Fused and spiro nitrogen heterocycles of quinuclidine and its C-nucleosides

Quinuclidin-3-one (1) was used as a versatile intermediate for the synthesis of fused and spiro quinuclidine and its C-nucleosides. The reaction of 1 with formalin and secondary amines namely; morpholine, piperidine, and piperazine afforded the corresponding Mannich bases 2-4 in acid medium. Quinuclidino[3,2-b]pyran 5 has been synthesized via a selective cyclocondensation reaction between Mannich base of quinuclidinone hydrochloride 2 and malononitrile. The transformation of 1 with formalin and methylamine in molar ratio (1:20:2) afforded the spiro compound 7. Ring expansion of 2 under Schmidt reaction conditions gave the 1,3-diazabicyclo[3.2.2]nonanone derivative 6. Eventually, the synthesis of C-nucleosides 10, 12-14 were achieved by using aldohexoses and aldopentose catalyzed by zinc chloride, while, the bis-quinuclidine derivative 15 was obtained by using sodium carbonate. Newly synthesized compounds were characterized by IR, 1H NMR, and mass spectral data

Peculiar reaction behavior of 1,3-oxathiolan-5-one toward various reagents: Molecular modeling studies and in vitro antioxidant and cytotoxicity evaluation

<p>Chemical reactivity of 2-methyl-2-phenyl-1,3-oxathiolan-5-one (<b>1</b>) toward various reagents such as hydroxyaldehyde, ketone, α,β unsaturated carbonyl compounds, heterocyclic amine, hydrazine, and hydrazide to give unpredicative opened and fused heterocyclic systems was investigated. Moreover, treatment of compound <b>1</b> with bromoester to afford the respective fused system, 2-methyl-2-phenylfuro[3,2-d][1,3]oxathiol-5(6<i>H</i>)-one (<b>6</b>) was implemented. Besides, ¹H–¹H nuclear overhauser effect spectroscopy was used for full confirmation of the compound <b>19</b>. In addition, the density functional theory modeling study outcomes were discussed and all of the new synthesized compounds were evaluated as antioxidants and cytotoxicity assay against hepatocellular carcinoma cell line.</p

Convenient synthesis, antimicrobial evaluation and molecular modeling of some novel quinoline derivatives

<p><i>α, β</i>-Unsaturated carbonyl compounds <b>2a, 2b, 3,</b> and <b>4</b> were synthesized by the Knoevenagel condensation between 2-substituted quionoline-3-carboxaldehyde <b>1a</b> and/or <b>1b</b> with active methylene compounds. In addition, the synthesis of azlactone is achieved starting from <b>1a</b> and <i>N</i>-acetylglycine. Synthesis of pyridine, pyrene, and pyrimidine derivatives <b>6</b>–<b>8</b> were accomplished via one-pot multicomponent reaction of <b>1b</b> with acetyl acetone, malononitrile, and ammonium acetate; acetophenone, malononitrile, and NaOH; or acetyl acetone and urea in acidic medium. The new synthesized compounds showed good antimicrobial activities. The DFT calculations have been used to predict the electronic properties of the studied compounds.</p