ChemInform Abstract: Cycloadditions with 2,2‐Dialkyl‐3‐thioxochroman‐4‐one S‐Sulfides Including an Unprecedented [3 + 5] Cycloaddition.

Abstract

1999 cycloaddition reactions cycloaddition reactions O 0070 22 -045 Cycloadditions with 2,2-Dialkyl-3-thioxochroman-4-one S-Sulfides Including an Unprecedented [3 + 5] Cycloaddition. -Acetyldisulfides (III) undergo a well-established conversion to intermediate thiosulfines (IV) which further react in a precedent fashion to give adducts (V), (VII), and (VIII). The formation of adducts (VI) is the result of an unprecedented concerted [3+5] addition of two sulfines (IV), where one molecule behaves as a 1,5-dipole and a second molecule as a 1,3-dipole. In the case of spiro derivative (IIIc) thiepane (IXc) is formed. The studied reactions of disulfides (III) show that minor variations of the substituents in the 2-position effect remarkable differences in the reaction pathway. -(EL-ESSAWY, FARAG A. G.; YASSIN, SALAH M.; EL-SAKKA, IBRAHIM A.; KHATTAB, AHMED F.; SOETOFTE, INGER; MADSEN, JOERGEN OEGAARD; SENNING, ALEXANDER; J. Org. Chem. 63 (1998) 26, 9840-9845; Dep. Appl. Chem., Tech. Univ. Den., DK-2800 Lyngby, Den.; EN)

Synthesis of New Chromeno[4,3‐b]pyrazolo[4,3‐e]pyridines Derivatives with Antimicrobial Evaluation

“…In addition, 1 H ‐pyrazolo[3,4‐ b ]pyridines comprise a very interesting class of compounds because of their significant and versatile biological and pharmacological activities, such as antimalarial , antiproliferative , antimicrobial , inhibition of cyclin‐dependent kinases , cardiovascular , antiviral , and antileishmanial activities . Our goal, in the past, and recent work is to synthesize a new heterocyclic compounds incorporating pyrazolo[3,4‐ b ]pyridine and 2,2‐disubstituted chromane‐4‐one derivatives . We reported here the development of tricyclic and tetracyclic ring systems from 2,2‐disubstituted chroman‐4‐one.…”