-dipolar cycloaddition reactions and it highly effect the rate of cycloaddition reaction. - we studied also the biological activity of nitrone and isoxazolidine compounds.
The first part of the present review is devoted to the synthesis of 2-aroyl-3-aryl aziridines. Scientists are interested in these classes of heterocyclic compounds, first of all by their photochromic properties and high sensitivity towards UV-VIS irradiation. In addition, these compounds are interesting from the viewpoint of reactivity, chemo- and regio-selectivity, stereochemistry and many other. The last part is concerned with chemical behavior of 2-aroyl-3-aryl aziridines in numerous organic reactions including photochemical transformations, cycloadditions, rearrangements, regio- and stereo-selectivity, 1,3-diolar reaction, ring expansion, ring opening, deamination and other.
The Book entitled "Cycloaddition Reactions Using Greener Techniques and Applications" reports newly synthesized N-methyl & N-phenyl- -chloro nitrones from chlorohydrin and their cycloaddition reactions with different olefins, alkynes leading to the formation of regio and stereoselective cycloadducts following green chemistry methodologies. The book also reports about the synthesis of -chloro nitrone synthesized from dry distilled chloral and cycloaddition reactions leading to the formation of regio and stereoselective cycloadducts. Majority of the reactions have been carried out in water and under microwave irradiation. High yield of cycloadducts (both isoxazolidine and isoxazoline derivatives) have been reported compared with the reactions performed in conventional solvents and thereby applications of green chemistry methodology of nirone-cycloaddition reactions have been achieved. N-methyl & N-phenyl- -chloro nitrones have been also used successfully as potential oxidizing reagents for the synthesis of aldehyde and ketones with unexpected high yields and the side products of the reaction are also used as new dipolarophiles in the synthesis of spiro cycloadducts.
Due to growing number of bacterial strains acquiring resistance to the current arsenal of chemotherapeutic drugs, the search for novel anti bacterial agents continue to be a major area of research in many fronts.During the last decade,various groups have directed their efforts to synthesize various bioactive gamma-lactams. Modification of lactam ring has been playing a vital role in determining the bio-activities of these derivatives and so exploration of a novel methodology in a simple way is a pivotal focal point of research activity in bioorganic chemistry. Progress in the art of organic synthesis in the last decades has been achieved by marked advances in chemo-,regio-and stereoselective functional group transformations by using classical and newly developed reagents. The book entitled "Synthetic Studies on N-aryl- gamma-lactams" is an embodiment of research aimed at developing simple methodologies for selective functional group transformations of N-aryl- gamma-lactams and an effort towards the development of new synthetic strategies for conversion of N-aryl- gamma-lactams to substituted pyrrole and pyrroloquinoline derivatives.
The enamide moiety is an important substructure often encountered in biologically active compounds and synthetic drugs. Furthermore, enamides and their derivatives are versatile synthetic intermediates for polymerization, [4+2] cycloaddition, crosscoupling, Heck-olefinination, Halogenation, enantioselective addition or asymmetric hydrogenation. Traditional syntheses of this important substrate class involve rather harsh reaction conditions such as high temperatures and/or the use of strong bases. Based on previous work on the addition of secondary amides to alkynes, a new broadly applicable protocol for the catalytic addition of N-nucleophiles such as primary amides, imides and thioamides to terminal alkynes was developed. The choice of ligands and additives determines the regiochemical outcome so that with two complementary catalyst systems, both the E-anti-Markovnikov products and the Z-anti-Markovnikov products can be synthesized highly regio- and stereoselectively.
The administration of chiral compounds in an enantiomerically pure form, instead of racemic mixtures, become an important issue especially in the pharmaceutical and agrochemical industries due to the well established correlation between the biological activity and stereochemistry. Pure enantiomers could be formed by the asymmetric synthesis and /or the resolution of racemates. This could be achieved by the use of enzymes as chiral catalysts. The advantages of enzymes are their high stereo- (chiral), regio- (positional) and chemo- (functional group specific) selectivity. This selectivity offers several benefits like high catalytic efficiency, preservation of asymmetric centres, single step transformations, easier separation, mild operating conditions and fewer environmental problems. The organic reactions that are catalyzed by enzymes to give chiral bioactive organic compounds include, for example, reduction (e.g. by dehydrogenases, ketoreductases), oxidation (e.g. by monooxygenases, dioxygenases), hydrolytic (e.g. by lipases, esterases) reactions.
High Quality Content by WIKIPEDIA articles! The Italian Co-Belligerent Army, or the Army of the South was the army of the Italian Royalist forces fighting on the side of the Allies during World War II. The Italian Co-Belligerent Army was formed in southern Italy after the Allied armistice with Italy was declared on September 8, 1943. The Italians soldiers of the Co-Belligerent Army no longer fought for Italian dictator Benito Mussolini or for the Axis. Their allegiance was to the Allies, to King Victor Emmanuel and to Marshal of Italy (Maresciallo d'Italia) Pietro Badoglio. The King and Badoglio were the men who ousted Mussolini and who created what was known as the "Badoglio government." In many regards, the Italian Co-Belligerent Army was a reorganized version of the Italian Royal Army (Regio Esercito)
El Círculo Theater (in Spanish, Teatro El Círculo) is a theater in Rosario, Argentina.It is located near the historical center of the city, at the intersection of Laprida and Mendoza Streets. Planned as a lyric theater, it was developed as Teatro La Ópera by Emilio O. Schiffner, who purchased the society of the same name in 1889. Schiffner contracted German engineer George Goldammer, an acoustician who modified the original design, and the construction firm of Bianchi, Vila y Compañía. Following delays caused by the Panic of 1890, as well as the earlier society's debts, the theatre was started in 1903. Italian artists, directed by Luggi Levoni, decorated both the interiors and exteriors, among their notable creations was the stage curtain designed by Giuseppe Carmignani with images from Greek mythology similar to those found in the Teatro Regio di Parma.
Homoallylic alcohols and amines are fundamental building blocks for many biologically active compounds. The allylation of carbonyl compounds with allyl organometallic reagents constitutes a simple and straight forward approach for their synthesis. Allyl indium reagents have emerged as a reagent of choice for allylation of carbonyl compounds under both aqueous and non-aqueous conditions. However, in application of this approach for the synthesis of homoallylic alcohols/ amines from ketones/ imines, the lower electrophilicity of ketone/imine carbon makes the transfer of allyl group to ketone/imine carbon much more challenging. The ease of hydrolysis of imine to carbonyl compound and amine further add to the difficulties. The present work is aimed to unravel the regio- and diastereochemical aspects in indium mediated allylation of ketones bearing proton donor groups (OH, COOH) alpha to carbonyl moiety and imines derived from heterocycles like pyridine-2-imines, quinoline-2-imines and indole-3-imines. In selected cases the homoallylic alcohols have been subjected to iodine mediated cyclization to provide 2,3-diaryltetrahydrofuran and 3-hydroxy-3,4-dihydrofuran-2(5H)-one derivatives.