Introduction of a clean and promising protocol for the synthesis of β-amino-acrylates and 1,4-benzoheterocycles: an emerging innovation

Abstract

A highly efficient, elegant and simple procedure with exceptionally mild conditions has been proposed for the synthesis of b-amino-acrylate derivatives and an array of biologically and pharmaceutically active benzoheterocycles. The protocol offers a valuable alternative to known methods and will find applications in the field of green synthesis. The regio-and stereo-chemistry of the products were established by IR, NMR and single crystal X-ray analysis.

Hydroamination Reactions of Alkynes with ortho‐Substituted Anilines in Ball Mills: Synthesis of Benzannulated N‐Heterocycles by a Cascade Reaction

“…From the literature, it is known that mixingo ft hose reagents with as patula on aP etri dish for less than 5min leads to the same result. [14] Beside this solventfree protocol, synthesis can be carried out in MeOH at room temperature, [30] in refluxing EtOH, [31] or in ice-coldE tOH. [32] Compound 4a is also available by cyclocondensation of 1g with methyl 3-hydroxy-4-oxo-4-(phenylamino)but-2-enoate.…”

“…However,asubsequent reaction during sample preparation by dissolution cannot be excluded, although the literature reports mainly water or alcohols as the preferred solvents. [34] Thef act that simple mixing of the reagents on aP etri dish results in almost quantitative yields after only af ew minutes [14] indicates that af ast andd irecta nalysis is required for the product mixtures,i deally withoutp retreatment (like extraction). The use of ATRF TIR spectroscopy is one option because no sample workup is necessary andt he time gap between sampling and measurement can be reduced to less than 40 s. The FTIR spectra of the products from the reactiono f1g and 2a or 2b contain several signals, which are suitable for semiquantitative analysiso ft he reaction progress.…”

“…It has also been demonstrated that simple mixing of electron-deficient alkynes with as patula is sufficient for the preparation of enamines based on aniline(s), morpholine, n-PrNH 2 ,o rp iperidine. [14] With respect to reproducibility, the advantages of ballm illing over mixingt he reaction with mortara nd pestle have been described already. [15] Application of K 2 HPO 4 as the catalyst allowed the hydroamination of succinimide andp hthalimide with similare lectron-deficient alkynes.…”

BF3·OEt2‐Mediated Synthesis of 2‐Arylthio‐ and (N‐Aryl‐2,5‐dioxopyrrolidin‐3‐yl)‐Substituted 1,4‐Benzoxazine Derivatives

“…[4] Among benzoheterocycles, 1,4benzoxazine derivatives exhibit a wide range of biological activities and act as vasodilator agents, [5] antagonists, [6] antibacterial agents, [7] and antipsychotic agents [8] and have also been used in the treatment of infections, diabetes, asthma, depression as well as neurodegenerative, autoimmune, inflammatory, and cardiovascular disorders. [10] These benzoxazine derivatives belong to two different reactive classes of compounds, namely vinylogous carbamates and lactones (Figure 1), which have been utilized for the synthesis of various biologically active novel molecules, such as pyrrole-fused benzoxazines, [11] 3-arylcoumarins, [11] 3-substituted 1,4-benzoxazines, [11] 2-amino-1,4-benzoxazines, [12] and 2-aryl-1,4-benzoxazines (Scheme 1). [10] These benzoxazine derivatives belong to two different reactive classes of compounds, namely vinylogous carbamates and lactones (Figure 1), which have been utilized for the synthesis of various biologically active novel molecules, such as pyrrole-fused benzoxazines, [11] 3-arylcoumarins, [11] 3-substituted 1,4-benzoxazines, [11] 2-amino-1,4-benzoxazines, [12] and 2-aryl-1,4-benzoxazines (Scheme 1).…”

“…[9] Recently, our group reported a simple and highly efficient protocol for the synthesis of various highly functionalized benzoxazine derivatives. [10] These benzoxazine derivatives belong to two different reactive classes of compounds, namely vinylogous carbamates and lactones (Figure 1), which have been utilized for the synthesis of various biologically active novel molecules, such as pyrrole-fused benzoxazines, [11] 3-arylcoumarins, [11] 3-substituted 1,4-benzoxazines, [11] 2-amino-1,4-benzoxazines, [12] and 2-aryl-1,4-benzoxazines (Scheme 1). [13] [a] Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India E-mail: rkpedfcy@iitr.ac.in ramakpeddinti@gmail.com http://faculty.iitr.ac.in/~rkpedfcy/ Supporting information and ORCID(s) from the author(s) for this article are available on the WWW under https://doi.org /10.1002/ejoc.201700407. promoter.…”