Winston D. Lloyd

Stereochemistry and fungitoxicity of complexes of p-anisaldehydethiosemicarbazone with Mn(II), Fe(II), Co(II) and Ni(II)

The complexes of p-Anisaldehydethiosemicarbazone (PAT) with Mn(II), Fe(II), Co(II) and Ni(II) have been isolated and characterised on the basis of elemental analyses, molar conductance, magnetic moment and spectral studies. Fungicidal activity has been evaluated against Alternaria (Sp.), Paecilomyces (Sp.) and Pestalotia (Sp.).

Biologically important coordination compounds of 4-acetyl-2-(acetylamino)-5-dimethyl-δ2-1,3,4-thiadiazole with manganese(II), iron(II), cobalt(II) and nickel(II)

Abstract The complexes of 4-Acetyl-2-(acetylamino)-5- dimethyl-δ 2 -1,3,4-thiadiazole (AAT) with Mn(II), Fe(II), Co(Il) and Ni(II) have been prepared and characterized on the basis of elemental analyses, molar conductance, magnetic moments, electronic and infrared spectral studies. The most probable structures of the complexes have been proposed on the basis of their physicochemical properties. The fungitoxicity of AAT and its complexes has been evaluated on pathogenic fungi.

Synthesis and chemical characterization of biologically important complexes of vanillin thiosemicarbazone with manganese(II), iron(II), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), and mercury(II)

SummaryVanillin thiosemicarbazone (VTSC) has been used to isolate the complexes of the types [M(VTSC)2(H2O)2]X2 (M=MnII, FeII, CoII, or NiII and X=Cl) and [M(VTSC)X2]H2O (M=CuII, ZnII, CdII or HgII and X=Cl). Probable structures of these complexes are suggested on the basis of elemental analysis, molar conductance, magnetic moment and electronic and i.r. spectral data. The fungicidal activity of VTSC and the isolated complexes has been evaluated on pathogenic fungi,Alternaria (Sp.),Paecilomyces (Sp.) andPestalotia (Sp.).

Synthesis and structural investigation of biologically active complexes of 4-acetyl-2-(acetylamino)-5-dimethyl-Δ2-1,3,4-thiadiazole with Zn(II), Hg(II), Cd(II) and Cu(II)

Abstract 4-Acetyl-2-(acetylamino)-5-dimethyl-Δ2-1,3,4-thiadiazole (AAT) has been used to obtain the complexes of the general formula [M(AAT)X 2 ]·H 2 O where M(II) = Zn, Hg, Cd and Cu, and X  Cl or 1 2 SO 4 . The complexes have been characterized on the basis of their elemental analysis, molar conductance, magnetic susceptibility and spectral data. Probable structures for the complexes have been proposed on the basis of their physico-chemical properties. The fungitoxicity of AAT and the isolated complexes has been tested on pathogenic fungi.

Extractive spectrophotometric determination of molybdenum(V) in molybdenum steels

Abstract An extraction spectrophotometric method has been developed for the determination of traces of molybdenum present in molybdenum steels which is based on the extraction of the orange-red molybdenum-thiocyanate-acetonethiosemicarbazone complex into chloroform from hydrochloric acid medium. The complex has an absorption maximum at 472 nm with a molar absorptivity of 1.9 × 104 liters mol−1 cm−1. Beers law is valid over the concentration range 0.1–9.5 ppm of molybdenum with an optimum concentration range of 0.4–9 ppm. The equilibrium shift method indicates 1:4:2 composition for molybdenumthiocyanate-acetonethiosemicarbazone complex. The effect of acidity, reagent concentrations, temperature, and interferences from various ions are reported.

Structural features of biologically active coordination compounds of vanillinsemicarbazone

SummaryComplexes of vanillinsemicarbazone (VSC) with MnII, FeII, CoII, NiII, CuII, ZnII, CdII and HgII have been prepared and characterised by elemental analyses, molar conductance, magnetic susceptibility and spectral data. Probable structures for the complexes are suggested on the basis of their physico-chemical properties. The fungitoxicity of VSC and the isolated complexes have been tested on pathogenic fungi.

Chemical characterization of the in vitro degradation products of vindesine sulfate.

Abstract Vindesine (VDS) was incubated in 0.2 M glycine buffer (pH 4.0, 7.4, or 8.8) containing bovine serum albumin (1%) at 37 °C for 24 or 72 h. The reaction mixture was extracted with CH 2 Cl 2 . HPLC analysis (μBondapak C 18 , 10 μm, reverse-phase steel column; isocratic solvent system: 50% MeOH in 10 m M KH 2 PO 4 , pH 4.0; flow rate, 1 ml/min; detector, 254 nm) of the extract gave three major peaks A, B, and C with retention times of 4.3, 5.3, and 13.0 min, respectively. At pH 8.8, peaks A and C accounted for about 11 and 28%, respectively, of the parent VDS. VDS in this system corresponded with peak B and its spectral data (UV, IR, MS, and 1 H and 13 C NMR) were identical to those of the parent compound. The UV, IR, and MS spectral properties of these peaks were as follows: peak A: UV (λ max ): 208, 258, 290, 310 nm; IR (cm −1 ): 3450, 1731, 1673, 1611, 1503, 1460, 1380, 1228, 743; MS ( m z ): 752 (MH + ); peak B: UV (λ max ): 210, 263, 279, 290, 306 nm; IR (cm −1 ): 3457, 2922, 2850, 1723, 1676, 1500, 1456, 1369, 812, 733; MS ( m z ): 754 (MH + ); peak C: UV (λ max ): 212, 268, 280, 290, 310 nm; IR (cm −1 ): 3457, 2922, 2850, 1727, 1662, 1456, 1380, 1040, 740; MS ( m z ): 768 (MH + ). On the basis of these spectral data and 1 H NMR spectroscopy, peaks A and C are tentatively identified as an enamine/ether derivative of VDS and 3′,4′-epoxyvindesine N -oxide, respectively.

Synthesis of (E,Z)-5-Bromo-1,1-dimethoxy-5-trimethylsilyl-4-pentene, an Upper Chain Allenic Prostaglandin Building Block

Abstract This work explores the synthetic route to allenic prostaglandins. In a search for more efficient and reliable methods for the introduction of the allene moiety into the side chains of prostaglandins, the synthons, the (E) and (Z) isomers of 1-bromo-5,5-dimethoxy-1-trimethylsilyl-1-pentene (13a) and (13b), have been prepared and converted to R,S-1,1-dimethoxy-6-phenyl-4,5-hexadiene (16), a prostaglandin analog.