Synthesis of (−)-julocrotine and a diversity oriented Ugi-approach to analogues and probes

• Ricardo A. W. Neves Filho,
• Bernhard Westermann and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2011, 7, 1504–1507, doi:10.3762/bjoc.7.175

• Leishmania amazonensis (L.). It could be helpful to elucidate the to-date unknown mode of action of this natural product in the parasite. Conclusion In summary, a highly efficient method to synthesize (−)-julocrotine (1) in three steps from Cbz-glutamine 2 was developed. The approach affords the natural

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

• carvedilol has an additional antioxidant mode of action. It has been proposed that the carbazole ring may be involved in scavenging oxygen radicals thereby accounting for reduced myocardial damage [41]. Since carbazoles are similar to indoles, analogous methods can be used for their synthesis. The key

The allylic chalcogen effect in olefin metathesis

• Yuya A. Lin and
• Benjamin G. Davis

Beilstein J. Org. Chem. 2010, 6, 1219–1228, doi:10.3762/bjoc.6.140

• ]. a) Acceleration of ring-closing enyne metathesis by the allylic hydroxy group [23]. b) Proposed mode of action by the allylic hydroxy group in this reaction. a) Effect of the hydroxy group on the rate and steroselectivity of ROCM [24]. b) Proposed H-bonded ruthenium complex for stereoselective ROCM

Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate

• Michael North and
• Marta Omedes-Pujol

Beilstein J. Org. Chem. 2010, 6, 1043–1055, doi:10.3762/bjoc.6.119

• used by other groups as part of synthetic studies [44][45][46]. Mechanistically, the mode of action of catalyst 1 is well understood [15][20][47][48][49], involving a bimetallic transition state in which one titanium atom acts as a Lewis acid, coordinating to the aldehyde, and the other forms a

• titanium–cyanide bond, thus allowing transfer of cyanide to the carbonyl to occur intramolecularly in a highly organized transition state structure. The mode of action of vanadium based catalysts such as 2 is believed to involve two parallel catalytic cycles, the slower of which involves only monometallic

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• unique activity was thought to originate from their ability to transform in vivo to generate the active metabolite. This was followed by decades of investigations to understand in detail their singular mode of action. It was found that the aziridine played a crucial role, allowing an irreversible bis

• ), D-glucosamine 21 and carbamoyl phosphate (Scheme 4) [29][30][31][32]. The key intermediate, AHBA, is also a common precursor to other anticancer drugs, such as rifamycin and ansamycin. 2.2. Mode of action Mitomycins are quinone antitumor antibiotics that exert their biological activity through DNA

Sordarin, an antifungal agent with a unique mode of action

• Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

• fungi by stabilizing the ribosome/EF2 complex. This mode of action is in contrast to typical antifungals, which target the cell membrane. This unusual bioactivity makes sordarin a promising candidate for the development of new fungicidal agents, and provided the motivation for extensive research. Three