bluuebunny/crossref_metadata_2025 huggingface dataset:
Excess enthalpies of mixing of chloroform and carbon tetrachloride with tetrahydrothiophen and thiophen
Authors: Waghorn GW , Malcolm GN , Watson ID
Published: September 2010

The excess enthalpies of
mixing of the systems CHCl3 + C4H4S, CHCl3
+ C4H8S, CCl4 + C4H4S
and CCl4+C4H8S have been measured at 25�C. The
results for the chloroform system are interpreted both in terms of a 1 : 1
association complex,1 and in terms of this plus an additional effect
due to chlorine-sulphur interactions.
The adsorption of CO on MgO: The effect of γ-irradiation
Authors: Breakspere RJ , Al-Dugaither MA
Published: September 2010

The adsorption of carbon
monoxide on magnesium oxide has been investigated between 294 K and 873 K with
and without the influence of continuous γ-irradiation. The adsorption
exhibits a fast initial step, which above 573 K is associated with an adsorbed
bidentate species requiring an activation energy, Ea of 40.1 � 6.0
kJ mol-1. This fast adsorption is followed by a slower process which
obeys first-order kinetics with respect to the presence of CO. The Arrhenius
plot of this slow adsorption on unirradiated MgO, at
673 K and above, indicated that two processes, of Ea 181.4 � 5.0 kJ
mol-1 and 78.1 � 6.0 kJ mol-1, were operative above and
below 773 K respectively. Below 773 K a (CO32-)ads
species is produced, whereas above this temperature the incorporation of (CO32-)ads
species into the bulk of the MgO lattice and the
regeneration of the surface by outward diffusion of lattice oxygen ions became
rate-determining. The adsorption of CO during γ-irradiation occurred over
the complete temperature range 573-773 K, with an Ea of 69.0�6.0 kJ
mol-1; this implies that the rates of these diffusion processes are
enhanced by the radiation. ��� The Gads values at 373, 573 and
673 K show a maximum in the initial adsorption region. This is caused by the
destruction of the shallow trapped positive holes-which are associated with
impurity atoms and used in the adsorption process-by radiation-generated
electrons.
Magnetization studies of Tris(ethylenediamine)nickel(II) complexes down to 2 K
Authors: Mackey DJ
Published: September 2010

Single crystal magnetization
studies of Ni(en)3(NO3)2 down to 2 K show that
there are appreciable antiferromagnetic interactions parallel and perpendicular
to the hexagonal c axis. Deuteration of the NH2 groups has no effect
on the average magnetic moment of the compound and it seems that hydrogen
bonding does not play a dominant role in the exchange mechanism. The structurally
related compound Ni(en)3SO4 behaves as a simple
paramagnet down to 2 K.
Chromic acid oxidation of benzhydrols-kinetics and mechanism
Authors: Ramanujam VMS , Venkatasubramanian N , Sundaram S
Published: September 2010

The kinetics of the
oxidation of benzhydrol (diphenylmethanol) and several of its substituents by
chromium(VI) oxide in aqueous acetic acid have been studied in detail. The rate
of oxidation is expressed as
��������������������� v = k3[ArAr'CHOH][CrVI][H+]2
The effect of ring substituents
on the rate gives a p+ value of -0.546 (r = 0.959) pointing to the
development of an electron-deficient centre in the transition state. The
oxidation of benzhydrol[α-D] proceeds 6.5 times slower than that of its
protio analogue at 55°C. From the Arrhenius plots, activation parameters have
beep evaluated and the isokinetic relationship has been analysed. The results
are discussed in terms of a mechanism involving a rate-determining loss of
hydride ion from the α-carbon of benzhydroxy chromate ester.
Carbon-13 nuclear magnetic resonance study of tricarbonyldieneiron complexes: Substituent effects in relation to π-bond orderdistributions
Authors: Pearson AJ
Published: September 2010

The changes in 13C
shieldings of C 1 and C 3, produced by methoxyl and
methoxycarbonyl substituents at C 2, reflect the distribution of π-bond
orders in uncomplexed 1,3-dienes, and indicate a substantial reorganization of
this distribution upon forming diene-Fe(CO)3 complexes.
Additivity of deshielding effects in the 1H N.M.R. spectra of some exo-Triazatricyclo[5,2,1,02,6]decenes and exo-Azatricyclo[3,2,1,02,4]octanes
Authors: Ang WH , Halton B
Published: September 2010

