Willgerodt-Kindler reaction at room temperature: Synthesis of thioamides from aromatic aldehydes and cyclic secondary amines
作者:Arun D. Kale、Yogesh A. Tayade、Sachin D. Mahale、Rahul D. Patil、Dipak S. Dalal
DOI:10.1016/j.tet.2019.130575
日期:2019.10
out Willgerodt-Kindlerreaction of aromatic aldehydes at room temperature. At 120 °C, it is catalyst free reaction with lower reaction time whereas at room temperature, due to the additional amine molecule, Willgerodt-Kindlerreaction of aromatic aldehydes is successfully carried out at room temperature. On gram-scale, the reaction is successfully attempted under both conditions with good yields.
Leveraging the Domino Skeletal Expansion of Thia-/Selenazolidinones via Nitrogen-Atom Transfer in Hexafluoroisopropanol: Room Temperature Access to Six-Membered S/Se,N-Heterocycles
作者:Vandana Jaiswal、Mangilal Godara、Dinabandhu Das、Vincent Gandon、Jaideep Saha
DOI:10.1021/acs.joc.1c02621
日期:2022.1.7
Herein, a highly regioselective domino skeletal-expansion process that transforms 2-aminothiazolidinone into six-membered S,N-heterocycle is developed with the aid of TMS-azide in hexafluoroisopropanol (HFIP) at ambient temperature. Functioning of the C2 tertiaryamine as latent reactive group on thiazolidinone moiety was the key to this development, which allowed relay substitution with azide and
analysis showed that N-thiobenzoyl-7-azabicyclo[2.2.1]heptane displays marked nonplanarity of the thioamide (1a, alpha = 167.1 degrees and |tau| = 11.2 degrees) as compared with the corresponding monocyclic pyrrolidine thioamide (2a, alpha = 174.7 degrees and |tau| = 3.9 degrees). In a series of para-substituted or unsubstituted thioaroyl-7-azabicyclo[2.2.1]heptanes (1a-1h), the planarity of the thioamide
X射线晶体学分析表明,与相应的单环吡咯烷硫代酰胺(1a,α= 167.1度和| tau | = 11.2度)相比,N-硫代苯甲酰基-7-氮杂双环[2.2.1]庚烷显示出明显的非平面度(1a,α= 167.1度和| tau | = 11.2度)。在图2a中,alpha = 174.7度,| tau | = 3.9度。在一系列对位取代或未取代的硫代芳酰基-7-氮杂双环[2.2.1]庚烷(1a-1h)中,硫代酰胺的平面度显着取决于取代基的电子性质。例如,在对硝基取代的化合物中,基本上恢复了平面度(1h,α= 175.2度,|τ| = 0.1度)。在溶液中,芳族取代基的吸电子特性增加与双环硫代酰胺的更大的旋转势垒有关,通过变温(1)H NMR光谱法和线形分析法测定。硝基苯-d5中1a的旋转势垒降低,即硫酰胺旋转的活化焓(DeltaH(双匕首))降低,与2a在硝基苯-d5中的降低相比,这与1a假定溶