Batzelladine A and

The pyrimidine skeleton has also been found in several marine natural products with interesting biological activities [103]. Among the most notable of these are the crambescidin (9-125) [104] and the batzelladine (9-126) [105] alkaloids which show pronounced bioactivity (Scheme 9.26). Thus, batzelladine A and B are new leads for... 

The validity of the oxauracil strategy for a stereoselective construction of the azabicyclic core has been proven for the syntheses of biologically important polyguanidinium alkaloids, namely, batzelladine A and D [58]. Reaction (7.48) shows that treatment of 41 under the standard free-radical conditions furnished the desired azabicycle in a 77 % yield, in a high diastereoisomeric ratio. Here it can be seen the effect of H donation from the more accessible face of the molecule. 

There is a primary alcohol-to-aldehyde step in the synthesis of (+)-batzelladine A, and it was suggested that the oxidation of the primary alcohol (1) with TRAP/ NMO/PMS/CH Cl proceeds through an iminium-Ru alkoxide complex (2), rearranging as in (3)-(4) to give the aldehyde (5) (Fig. 1.13) [101] (a similar mechanism was proposed for the Ru-catalysed oxidative cyanation of tertiary amines [403] cf. 5.1.3.4, Fig. 5.3). 

Shimokawa, J., Ishiwata, T., Shirai, K. et al. (2005) Total synthesis of (+)-batzelladine A and (—)-batzelladine D, and identification of their target protein. Chemistry -A European Journal, 11, 6878-6888. 

Marine alkaloids (-f)-batzelladine A and ( )-batzel-ladine D. Nine novel tricyclic guanidine marine alkaloids were isolated as metabolites of the Crambe genus. Members of the batzelladine alkaloid class exhibit potential antiviral activity in the inhibition of HIV gp 120-Human CD4 binding, as well as potential immunosuppressive... 

Several natural products and pharmaceuticals have been made in which a TRAP-catalysed oxidation of a primary alcohol to aldehyde step occnrs, and these are listed in 2.1.3 abscisic acid, altohyrtin A, (+)-arisngacin A, 14-[2H]-arteether (Fig. 2.4), astrogorgin, avermectin-Bla (Fig. 2.6), (H-)-batzelladine A (Fig. 1.13), brevetoxin B, (+)-catharanthin, ( )-epibatidine, 2-epibotcinolide, (-)-7-epicylin-drospermopsin, ( )-epimaritidine, epothilone C, irisqninone (Fig. 2.3), gambieric... 

Other procedures using TPAP/NMO/PMS/CH Cl include steps in the synthesis of (+)-altholactone (lactol to lactone) [78] antheliolide A [168] the AChE inhibitor (+)-arisugacin A and B (primary alcohol to aldehyde step also) [83] the marine macrolide amphidinolide T1 [169] the alkaloid (+)-batzelladine D cf. mech. 

On scanning numerous natural sources only the extracts from the Caribbean sponge Batzella sp. proved to be active [9], This led to the isolation of the batzelladines A (12) and B as the first low-molecular-weight compounds able to inhibit this interaction. Subsequently, batzelladines F (13) and G (14) were shown to induce dissociation of thyrosin kinase p56 and CD4 cells highly specific in an immunosuppressivity-based assay [lOJ. 

Rao, A.V.R., Gurjar, M.K., and Vasudevan, J. (1995) An enantiospecific synthesis of the tricychc guanidine segment of the anti-HIV marine alkaloid batzelladine A. J. Chem. Soc. Chem. Common., 1369-1370. 

Elliott, M.C. and Loirg, M.S. (2004) Studies toward the total synthesis of batzelladine A Org. Biomol. Chem., 2, 2003-2011. 

Six-membered cyclic guanidine 197 was transformed into the corresponding bicyclic guanidine hemiaminal after deprotection of the Cbz and contemporary cyclization on the masked aldehyde function (Equation 4). This product, 198, was then employed in a Biginelli reaction to form a precursor of alkaloid batzelladine F <1999JOC1512>. 

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