The presence of an
endo-chloro substituent at C8 (or C9) of 5-phenyl-exo-3,4,5-triazatricyclo-[5,2,1,02,6]dec-3-enes
and at C 6 (or C 7) of 3- phenyl-exo-3-azatricyclo[3,2,1,02,4]octanes
causes significant deshielding of the endo-bridgehead protons. The through-space
deshielding effect is remarkably additive in cis,endo-dichloro
analogues.
Formic acid solvent system. II. Conductance and solvation studies of 1 : 1 electrolytes in formic acid
Authors: Paul RC , Sharma R , Puri T , Kapoor R
Published: September 2010

Conductances of some 1 : 1
electrolytes have been measured in the concentration range (5-100) x 10-3
mol l-1 in anhydrous formic
acid at 25�. The conductance data have been analysed by Fuoss-Shedlovsky equations. Transference numbers of sodium and
potassium formates have been measured in this solvent at 25� by a modified Hittorf's method in the concentration range (3-80) x mol l-1.
Ionic mobilities, effective ionic radii and solvation numbers of various ions
in solution have been calculated. Solvation of cations decreases with the
increase in the crystal radii of the ions.
The stereochemistry of organometallic compounds. XV. Reactions of the allylpalladium complexes of α,β-unsaturated ketones and esters with nucleophiles
Authors: Jackson WR , Strauss JU
Published: September 2010

Reactions of π-allylpalladium
complexes of α,β-unsaturated ketones and
esters with nucleophiles occur regioselectively at the γ-carbon atom to
give high yields of γ-functionalized products. The E/Z-stereochemistry of
the products is discussed in relation to the syn/anti-
stereochemistry of the π-allylpalladium compounds and the reactivity of
the latter compounds is discussed in terms of their 1H and 13C
N.M.R. spectra.
An E.S.R study of the oxidation of sodium alkyl sulphates by hydroxyl radicals
Authors: Hewgill FR , Proudfoot GM
Published: September 2010

Radicals detected by
electron spin resonance show that hydrogen abstraction in the oxidation of
alkyl sulphates by the TiCl3/H2O2 system is
not selective. In the light of these results and of evidence obtained by
reduction of γ-iodocaproic acid, the previous claim1 that
hydrogen abstraction from aliphatic carboxylic acids containing 6-8 carbons
occurs chiefly at the α and ω-1 position scan no longer be supported.
Comparison of the values of the interaction parameter ξ from upper critical solution temperatures of acetone + alkanes with values obtained from gas-liquid critical temperatures
Authors: Toczylkin LS , Young CL
Published: September 2010

The upper critical solution
temperatures, UCST , of acetone + alkane (n- C5H12 to n-C17H36)
and acetone + hexane isomers have been measured. These results are used to
calculate an interaction parameter ξ by using the van der
Waals one-fluid model together with the Guggenheim
equation of state. Values of ξ are compared with those obtained from the
gas-liquid critical temperatures. The gas-liquid critical temperatures for the
n- alkane + acetone systems were taken from the literature whereas those for
the hexane isomers + acetone were measured in this work. The values of ξ
calculated from gas-liquid critical temperatures are slightly greater than
those calculated from the UCST as has been observed previously for other
systems.
Studies on Chloroplast Membranes. II. 13C Chemical Shifts and Longitudinal Relaxation Times of 1,2-Di[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3-galactosyl-sn-glycerol and 1,2-Di[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3-digalactosyl-sn-glycerol
Authors: Johns S , Leslie D , Willing R , Bishop D
Published: September 2010

The 13C chemical
shift and longitudinal relaxation time (T1) of the individual carbon
atoms in the two major lipids of chloroplast thylakoids,
1,2-di[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3- galactosyl-sn-glycerol and 1,2-di[(9Z,12Z,15Z)-octadeca-9,12,15- trienoyl]-3-digalactosyl-sn-glycerol, have been measured in
the three solvents: methanol[D4], chloroform[D] and water[D2].
The longitudinal relaxation time data are interpreted in terms of different
secondary structures in the different solvents, a monomeric structure in
methanol[D4], an inverted micellar structure in chloroform[D] and a
bilayer structure in water[D2]. Two possible correlations times can
be obtained from the longitudinal relaxation times of the galactosyl and
glyceryl carbon atoms in chloroform[D] and water[D2] and nuclear
Overhauser enhancement values have been used to assign the correlation times to
these carbon atoms.
Cyclophanes. VIII. An attempted preparation of [7]circulene from [2,2](3,6)Phenanthro(2,7)naphthalenophane-1,11-diene
Authors: Jessup PJ , Reiss JA
Published: September 2010

