5‐Indolylidene‐2‐iminothiazolidin‐4‐ones – Convenient Starting Compounds for Stereoselective Synthesis of Novel Dispirooxindole Derivatives

Abstract

A convenient method for the synthesis of novel dispirooxindoles containing 2‐iminothiazolidin‐4‐one moiety has been proposed. The method relies on a 1,3‐dipolar cycloaddition of azomethine ylides generated in situ from paraformaldehyde and N‐alkyl amino acids including chiral ones to 5‐indolylidene‐2‐iminothiazolidin‐4‐ones. The method is suitable for preparing enantiomerically pure derivatives.

Design, synthesis andin vitroevaluation of the hybrids of oxindolylidene and imidazothiazolotriazine as efficient antiproliferative agents

“…In the 1 H NMR spectra of products 1a–w and 5a–z , a strong downfield shift of the indole H-4′ proton signals (8.79–8.89 and 8.26–8.86 ppm, respectively) was observed, which is characteristic of proximity of the carbonyl group C(7)O or C(8)O. 5,6 The homogeneity of compounds 1f–h , 1j , 1k , 1n , 1p , 1r , 1u–w and 5b , 5e , 5f , 5h , 5k , 5p , 5r , 5x–z was confirmed by powder X-ray diffraction. The results of the analysis of the experimental powder diffraction patterns of the compounds 1f–h , 1j , 1k , 1n , 1p , 1r , 1u–w and 5b , 5e , 5f , 5h , 5k , 5p , 5r , 5x–z showed that the investigated samples were single-phase.…”

A new reversible transformation of oxindolylidene derivatives of imidazothiazolotriazine into 3-[(imidazotriazin-3-yl)thio]-2-oxoquinoline-4-carboxylates

“…This indicates the Z -configuration of the exocyclic double bond. 5,6,9 In addition, there are a doublet and a doublet of doublets of the bridging CH protons in the region of 4.8–6.5 ppm and a doublet of the NH group proton at 6.9–7.8 ppm. In the 1 H NMR spectra of compounds 3 , the most downfield signal attributed to the quinoline H-5′ proton is observed at 7.46–7.64 ppm.…”

Diastereoselective Synthesis of Dispiro[Imidazothiazolotriazine-Pyrrolidin-Oxindoles] and Their Isomerization Pathways in Basic Medium

“…The starting dipolarophiles 9a,b and 10a,b were prepared according to a procedure described in the literature [30]. Amino acid 7e was prepared according to a procedure mentioned in the literature [40].…”