Search results for "Chemical Synthesis"
showing 10 items of 285 documents
Synthesis of the new ring system pyrrolizino[2,3-b]indol-4(5H)-one
2011
Derivatives of the new ring system pyrrolizino[2,3-b]indol-4(5H)-one were prepared in four steps starting from substituted benzonitriles bearing a functionalized amino group in the adjacent position. The unsubstituted- and the dimethoxy-pyrrolizinoindolones 5a and 5b exhibited modest activity against the HL-60(TB) human leukemia cell line, whereas the N-methylated dimethoxy-pyrrolizinoindolone 6b showed to be selective against MOLT-4 leukemia, A549/ATCC, HOP-92, and NCI-H460 non-small cell lung cancer, and CAKI-1 renal cancer cell lines.
Triazolopyridines. Part 28. The ring–chain isomerization strategy: triazolopyridine- and triazoloquinoline–pyridine based fluorescence ligands
2012
Abstract The ring–chain isomerization of [1,2,3]triazolo[1,5-a]pyridines or [1,2,3]triazolo[1,5-a] quinolines has been efficiently employed as a tool to provide tridentate fluorescent structures. Based on these scaffolds, a new family of highly fluorescent compounds has been synthesized and evaluated for the recognition of zinc or copper cations. In addition, the 1:1 Zn+2-L complex of a naphthalene triazolopyridine–pyridine derivative revealed high efficiency as sensor for anions providing large binding constants for nitrite and cyanide.
Radiosynthesis of 1-(4-(2-[18F]fluoroethoxy)benzenesulfonyl)-3-butyl urea: a potentialβ-cell imaging agent
2002
Summary Tolbutamide (1) is a sulfonurea agent used to stimulate insulin secretion in type 2 diabetic patients. Its analogue 1-(4-(2-[ 18 F]fluoroethoxy)benzenesulfonyl)-3butyl urea (3) was synthesized in overall radiochemical yields of 45% as a potential b-cell imaging agent. Compound 3 was synthesized by 18 F-fluoroalkylation of the corresponding hydroxy precursor (2 )w ith 2-[ 18 F]fluoroethyltosylate in DMF at 1208C for 10 min followed by purification with HPLC in a synthesis time of 50 min. Insulin secretion experiments of the authentic 19 F-standard compound on rat islets showed that the compound has a similar stimulating effect on insulin secretion as that of tolbutamide (1). The part…
Synthesis of 1-Palmitoyl-2-((E)-9- and (E)-10-nitrooleoyl)-sn-glycero-3-phosphatidylcholines
2019
Extensive investigation of nitrated phospholipids in connection with various biologically important processes requires reliable access to suitable material. A selective chemical synthesis introducing a defined nitrofatty acid at the sn-2 position of a 2-lyso sn-glycero-3-phosphatidylcholine was developed. Given that the nitroalkene moiety of both reactant nitrofatty acid derivative and the product esters is characterised by particular sensitivity to nucleophile addition and, depending on the intermediate, subsequent olefin isomerisation and retro-Henry-type reaction, a reliable two-step ester formation was introduced. The activation of the nitrofatty acid succeeded after reaction with trich…
Improved scalable syntheses of mono- and bis-urethane derivatives of ornithine.
2001
In the search for a practical route to ornithine bisurethane derivatives useful for peptide synthesis, we elaborated the simple and efficient (86% yield) synthesis of N(epsilon)-tert-butoxycarbonyl-L-ornithine copper(II) complex (1). This served as substrate for obtaining N(epsilon)-tert-butoxycarbonyl-L-ornithine (2), N(alpha)-benzyloxycarbonyl-N(epsilon)-tert-butoxycarbonyl-L-ornithine (3) and N(alpha)-(9-fluorenyl)methoxycarbonyl-N(epsilon)-tert-butoxycarbonyl-L-ornithine (4). These were synthesized in 94-95% yields and with a purity above 99%.
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…