The synthesis of
[2,2](3,6)phenanthro(2,7)naphthalenophane-1,11-diene (13) from
2,13-dithia[3,3]-(3,6)phenanthro(2,7)naphthalenophane (6) is described.
Attempts to oxidatively cyclize the diene (13)to [7]circulene (3) failed, and
these observations have been rationalized in terms of the probable syn stereochemistry
of the diene (13). Several other reactions of the phenanthronaphthalenophane
ring system are described.
Calculations on open shell small molecules using different Gaussian orbitals for electrons with different spins
Authors: Farmer RG , Peacock TE
Published: September 2010

An extension of Frost's
method to open shell systems using different floating spherical Gaussian
orbitals for electrons with different spins is presented. The results of ab initio computations on some small molecules are given
and the degree to which electron correlation is included is discussed.
The effect of pressure on the infrared spectra of the formates of the alkali and alkaline earth metals
Authors: Hamann SD , Spinner E
Published: September 2010

The infrared spectra of the
solid metal formates HCO2Li, HCO2Li,H2O, HCO2Na,
DCO2Na, H13CO2Na, HCO2K, DCO2K,
HCO2Rb, DCO2Rb, HCO2Cs, DCO2Cs,
(HCO2)2Ca, (HCO2)2Sr, (HCO2)2Ba
and (HCO2)2Pb have been measured in the pressure range
0-42 kbar at 25�C. For the sodium salt two new
modifications formed at high pressure have been observed, but the potassium,
rubidium and caesium salts show only one phase transition. A phase change,
though only at pressures far above 42 kbar, is
indicated also for the calcium, the barium and probably the anhydrous lithium
salt. The various spectral responses to changes in pressure strongly indicate
that in the form prevailing at ordinary pressure and temperature, phase I, the
formates of sodium and potassium have the same type of molecular packing in the
crystal structure. Phases II of the sodium and potassium salt appear to belong
to a new modification (?C?), whereas phase III of the sodium and phase II of
the caesium salt belong to the modification ?B? previously observed in disc spectra.
In a given phase, the effect of pressure on the formate vibration frequencies
is sometimes quite different for the pure crystalline salt in bulk and for the
same species when isolated by isotopic dilution. In these cases the main effect
of pressure is that on the intermolecular coupling of vibrations. Several
frequency changes accompanying phase transitions, by contrast, are essentially
unchanged on isotopic dilution and arise mainly from changes in the effective
intramolecular force constants.
Kinetics of pyroarsenate hydrolysis in aqueous solution
Authors: Richmond TG , Johnson JR , Edwards JO , Rieger PH
Published: September 2010

The rate of hydrolysis of
pyroarsenate in 0.1 mol dm-3 NaClO4 solutions, pH 6-9,
was measured by a pH-stat technique at temperatures ranging from 278 to 298 K.
The pKa of HAs2O73-, found to be
the predominant reactant under these conditions, was 7.3 and 7.6 at 283 and 298
K, respectively. The hydrolysis rate constant for HAs2O73-
was 0.05 s-1 at 298 K with activation parameters ΔH?
= 49 � 9 kJ mol-1 and ΔS? = -107 � 30 J mol-1
K-1. An associative mechanism is indicated.
Oxidative addition of monosilanes to planar iridium(I) complexes and carbonylation of the resulting adducts
Authors: Bennett MA , Charles R , Fraser PJ
Published: September 2010

