Two pseudopolymorphic hydrates of brucine: brucine-water (1/4) and brucine-water (1/5.25) at 130 K.
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Journal Article↗
Biomedical subjects
Peter C Healy
Publications and source records attributed to Peter C Healy.
Efficient formal synthesis of (+/-)-hyphodermin B.
An efficient formal synthesis of hyphodermin B 1, a metabolite of Hyphoderma radula, has been completed in 15% overall yield. The tricyclic carbon skeleton 3 was rapidly assembled from a novel vinyl enone via a Diels-Alder reaction, followed by dehydrogenation and anhydride formation. Selective reduction of anhydride 3 with LiAlH(t-BuO)3 gave hyphodermin B 1 in 99% yield. The structure of hyphodermin B 1 was confirmed by X-ray crystallographic analysis. The anhydride 3, bearing a gamma-carbonyl group, displayed unexpected reactivity with the anhydride carbonyl closest to the gamma-ketone being the most electrophilic site. This was confirmed by HF/6-31G calculations. In the presence of base, 3 underwent a rearrangement to the novel lactone 16.
Crystallography, X-Ray↗
Synthesis and structure-activity relationships of novel benzene sulfonamides with potent binding affinity for bovine carbonic anhydrase II.
This manuscript reports the identification of a novel series of mono- and bis- benzene sulfonamides with potent binding affinity for bovine carbonic anhydrase II (bCAII). These compounds exhibited nanomolar equilibrium dissociation constants with K(i)'s ranging from 4.7 to 9.3nM. All compounds were ester derivatives of the weak affinity bCAII inhibitor, 4-carboxybenzenesulfonamide. Structure-activity relationships for this novel series of compounds are discussed.
Animals↗
Layered structures in proton-transfer compounds of 5-sulfosalicylic acid with the aromatic polyamines 2,6-diaminopyridine and 1,4-phenylenediamine.
The crystal structures of two proton-transfer compounds of 3-carboxy-4-hydroxybenzenesulfonic acid (5-sulfosalicylic acid) with the aromatic polyamines 2,6-diaminopyridine [namely 2,6-diaminopyridinium 3-carboxy-4-hydroxybenzenesulfonate monohydrate, C5H8N3+.C7H5O6S-.H2O, (I)] and 1,4-phenylenediamine [namely 1,4-phenylenediaminium 3-carboxylato-4-hydroxybenzenesulfonate, C6H10N2(2+).C7H4O6S2-, (II)] have been determined. Both compounds feature extensively hydrogen-bonded three-dimensional layered polymer structures having significant interlayer pi-pi interactions between the cation and anion species. In (I), the pyridine N atom of the Lewis base is protonated and forms a direct hydrogen-bonding interaction with the water molecule, which together with the two amine groups of the cation and the carboxylic acid group of the anion also give additional interactions with O-atom acceptors of the sulfonate group. In (II), a dianionic species results from deprotonation of both the sulfonic and the carboxylic acid groups, and all available O-atom acceptors interact with all dication donors, which lie about inversion centres.
Journal Article↗
Structural and solid state 31P NMR studies of the four-coordinate copper(I) complexes [Cu(PPh3)3X] and [Cu(PPh3)3(CH3CN)]X.
