bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclic hydroxycarboxylic acids. III. Tosylation studies on Mono- and Di-hydroxycyclopentanecarboxylates and Mono- and Di-hydroxyprolines
Authors: Philp RP , Robertson AV
Published: December 2006

A large excess of reagent
is needed for satisfactory ditosylation of methyl c-2,t-3- and t-2,c-3-di-hydroxycyclopentane-r-1-carboxylates
using tosyl chloride-pyridine at 5° overnight. With less reagent, mixtures are
produced from which one monotosyl derivative of the t-2,c- 3-series was
isolated and its structure proved. By contrast, the methyl cis- and
trans-2-hydroxycyclopentanecarboxylates readily tosylate with normal molar
ratios of reagent. In the proline series ditosylation of 2,3-trans-
3,4-cis-3,4-dihydroxy-N-tosylproline methyl ester occurs normally in tosyl
chloride-pyridine, and so does tosylation of both cis- and
trans-4-hydroxy-N-tosylproline methyl esters. On the other hand tosylation of
the 3-hydroxy counterparts is very slow, although acetylation of these
3-hydroxyl groups proceeds normally. The O-tosylation results are striking for
the lack of pattern. A comparison is also made of O-tosylation accompanying
N-tosylation of the free amino acids cis- and trans-3-hydroxy-proline, cis- and
trans- 4- hydroxyproline, and the two cis-glycols of
3,4-dihydroxyproline in the heterogeneous system tosyl chloride-ether-aqueous NaOH. Significant O- tosylation occurs in some cases but
not in others. This correlation permits assignment of structure to a mono-O-tosyl
derivative of a 3,4- dihydroxy-N-tosylproline obtained previously by us.
The reaction of some styrene oxides with diborane
Authors: Marshall PA , Prager RH
Published: December 2006

Some factors which
influence the reaction of styrene oxide and related epoxides with diborane in
tetrahydrofuran at 25° have been studied. Styrene oxide (2-phenyloxiran) and o-
and p-methyl-styrene oxide afford essentially the 2-arylethanol. (E)-1-Phenylpropene
oxide (trans-2-methyl-3-phenyloxiran) yields 76% 1-phenylpropan-2-ol and 24%
1-phenylpropanol. Indene oxide and
1,2-dihydronaphthalene oxide are both cleanly reduced to indan-2-ol and
1,2,3,4-tetrahydronaphthalen-2-ol respectively. Reduction of 2-phenylpropene
oxide afforded only 15% 2-phenylpropanol and 85% of
an organoborane which gave 2-phenylpropane-1,3-diol on oxidation, and
(E)-2-phenylbut-2-ene oxide gave almost exclusively the corresponding
2-phenylbutane-1,3-diol. The stereochemistry of the diol products is discussed,
and it is suggested that the relative stability of incipient benzyl and alkyl
carbonium ions influences the mode of reaction.
Photolysis of some β,γ-epoxycarbonyl compounds
Authors: Coxon JM , Hii GSC
Published: December 2006

Photolysis of
(3RS)-3,4-epoxy-1-phenylbutan-1-one (1a) gives in high yield a 1.7 : 1 mixture
of (1RS,2RS,3RS)- and (1RS,2SR,3SR)-2,3-epoxy-1-phenylcyclobutan-1-ols (4) and
(5). Fragmentation of the intermediate biradical is not a competitive reaction
process. Alkyl substitution at C 2 facilitates α-cleavage while the 2-oxa
analogue, oxiranyl benzoate (2), is unreactive under normal photolysis
conditions.
Sylvestrene nitrosochloride and derived amino oximes
Authors: Brecknell DJ , Carman RM , Singaram B , Verghese J
Published: December 2006

Configurational and
conformational effects in amino oximes derived from sylvestrene
(m-mentha-6,8-diene) nitrosochloride are discussed in terms of o.r.d. and 1H n.m.r, observations.
The gas-liquid critical properties of alkane mixtures: Cycloalkanes + n-Alkanes and Cycloalkanes + Branched Alkanes
Authors: Marsh KN , Young CL
Published: December 2006

The gas-liquid critical
temperatures, Tcm of cycloalkane + n-alkane and
cycloalkane + branched alkane mixtures are reported. The interaction energy
parameter, ξ(expressing the deviation from the Berthelot
combining rule), has been calculated for each mixture from the values of Tcm
using the van der Waals one-fluid
model. The values of ξ are within 0.5% of unity.
Ultraviolet absorption spectra of the benzyl radical formed during pulse radiolysis
Authors: McAskill NA , Sangster DF
Published: December 2006

Solutions of benzyl
chloride and benzyl alcohol in cyclohexane were subjected to pulse radiolysis.
The absorption of the band at 307/318 nm (22A2 excited
state) of the benzyl radical increased with solute concentration as expected
over the range from to 10-5 to 10-1 M. On the other hand,
the absorption of the 258-nm band (42B2 state) decreased
with concentration and is zero at 10-2 M. It is considered that the
population of radicals in the vibrational or electronic sub-levels of the
ground state from which the 42B2 transitions take place
is affected by an interaction or association process dependent on solute
concentration. Extinction coefficients (l. mol-1 cm-1)
for the benzyl radical in 10-5 M solution are 9000 at 318 nm, 4500
at 307 nm and 41000 at 258 nm.
Thermodynamics of metal-ligand bond formation. XXIX. Nickel(II) dialkylmonothiocarbamate complexes
Authors: Graddon DP , Siddiqi IA
Published: December 2006

In benzene solution at
concentrations below 10-2 M, measurements of molecular weights,
absorption spectra and the enthalpies of reaction with bases are all consistent
with Ni(SOCNR2)2 (R = Pr or Bu) existing as an
equilibrium between low-spin monomeric and high-spin dimeric, probably five-coordinate,
species. Enthalpies of dimerization are about -55 kJ (g-atom Ni)-1
and dimerization constants increase from 250 l. mol-1 at about 5�C
to 1000 l. mol-1 at 30�C, which shows that the entropy of
dimerization is not temperature-invariant. Addition of bidentate bases to the
monomer is quantitative with ΔH� about -100 kJ mol-1. Addition
of pyridine, 4-methylpyridine or piperidine occurs in two steps, giving
high-spin adducts, first five-coordinate NiL2B then six-coordinate
NiL2B2 with K1 ≈ K2, ΔH1�
≈ -100 and ΔH2� near zero. Comparisons are made with
other low-spin nickel(II) complexes which form high-spin polymers or adducts.
An efficient route to steroidal 6α- and 6β-Malonates and acetates by alkylation of π-Allylpalladium complexes
Authors: Collins DJ , Jackson WR , Timms RN
Published: December 2006