Silanes [R3SiH;
R3 = Cl3, MeCl2, (EtO)3,
Ph3] undergo irreversible oxidative addition to planar iridium(I)
complexes IrClL3 (L = PPh3, PMePh2 or AsPh3)
to give silyliridium(III) hydrides IrHCl(SiR3)Ln
(n = 2 or 3). The yellow, five-coordinate, probably tetragonal pyramidal
complexes(n = 2) are formed mainly when L = PPh3 or AsPh3,
and also in the case of L = PmePh2, R = Ph, whereas the colourless,
six-coordinate, presumably octahedral adducts are formed predominantly when L =
PMePh2. Both five- and six-coordinate adducts can be isolated from
the addition of dichloro(methyl)silane to IrCl(AsPh3)3.
Most of the adducts react with carbon monoxide under ambient conditions to give
silyliridium(III) hydrido carbonyls, IrHCl(SiR3)(CO)L2,
which may undergo partial or complete reductive elimination to IrCl(CO)L2 and R3SiH; the ease with
which this occurs depends on L (PPh3 > PMePh2 >
AsPh3) and on R3 [Ph3 > (EtO)3 > Cl3 ≈ MeCl2].
The reactions of silanes with IrClL3, RhClL3 and IrCl(CO)(PPh3)2 are compared, and the
trends observed in the case of IrClL3 are discussed in terms of
electronic and steric effects in the silyl and Group
5 donors. Structural assignments for the new complexes are based on i.r., far-i.r. and 1H
N.M.R. data.
Bis(tridentate)cobalt(III) complexes with diethylenetriamine and 4-Methyldiethylenetriamine [2,2'-Methyliminodi(ethylamine)]: Assignment of geometric configurations by 1H and 13C N.M.R. spectroscopy
Authors: Searle GH , Lincoln SF , Keene FR , Teague SG , Rowe DG
Published: September 2010

The new complexes symmetrical-facial-[Co(medien)2]3+
and s-fac- [Co(dien)(medien)]3+ have been
isolated. The 1H N.M.R. spectra of these complexes, the s-far, u-far
and meridional isomers of [Co(dien)2]3+,
and u-fac-[Co(daes)2]3+ show
different splittings of the NH2 proton resonances [dien = diethylenetriamine, medien = 4- methyldiethylenetriamine
or 2,2?-methyliminodi(ethyl-amine), daes = di(2-aminoethyl) sulphide or 2,2?-thiodi(ethylamine)].
These splittings depend on the geometries of the complexes (different numbers of
stereochemically distinct NH2 groups), the particular chelated
ligands (splittings due to coupling between the two protons on each NH2
may vary with chelate ring conformational mobility), and the counter-anions
(different extents of ion- association through hydrogen bonding). Thus NH2
proton resonance signals may not always provide a reliable method for
establishing molecular geometries. In contrast, the 13C N.M.R.
spectra of all these complexes are completely diagnostic of the detailed geometries,
and most of the resonances observed have been assigned to particular carbon
atoms.
A synthesis of abequose (3,6-Dideoxy-D-xylo-hexose)
Authors: Copeland C , Stick RV
Published: September 2010

The S-methyl 3-O-dithiocarbonates
of 1,2:5,6-di-O-isopropylidene-α-D-galactofuranose and ?gulofuranose have been prepared and subsequently reduced
with tributylstannane to 3-deoxy-1,2:5,6-di-O-isopropylidene-μ- D-xylo-hexofuranose. Partial hydrolysis of this compound led
to the 5,6-diolwhich was deoxygenated at C 6 to form 3,6-dideoxy-1,2-O-
isopropylidene-α-D-xylo-hexofuranose, and subsequently
abequose on acid hydrolysis. A rationale has been proposed for the variations
in hydrolysis of di-O-isopropylidene-α-D-hexofuranoses and derivatives to
their 5,6-diols.
Abnormal behaviour of 8b,8c,9,11,11a,11b-Hexahydro- and 8c,9,11,11a-Tetrahydro-phenanthro[9',10':3,4]cyclobuta[1,2-c]furan during bromination with N-bromosuccinimide
Authors: McCulloch RK , Stringer MB , Wege D
Published: September 2010

Dimethyl
1,2,2a,10b-tetrahydrocyclobuta[l]phenantene-cis-1,2- dicarboxylate
has been converted into 8b,8c,9,11,11a,11b- hexahydrophenanthro[9?,10?:3,4]cyclobuta[1,2-c]furan
(9) and 8c,9,11,11a-tetrahydrophenanthro[9?,10?:3,4]cyclobuta[1,2-c]furan (5)
by a series of standard reactions. Bromination of (9) with N- bromosuccinimide
gave 3-bromo-4-(9?-phenanthryl)tetrahydrofuran (14) by an unusual fragmentation
of the cyclobutyl ring. Reaction of (5) with N-bromosuccinimide resulted in the
introduction of the N-succinimyl substituents into the α-position of the
tetrahydrofuran ring.
Spectrophotometric determination of monomeric plus oligomeric and polymeric hydroxy species of chromium(III) in aqueous solutions
Authors: Rengasamy P , Oades JM
Published: September 2010

