Nitroalkyl pyridines

Other examples of monomeric 3-APs are cribrochalinamine oxides (27, 28) Fig. (6) from the sponge Cribrochalina sp., two -substituted pyridine alkaloids bearing a rare azomethine A-oxide function in the side chain [15], Untenines are nitroalkyl pyridine derivatives (29-31), Fig. (7) from the sponge Callyspongia sp. [16]. 

The only other reported 3-AP compounds with antimicrofouling activity are untenines A-C (29-31), monomeric nitroalkyl pyridine alkaloids from Okinawan marine sponge Callyspongia sp. Their ICioo values against the marine bacterium Phodospirillum salexigens were 3.0, 6.1 and 5.8 pg/cm respectively [16]. 

Untenines A-C (12 and 13) Three novel nitroalkyl pyridine alkaloids... 

Three Novel Anti-Microfouling Nitroalkyl Pyridine Alkaloids from the Okinawan marine sponge Callyspongia sp. Wang, G. Y. S. Kuramoto, M. Uemura, D. Yamada, A. Yamaguchi, K. and Yazawa, K. Tetrahedron Lett. 1996,37, 1813. 

The nucleophilic nature of these radicals allows addition to carbon-nitrogen multiple bonds, and in selected cases this has been demonstrated. Suitable substrates for such additions include protonated pyridines, thiazoles and imidazoles (equation 183), and nitroalkyl anions359. Yamamoto and coworkers have also described cobalt-mediated multiple additions of carbon tetrahalides, benzyl bromides or a-bromo ketones to isocyanides, which are postulated to occur through the corresponding alkylcobalt(III) complexes360. 

The phosphonates 82 undergo O-acetylation under conventional conditions, and the products may be deacetyloxylated under basic conditions to give dialkyl (2-nitroethenyl)-phosphonates (83) when R = Me or Et, the tertiary alcohols 82 also suffer dehydration to the same 83 when treated wiht pyridine and SOCI2, whereas the secondary alcohols 83 (R = H) suffer dehydration but also furnish the dialkyl (l-chloro-2-nitroalkyl)-phosphonates ... 

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