Reaction of the π-allylpalladium
compounds derived from some 3-oxo 4- ene steroids
with malonate ion gives dialkyl (3-oxo-steroid-4-en-6β- yl)malonates in high yield and with complete
stereo-specificity. The 6β-malonates can be epimerized to give the more stable
6α-epimers or decarboalkoxylated to give the corresponding acetic acid
derivatives.
The reaction of β-N,N-Dialkylaminocrotonates with phosphorus oxychloride
Authors: Harris RLN , Huppatz JL , Phillips JN
Published: December 2006

β-Dialkylaminocrotonates
self-condense in excess phosphorus oxychloride at room temperature to give
N,N-dialkylanthranilates in high yield. When stoichiometric amounts of
phosphorus oxychloride are used and the reaction is carried out in benzene at
80�, significant amounts of phenolic by-products are also formed, which, in the
case of β- morpholinocrotonates, become the major products. These
compounds have been subjected to a number of transformations which establish
their structure and at the same time provide methods of synthesis for
N,N-dialkylaniline derivatives which are otherwise difficult to obtain.
Synthetic plant growth regulators. The synthesis of C-o-Carboxyphenyl derivatives of some five-membered heterocycles
Authors: Harris RLN , Huppatz JL
Published: December 2006

Synthetic routes to
o-carboxyphenyl derivatives of certain heterocyclic compounds, required for
testing as plant growth regulators, were investigated. The preparation of
2-(5-phenyl-1,3,4-oxadiazol-2- yl)benzoic acid (3),
2-(5-phenyl-1,3,4-thiadiazol-2-yl)benzoic acid (4),
2-(5-phenyl-1H-1,2,4-triazol-3-yl)benzoic acid (5), 2-(3-phenyl-
1,2,4-oxadiazol-5-yl)benzoic acid (6), 2-(2-phenylthiazol-4-yl)benzoic acid
(7), 2-(3-phenylisoxazol-5-yl)benzoic acid (8), 2-(5- phenylisoxazol-3-yl)benzoic
acid (9) and chloro derivatives of (3), (4), (8) and (9) is described.
Colouring matters of Australian plants. XIX. Haemocorin: Unequivocal synthesis of the aglycone and some derivatives
Authors: Cooke RG , Rainbow IJ
Published: December 2006

The structures of
haemocorin aglycone, a pigment of Haemodorum corymbosum Vahl., and its methyl
ethers have been confirmed by unequivocal specific synthesis.
Acetolytic cleavage of 2β,19-Epoxy-5α-cholestane involving a 1,2-Hydride shift to C2
Authors: Gall RE , Taylor J
Published: December 2006

Acetolytic cleavage of
2β,19-epoxy-5α-cholestane (1a) with boron trifluoride and acetic
anhydride followed by hydrolysis gave the 2α,19- diol (2b), the only
rearrangement product the 1α,19-diol (3b) and a mixture of olefins (4b).
Deuterium exchange studies and the use of a paramagnetic shift reagent have
shown that the reaction leading to the rearranged diol(3b) is not concerted and
appears to involve an intermediate carbonium ion since hydride shift from both
C 1 and C 3 occur. The formation of the 1α,19-diol (3b) as the only
rearranged product can be rationalized as nucleophilic attack on the
acetoxonium ion (8).
Fluorescent whitening agents. IX.The effect of proteins on the photodecomposition of pyrazolines
Authors: Evans NA , Holt LA , Milligan B
Published: December 2006

Ultraviolet irradiation of
the diaryl-2-pyrazoline (1) in water gives the corresponding pyrazole (3), the
4-hydroxypyrazole (4) and several unidentified products. Irradiation of the
tetraaryl-2-pyrazoline (2) gives the pyrazole (6) as the major product. The
rates of photodegradation are increased if lysozyme is present and the
corresponding pyrazoles are formed preferentially. Pyrazoles are also the major
products when wool containing (1) or (2) is irradiated. Both pyrazolines
photosensitize the degradation of lysozyme, the tryptophan, histidine and
methionine residues being the main sites of attack.
Synthesis of some benzopyran derivatives related to the seed germination stimulant of Orobanche crenata. I. 3,3a,4,9b-Tetrahydro-2H-furo[3,2-c][l]benzopyrans
Authors: Davis M , Pettett M , Scanlon DB , Ferrito V
Published: December 2006

The furobenzopyran
derivatives (1a) and (1b) have been prepared by a simple route from m-methoxy-phenol.
Solvent extraction of iron(III) from hydrochloric acid solution by sulphoxides and their mixtures
Authors: Misra BB , Mohanty SR
Published: December 2006

The extraction of iron(III)
from hydrochloric acid solution by the series of sulphoxides (R2SO)
from dipentyl to didecyl sulphoxide in 1,1,2-trichloroethane has been studied.
At a given strength of the extractant, extraction increases initially with
increase in the acid concentration to a maximum at 8 M and decreases thereafter.
Increase in H+ at constant Cl-
strength or increase in Cl- at a given H+
increases the extraction. Under otherwise identical conditions, extraction
increases with increase in the extractant concentration. The extracted species
would appear to be HFeCl4,2R2SO. A mixture of two
sulphoxides or of a sulphoxide and tributyl phosphate extracts the metal ion
more than the sum of extractions due to the individual components.
The coefficients of the Jones-Dole equation for the viscosity of solutions of potassium iodide in mixtures of water and dimethylacetamide at 35°C
Authors: Singh NP , Singh MM , Tikoo PK
Published: December 2006

The viscosities of
solutions of KI in binary mixtures of water and dimethylacetamide at 35�C in
the concentration range 0.005-0.2 mol dm-3 are reported. The data
are analysed in terms of the A and B parameters of the Jones-Dole equation. The
value of the B coefficient first decreases and then increases after attaining a
minimum at about 0.05 mole fraction of dimethylacetamide.
Regiochemical aspects of Diels-Alder reactions of cyclopentadienone
Authors: Paddon-Row MN , Patney HK , Warrener RN
Published: December 2006

