Diastereoselective synthesis of fused [1,3]thiazolo[1,3]oxazins and [1,3]oxazino[2,3-b][1,3]benzothiazoles

Abstract

An efficient diastereoselective synthesis of 7-ethyl 5,6-dialkyl 7H-[1,3]thiazolo[2,3-b][1,3]oxazin-5,6, 7-tricarboxylates and 2-ethyl 3,4-dialkyl 2H-[1,3]oxazino [2,3-b][1,3]benzothiazole-2,3,4-tricarboxylates via reaction of thiazole and benzothiazole with dialkyl acetylenedicarboxylates in the presence of ethyl pyruvate is described.

Molecular Diversity of Three‐Component Reactions of N‐Benzylbenzimidazolium Salts, Isatin, and Malononitrile or Ethyl Cyanoacetate

“…[ It should be noted that isatins bearing 1-benzyl and 1-n-butyl groups gave relatively higher yields than those of other isatins due to the better solubility of the zwitterionic salts. The structures of prepared zwitterionic salts 2a-n were fully confirmed by 1 H NMR, 13 C NMR, and IR spectroscopy and HRMS and were further confirmed by single-crystal X-ray diffraction studies performed for compound 2e (Figure 1). The structures of prepared zwitterionic salts 2a-n were fully confirmed by 1 H NMR, 13 C NMR, and IR spectroscopy and HRMS and were further confirmed by single-crystal X-ray diffraction studies performed for compound 2e (Figure 1).…”

“…[1][2][3][4][5][6] Five-membered heterocyclic ammonium salts such as imidazolium salts have also attracted much attention [7][8][9] aside from their use as ionic liquids and precursors of N-heterocyclic carbenes. [10][11][12][13] Recently, we found that the one-pot reactions of N-benzylbenzimidazolium salts, aromatic aldehydes, and active methylene compounds gave a series of zwitterionic salts or functionalized pyrrolo[1,2-a]benzimidazoles in good yields. [10][11][12][13] Recently, we found that the one-pot reactions of N-benzylbenzimidazolium salts, aromatic aldehydes, and active methylene compounds gave a series of zwitterionic salts or functionalized pyrrolo[1,2-a]benzimidazoles in good yields.…”

Synthesis of Spiro Pyrrolobenzothiazole Derivatives via a Three‐Component Reaction

“…The 13 C NMR spectrum of 4a showed 20 distinct resonances in agreement with the proposed structure. In addition, product 4a displayed 13 C NMR resonances at δ = 50.25, 66.52, 68.19 and 88.71 ppm, respectively, for the O═C– C –C═O, N‐CH‐ C H‐CO 2 Me, N‐ C H‐CH‐CO 2 Me and S‐ C ‐N units . In the 13 C NMR spectrum, the five carbonyl groups were seen at δ = 150.99, 165.39, 167.81, 169.82, and 171.62 for the 2C═O amid and 2C═O ester.…”

A Novel Three-Component Reaction Involving Benzothiazole, Dialkyl Acethylenedicarboxylate and 1,3-Dicarbonyl Compounds or Anthrone

“…The residue was recrystallised from 2:1 n-hexane/EtOAc. 3.79 (3H, s, OMe), 6.63 (1H, s, N-C=CH-CO 2 Me), 6.63-7.97 (4H aro ). 13 …”

“…1,2 Some heterocyclic compounds containing a thiazole ring in their structures have important applications in pharmaceutical as well as in agrochemical chemistry. [3][4][5] Compounds with benzothiazole skeletons are of paramount interest because of their antitumour, anticancer, and antibacterial activities. [6][7][8][9][10] In addition, the benzothiazole nucleus is a key element in some thermally stable rigid-rod polymers, possessing high tensile strength and modulus.…”