A novel bifunctional ligand (3p-C-NETA) for antibody-targeted radioimmunotherapy (RIT) of β-emitting radioisotopes (90)Y and (177)Lu was efficiently synthesized via an unexpected regiospecific ring opening of an aziridinium ion. 3p-C-NETA instantly formed a very stable complex with (90)Y or (177)Lu. 3p-C-NETA is an excellent bifunctional ligand for RIT.

The Morita-Baylis-Hillman (MBH) adducts of beta-aryl nitroethylenes with methyl vinyl ketone (MVK) and acrylate, formed in moderate to good yield when mediated by imidazole/LiCl in THF at room temperature, inhibit HeLa cell proliferation by binding to tubulin.

Reaction of nitroalkenes or nitrodienes with methyl vinyl ketone (MVK) or acrylate in the presence of the imidazole-LiCl catalyst system provides Rauhut-Currier (vinylogous Morita-Baylis-Hillman) adducts in moderate yield. Under similar conditions (imidazole-hydroquinone), nitroalkenes and nitrodienes undergo self-dimerization to afford the Rauhut-Currier adducts in varying yields. An alternative self-dimerization-nitro group elimination pathway in the presence tricyclohexylphosphine was observed with heteroaromatic nitroalkenes. A synthetically useful one-pot two step transformation of Rauhut-Currier adducts of nitroalkenes with MVK to 2,3-disubstituted cyclopentenones is also described.

Novel a-hydrazino-a,b-unsaturated nitroalkenes, which exhibit dynamic phenomenon on the NMR time scale, were synthesized in excellent yields via imidazole or DMAP mediated Morita-Baylis-Hillman (MBH) type reaction of nitroalkenes with azodicarboxylates.The coupling of the a-position of activated alkenes (vinyl anion equivalents) with various carbon electrophiles mediated by a tertiary amine or tertiary phosphine, popularly known as the Morita-Baylis-Hillman (MBH) reaction, has emerged as an important C-C bond forming reaction in organic synthesis. 1-4 It provides a simple, convenient and atom-economical methodology for the synthesis of densely functionalized molecules. 3 However, Chetero atom bond formation via similar strategy has not received much attention. 5, 6 For instance, C-N bond formation via the MBH reaction is equivalent to electrophilic amination of a vinyl anion.Electrophilic amination of carbanion equivalents is, in fact, an important C-N bond forming strategy offering a convenient entry into natural/unnatural amino acids and other synthetically and biologically useful building blocks. 7 Commonly employed electrophiles for this purpose are azodicarboxylates, 8 azides, 8,9 oxaziridines 10 etc. 7 Among the handful of methods available in the literature for the synthesis of a-hydrazino-a,bunsaturated compounds 5,11 which are potential precursors to bioactive compounds, 12 only two reports, to our knowledge, involve the electrophilic amination of vinyl anion equivalents with azodicarboxylate. 5 More importantly, there is no report, to our knowledge, on the MBH type coupling of the a-position of bsubstituted activated alkenes with azodicarboxylate or any other electrophilic aminating agents mentioned above. 13 Furthermore, despite their well documented synthetic utility, especially as powerful Michael acceptors, conjugated nitroalkenes 14 have been scarcely employed as substrates in more than three decades of the MBH chemistry. 15-18The possible application of multifunctional MBH adducts arising from nitroalkenes as novel synthetic scaffolds and biologically active molecules 17 prompted us to pursue a fundamentally novel coupling of nitrovinyl anion with N-centered electrophiles. Thus, in this report, we describe our results on the successful MBH type reaction of b-substituted nitroalkenes with activated azo compounds, namely, azodicarboxylates leading to a-hydrazinoa,b-unsaturated nitro compounds in excellent yields. Our initial optimization studies using 2-nitrovinyl furan (NVF) 1a as the model substrate with diisopropyl azodicarboxylate (DIAD) 2a as the electrophile in THF at room temperature in the presence of 10 mol% of various catalysts revealed the suitability of imidazole 19 and/or DMAP 20 as catalyst(s) of choice for further optimization (Scheme 1) (see ESI †). Scheme 1Subsequent optimization experiments suggested that stoichiometric amounts of imidazole or DMAP, would be beneficial to obtain the best yield of the MBH adduct 3a in the shortest possible reaction time. In contrast to the excellen...

[reaction: see text] The Morita-Baylis-Hillman reaction of a variety of conjugated nitroalkenes with activated nonenolizable carbonyl compounds such as glyoxylate, trifluoropyruvate, pyruvaldehyde, and ninhydrin in the presence of 40-100 mol % of DMAP in acetonitrile or 100 mol % of imidazole in CHCl(3) or THF provided the adducts in decent to good yields. In most cases, the reactions catalyzed by DMAP in acetonitrile were faster and provided the desired MBH adducts in higher yields as compared to the imidazole catalyzed reactions.