Synthesis of 5,5′-Dinitro- and 5,5′-Diaminobis(cyclopenta[<i>b</i>]indoles) Bound at <i>N</i>⁴,<i>N</i>^4′ Atoms with a Dioxoalkane Spacer

Abstract

Upon condensation of 2 equiv. of 3R*,3aR*,8bS*-3-iodo-7-methyl-1,2,3,3а,4,8b-hexahydrocyclopenta[b]indole with 1 equiv. of glutaric or decanedicarboxylic acid dichloranhydride [N4,N4′-di-(3R*,3aR*,8bS*,3′R*,3a′R*,8b′S*)- and N4,N4′-di-(3aR*,3aR*,8bS*,3′S*,3a′S*,8b′R*)-3-iodo-7-methyl-1,2,3,3а,4,8b-hexahydrocyclopenta[b]indolyl]alkanediamides were synthesized. Their didehydrohalogenation to 3aR*,8bR*,3a′R*,8b′R*- and 3aS*,8bS*,3a′R*,8b′R*-1,3a,4,8b-tetrahydroanalogues was carried out by boiling these diiodides in piperidine. The presence of rotamerism in the products of dehydrohalogenation was shown, which is manifested by doubling the signals in the NMR spectra in different ratios. Nitration with trifluoroacetyl nitrate in CH2Cl2 yielded their 5,5′-dinitro analogs, which, when reacted with freshly prepared Fe(OH)2, along with 5,5′-diamino derivatives, also formed 5-amino-5′-nitro-substituted products of incomplete reduction. When a nitro group or an amino group appears at the C5 and C5′ carbon atoms of the cyclopenta[b]indole fragments, the doubling of the signals in the NMR spectra disappears. The interaction of a 5,5′-diamino derivative (n = 8) with decanedicarboxylic acid dichloride yielded a compound with 30 atoms in the macrocyclic ring.