Diastereoselective Synthesis of Isoindole‐Fused Diazacyclooctaindenones from Spiro­chromenes through Domino Reactions with Aliphatic 1,2‐Diamines

Abstract

A diastereoselective synthesis of isoindole‐fused diazacyclooctaindenone derivatives has been accomplished through tandem ring‐opening and ring‐closing of spirochromene derivatives triggered by different aliphatic 1,2‐diamines. When ethanolic solutions of spirochromenes are refluxed with different aliphatic 1,2‐diamines such as 1,2‐ethylenediamine, (±)‐1,2‐propylenediamine and (±)‐trans‐1,2‐cyclohexanediamine, the isoindole‐fused eight‐membered heterocycles are formed in moderate to high yields within 5–15 min.

Ninhydrin Adducts as Valid Synthon in Organic Synthesis: A Review

“…Ninhydrin‐1,3‐indanedione adduct, 2‐hydroxy‐2,2′‐biindan‐1,1′,3,3′‐tetrone 32 (commonly known as tetrone), could be prepared in acetic acidvia condensation of ninhydrin 1 and 1,3‐indanedione 31 . The reaction of tetrones 32 with meta ‐and‐ para substituted phenols 2 afforded spirochromene derivatives 33 which in turn reacted with aliphatic 1,2‐diamines 6 to furnish isoindole fused eight‐membered heterocycles 34 (Scheme ) . Various aliphatic diamines such as 1,2‐ethylenediamine, (±)‐1,2‐propylenediamine, and (±)‐ trans ‐1,2‐cyclohexanediamines responded the reaction well resulting in the formation of structurally complex diastereoisomers.…”

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

“…SSA, a product that is easily synthesized from silica gel and chlorosulfonic acid [26], was observed to improve the reactivity and selectivity in carbon–carbon bond-formation reactions [27–28], in cycloaddition reactions [29–30], in protection–deprotection reactions of multistep syntheses [31–33], in esterifications [34] and in syntheses of heterocycles [35]. Since we are actively involved in the synthesis of biologically important heterocycles [36–42], we wish to report herein a green methodology for the construction of pyrrole-fused isocoumarins, which uses SSA as a solid-supported acid catalyst under solvent-free conditions (Scheme 1, present work).…”