Synthesis of new spiro pyrrole/pyrrolizine/thiazole derivatives (3+2) cycloaddition reactions

• Published in: New journal of chemistry 2018-08, Vol.42 (16), p.13819-13827
• Main Authors: Mali, Prakash R, Khomane, Navnath B, Sridhar, B, Meshram, H. M, Likhar, Pravin R
• Format: Article
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c8nj02127a

A new series of spiro pyrrole/pyrrolizine/thiazole compounds have been synthesized using (3+2) dipolar cycloaddition via three-component condensation reactions of ninhydrin and α-amino acids with different dipolarophiles such as maleimide, malic anhydride, 2-benzyl-2-methylcyclopent-4-ene-1,3-dione and isothiocyanates. Another four-component protocol has been developed in which ninhydrin, proline, maleimide and phenacyl bromides are reacted to afford a novel library of pyrrolizine derivatives in good yields without the use of catalyst. An efficient one-pot multi-component protocol has been developed for the synthesis of novel spiro-fused pyrrole/pyrrolizine/thiazole derivatives using (3+2) cycloaddition reactions; all products were obtained in moderate to excellent yields and synthesized from commercially available starting materials.