Search results for "Chemical synthesi"
showing 10 items of 292 documents
Organometallic complexes with biological molecules. X: dialkyltin(IV) and trialkyltin(IV) orotates: spectroscopic andin vivo investigations
1999
Several novel diorgano- and triorgano-tin(IV) derivatives of orotic acid, (2,6-dihydroxypyrimidine-4-carboxylic acid; H 3 or) have been synthesized. In the diorganotin(IV) derivatives, the orotic acid behaved either as a monoanionic or as a dianionic ligand, yielding R 2 Sn(H 2 or) 2 and R 2 SnHor (R = Me, Bu) species, respectively, while in the triorganotin(IV) orotates only monodeprotonation of the orotic acid occurred, giving R 3 SnH 2 or (R = Me, Bu) derivatives. Structural hypotheses are proposed and discussed for the solid state based on Mossbauer and IR spectroscopic data, and for solution on 1 H and 1 C NMR results. Finally, investigations have been carried out in vivo, showing the …
On the Rearrangement in Dioxane/Water of (Z)-Arylhydrazones of 5-Amino-3-benzoyl-1,2,4-oxadiazole into (2-Aryl-5-phenyl-2H-1,2,3-triazol-4-yl)ureas: …
2006
We have recently evidenced an interesting differential behavior in the reactivity in dioxane/water between the (Z)-2,4-dinitrophenylhydrazone (1a) and the (Z)-phenylhydrazone (1b) of 5-amino-3-benzoyl-1,2,4- oxadiazole. The former rearranges into the relevant triazole 2a only at pS+ > 4.5 while undergoing hydrolysis at high proton concentration (pS+ < 3.5); on the contrary, the latter rearranges into 2b in the whole pS+ range examined (0.1 e pS+ e 14.9). Thus, for a deeper understanding of these differences we have now collected kinetic data on the rearrangement in dioxane/water of a series of 3- or 4-substituted (Z)-phenylhydrazones (1c-l) of 5-amino-3-benzoyl-1,2,4-oxadiazole in a wide ra…
SYNTHESIS OF PYRROLO[3,2-H]QUINOLINONES WITH GOOD PHOTOCHEMOTHERAPEUTIC ACTIVITY AND NO DNA DAMAGE
2010
In the search for new photochemotherapeutic agents, a series of derivatives of the ring system pyrrolo[3,2-h]quinoline--bioisosters of the angular furocoumarin angelicin--were synthesized through a four-step synthetic approach, in reasonable overall yields. Eight of the synthesized derivatives showed a remarkable phototoxicity against a panel of four human tumor cell lines and a great dose UV-A dependence, reaching IC₅₀ values at submicromolar level. The mode of cellular death photoinduced by pyrrolo[3,2-h]quinolines was evaluated through a series of flow cytometric analysis and other tests were performed to clarify their mechanism of action.
Chemistry and biology of new marine alkaloids from the indole and annelated indole series.
2003
Chemistry and biology of marine natural products from the indole and annelated indole series have become an attractive research field for development of new pharmacological lead substances. In the past years some of the isolated natural organic compounds were synthesized by chemists and evaluated with great enthusiasm to find new lead natural compounds against different diseases. In this review the latest results for new compounds including isolation, biological evaluation, synthetic pathways and some retrosynthetic analyses are summarized.
A phosphonamidate containing aromatic N-terminal amino group as inhibitor of leucine aminopeptidase-design, synthesis and stability.
2006
Fully deprotected phosphonamidate dipeptides, predicted as effective inhibitors of cytosolic leucine aminopeptidase, showed unexpected instability in water solution at pH below 12. Their hydrolysis rate was strictly correlated with basicity of the N-terminal amino group. To improve this feature a phosphonamidate analogue containing less basic, aromatic 2-aminophenylphosphonate residue in P1 position of the inhibitor was designed. The target compound was synthesised starting from diethyl 2-nitrophosphonate in several step procedure. The decrease in basicity of the terminal amino moiety of the modified analogue in fact resulted in satisfactory improvement of hydrolytic stability of the P–N bo…
Pyrrolo[1,2-f]phenanthridines and related non-rigid analogues as antiviral agents.
2002
Abstract The pyrrolo[1,2- f ]phenanthridines 8 – 22 and the corresponding non-rigid analogues 23 – 41 were synthesised and their ability to inhibit the replication of HIV-1 was tested. Only the polycyclic derivatives 10 , 11 , and 13 showed a weak anti -HIV activity, whereas several pyrrolo-phenanthridines ( 8 , 10 , 16 – 18 ) were found to stimulate the multiplication of MT-4 cells at low concentrations. Derivative 10 demonstrated to possess the unique property of stimulating the multiplication of lymphocytes joined to HIV inhibition.
A Bioinspired Approach to Tri-nor-guaianes. Synthesis of (−)-Clavukerin A
2006
A bioinspired approach to tri-nor-guaianes by degradation of the C-7 side chain of related guaia-11-enes is described. In this approach (-)-clavukerin A (1) is obtained by selective ozonolysis-Criegge rearrangement of (+)-1alphaH,7alphaH,10alphaH-guaia-4,11-dien-3-one (4) to afford 7beta-hydroxy and 7beta-acetoxy tri-nor-guaiane derivatives 6 and 7, respectively, which after elimination and deoxygenation give the title compound. The starting guaiadienone is readily obtained from commercially available santonin or (+)-dihydrocarvone.
Isolation, Identification, and Chemical Synthesis of 6α-Hydroxyraumacline: A Novel Alkaloid from CultivatedRauwolfia serpentinaCells
1992
From RAUWOLFIA SERPENTINA cells cultivated in the presence of ajmaline ( 2) the new indole alkaloid, 6alpha-hydroxyraumacline ( 1), was isolated. This alkaloid also occurs in significant amounts in the nutrition medium. A simple chemical synthesis of 1 was developed starting from ajmaline ( 2).
NODAPA-OH and NODAPA-(NCS)n: Synthesis, 68Ga-radiolabelling and in vitro characterisation of novel versatile bifunctional chelators for molecular ima…
2008
This report concerns synthesis, (68)Ga-radiolabelling and stability data of 1,4,7-triazacyclononane-1,4-diacetic acid-7-p-isothio-cyanatophenyl-acetic acid (NODAPA-NCS), 1,4,7-triazacyclononane-1-acetic acid-4,7-di-p-isothiocyanatophenyl-acetic acid (NODAPA-(NCS)(2)) and 1,4,7-triazacyclononane-1,4-diacetic acid-7-p-hydroxyphenyl-acetic acid (NODAPA-OH), versatile bifunctional chelators with potential for molecular imaging. Protein binding and exemplified conjugation are also reported.