The anion of edta formed complexes with monomeric and oligomeric species
of chromium(III), whereas no reaction was observed with polymeric hydroxy forms
in aqueous solutions of Cr(NO3)3 and CrCl3. A
procedure is described to distinguish monomeric plus oligomeric from polymeric
forms of chromium(III) in aqueous solutions by determining the CrIII-edta complex spectrophoto- metrically at
546 nm.
Liquid mixtures involving complex formation : Extensions of the ideal associated solution theory
Authors: Fenby DV , Chand A , Inglese A , Grolier JE , Kehiaian HV
Published: September 2010

Extensions of the ideal
associated solution theory which take into account intermolecular interaction
and/or size factors are derived and applied to triethylamine+ CHCl3
and diethyl ether+CHCl3. Evidence is presented for
non-hydrogen-bonding specific interactions between the unlike molecules in
these systems. Theories that do not take this into consideration are likely to
be unsatisfactory for the determination of hydrogen-bond properties. With
respect to the evaluation of ?net complex formation? properties, the extensions
considered do not represent significant improvements of the simple theory. The
molar enthalpies of mixing of triethylamine+CH3CCl, and diethyl
ether+ CH3CCl3 have been measured at 288.15 and 298.15 K.
Molar Kerr constants and solute polarizability anisotropies of ammonia, trimethylamine, trimethylamine oxide and 1,4-Diazabicyclo[2,2,2]octane
Authors: Armstrong RS , Aroney MJ , Calderbank KE , Pierens RK
Published: September 2010

Electric dipole moments and
molar Kerr constants are reported for ammonia, trimethylamine, trimethylamine
oxide, 1,4- diazabicyclo[2,2,2]octane and its monohydrate in non-polar
solvents. The dipole moment now found for 1,4-diazabicyclo[2,2,2]octane differs
substantially from previously recorded values. Effective polarizability
anisotropies are derived for each of the anhydrous molecules and for the N-H
and N-C bonds. The effect of solute interactions with benzene is explored.
Reactions of iron(II) and iron(III) chlorides with formic acid
Authors: Paul RC , Baidya OB , Kaur AJ , Sharma RD , Kapoor R
Published: September 2010

Formic acid reacts with
iron(II) and iron(III) chlorides to give FeCl(OOCH),HCOOH
and FeCl2(OOCH),2H2O at low temperatures and Fe(OOCH)2,2HCOOH
and FeCl(OOCH)2,H2O at higher
temperatures respectively. These compounds have been characterized by
elementary analyses, infrared, thermal and magnetic susceptibility
measurements.
The viscosity of glycine and DL-alanine in dimethylformamide-water mixtures at 298.15 K
Authors: Phang S
Published: September 2010

The viscosity
B-coefficients of glycine and DL-alanine in 5%, 15% and 25% w/w
dimethylformamide-water mixtures have been measured. The densities and limiting
apparent molal volumes are also presented. It is shown that dimethylformamide
is a structure-breaker whereas DL-alanine is only a weak structure-breaker.
Reactions of stabilized phosphoranes with enol lactones
Authors: Babidge PJ , Massy-Westropp RA
Published: September 2010

Enol lactones in which the
double bond is conjugated with an ester group react with ethoxycarbonyl-methylenetriphenylphosphoraneunder mild conditions to
yield the normal Wittig product, derivedfrom the lactone carbonyl
group. When the double bond is conjugated with a ketone group reaction occurs
at both carbonyl groups. Factors influencing reactivity are discussed.
13C N.M.R. spectral studies of some naturally occurring quinones and related compounds
Authors: McDonald IA , Simpson TJ , Sierakowski AF
Published: September 2010

The 13C N.M.R.
spectra of quinones (1)-(14) have been recorded and fully interpreted. Analysis
of the fully 1H-coupled spectra has enabled the assignment of
substituents in the benzene ring and has allowed the relative orientation of
the benzene and quinone rings to be established.
The oxidation products of 1-Alkyl-3-arylthioureas: A chemical and spectral study
Authors: Joshua CP , Rajasekharan KN
Published: September 2010