The tris(triphenylphosphine)copper(I) complexes [(PPh3)3CuX] for X = Cl (1), Br (2), I (3), ClO4 (4), BF4 (5), [(PPh3)3CuCl].CH3CN (1a), [Cu(PPh3)3(CH3CN)]X for X = ClO4 (6), BF4 (7), and [Cu(PPh3)3(CH3CN)]X.CH3CN for X = SiF5 (8), PF6 (9) have been studied by solid state 31P CP/MAS NMR spectroscopy together with single crystal X-ray diffraction for compounds (6)-(9), the latter completing the availability of crystal structure data for the series. Compounds (1)-(5) form an isomorphous series in space group P3 (a approximately 19, c approximately 11 A) with three independent molecules in the unit cell, all disposed about 3-fold symmetry axes. Average values (with estimated standard deviations) for the P-Cu-P, P-Cu-X bond angles and Cu-P bond lengths in compounds (1)-(3) are 110.1(6) degrees, 108.8(6) degrees and 2.354(8)A and 115.2(6) degrees, 102.8(9) degrees and 2.306(9)A for compounds (4) and (5). For the acetonitrile solvated compound (1a), the corresponding parameters are 115(4) degrees, 103(3) degrees and 2.309(3)A. The solid state 31P CP/MAS NMR quadrupole distortion parameters, dnu Cu, for (1)-(3) and (1a) are all less than 1 x 10(9) Hz2, despite the changes in donor properties of the halide in (1)-(3), and the coordination geometry of the P3CuX core in (1a). Change of anion to ClO4- and BF4- in compounds (4) and (5) results in a significant increase of dnu Cu to 4.4-5.2 10(9) Hz2 and 5.2-6.0 x 10(9) Hz2, respectively. Compounds (6) and (7) crystallise as isomorphous [Cu(PPh3)3(CH3CN)]X salts in space group Pbca, (a approximately 17.6, b approximately 22.3, c approximately 24.2 A), while compounds (8) and (9) crystallize as isomorphous acetonitrile solvated salts [Cu(PPh3)3(CH3CN)]X.CH3CN in space group P1(a approximately 10.5, b approximately 13.0, c approximately 19.5 A, alpha approximately 104, beta approximately 104, gamma approximately 94 degrees). The P3CuN angular geometries in all four compounds are distorted from tetrahedral symmetry with average P-Cu-P, P-Cu-N angles and Cu-P bond lengths of 115(4) degrees, 103(4) degrees and 2.32(1)A, with dnu Cu ranging between 1.3 and 2.5 x 10(9) Hz2. The solid state 29Si CP/MAS NMR spectrum of the pentafluorosilicate anion in compound (8) is also reported, affording 1J(29Si, 19F) = 146 Hz.
Copper↗
Probing the formation of bicyclo[4.2.0]octan-1-ols.
Reaction of lithium enolates of simple ketones with (+/-)-phenyl vinyl sulfoxide has potential for the convergent construction of complex fused ring systems containing a bicyclo[n.2.0]alkan-1-ol. The formation of sulfinylbicyclo[4.2.0]octan-1-ols 1-3 from the lithium enolate of cyclohexanone with (+/-)-phenyl vinyl sulfoxide or (R)-(+)-p-tolyl vinyl sulfoxide 18 was used to probe the mode of this novel cyclization reaction. Using phenyl vinyl sulfoxide, variations in the reaction lighting and solvent were investigated, in conjunction with radical trapping (TEMPO) and isotope labeling (deuterium) experiments. Cyclization to form sulfinylbicyclooctanols 1-3 is likely to proceed via an intermediate that ring closes to the bicycloalkanol anion 11 and was presently favored by the use of solvents such as THF or DME.
Journal Article↗
Hydrogen bonding in proton-transfer compounds of 8-quinolinol (oxine) with aromatic sulfonic acids.
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Journal Article↗
Xanthones from a microfungus of the genus Xylaria.
Chemical investigations of a microfungus Xylaria sp. isolated from the Australian rainforest tree Glochidion ferdinandi have afforded two new natural products, 2-hydroxy-6-methyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid (1) and 2-hydroxy-6-hydroxymethyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid (2). Compound 1 has previously been synthesised but only partially characterised. Methylation of 1 using diazomethane afforded the crystalline compound 2,8-dimethoxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester (3), whose structure was determined by single crystal X-ray analysis. This paper reports the full spectroscopic characterisation of compounds 1-3 by NMR, UV, IR and MS data. All compounds were inactive in a brine shrimp lethality assay and several antimicrobial screens.
Ascomycota↗