Ol’ Bimane is Learning New Tricks

Bimanes are hetero-bicyclic molecules that can be readily synthesized in moderate to good yields. These low molecular weight fluorophores were developed by Prof. E. Kosower and co-workers about 40 years ago.[i] From the two possible diastereomeric forms, only syn-bimanes are strongly fluorescent. Some bimane derivatives have become useful as fluorescent probes for different applications ranging from biological labeling to LASER dyes. Recently, we showed that when attached to an appropriate carrier moiety, syn-bimane can cross the blood-brain-barrier (BBB) of living mice and be clearly detected in brain tissue.[ii] syn-Bimanes present an N-imide structure as an integral part of their skeleton which, in the past, was never exploited as a metal binding motif. We showed that a cationic Pd(II) complex (2) containing syn-(Me,Me)bimane (1, R^1-4 = Me) as a ligand could be prepared and was fully characterized.[iii] We are currently involved in the preparation of bimane derivatives where the oxygen atoms are replaced by sulfur atoms. The novel mono- and di-thioxo-bimanes are expected to display novel spectroscopic properties and give rise to more stable complexes with different metals. Our latest results with oxo- and thioxo-bimanes, their structures, chemistry, and spectroscopic studies will be presented.

[i] E. M. Kosower, B. Pazhenchevsky, E. Hershkowitz, J. Am. Chem. Soc., 1978, 100, 6516.

[ii] I. Lapidot, D. Baranes, A. Pinhasov, G. Gellerman, A. Albeck, F. Grynszpan, S. E. Shatzmiller, Med. Chem., 2016, 12, 48.

[iii] P.J. Das, Y. Diskin-Posner, M. Firer, M. Montag, F. Grynszpan, Dalton Trans., 2016,45, 17123-17131