title: 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.
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA.
authors.forename: Gary L N
authors.initials: GL
authors.lastname: Smith
authors.forename: Susan S
authors.initials: SS
authors.lastname: Alguindigue
authors.forename: Masood A
authors.initials: MA
authors.lastname: Khan
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Powell
authors.forename: Richard W
authors.initials: RW
authors.lastname: Taylor
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis; D018360:Crystallography, X-Ray; D004987:Ethers / Q000737:chemistry; D004988:Ethers, Cyclic / Q000737:chemistry*; D006859:Hydrogen / Q000032:analysis; D007769:Lactams / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure
chemical_list: C522176:17,18-dihydro-5H,9H-dibenzo(e,n)(1,4,10,7,13)trioxadiazacyclopentadecine-6,10(7H,11H)-dione; C522178:6,7,9,10-tetrahydro-16H,20H-dibenzo(h,q)1,4,7,13,10,16-tetraoxadiazacyclooctadecine-27,21(18H,22H)-dione; C522177:9,10,20,21-tetrahydro-5H,12H-dibenzo(e,q)(1,4,10.13,7,16)tetraoxadiazacyclooctadecine-6,13(7H,14H)-dione; D002247:Carbon Isotopes; D004987:Ethers; D004988:Ethers, Cyclic; D007769:Lactams; D006859:Hydrogen