Complete ¹H and ¹³C NMR spectral assignment of pentacyclo [6.4.0.0^2,6.0^5,9.0^4,12]dodecane derivatives and structure elucidation of pentacyclo [6.4.0.0^2,6.0^3,11.0^5,9]dodecane

NMR elucidation of some ligands derived from the pentacycloundecane skeleton

“…The geminal bridge methylene protons (H-4) for PCU compounds register as an AB spin system at approximately 1.1 and 1.5 ppm with a coupling constant of about 11 Hz [6][7][8][9]. This proved to be a convenient starting point in solving the NMR spectra of such compounds as H-4a (H-4s) which normally exhibits COSY and NOESY interactions with H-3/5 and H-2/6 (H-3/5 and H-9/10).…”

“…The difficulties associated with the NMR elucidation of these compounds have been widely commented upon by groups that have reported 1 H and 13 C NMR data before [4][5][6][7]. Through-space effects as well as geminal and vicinal proton-proton coupling and long-range proton-proton interactions result in broad unresolved resonances that are difficult to assign in the 1 H NMR spectra.…”

Structure elucidation of 11‐amino‐8‐hydroxypentacyclo[5.4.0.02, 6.03, 10.05, 9]undecane‐8,11‐lactam through selective acetylation and complete 1H and 13C NMR spectral assignment of the mono‐, di‐ and triacetates

“…We recently reported 6 that treatment of pentacyclo [5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane-8,11-dione (1) with an aqueous mixture of sodium cyanide, ammonium chloride and ammonia unexpectedly led to 11-amino-8-hydroxypentacyclo [5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane-8,11-lactam (2). Suitable crystals for x-ray crystallographic analysis could not be obtained, which left little choice of method for structural studies.…”

Synthesis and NMR elucidation of novel pentacyclo-undecane diamine ligands

“…As part of an ongoing programme to utilize NMR spectroscopy for the structure elucidation of pentacyclo-undecane (PCU) derivatives, the NMR assignments of eight PCU diamine derivatives (1)(2)(3)(4)(5)(6)(7)(8) was attempted (Fig. 1).…”