Dipyridodiazepinone derivatives; synthesis and anti HIV-1 activity

• Nisachon Khunnawutmanotham,
• Nitirat Chimnoi,
• Arunee Thitithanyanont,
• Patchreenart Saparpakorn,
• Kiattawee Choowongkomon,
• Pornpan Pungpo,
• Supa Hannongbua and
• Supanna Techasakul

Beilstein J. Org. Chem. 2009, 5, No. 36, doi:10.3762/bjoc.5.36

• groups in 7 and 8 led to diminished activity relative to that of 5 and 6. 10 and 11, 8-amino analogues of nevirapine, were found to be ineffective inhibitors. Molecular docking To understand the binding mode of the new potent derivatives 5, 6 and 9 were docked into the HIV-1 RT binding site by using the

• program. The docked conformations of 5, 6, 9 and nevirapine are shown in Figure 3, and their GoldScores are presented in Table 2. In the wild-type and K103N binding sites, the docked orientations of 5, 6 and 9 are similar to that of nevirapine. In the Y181C binding site, except for 5, the orientations of

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• -groups at the 5-position of 4 should allow us to probe the hydrophobic binding pocket defined by P565, A566, V567, and F584 in the substrate binding site and optimize this interaction. Figure 2 shows the docking mode for 3 and 4a in rat nNOS. Initially, attempts were made to construct 3 and 4 using

Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties

• Harald Schmaderer,
• Mouchumi Bhuyan and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26

• catalytic efficacy, flavin derivatives bearing a guanidinium ion as oxoanion binding site were prepared. Chromophore and substrate binding site are linked by a rigid Kemp’s acid structure. The molecular structure of the new flavins was confirmed by an X-ray structure analysis and their photocatalytic

• activity was investigated in benzyl ester cleavage, nitroarene reduction and a Diels–Alder reaction. The modified flavins photocatalyze the reactions, but the introduced substrate binding site does not enhance their performance. Keywords: flavin; guanidine; Kemp’s acid; photocatalysis; template

• flavin chromophore, the guanidinium substrate binding site and a Kemp’s acid derived rigid linker, starts from Kemp’s acid anhydride (5) [50][51][52]. The anhydride 5 was allowed to react with previously prepared flavins 4 and 8 [21] in the presence of DMAP as catalyst. The amide formation of the

The first salen- type ligands derived from 3',5'-diamino- 3',5'-dideoxythymidine and -dideoxyxylothymidine and their corresponding copper(II) complexes

• Daniel Koth,
• Michael Gottschaldt,
• Helmar Görls and
• Karolin Pohle

Beilstein J. Org. Chem. 2006, 2, No. 17, doi:10.1186/1860-5397-2-17

• binding site and the N-glycosidic bound thymine provides an additional chiral information and steric shielding. After the ligands had been added to a mixture of copper(II) acetate in THF the complexes were formed within a few minutes resulting in a dark green solution (Scheme 2). All four ligands 8–11

• 15 (384 nm). The complexes of the diastereomeric ligands could be obtained in a straightforward synthesis. They possess interesting features especially with regard to chiral catalysts or DNA strand formation. Although located off the metal ion the thymine base may act as a substrate binding site in

Colchitaxel, a coupled compound made from microtubule inhibitors colchicine and paclitaxel

• Karunananda Bombuwala,
• Thomas Kinstle,
• Vladimir Popik,
• Sonal O. Uppal,
• James B. Olesen,
• Jose Viña and
• Carol A. Heckman

Beilstein J. Org. Chem. 2006, 2, No. 13, doi:10.1186/1860-5397-2-13

• stacked on it in such a way that the nucleotide-binding site is embedded in the interface [8]. Ravelli and coworkers found colchicine binding site to be buried in the β subunit, boxed in by β-strands of the second domain and helices #7 and #8. The A ring of colchicine contacts residue 241[9], consistent

• binding. However, the acetamide linkage on ring B could be replaced by other alkyl amides with little change in potency [32]. Moreover, colchicine with an altered B ring still bound tubulin [33]. The binding site of paclitaxel is situated on the inner face of the polymerized microtubule, tucked into a

• bend formed by helix #6 and helix #7 near the + end of the microtubule and adjacent to strand #7. Here, the taxane may affect both the structure of the M loop and that of helix #6 which contacts the GTP binding site, so that it may both stabilize GTP against hydrolysis and stabilize the M loop against