Colforsin analogues: tritiation and characterization

Tritium NMR: A compilation of data and a practical guide

“…Reproduced with minor editing privilege from Shu and Heys [32] with the permission of John Wiley and Sons results of tritium NMR of that period are shortly outlined in his early reviews. [44,45] Crist N. In line with the studies performed by Kapur and Seeman [46] dealing with the receptors incorporating into a central ion channel, which is a key factor in excitatory synaptic transmission for the brain and spinal cord, Filer and coauthors [47] In one of the early publications from this group, [48] tritium NMR spectra were recorded for the colforsin analogues tritiated at the 12-th position of the colforsin basic structure, which is shown in Figure 27. Tritium NMR spectra of two compounds from that series look very F I G U R E 2 1 1 H NMR (bottom) and 3 H proton decoupled NMR (top) spectra of (S)-10-bromoacetamidomethylcamptothecin in DMSOd 6 recorded at accordingly, 400 and 426 MHz.…”

“…In one of the early publications from this group, [ 48 ] tritium NMR spectra were recorded for the colforsin analogues tritiated at the 12‐th position of the colforsin basic structure, which is shown in Figure 27. Tritium NMR spectra of two compounds from that series look very much the same, differing only in peak intensities of mono‐labeled and doubly labeled species.…”

“…Tritium NMR spectrum of monotritiated and ditritiated derivatives of colforsin, recorded in CD 3 OD at 320 MHz. Reproduced with minor editing privilege from Egan et al [ 48 ] with the permission of Elsevier…”

“…Tritium NMR spectrum of monotritiated and ditritiated derivatives of colforsin, recorded in CD 3 OD at 320 MHz. Reproduced with minor editing privilege from Egan et al [48] with the permission of Elsevier Egan and others [59] performed tritium NMR investigation of the tritium-labeled A-4334 analgesic, belonging to the short-acting 4-anilidopiperidine class of analgesics, which had been a valuable source for clinical trial candidates. The proton decoupled 3 H NMR spectrum provided a single sharp resonance at 7.56 ppm showing exclusive tritium labeling at the m-position of the phenyl ring, as illustrated in Figure 38.…”

Tritiated dihydro compounds employed as radioligand surrogates

“…Clearly, the structure of 22 provided some daunting challenges to tritium labeling, not the least of which was its vulnerable olefin group, confounding many usual tritiation strategies. We were the first to describe the preparation of [ 3 H] 22 and several analogues by means of a mild, base‐catalyzed tritiated water exchange process, placing tritium exclusively at the 12‐position adjacent to the cyclic ketone as confirmed by tritium NMR . By this method, we were able to routinely obtain specific activities approaching 30 Ci/mmol for [ 3 H] 22 .…”