The oxidation of
1-alkyl-3-arylthioureas with hydrogen peroxide in acidic aqueous ethanol yields
2,4-dialkyl-3,5-bis(arylimino)-1,2,4- thiadiazoles and
N,N?-dialkyl-N?-aryl-N-benzothiazolylguanidines as the final products. The
former were found to rearrange into the latter in acidic solutions. The
formation of amidinothioureas as the precursors of thiadiazoles is established
by their isolation from solutions which were partly oxidized. The reduction of
the thiadiazole afforded an amidino-thiourea which was different from the one
obtained by partial oxidation of thiourea. The reaction of benzenesulphonyl
chloride on these thioureas also yielded amidinothioureas. The N.M.R. and mass
spectra of the products obtained by the oxidation of these thioureas are also discussed
briefly.
Extractives of Australian timbers. XVII. The isolation, structure and synthesis of koparin (7,2',3'-Trihydroxy-4'-methoxyisoflavone)
Authors: Berry RC , Eade RA , Simes JJH
Published: September 2010

The isolation of koparin, a
minor constituent of the wood of Castanospermum australe,
is described. By a combination of chemical and spectroscopic methods koparin
was shown to be either 7,3?,4?-tri- hydroxy-2?-methoxyisoflavone (5) or
7,2?,3?-trihydroxy-4?- methoxyisoflavone (6). The latter compound has been
synthesized by demethylenation of 7-hydroxy-4?-methoxy-2?,3?-methylenedioxyiso-
flavone (9) and is identical with koparin.
Studies of Australian soft corals. II. A novel cembrenoid diterpene from Lobophytum michaelae
Authors: Coll JC , Mitchell SJ , Stokie GJ
Published: September 2010

A new cembrenoid diterpene
is reported from Lobophytum michaelae, a soft coral. It is shown to have structure
(3) and is clearly related to lobophytolide (1).1 Evidence for the
structure is largely spectroscopic, relying especially on infrared and nuclear magnetic
resonance data, and is consistent with the results of ozonolysis.
Criteria for assessing theoretically derived electric field gradient tensor components
Authors: Sheps M , Hacobian S
Published: September 2010

It is possible to set up an
electric field gradient criteria scheme as an aid in assessing the quality of
theoretically derived electric field gradient (EFG) tensor components
characterized by a non-zero asymmetry parameter. The analysis draws attention to
the importance of checking that the theoretically predicted coordinate axes
assignments of the principal axes system (PAS) for the EFG tensor components
respectively agree with the assignments of the experimental PAS. An application
of the PAS-assignment-criterion shows that some well known LCAO MO based EFG
approximation schemes when tested on the hydrazoic acid molecule possess a
serious limitation, as evidenced by their failure to obey this criterion.
The thermal decomposition of methyl chloroformate
Authors: Johnson RL , Stimson VR
Published: September 2010

In the presence of
inhibitors, methyl chloroformate decomposes at 425- 480� to methyl chloride and
carbon dioxide in a homogeneous molecular reaction. The rate constant is given
by

k1 = 10(14.26�0.20)exp[(-251000�2000)/8.314T] s-1
Reaction of peri-Aminonaphthoquinones and Dihydroperimidinones with piperidine
Authors: Cameron DW , Samuel EL
Published: September 2010

Reaction of
methyl-substituted 5-amino-1,4-naphthoquinones with piperidine gave
preferentially 3-piperidino derivatives. The corresponding orientation also
resulted from amination of the dihydroperimidinone
system (1), a slower process. When position 3 of the naphthoquinone was
substituted by a methyl group, preferential side-chain amination of that group
was observed.
Synthesis of new 14-, 15- and 16-membered crown compounds containing oxygen and nitrogen heteroatoms
Authors: Grimsley PG , Lindoy LF , Lip HC , Smith RJ , Baker JT
Published: September 2010

Facile syntheses for new
14-, 15-, and 16-membered crown compounds derived from salicylaldehyde and
5-chlorosalicylaldehyde are reported. The new compounds contain both oxygen and
nitrogen heteroatoms.
The crystal structure of Bis(benzothiazole-2-thiolato)bis(pyridine)cobalt(II)
Authors: Dance IG , Isaac D
Published: September 2010