The regiochemistry of the
Diels-Alder reaction between cyclopentadienone and 6,6-dimethylfulvene (isopropylidenecyclopentadiene) has been studied. Two
adducts (in addition to cyclopentadienone dimer) were isolated and their
structures were shown to be endo-10-isopropylidenetricyclo[5,2,1,02,6]-deca-4,8-
dien-3-one (6a) and endo-3-isopropylidenetricyclo[5,2,1,02,6]deca-4,8-
dien-10-one (7a). Kinetic parameters for the Cope rearrangement (6a) ↔
(7a) have been determined. The adducts (6a) and (7a) were formed in the ratio
45 : 55 respectively. Thus, in contrast to FMO predictions, and to its reaction
with cyclopentadiene, cyclopentadienone tends to behave as a diene towards the
fulvene. A tentative explanation of these results, based on angle strain in the
transition states for the formation of Diels-Alder adducts, is proposed.
Crystal structure of methyl 8-Iodo-4,5,7-trimethoxy-2-naphthoate
Authors: Cameron DW , Feutrill GI , Lammerts vB , Raston CL , White AH
Published: December 2006

The crystal structure of
the title compound, C15H15IO5, has been
determined by single crystal X-ray diffraction at 295 K and refined by least
squares to a residual of 0.04 (2210 ?observed? reflections). Crystals are
monoclinic, P21/c, a 10.294(5), b 18.868(9), c 7.549(6) Ǻ,
β 90.29(5)�, Z 4. The molecular geometry apart from the iodine environment
is as expected; the crystal packing is such that the iodine lies close to a
symmetry-related neighbour at I...I 4.148(2) Ǻ and may account for the
observed facile elimination of iodine from the solid on heating to 120�C.
Nordivaricatic acid, a new depside from the lichen Heterodea beaugleholei
Authors: Elix JA , Tearne PD
Published: December 2006

The depside nordivaricatic
acid (5) has been isolated from the lichen Heterodea beaugleholei R. Filson. The structure of this compound followed from the
spectroscopic data and has been confirmed by total synthesis.
Cyanogen-Bromide-Mediated and Methyl-Chloroformate-Mediated Synthesis of Some [3]Benzazonino[8,7,6-abc]Carbazole, [3]Benzazecino[9,8,7-abc]Carbazole, Naphth[1,8,7-def]Azonine and Naphth[1,8,7-def]Azecine Derivatives
Authors: Bremner JB , Winzenberg KN
Published: December 2006

Reaction of 7,8-dimethoxy-1,4,5,9,13c,13d-hexahydro-2H-indolo [3′,2′:4,5] indolo [1,7,6-aji] isoquinoline (4a) and 8,9-dimethoxy- 1,2,3,5,6,10,14c,14d-octahydro-indolo[3′,2′:3,4] naphtho [2,1,8-ija] quinolizine (4b) with cyanogen bromide in the presence of potassium carbonate afforded the elimination products 7,8-dimethoxy-1,2,3,4,5,9- hexahydro [3] benzazonino [8,7,6-abc]carbazole-3-carbonitrile (5a) and 8,9-dimethoxy-2,3,4,5,6,10-hexahydro-1H-[3] benzazecino [9,8,7-abc]carbazole-4-carbonitrile (5b) in 4% and 88% yield respectively; 7- (2-bromo)ethyl-1,2-dimethoxy-4,5,6,6a,7,12-hexahydroisoquino[8,1-ab ]carbazole-6-carbonitrile (6a) was also isolated in 20% yield from the former reaction. Products of analogous structure were also obtained from (4a,b) when methyl chloroformate was used in place of cyanogen bromide. Reaction of (4b) with cyanogen bromide in the presence of water and magnesium oxide afforded the solvolysis product 14d-hydroxy-8,9-dimethoxy-2,3,4,5,6,10,14d,14d-octahydro-1H-[3] benzazecino [9,8,7- abc ]carbazole-4-carbonitrile (8b) together with (5b). Similarly application of this reaction to 8,9-dimethoxy-2,3,5,6,11a,11b-hexahydro-1H-naphtho[2,1,8-ija] quinolizine (1b) afforded both the corresponding solvolysis and elimination products; (4a) and 7,8- dimethoxy-1,2,4,5,10a,10b-hexahydronaphtho[1,8,7-ghi] indolizine (1a), however, gave only solvolysis products. Solvolysis and elimination products were also isolated when (1b) and (4b) were subjected to cyanogen -bromide-mediated methanolysis reactions. Acid-catalysed elimination reactions of the alcohol solvolysis products are described along with reaction of some of the elimination products with lithium tetrahydroaluminate.
Synthesis of 4,6-Dimethoxyindoles
Authors: Black DSC , Kumar N , Wong LCH
Published: December 2006

Syntheses are described for nine new 4,6-dimethoxyindoles, incorporating phenyl, pyridin-2-yl, methoxycarbonyl , carboxy and methyl groups in the 2- and/or 3-positions.
Halogenated Terpenoids. XXII. Uroterpenol. the C8 Stereochemistry
Authors: Carman RM , Greenfield KL , Robinson WT
Published: December 2006

The two diastereoisomeric p-menth-1-ene-8,9-diols ( uroterpenols ) have been separated and crystallized. A crystallographic analysis of a dibromo derivative enables relative and absolute configurations to be assigned throughout the series.
Pyrolysis of Aryl Azides. VII. Interpretation of Hammett Correlations of Rates of Pyrolysis of Substituted 2-Nitroazidobenzenes
Authors: Dyall LK
Published: December 2006

Rates and products of pyrolysis have been obtained for ten 2- nitroazidobenzenes with 4- or 5-substituents. Rate data at 100° are correlated with Hammett constants of the 4- or 5-substituents, with respect to both the azido (A) and nitro (N) reaction centres, and yield the equation log k = -3.23 + 1.20σ-/A -0.716σN. Dissection of this equation into σI and σR components was usefully attempted. The results are consistent with an electrocyclic process in which delocalization of negative charge from the innermost azido nitrogen is important at the transition state, whereas substituent effects on bridging by nitro are less important. An interpretation is made of pyrolysis rates of 4-azido-3-nitropyridine, several 2,6- dinitroazidobenzenes, and methyl 2-azidobenzoate. The rate for 4-azido- 3-nitropyridine yields a σ- value of 1.2 for the 4-aza 'substituent'.
Ion Ion Solvent Interactions in Solution .XI. Spectroscopic Studies of Group-2 Perchlorates in Acetone
Authors: James DW , Cutler PG
Published: December 2006

