¹H and ¹³C NMR assignments and X‐ray structures for three monocyclic benzoannelated dilactam polyethers

Abstract

Three monocyclic polyether dilactams, 17,18-dihydro-5H, 9H-dibenzo[e,n]1,4,10,7,13trioxadiazacyclopentadecine-6,10(7H,11H)-dione (1); 9,10,20,21-tetrahydro-5H, 12H-dibenzo[e,q]1,4,10,13,7,16tetraoxadiazacyclooctadecine-6, 13(7H,14H)-dione (2); and 6,7,9,10-tetrahydro-16H, 20H-dibenzo[h,q]1,4,7,13, 10,16tetraoxadiazacyclooctadecine-17, 21(18H,22H)-dione (3) were isolated during the synthesis of several benzoannelated cryptands. The complete assignments of the 1H and 13C NMR spectra of 1, 2 and 3 in CDCl3 were made using gCOSY, gHMBC, gHMQC, HMQC, HSQC, and NOESY 1D techniques. The ortho (H2) benzene protons show significant downfield shifts (1.16-1.43 ppm) that are consistent with an exodentate orientation for the amide carbonyl groups. The X-ray crystal structures of 1, 2 and 3 show that the carbonyl groups adopt an exodentate conformation in the solid state.

Three related benzoannelated diazapolyether macrocycles: effects of macrocycle ring size and position of benzo groups on hydrogen bonding of the amine H atoms

“…Monocyclic diamines (I), (II) and (III) were prepared by condensation of the appropriate ,3-polyoxadianiline with the corresponding diacid chloride ether under high-dilution conditions (Dietrich et al, 1973) according to reported methods (Lockhart & Thompson, 1977;Aguilar et al, 2001;Formanovskii & Murakhovskaya, 1985;Formanovskii et al, 1988;Crossley et al, 1994). The resulting dilactams were puri®ed by recrystallization from ethanol [for (I) and (II)] or benzene/toluene [for (III)] (Smith et al, 2006). Reduction of the dilactams using BH 3 in THF and subsequent work-up (Smith et al, 1986(Smith et al, , 1988 gave the title compounds.…”

6,7,9,10-Tetrahydro-16,22-ethanooxyethano-5,8,11,19-tetraoxa-16,22-diazadibenzo[h,q]cyclooctadecine-17,21-dione: a benzylannelated macrobicyclic diamide

“…In this conformation the distances between protons H2 and H20 and the carbonyl O atoms (O5 and O7) are 3.70Å and 3.80 Å, respectively. In the solid-state structure of the analogous monocyclic diamide (i.e., donor atoms N1, O1, O2, O3, N2, O6), each amide group and adjacent benzene ring are nearly co-planar (dihedral angles = 14.3 (2)°, 17.1 (2)°) and the distances between protons analogous to H2 and H20 to the adjacent carbonyl O atoms are between 2.29Å and 2.40Å (Smith et al, 2006). In CDCl 3 , the 1 H chemical shift values of the aromatic protons of (I) lie in the expected range from 6.96 -7.25 p.p.m.…”