Crystalline
bis(benzothiazole-2-thiolato)bis(pyridine)cobalt(II) [Co(mbt)2(py)2] contains molecular complexes with C2 point
symmetry, in which the cobalt is coordinated by two thiazole nitrogen
atoms[cis, Co- N = 2.158(4) Ǻ], two mbt-
exocyclic sulphur (Se) atoms [trans, Co-S = 2.595(5) Ǻ],and two
pyridine nitrogen atoms [cis, Co-N = 2.120(4) Ǻ]. The N-C-S, section of mbt- is loosely coordinated to cobalt, forming a
four-membered chelate ring. It is inferred from the observed dimensions that
the electronic structure of coordinated mbt-
is ?allylic?, N=C=Se. The crystals are orthorhombic, a 16.165(1), b
16.302(1), c 18.533(1) , Ǻ, space group Pccn, Z
8 [2 x 1/2 x Co(mbt)2(py)2],pobs
1.495, pcalc 1.495 g cm-3: Ni(mbt)2(py)2 is isostructural. The structure was obtained
from 1847 observed diffractometer data (Cu Kα, θmax 55�), and refined to R 0.035, Rw
0.031.
Thiohydroxamato complexes of iron(III). Synthesis, magnetism and Mössbauer spectra
Authors: Mitchell AJ , Murray KS , Newman PJ , Clark PE
Published: September 2010

The syntheses of
thiohydroxamic acid ligands and their iron(III) complexes are described in
detail. The tris-chelates are of particular importance because of their
relation to one such complex which is thought to be involved in bacterial
iron-transport systems. Magnetic and spectral measurements show that the
tris-chelates generally display high-spin behaviour similar to that exhibited
by corresponding hydroxamato complexes. Variable temperature magnetic and
Mossbauer measurements on samples of the tris(benzothiohydroxamato)
derivative confirm earlier postulates of spin-crossover behaviour for this
compound, with a low-spin (S 1/2 or 3/2) component at low temperatures of c.
8%. Efforts to obtain crystal structures on a tris(thiohydroxamato)iron(III)
complex have been thwarted by twinning effects and by powder-like formation
within well formed crystal faces. The molecular structure of these, and of the
related cobalt(III) chelates, most likely contains the cis (facial) isomer. ��� A new series of bis-chelates, FeL2Cl,
has also been prepared and physical measurements show high-spin iron(III)
behaviour.
One-step synthesis of mixed carboxylate sulphonate esters of diols
Authors: Auteri SC , Cameron DW , Drake CB
Published: September 2010

Reaction between 1,2- or 1,3-diols,
sulphonic acids and carboxylic acid derivatives leads directly to mixed
carboxylate sulphonate esters. The process is believed to involve
1,3-dioxolan-2-yl cation or 1,3-dioxan- 2-yl cation intermediates.
Synthesis of the major encephalitogenic determinant of myelin basic protein and the 13C N.M.R. of some protected intermediates
Authors: Pasaribu SJ
Published: September 2010

The main encephalitogenic
determinant of bovine myelin basic protein (MBP 114-122) has been synthesized
through fragment condensation of tetrapeptide, Boc-Phe-Ser-Trp-Gly-OH,
and penta-peptide, H-Ala- Glu(OBzl)-Gly-Gln-Lys(Nε-Cbz)-Obzl. It
was observed that the benzyl ether protecting group of the serine side chain
was not removed during catalytic hydrogenation (Pd/C-H2) of the
tetrapeptide, Boc-Phe- Ser(OBzl)-Trp-Gly-OBzl. 13C N.M.R. spectra of some other
intermediates are discussed.
Synthesis of (Z)- and (E)-4-Oxooct-2-enal
Authors: Macleod JK , Bott G , Cable J
Published: September 2010

The (Z) and (E) isomers of
4-oxooct-2-enal have been prepared from a common starting material,
2-butyl-2,5-dimethoxy-2,5-dihydrofuran, by acid-catalysed ring opening for
differing times and acid concentrations. The differences in the mass spectra of
the two isomers has allowed positive identification of the (E) isomer as a
component of the scent glands of a number of bugs.
3,5-Di-t-butyl-4-hydroxyphenylglycine: A potential spin label
Authors: Hewgill FR , Webb RJ
Published: September 2010