Solutions of Mg(ClO4)2 and Sr (ClO4)2 in acetone have been studied at various concentrations up to saturation by using infrared absorption, Raman scattering and multinuclear n.m.r (1H, 13C, 17O, 25Mg, 35Cl). Solvation numbers of c. 4.5 (Mg2+) and c. 5.5 (Sr2+) were determined from component band analysis of the c. 800 cm-1 acetone band in the Raman spectra. The solvent shell about the Mg2+ had a high level of steric crowding. There was a small amount of solvent-shared ion-pair formation at all oncentrations in solutions of Mg(ClO4)2 which showed little concentration dependence. In solutions of Sr (ClO4)2 there was evidence for the formation of both solvent-shared associated-ion species and ion-contact species. The solvent-shared species appeared to have two alternative configurations in one of which the anion was both polarized and highly hindered. There was a salt-promoted reaction in which the perchlorate was reduced to chloride and the solution darkened. This reaction prevented the use of Raman spectra to quantify the association equilibria.
Reactions of Transition-Metal Sigma-Acetylides. V. Synthesis and X-Ray Structure of Co2(µ-η2-PhC2Fe(Co)2(η-C5h5))(Co)6
Authors: Bruce MI , Duffy DN , Humphrey MG
Published: December 2006

The reaction between Co2(CO)8 and Fe(C2Ph)(CO)2(η-C5H5) gave the title complex in 44% yield. The molecular structure was determined from a single-crystal X-ray diffraction study, and consists of the transition metal acetylide acting as a conventional μ- alkyne ligand to a Co2(CO)6 unit. Crystals are monoclinic, space group P21/n, with a 11.610(8), b 14.657(4), c 12.526(6)Ǻ, β 90.30(5)°, and Z 4; 1683 independent data were refined to R 0.080, Rw 0.087.
Confirmation of the Structure of Fibraurin as [2r-(2-α,6aα,7α,7a-Β,8aΒ,9Β,9aα,9bΒ)]- 2-(Furan-3-yl)-7-Hydroxy-6a,9b-Dimethyl-1,2,6,6a,7,7a,8a,9,9a,9b-Decahyd Ro-9,7-Epoxymethano-4h-Oxireno-[6,7]Naphtho[2,1-C]Pyran-4,11-Dione
Authors: Dampawan P , Engelhardt LM , Taylor WC , White AH , Wiriyachitra P
Published: December 2006

The structure of fibraurin has been confirmed as [2R-(2α,6aα,7α,7aβ,8aβ,9β,9bβ)]-2-(furan-3-yl)-7-hydroxy-6a,9b dimethyl - 1,2,6,6a,7,7a,8a,9,9a,9b-decahydro-9,7-epoxymethano-4H-oxireno- [6,7] naphtho [2,1-c]pyran-4,11-dione(2) by a single-crystal X-ray structure determination. The relative stereochemistry is supported by nuclear Overhauser enhancement results.
Substituent Rate Effects in Sigmatropic Homodienyl [1,5]-Hydrogen Migrations
Authors: Pegg GG , Meehan GV
Published: December 2006

The small but systematic polar substituent effect on the rates of [1,5]- homodienyl hydrogen migrations previously observed for the series of alkenylcyclopropane substrates (1) has been further explored through two additional substrate series (4) and (6) bearing the aryl probe at C4 and at the migration origin C1 respectively. However, negligible substituent effects were apparent at these positions. It now seems that the substituent effect originally observed at C5 reflects electronic perturbation by the substituent, rather than an inherent charge separation in the transition state for homodienyl rearrangement. The aryl group at C1 of the series (6) does, however, afford a substantial rate enhancement relative to the parent cis-1-methyl-2-vinylcyclopropane. In addition, exclusive formation of (1E,4Z)-1-arylhexa-1,4-diene rearrangement products is observed. These kinetic and stereochemical observations are interpreted in terms of a stereoelectronically favoured equatorial conformation for the aryl group in the transition state for rearrangement.
Efficient Trapping of Ketone Enolates With Acrylate and β-Sulfonylacrylate Thioesters, β-Sulfonyl-, β-Sulfinyl- and β-Chloro-Vinyl Ketones; Facile Preparation of a Hydrindanone, cis-Dimethyloctalone, and Unsaturated 1,5-Dicarbonyl Compounds
Authors: Dancer RJ , Haynes RK , Loughlin WA , Vonwiller SC
Published: December 2006

Tandem conjugate addition-ring closure involving reaction of the lithium enolate arising from conjugate addition of lithiated (E)-but-2- enyldiphenylphosphine oxide to 2-methyl-cyclopent-2-enone with two moles of t-butylthioacrylate generates a hydrindanol, and, in the presence of copper(I), a lactone derived from the hydrindanol. β-Sulfonylacrylate phenyl and t-butyl thioesters, β-chlorovinyl, β- sulfonyl- and β-sulfinyl-vinyl ketones react with the foregoing enolate, and with the enolate generated through conjugate addition of a methylcuprate to 2-methylcyclohexenone to give unsaturated 1,5-dicarbonyl compounds. The β-chlorovinyl ketones in particular react rapidly and in high yield. 2-Methylcyclohexenone has thereby been converted into a cis-dimethyl octalone; the conversion illustrates the effectiveness of β-chlorovinyl methyl ketone in the Robinson annelation. Reactions of the lithium enolate and titanium enol of 2,6- dimethylcyclohexanone with the β-substituted enones to give the corresponding unsaturated 1,5-dicarbonyl compounds and other products are also recorded.
Synthesis, X-Ray Crystal Structure and Magnetic Studies of a Biscopper(II) Complex of a C-Spiro Binucleating Linear Octadentate Ligand
Authors: Donlevy TM , Gahan LR , Hambley TW , Hanson GR , Markiewicz A , Murray KS , Swann IL , Pickering SR
Published: December 2006

