Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Intramolecular ring closure of anhydrides IIa-IIc, under conditions of the Friedel-Crafts reaction, gave 6-carboxy derivatives III-V. Esterification of the acid V by the chloride method led to esters VI and VII. Reaction of the ester VI with hydrazine gave rise to compound XXI, having a pentacyclic structure. Alkylation or acylation of the 5-hydroxy group in compounds Ia-Ic with alkyl halides or acyl chlorides afforded compounds VIII-XIII and XVIII. Compound XI was also formed as a by-product in the Friedel-Crafts reaction of compound Ic with acetyl chloride in 1,2-dichloroethane, in addition to the 6-acetyl derivative XV. An analogous reaction of Ic with dichloracetyl chloride gave compound XIV as a sole product. Substitution reactions on the 7-oxo group in Ic afforded semicarbazone XVI and thiosemicarbazone XVII, and reaction of the compound XVIII with hydroxylamine hydrochloride gave the oxime XIX. The action of N-methylolchloracetamide on Ia in sulphuric acid produced compound XX. The compounds prepared proved to have no antineoplastic effects. In tests for activity against the viruses of vaccinia and encephalomyocarditis they proved to be weaker than Tiloron as control. In assessing the efficacy against influenza virus A2 Singapore compound V exhibited the same effect as Tiloron.