Adenosylrhodibinamide and methylrhodibinamide – organometallic rhodium analogues of the natural cobinamides

The replacement of cobalt in vitamin B[Formula: see text] derivatives by rhodium furnishes non-functional structural mimics of the corresponding natural corrins. Here, we describe the synthesis and spectral characterization of adenosylrhodibinamide (AdoRhbi) and methylrhodibinamide (MeRhbi), as well as of Rh[Formula: see text]-methylrhodibyrate (Me[Formula: see text]Rhby), the synthetic precursor of MeRhbi. The organometallic rhodibinamides AdoRhbi and MeRhbi are Rh(III)-homologues of the vitamin B[Formula: see text]-derivatives adenosylcobinamide (AdoCbi) and methylcobinamide (MeCbi). The two new rhodibinamides were prepared from Rh[Formula: see text]-adenosylrhodibyrate (AdoRhby) and Me[Formula: see text]Rhby, respectively. AdoRhbi and adenosylcobinamide, the biosynthetic precursor of coenzyme B[Formula: see text]have similar structures, as derived from NMR-spectra, in particular. Likewise, MeRhbi represents a structural mimic of the well-known Co[Formula: see text]-methylcobinamide. Hence, as rhodium analogues of the corresponding organometallic cobinamides, AdoRhbi and MeRhbi may represent a new class of potential B[Formula: see text]-antimetabolites and surrogate substrates for the biosynthesis of rhodium-based antivitamins B[Formula: see text] in bacteria.