Reaction of the binucleating ligand 5,5-bis(4-amino-2-thiabutyl)-3,7- dithianonane-1,9-diamine (L1) with a copper(II) salt in aqueous solution, and in the presence of lithium dithionate, results in the isolation of a dark blue crystalline solid identified as [Cu2(L1)](S2O6)2.4H2O. Crystals of the complex are triclinic, space group Pī , a 8.227(2), b 13.103(3), c 16.423(4) Ǻ, α 68.68(2), β 86.68(2), γ 75.50(2)°, Z 2, R 0.026 (5039 F). The structure consists of two copper(II) atoms each of which is coordinated through two thioether and two primary amine atoms. The two copper sites are linked through a saturated spiro carbon atom. Each copper atom is also coordinated to one water molecule; one of the copper atoms is coordinated to an oxygen atom of one dithionate anion. Thus, one copper atom is six-coordinate (4+2 tetragonally distorted), and the other is five-coordinate. The intramolecular Cu...Cu distance is 7.127 Ǻ; the shortest intermolecular Cu...Cu distance is 6.591 Ǻ. The angle between the two N2S2 planes is 92.2°. Low-temperature magnetic studies indicate weak intra- and inter-molecular antiferromagnetic interactions with a singlet-triplet splitting 2J of -10 cm-1 and a θ of -5 K. E.p.r. studies indicate a magnetic dipole-dipole interaction between the two copper(II) sites and a weak intermolecular antiferromagnetic interaction.
Nucleophilic Substitution Reactions in Benzo[C][1,8]naphthyridines. II.
Authors: Cherubim P , Deady LW
Published: December 2006

3-Chloro-1-methyl-6-(p- methylphenoxy ) benzo [c][1,8] naphthyridine has been prepared, the reactions with various nitrogen, oxygen and sulfur nucleophiles studied, and the results compared with those for the 1- chloro-3-methyl isomer. The 6-position was more reactive for oxygen and nitrogen nucleophiles, so much so that an initially added 6-NHR group was displaced by a second R′NH2 nucleophile at least as readily as was the 3-chloro group. With p- chloro ( thiophenol ), however, the 3-chloro group was preferentially displaced.
Synthesis of Casein-Related Peptides and Phosphopeptides. IV. Phosphorotriester and 'Phosphite-Triester' Phosphorylation of Protected Serine-Containing Peptides
Authors: Perich JW , Johns RB
Published: December 2006

The phosphorylation of Ac-Ser- NHMe or Ac- Gly-Ser-Gly-NHMe with diphenyl phosphorochloridate /pyridine gave diphenyl hydrogen phosphate in high yield instead of the expected-Ser(PO3Ph2)-peptide. A 31P n.m.r . spectroscopy study of the phosphorylation reaction established that, with the use of diphenyl phosphorochloridate in pyridine, the intermediate diphenyl phosphoro-N-pyridinium chloride was the active phosphorylation species and that phosphorylation of the hydroxy group of Ac-Ser- NHMe or Ac- Gly-Ser-Gly-NHMe was followed by rapid dephosphorylation of the O-( diphenylphosphono ) seryl residue. While diethyl phosphorochloridate /pyridine phosphorylation of Ac-Ser- NHMe also did not give Ac-Ser(PO3Et2)- NHMe, both the two-step ( i ) diethyl phosphorochloridite /pyridine, (ii) iodine/water and the two-step (i) diethyl N,N-diethylphosphoramidite/1H-tetrazole, (ii) iodine/water 'phosphite-triester' phosphorylation of Ac-Ser- NHMe gave Ac- Ser(PO3Et2)- NHMe in high yield.
Synthesis of Casein-Related Peptides and Phosphopeptides. VI. The Efficient Global 'Phosphite-Triester' Phosphorylation of Multiple-Serine-Containing Peptides by Using Dibenzyl N,N-Diethylphosphoramidite
Authors: Perich JW , Johns RB
Published: December 2006

The peptide Ac-Ser(P)- NHMe and the multiple-Ser(P)-containing peptides Ac-Ser(P)-Ser(P)- NHMe and Ac-Ser(P)-Ser(P)-Ser(P)- NHMe were prepared in good yield by a global phosphorylation approach which employed benzyl phosphate protection. The three serine-containing peptides were phosphorylated by the use of dibenzyl N,N-diethylphosphoramidite/1H-tetrazole followed by in situ oxidation of the resultant dibenzyl phosphite-triesters with m- chloroperoxybenzoic acid. The protected Ser(PO3Bzl2)-containing peptides were purified by C18 reverse-phase silica flash column chromatography and the benzyl phosphate groups were cleaved from the protected Ser(PO3Bzl2) peptides by palladium- catalysed hydrogenolysis.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. LIX. Crystal Structure Determinations of Tetrakis(trimethylphosphine)copper(I) Halides and Tetrakis(triphenylphosphine)-copper(I) and -silver(I) Hexafluorophosphates
Authors: Bowmaker GA , Healy PC , Engelhardt LM , Kildea JD , Skelton BW , White AH
Published: December 2006

The crystal structures of [Cu(Pme3)4]X (X = Cl , Br, I) and of [M(PPh3)4] [PF6] (M = Cu, Ag) have been determined by single-crystal X-ray diffraction methods at 295 K. The former compounds contain nearly tetrahedral [Cu(PMe3)4]+ ions on sites of m symmetry with mean Cu-P bond lengths of 2.270, 2.271 and 2.278 Ǻ for X = Cl , Br and I respectively. The latter compounds contain [M(PPh3)4]+ ions on sites of 3 symmetry. In the M =Ag complex the coordination environment is close to tetrahedral, but in the M =Cu complex the length of the axial Cu-P bond [2.465(2)Ǻ] is significantly shorter than that of the off-axis bonds [2.566(2)Ǻ]. Possible reasons for this are discussed.
Silver(I) Phenoxyalkanoates: The Crystal and Molecular-Structures of catena-[Bis-μ-(phenoxyacetato-O,O')-disilver(I)] and Bis[bis-μ-(4-fluoro-phenoxyacetato-O,O')-bis{aquasilver(I)}]
Authors: Smith G , Sagatys DS , Campbell CA , Lynch DE , Kennard CHL
Published: December 2006

The crystal structures of the silver(I) complexes with phenoxyacetic acid and 4-fluorophenoxyacetic acid, catena-[ bis-μ-(phenoxyacetato-O,O′)- disiver (I)] (1) and bis [ bis-μ(4-fluorophenoxyacetato-O,O′)-{ aquasilver (I)}] (2) have been determined and refined to residuals R 0.068 and 0.036 respectively for 1783 and 2549 observed reflections. Both structures are based on similar bis ( carboxylato -O,O′) bridged dimers with Ag-Ag 2.866(2)Ǻ (1) and 2.836(2)Ǻ (2). However, (1) forms a step polymer through terminal oxygens [Ag-O 2.417, 2.443(9)Ǻ], while (2) is a discrete centrosymmetric tetramer with a water molecule on each of the four silver atoms [Ag- Ow 2.499(4)Ǻ], and an Ag-O bridge distance of 2.498(4)Ǻ. This results in triangular coordination about one silver and tetrahedral about the second. Experimental data indicate that anhydrous silver(I) 4-chlorophenoxyacetate (3) is similar to complex (1).
The Chlorination of 4-Chloro-2,3,6-trimethylphenol. Some Addition-Reactions of 4,6-Dichlorocyclohexa-2,4-dienones
Authors: Hartshorn MP , Hayman KA , Martyn RJ , Robinson WT , Vaughan J , Wells BA , Wright GJ
Published: December 2006

