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A simple and efficient methodology for the synthesis of a small library of substituted indolizines with different degrees of saturation starting from the racemic 2-formyl-1,4-DHP reagent is presented. The main step of the sequential reaction was based on the highly diastereoselective tandem Michael addition/intramolecular amino-nitrile cyclization catalyzed by an organic base, which produced 1,7-dihydroindolizines in a diastereoselective manner.

Research has been conducted on the ring closure reactions. Results indicate that these reactions proceed via a nicleophilic attack of the electron pi-aromatic or the lone sulfur atom pair onto the endo- or exocyclic N-acyliminium ions generated from the omega-carbinol lactams under acidic conditions.

Iron‐based catalysts were applied in cascade‐type reactions for the synthesis of different carbonyl compounds. The reactions proceeded by a new iron‐catalyzed cascade of alkynylation/hydration by using both the σ‐ and π‐Lewis acid properties of iron salts. The alkynylation reactions of several endo and exocyclic acetoxylactams were achieved with three different catalysts including FeCl3 ⋅ 6H2O, FeCl3, and Fe(OTf)3 showing the efficiency of σ‐Lewis acidity of iron (III) salts in catalyzing the alkynylation reaction. We also demonstrated that the reaction sequence could be shortened by the direct use of hydroxylactams, leading to an environmentally friendly protocol, avoiding the need to perform unnecessary lengthy steps. A combination of the hard/soft iron Lewis acid properties was then used to implement an unprecedented tandem intermolecular alkynylation/intramolecular hydration sequence allowing expedient access to a new carbonyl structures from trivial materials. [ABSTRACT FROM AUTHOR]

A new and highly diastereoselective tandem reaction aza-Michael/intramolecular nucleophilic substitution and the synthesis of the tricyclic core of (+-)-martinelline alkaloids are described. The unprecedented tandem reaction between N-substituted [alpha]-bromoacetamides and Michael has provided the corresponding trisubstituted [gamma]-lactam systems.

A novel domino N-amidoacylation/aldol-type condensation followed by decarboxylation of the ester function was used to perform the pot, atom and step-economic synthesis of rosettacin topo-I poison and its derivatives. The key step in the process involves mixing HOBt ester as new reagent with lactam and NaH together in THF or THF/DMF which yields moderate to good N-heterocyclic products.

A catalytic amount of bismuth triflate (Bi[(OTf).sub.3]) was used to study intermolecular [alpha]-amidoalkylation of various [alpha]-acetoxy lactams with C-nucleophiles. The results compared with classical Lewis acids as catalysts showed that the use of bismuth(II) triflate is very efficient for nearly all [alpha]-acetoxy lactams utilized, except for N-acyliminium precursors bearing a sulfur atom.

A description of a simple and efficient four-step methodology for the synthesis of 4,5-fused imidazolidin-2-on3 from bicyclic and tricyclic ketones is provided. The process seems to be easy, general, regiospecific, resulted in the formation of polyheterocyclic systems containing an imidazolidin-2-one nucleus in good to excellent yields, and is compatible with a large-scale production.

(R)- and (S)-Alpha-phenylethylamine (Alpha-PEA: 7) is used seperately to resolve successfully a racemate 2-formyl-1,4-DHP derivative 4. It is recognized that the absolute configuration at the C(sub 4) position of the 1,4-DHP nucleus is indispensable for activity modulation.

Objectives This work describes the phytochemical and biological investigation of the Tunisian Atriplex inflata F. Muell (Chenopodiaceae). Methods Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including 1D NMR and 2D NMR, ESI- HRMS and comparison with available literature data. The isolates were evaluated for their antioxidant activity by the DPPH•, ABTS+•, Fe3+ and catalase assays and also for their antibacterial and anticholinesterase activity. Key findings The chemical study of Atriplex inflata F. Muell led to the isolation of two fatty acids (9 E)-methyl-8,11,12-trihydroxyoctadec-9-enoate 1 and (9 E)-8,11,12-trihydroxyoctadecenoic acid 2 together with ( Z)-litchiol B 3 and 20-hydroxyecdysone 4. Three of which are reported here for the first time in Atriplex genus. Based on the biosynthesis of hydroxylated arachidonic acid and derivatives, a plausible biogenesis pathway of the two fatty acids ( 1 and 2) was proposed. (Z)-litchiol B ( 3) was found to be the most active against Staphylococcus aureus. According to the literature, this is the first time that compounds 1, 2 and 3 were tested for their eventual biological activity. Conclusions In the results of the present work, we have proposed the biogenesis pathway of unsaturated fatty acid and described the structure-activity relationship. [ABSTRACT FROM AUTHOR]

The article presents chemical equations for the article "Impact of Functional Groups on the Copper-Initiated N-Arylation of 5-Functionalized Pyrrolidin-2-ones and Their Vinylogues" by D. Baudelet and others published in "Synthesis" in 2016.