Prostanoids: LXXVI. Synthesis and Specific Features of Reductive Dechlorination with the System Zn-NH4Cl-MeOH of Some 3-N-, O-, S-, Cl-, and Alkyl-substituted 2-Chloro-4,4-ethylenedioxycyclopent-2-en-1-ones Ozonolysis of 3-Caren-5-one

Reaction of a number of 3-N-, O-, S-, Cl-, and alkyl-substituted 2-chloro-4,4-ethylenedioxycyclopent-2-en-1-ones with Zn in NH4Cl-MeOH medium were investigated.The expected or partially transformed dehydrochlorination products were isolated. An exclusive chemical stability of 3N-containing cyclopentenones was disclosed. This phenomenon was understood as originating from stabilizing n-d-p-interaction of electrons belonging to heteroatoms in the planar C1(O)-C2(Cl)-C33(N) fragment contained in the molecules of the compounds.