Reaction of a mixture of 6-chlorocyclohexa-2,4-dienones (4) and (5) with chlorine in acetic acid gives the tetrachloro ketones (2) and (3), the major products of chlorination of 2,3,6-trimethylphenol (1a) or 4-chloro-2,3,6-trimethylphenol (1b). Reactions of this mixture of 6- chlorocyclohexa-2,4-dienones (4) and (5) in acetic acid with chlorine acetate, chlorine, chlorine in the presence of sodium acetate, and in benzene with nitrogen dioxide are described. -Ray crystal structure determinations are reported for compounds (3), (6)-(8) and (11)-(13).
A New Synthesis of Xanthones. 2,4,7-Trichloronorlichexanthone and 4,5,7-Trichloronorlichexanthone, Two New Lichen Xanthones
Authors: Elix JA , Jiang H , Wardlaw JH
Published: December 2006

A new synthetic route to norlichexanthone (1,3,6-trihydroxy-8-methyl- 9H-xanthen-9-one) derivatives has been developed by using a Smiles rearrangement of an appropriately substituted depside in the key step. 2,4,7-Trichloronorlichexanthone (22) and 4,5,7- trichloronorlichexanthone (29) have been prepared by this method. The former xanthone (22) was shown to be a constituent of the lichens Lecanora sulphurata and L. flavo-pallescens and the latter (29) a constituent of Micarea austroternaria var. isabellina.
2-Imino-1,3,4-thiadiazole Derivatives of GABA as GABAA Antagonists
Authors: Allan RD , Apostopoulos C , Richardson JA
Published: December 2006

New heterocyclic derivatives of GABA, with a GABA moiety on the 3 position of a 2-imino-1,3,4-thiadiazole ring, have been readily prepared by alkylation of 2-amino-5-aryl-1,3,4-thiadiazoles in dimethylformamide. They are active as GABAA antagonists, inhibiting the action of GABA on the guinea-pig ileum about 5 times less potently than bicuculline.
A Synthesis of the Lichen Xanthone Thiomelin
Authors: Elix JA , Portelli VJ
Published: December 2006

A total synthesis of thiomelin (2,4-dichloro-1,8-dihydroxy-5-methoxy-6-methyl-9H-xanthen-9-one) (1) has been achieved.
Biphenyl Inhibits Stereomutation in Semihydrogenation of 4-Arylbut-2-yn-1-ols
Authors: Pegg GG , Meehan GV
Published: December 2006

Semihydrogenation of 4-arylbut-2-yn-1-ols in the presence of a quinoline -deactivated palladium catalyst yielded mixtures of (Z)- and (E)-4-arylbut-2-en-1-ols. We find that stereomutation of the initially formed (Z)- alkene product is prevented if biphenyl (10% of the weight of the alkyne substrate) is included in the reaction mixture.
Nitrate Selectivity of Ion-Exchange Resins and of Their Model Compounds. I. Conductance Measurements on Benzyltrialkylammonium Salts
Authors: Steel BJ , Kayaalp AS , Kurucsev T , Ward AD , Jackson MB
Published: December 2006

The concentration dependence of the conductance in aqueous solution of a series of benzyltrialkylammonium chlorides, nitrates and sulfates was measured. The n-alkyl substituents in this series were methyl, ethyl, propyl , butyl and pentyl. The conductances of the chlorides, nitrates and sulfates fit satisfactorily the electrostatic ion pairing models relevant to 1 : 1 and 1 : 2 electrolytes. The extent of ion pairing is small in all the solutions studied but consistently larger for nitrates and sulfates compared with chlorides. The dependence of the association constants on the alkyl substitutents shows different trends for the monovalent anions compared with the sulfate salts.
The Fate of CrO2F2 in Highly Acidic Media: Fluoride Loss, O-Protonation or F-Protonation?
Authors: Marsden CJ
Published: December 2006

Theoretical calculations at the DZ/SCF level are reported for CrO2F2 and for three of its possible products of interaction with highly acidic anhydrous hydrogen fluoride. The molecular structure and vibrational frequencies of CrO2F2 are reproduced with reasonable accuracy. It seems unlikely that CrO2F+ is formed from CrO2F2 in anhydrous hydrogen fluoride, since that ion is structurally unstable as an isolated entity. While the thermodynamic stabilities of CrO (OH)F2+ and CrO2F(FH)+ are almost identical, comparison of calculated vibrational frequencies with the experimental results of O'Donnell and coworkers suggests that the product of interaction of CrO2F2 with anhydrous hydrogen fluoride/SbF5 is CrO2F(FH]+, rather than CrO (OH)F2+. However, the Cr-F(H) bond in CrO2F(FH)+ is so much longer than the bond to the unprotonated fluorine that CrO2F(FH)+ is perhaps best described as a CrO2F+ ion strongly solvated by one HF molecule.
Polarographic Study of the Complexation of Na+ and K+ Ions by Dibenzo-18-crown-6 in Non-Aqueous Solution
Authors: Lada E , Urbanczyk A , Kalinowski MK
Published: December 2006

Complexes of Na+ and K+ ions with dibenzo-18-crown-6 (6,7,9,10,17,18,20,21-octahydro-dibenzo[ b,k ] [1,4,7,10,13,16] hexaoxacyclooctadecin ) were studied by polarography in several non-proton-donating media. Their stability constants are strongly influenced by the solvents, and vary inversely with the Gutmann donicity scale and with the Persson HDS parameter which is a measure of the hardness for these solvents.
The Electron Impact Induced Fragmentation of 1-Aryl-5-hydroxy-1,2,3-triazole-4-carboxamides
Authors: Lebedev AT , Samguina TY , Blumenthal T , Kolobov MY
Published: December 2006

