Table of Contents

Abstract: The crystal and molecular structures of [Ni(Im)₆](dtp)₂ (Im = imidazole, dtp = O,O′-diphenyldithiophosphate) have been determined by X-ray crystallography. It crystallizes in the triclinic system, space group Pī, with cell parameters a = 9.375 (2), b = 12.324(3), c = 13.285(3) Å, α = 107.86(3), β = 102.28(3), γ = 109.24(3), and Z = 1. The crystal structure of the title compound is built up of discrete monomeric molecules of [Ni(Im)₆](dtp)₂. The nickel (II) ion is hexacoordinated by six imidazole molecules and the coordination environment of Ni (II) is of octahedral geometry. In the solid state, a network of N-H···S intermolecular hydrogen bonds connect the Ni(Im)₆ moieties and O,O′-diphenyldithiophosphate molecules, forming a three-dimensional structure.

Abstract: Alternative methods for the synthesis of pyridoxine have been investigated. The key intermediate, 5-hydroxy-6-methyl-pyridine-3,4-dicarboxylic acid diethyl ester (5), was reduced with either a silane monomer (MeSiH(OEt)₂) or a polysiloxane (polymethylhydrosiloxane, PMHS) to afford crude pyridoxine. An isolation technique utilizing a commercially available resin was devised, affording the desired product, vitamin B₆, in an overall yield of 38-54 % and a purity of 76%.

Abstract: (12E,14E,17E)-11-Hydroxy-12,14,17-dodecatrienoic acid was isolated from the stems of Ilex integra and its structure was determined on the basis of the spectroscopic data of its methyl ester.

Abstract: Upon treatment of 25(R)-spirost-5-en-3β-ol (diosgenin), 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with 30% H₂O₂ and 5% NaOH in methanol, diosgenin did not react, 25(R)-1,4,6-spirostatrien-3-one was converted to 25(R)-1α,2α-epoxy-4,6-spirostadien-3-one and 25(R)-4,6-spirostadien-3β-ol was oxidized to give a small amount of 25(R)-4,6-spirostadien-3-one, while most of the original starting material remained unchanged. On the other hand, reactions of diosgenin, 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with m-chloroperoxybenzoic acid in chloroform yielded 25(R)-5α,6α-epoxyspirostan-3β-ol, 25(R)-6α,7α-epoxy-1,4-spirostadien-3-one and 25(R)-4β,5β-epoxy-6-spirosten-3β-ol, respectively.

Abstract: New derivatives of benzo-15-crown-5 with flexible appended N₂O unsymmetrical Schiff bases were prepared by a two step procedure which involves: (i) preparation of N₂O Schiff bases by condensation of hydrazine with salicylaldehyde, 3-methoxysalicylaldehyde or 2-hydroxy-1-naphtaldehyde and (ii) reaction of the resulting NH₂ functionalized compounds with 4’-formyl-benzo-15-crown-5.

Abstract: Reaction of artemisinin (1) with ethanolamine, followed by acid treatment produced the lactam (4S,8S,9S,13S,1R,5R,12R)-11-aza-11-(2-hydroxyethyl)-1,5,9-trimethyl-14,15-dioxatetracyclo [10.2.1.0<4,13>.0<8,13>]pentadecan-10-one (4) and the diol (1S,2S,6S,7S,5R,8R)-4-aza-5,6-dihydroxy-4-(2-hydroxyethyl)-2,8-dimethyl-7-(3-oxobutyl) bicyclo[4.4.0]decan-3-one (7). When ethylenediamine was used instead of the ethanolamine, the dimeric lactam (1S,4S,8S,9S,13S,5R,12R)-11-[2-((1S,4S,8S,9S,13S,5R,12R)-11-aza-1,5,9-trimethyl-14,15-dioxa-10-oxotetracyclo[10.2.1.0<4,13>.0<8,13>] pentadec-11-yl)ethyl]-11-aza-1,5,9-tri-methyl-14,15-dioxatetracyclo-[10.2.1.0<4,13>.0<8,13>]-pentadecan-10-one (8) was obtained. All compounds are new azaartemisinin derivatives lacking the peroxide functionality. These compounds were evaluated for antimalarial and cytotoxic activities. Only the dimer 8 was found to possess antimalarial activity, while only the diol 7 exhibited cytotoxic activity against human breast ductal carcinoma.

Abstract: Utilization of 2-arylhydrazonopropanals for the synthesis of 2-arylhydrazonoimino propanones, 1,2,4-trizolo[4,3-a]pyrimidines, pyridopyridazine hydrazones, 3-oxaloalkanonitriles and 1,2,3-trizole derivatives by conventional heating and under microwave irradiation is described. Structural assignments are based on spectroscopic data and confirmed in some cases by X-ray crystallography.