Table of Contents

Abstract: The nitro group of methyl 3-nitropyridine-4-carboxylate (1) has successfully been replaced by fluoride anion via nucleophilic aromatic substitution to give the 3-fluoro- pyridine-4-carboxylate 2.

Abstract: (7-Hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide (2) was prepared from (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid ethyl ester (1) and 100% hydrazine hydrate. Compound 2, is the key intermediate for the synthesis of several series of new compounds such as Schiff’s bases 3a-l, formic acid N'-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)acetyl] hydrazide (4), acetic acid N'-[2-(7-hydroxy-2-oxo-2H-chromen-4- yl)-acetyl] hydrazide (5), (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid N'-[2-(4- hydroxy-2-oxo-2H-chromen-3-yl)-2-oxoethyl] hydrazide (6), 4-phenyl-1-(7-hydroxy-2- oxo-2H-chromen- 4-acetyl) thiosemicarbazide (7), ethyl 3-{2-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)-acetyl]hydrazono}butanoate (8), (7-hydroxy-2-oxo-2H-chromen-4-yl)- acetic acid N'-[(4-trifluoromethylphenylimino)methyl] hydrazide (9) and (7-hydroxy-2- oxo-2H-chromen-4-yl)acetic acid N'-[(2,3,4-trifluorophenylimino)-methyl] hydrazide (10). Cyclo- condensation of compound 2 with pentane-2,4-dione gave 4-[2-(3,5- dimethyl-1H-pyrazol-1-yl)-2-oxoethyl]-7-hydroxy-2H-chromen-2-one (11), while with carbon disulfide it afforded 7-hydroxy-4-[(5-mercapto-1,3,4-oxadiazol-2-yl)methyl]-2H- chromen-2-one (12) and with potassium isothiocyanate it gave 7-hydroxy-4-[(5- mercapto-4H-1,2,4-triazol-3-yl)methyl]-2H-chromen-2-one (14). Compound 7 was cyclized to afford 2-(7-hydroxy-2-oxo-2H-chromen-4-yl)-N ́-(4-oxo-2-phenylimino- thiazolidin-3-yl) acetamide (15).

Abstract: A series of three para-benzoquinone mono-oximes and four oxy-derivatives were prepared and tested for their antidepressant properties. The (4E) oxime of 2-isopropyl-5- methyl-para-benzoquinone (4) and the corresponding 2-diethylamino-ethyl derivative (10) present antidepressant activities and were slightly more potent than the reference standard.

Abstract: Electrocoagulation was used for dechlorophyllation of alcoholic extracts from five plants. The results showed that for every plant extract studied, electrocoagulation was more efficient than the classical solvent extraction method in removing plant pigments, while not affecting the important secondary metabolites in those extracts.

Abstract: The synthesis, spectroscopic characterization, and X-ray crystal structure ofthe sodium salt of a new sulfonated water-soluble ligand, sodium 2-(2-pyridin-2-yl-ethylamino)-benzenesulfonate (L) are described. Compound L crystallizes in thecentrosymmetric space group Pbcn, orthorhombic, a=31.930(13) å, b=7.153(3) å,c=14.193(6) å, α=90.00, β=90.00, γ=90.00, V=3220(2) å³, Z=9. π−π stacking contactsinvolving interactions between the π-donor benzene and the π-acceptor pyridine systemsreinforce and direct the self-assembly of the structural motifs in the solid state.

Abstract: The title compound 6-amino-3-benzylmercapto-1,2,4-triazolo[3,4-f][1,2,4]-triazin-8(7H)-one (4), molecular formula C₁₁H₁₀N₆OS, was obtained by the reaction of3-amino-2-benzyl-6-hydrazino-1,2,4-triazin-5(2H)-one (3) with carbon disulfide in awater/pyridine mixture. Compound 4 can also be synthesized by reacting6-amino-3(2H)mercapto-1,2,4-triazolo[3,4-f][1,2,4]triazin-8(7H)-one (7) with benzylbromide in methanolic ammonia water. The compound crystallizes in the monoclinicspace group P2₁/c with a = 7.2926(15), b = 14.456(2), c = 11.436(2) å, β = 105.30(2)°, V= 1162.9(4) å³ and Z = 4, resulting in a density Dcalc of 1.567 g/cm³. Molecules of 4 arelinked by extensive intermolecular N-H···N and N-H···O hydrogen bonding [graph set R₂² (9)]. The structure is further stabilized by π-π stacking interactions. 2

Abstract: The syntheses of new chiral cyclic 1,2-diacetals from (2R, 3R)-( )-tartaric acidare described. C₂-symmetrical diamines were prepared via direct amidation of the tartrate orfrom the corresponding bismesylate via reaction with sodium azide. For C1-symmetricalcompounds, the Appel reaction was used to form the key intermediate, amonochlorocarbinol, from the diol. Some of the new chiral compounds, produced in good tohigh yields, may be potentially useful as asymmetric organocatalysts or as nitrogen andsulfur chelating ligands for asymmetric metal catalyzed reactions. Thus, a bis-N-methyl-methanamine derivative, used in substoichiometric amounts, was found to catalyze theenantioselective addition of cyclohexanone to (E)-β-nitrostyrene with highdiastereoselectivity (syn / anti = 92:8), albeit giving moderate optical purity (syn: 30 %).

Abstract: L-Proline catalyzed additions of 13 different thiols to 11 different α-enoneMichael acceptors in [bmim] PF₆ are reported. Reasonable to high yields of the reactionproducts were isolated in most cases.

Abstract: Five novel Schiff bases have been prepared from o-formylphenoxyacetic acidand a series of aminothiazoles to form a number of potentially biologically activecompounds. The structures of these Schiff bases have been characterized using IR and ¹H-and ¹³C-NMR spectroscopy.