The pathways of the electron impact induced fragmentation of 1-aryl-5- hydroxy-1,2,3-triazole-4-carboxamides were studied. The compositions of the key ions were confirmed by high-resolution mass spectrometry. The proposed pathways were established from mass analysed ion kinetic energy spectra, and B/E and B2/E linked scans. A variety of structures for the molecular ion of the title compounds is proposed.
The Collision-Induced Dissociations of Deprotonated Isopropyl and t-Butyl Ketones. Some Unusual Alkyl Migrations
Authors: Alexander MJ , Bowie JH , Hayes RN
Published: December 2006

Rearrangement reactions involving hydride and methyl anion migrations are observed when certain enolate ions derived from isopropyl and t- butyl ketones are subjected to collisional activation. For example (i) -CH2CO-i-C3H7 → -(CH2CHO)+C3H6 and (ii) -CH2CO-t-C4H9 → -(CH2COCH3)+C3H6The mechanisms of these and related reactions have been investigated by denterium labelling and product ion studies.
The X-Ray Crystal Structure of 1,2-3,4-Di-O-isopropylidene-4-C-methylthiomethoxy-β-L-arabino-hexoseptanos-5-ulose
Authors: Craig DC , James VJ , Stevens JD
Published: December 2006

The crystal structure of the title compound (1) has been determined by X-ray diffraction. Crystals of (1) are orthorhombic, space group P21212 with a 11.425(1), b 24.916(1), c 5.8952(3)Ǻ, Z 4. Refinement on 1675 observed reflections measured with Cu Kα radiation converged at R 0.034. The seven- membered ring adopts a boat conformation in which the pseudo plane of symmetry passes through the ring oxygen.
Studies in the Cycloproparene Series: Cycloaddition Reactions With 1,3-Diphenylisobenzofuran
Authors: Halton B , Russell SGG
Published: December 2006

The behaviour of cyclopropabenzene (1) with 1,3-diphenylisobenzofuran ( dpibf ) is temperature dependent. Addition to the strained bridge bond of (1) gives the Diels -Alder adduct (13) in tetrahydrofuran at 20°C, but in chloroform at the same temperature the ring-expanded 5,10-epoxydibenzocycloheptene (12) is also formed. Compound (12) becomes the sole product from reaction at 30°C or higher. Cyclopropa [b]naphthalene (2) is inert to dpibf under similar conditions but provides the dimer 6,13-dihydropentacene (15). The triazoloindazole (19) results from reaction of (2) with 4-phenyl-3H-1,2,4-triazole-3,5(4H)- dione.
A Synthesis of the Lichen Dibenzofuran Pannaric Acid 6-Methyl Ester
Authors: Elix JA , Pratt SJ , Laundon JR
Published: December 2006

A total synthesis of pannaric acid 6-methyl ester (3,9-dihydroxy-6-methoxycarbonyl-1,7-dimethyldibenzofuran-2-carboxylic acid) (2) has been achieved by a biomimetic -type approach with palladium(II) acetate in the key cyclization step. This acid (2) was shown to be identical with the major metabolite of the lichen Leproloma vouauxii.
The Chlorination of 4-Methylbenzene-1,2-diamine: the Formation of 2,3,4,5,5-Pentachloro-6,6-dihydroxy-4-methylcyclohex-2-enone Hydrate and Some Transformation Products
Authors: Calvert JL , Hartshorn MP , Robinson WT , Wright GJ
Published: December 2006

Chlorination of 4-methylbenzene-1,2-diamine gives the pentachloro ketone (3) which, on treatment with base, is converted mainly into the hydroxy acid (4). Methylated derivatives (5) and (6), and an unexpected transformation product of the hydroxy acid (4) are described. The chlorination of tetrachlorocatechol (8) gives the hexachloro ketone (9). X-Ray crystal structure determinations are reported for compounds (3)-(7) and (9).
The Crystal and Molecular Structures of Bis(diethyldithiocarbamato)platinum(II) and Bis[di(2-hydroxyethyl)dithiocarbamato]platinum(II)
Authors: Baker AT , Emett MT
Published: December 2006

The structures of [Pt(S2CN(C2H5)2)2] (1) and [Pt(S2CN(C2H4OH)2)2] (2) have been determined by single-crystal X-ray diffractometry. Compound (1) crystallizes in the tetragonal space group P42/n, a 16.4692(10),c 6.2160(6) � (Z = 4); R was 0.029 for 1012 observed reflections. Compound (2) is monoclinic, space group Pc, a 6-0663(11), b 1.1784(15), c 12.5740(21) � ,β92.569(8)� (Z = 2); R was 0.019 for 1573 observed reflections. The presence of electron-withdrawing groups in the ligands of (2) appears to have little effect on the Pt-S distances but causes an increase in the C-N bond length, with the C-N bond lengths being significantly different at the 2 σ level.
Methylation of Some Deprotonated Sterically Hindered Pyrimidin-4-ols
Authors: Evans RF , Savage GP
Published: December 2006

Anions derived from t-butyl-substituted pyrimidin-4-ols were methylated with iodomethane . The site of methylation was determined by proton-coupled 13C n.m.r. and the relative proportions of isomers were determined by 1H n.m.r. A t-butyl substituent ortho to a ring nitrogen markedly reduced the propensity for methylation at that nitrogen to the point where O-methylation, uncommon under these conditions, was observed.
Yield of upland rice cultivars in rainfed and sprinkler-irrigated systems in the Cerrado region of Brazil
Authors: Crusciol C. A. C. , Soratto R. P. , Arf O. , Mateus G. P.
Published: December 2006

In upland rice, the reduced grain yield that originates from the moisture stress period is related to the plant’s tolerance of water deficiency and may vary between cultivars. The purpose of the work presented here was to evaluate the performance of upland rice cultivars in both rainfed and sprinkler-irrigated systems. A split-plot scheme with 8 replicates in a randomised block design was used. The plots were composed of 2 cropping systems (rainfed and sprinkler-irrigated) and the split-plot consisted of 2 cultivars (IAC 201 and Carajás) which are suggested for cultivation in upland ecosystems. Carajás had a greater number of panicles per square metre, higher spikelet fertility and grain mass, and, consequently, a higher grain yield than IAC 201 regardless of cropping system. IAC 201 was more sensitive to water deficiency than Carajás. Sprinkler irrigation improved spikelet fertility, grain mass and upland rice grain yield. Even when cultivars with a higher tolerance of water deficiency are used, a sprinkler-irrigated system may be a viable method to increase upland rice yield throughout most of the Brazilian Cerrado.
Effect of growing site, moisture stress and seed size on viability and dormancy of Sporobolus pyramidalis (giant rats tail grass) seed
Authors: Vogler W. D. , Bahnisch L. M.
Published: December 2006

Sporobolus pyramidalis P. Beauv (giant rats tail grass) is a serious agricultural and environmental weed in tropical and subtropical areas of Australia. Infestations of this unpalatable plant reduce the productivity of pastures and the profitability of industries dependent on grazing animals. This paper reports a series of studies undertaken to assist in the development of control strategies for this species. In particular, these studies measured the viability and dormancy status of fresh seed of S. pyramidalis and the decline of dormancy with time. Variability in these characteristics was determined in seeds collected from several sites within south-east Queensland. The effect of moisture availability during the inflorescence and seed production phases on seed viability and dormancy was also determined. The dormancy of freshly collected seed from several sites ranged from 15 to 95%, but decreased to negligible levels after 4–6 months. Seeds that matured under conditions of high moisture availability were initially more dormant than seeds matured where moisture was less readily available. The proportion of viable seeds was significantly lower in smaller than larger seeds even though viability for all seed sizes exceeded 90%. This study has shown that seed of S. pyramidalis generally has high viability with a large proportion of the seed germinable soon after maturity.
Influences of field pea (Pisum sativum) density on grain yield and competitiveness with annual ryegrass (Lolium rigidum) in south-eastern Australia
Authors: Lemerle D. , Verbeek B. , Diffey S.
Published: December 2006

The variation in field pea grain yield and competitiveness with annual ryegrass due to crop density, row spacing and cultivar was determined to enable farmers to better manage weeds with cultural control tactics. Crop density varied with seeding rate, cultivar, row spacing and year. Higher seeding rates were required to reach equivalent plant densities in cv. Dinkum (short, semi-leafless) compared with cv. Dundale (tall, conventional-leaf), and at 36 cm compared with 18 cm row spacing. Field pea grain yield was reduced more at low crop densities, in Dinkum, at 36 cm row spacing, and in the presence of weeds. Percentage yield losses from weed competition were similar in both cultivars (about 70–80%) at a low density of 10 plants/m2 in 2 seasons. At higher crop densities Dinkum had a larger loss than Dundale (i.e. at 30 plants/m2 losses were 60 and 35%, respectively, compared with 50 and 5% at 60 plants/m2). Seasonal variation influenced the effect of crop density on yield loss from weeds. The percentage yield loss from weeds in 1993 ranged from about 90 to 40% at plant densities of 10 to 40 plants/m2, in contrast to 1995 when 40% yield loss occurred at all these densities. Ryegrass dry weight was reduced with increasing field pea density in both years, and in the tall more than the short cultivar in 1 year. Maintaining recommended field pea seeding rates has considerable financial benefits in both weed-free (around $100/ha) and weed-affected crops (to $400/ha). In weedy situations, integrating cultural practices such as higher seeding rates and choice of cultivar that enhance crop competitiveness will improve weed management in south-eastern Australia.
Repeatability of pig body composition measurements using dual energy X-ray absorptiometry and influence of animal size and subregional analyses
Authors: Suster D. , Leury B. J. , Kerton D. J. , Dunshea F. R.
Published: December 2006

Fifteen Large White × Landrace male pigs were used to investigate the influence of animal size and subregional analysis technique on dual energy X-ray absorptiometry body composition measurements and their repeatability. Pigs were scanned in triplicate with an Hologic QDR4500A X-ray absorptiometer at the beginning of the study (3 weeks of age, liveweight 5–10 kg) and then every 4 weeks until 19 weeks of age. Measurements made by dual energy X-ray absorptiometry included total tissue mass, lean tissue mass, fat tissue mass and bone mineral content. The QDR4500 software allows the scanned image to be divided into head, arms, legs and trunk using an in-built regional analysis grid that contains algorithms unique to each region. Different regional grid manipulations were performed at each scan to evaluate the effects of incorporating subregions into a whole body analysis over time. The dual energy X-ray absorptiometry measurements were highly repeatable and measurement repeatability improved as animal size increased. When results were averaged across regional grid placement and scan time, the most repeatable measurement was total tissue mass (CV = 0.21%), followed by lean tissue mass (CV = 0.59%), bone mineral content (CV = 2.50%) and fat tissue mass (CV = 2.71%). The placement of the regional analysis grid influenced the repeatability of all measurements except for total weight; however, this influence reduced with increasing animal size. It is recommended that the body of the scan image be positioned in the arm region and the head in the head region of the software regional analysis grid to measure whole body composition in pigs because it provides the most repeatable measure overall. Animal placement into the trunk region or utilising the full regional analysis option as specified by the manufacturer provided less repeatable results.
Do flower-tripping bees enhance yields in peanut varieties grown in north Queensland?
Authors: Blanche K. R. , Hughes M. , Ludwig J. A. , Cunningham S. A.
Published: December 2006

It has been demonstrated that tripping of peanut flowers by large bees enhances pollination and improves peanut yields of some early commercial peanut varieties but this phenomenon has not been evaluated for recently developed peanut varieties. Our study aimed to establish whether bees provide this service for peanut varieties currently grown on the Atherton Tableland, north Queensland. To measure the impact of native and introduced bees occurring without assistance in crops, we set up 3 cage treatments (meshed to exclude large bees; partly meshed to allow bee access but take cage effects into account; and unmeshed) in each of 7 peanut crops. We also trapped bees in each crop for the entire flowering period. In a separate experiment, designed to ensure that suitable large bees were abundant nearby, we set up 6 replicates of the same 3 cage treatments in another peanut crop where 4 honeybee colonies were located. On a sunny day, during peak flowering, we monitored the number of honeybee visits to the peanut flowers in this crop between 0820 and 1730 hours. At harvest, we found that there was no effect of treatment on peanut yield (number of peanuts/g plant biomass). Thus, bees were not contributing to peanut pollination. This was reflected in the fact that no honeybees (or native bees) were observed visiting peanut flowers in the crop augmented with honeybees, and even though we caught 6 species of suitably sized bees in the other peanut crops, no bee species was common. It seems likely that selection for other desirable peanut traits has resulted in development of varieties that are no longer attractive to flower-tripping bees and that there is no advantage to be gained by north Queensland growers promoting bees in crops of these varieties.