The title amino acid has
been synthesized by the addition of ammonia to a quinone methide. Mild
oxidation produces a relatively stable aryloxy radical, and the e.s.r. spectra
of this and of related compounds are reported.
Potentiometric determinations of ionization constants of HSO4- and HCO3- ions in formamide
Authors: Dash UN
Published: September 2010

With the cell Ag-AgCl|KCl(m3), K2A(m2),
KHA(m1), QH2-Q|Pt, where A stands for SO42-
or CO32-, the ionization constants of the HSO4-
and HCO3- ions in formamide have been determined at
different temperatures. The standard thermodynamic quantities, ΔG�,
ΔH� and ΔS�, have been calculated.
The role of ion-association in the chromatographic separation of isomeric cationic cobalt(III)-amine complexes on cation-exchange resins, particularly SP-Sephadex
Authors: Searle GH
Published: September 2010

Chromatographic separations of a set of closely similar or isomeric cobalt(III) complexes, of the
kinds [Co(dien)2]3+, [Co(dien)(medien)]3+ and [Co(medien)2]3+ [dien = diethylenetriamine; medien
= 4-methyldiethylenetriamine or 2,2'-methyliminodi(ethylamine)] on SP-Sephadex C-25 and Dowex
50W-X2 cation-exchange resins have been examined with different eluents as sodium salts. The
separations obtained appear to be due primarily to differences in the association constants for
ion-pairs formed betwen the complex cations and the eluent anions, rather than due to differences
in affinities of the free cations for the resins. The strengths of the associations depend on: (1) the
availability on the complex cations of appropriately disposed N-H bonds for hydrogen-bonding to
oxyanions, and probably on the acidities of these hydrogens (acidity sec-NH > NH2), rather than
on polarity of charge distribution, and (2) the basicities of anions, in the order PO43- > SeO32-
> (+)-tartrate2- > SO42- > (+)-Sb2(C,4H2O6)22- > Cl- ≈ NO3- > ClO4-. The effects of
association with PO43-, SeO32- and (+)-tartrate2- may be so great that complex cations of different
charges are not necessarily eluted in the order of their increasing charges. Determinations of
charges and polarities (cis/trans) of cationic complexes by chromatographic procedures must
therefore be carried out under conditions where association is minimized, as with sodium
perchlorate as eluent. Under these conditions, separations are determined largely by cation-resin
interactions which are less specific and less discriminating than cation-anion interactions.
SP-Sephadex is a particularly sensitive medium for separating different cationic complexes, and tri-
sodium orthophosphate and sodium (+)-tartrate are the most effective and generally useful eluents.
Heterocladol, a halogenated selinane sesquiterpene of biosynthetic significance from the red alga Laurencia filiformis: Its isolation, crystal structure andabsolute configuration
Authors: Kazlauskas R , Murphy PT , Wells RJ , Daly JJ , Oberhansli WE
Published: September 2010

The structure and absolute
configuration of heterocladol, C15H26BrClO (6), have been
determined by single-crystal X-ray diffraction methods. This compound is the
first example of a selinane skeleton reported from Laurencia
species and its structure can be rationalized in terms of a trans-annular ring closure
of a germacradiene. The colourless crystals are monoclinic, space group P21,
with a 11.852, b 14.486, c 10.932 Ǻ, β 119.6�, Z4.
Crystal structure of exo-6-Bromo-exo-tricyclo[3,2,1,02,4]oct-anti-8-yl p-Nitrobenzoate
Authors: Johnson BL , Langley JW , Raston CL , White AH
Published: September 2010

The crystal structure of
the title compound has been determined by single-crystal X-ray diffraction at
295 K and refined by least squares to a residual of 0.064 for 775 ?observed?
reflections. The structure determination confirms the stereochemistry previously
proposed for the molecule. Crystals are monoclinic, P21/n, a
11.131(7), b 18.908(3), c 7.121(5) Ǻ, β 104.56(5)�, Z 4.
Crystal structure of Bis(tri-2-pyridylamine)iron(II) diperchlorate
Authors: Kucharski ES , McWhinnie WR , White AH
Published: September 2010

The crystal structure of
the title compound, [Fe((C5H4N)3N)2]
(ClO4)2, has been determined by single-crystal X-ray
diffraction at 295 K and refined by least squares to a residual of 0.059 (1995
'observed' reflections). Crystals are monoclinic, P21/a, a 12.815(4),
b 17.503(7), c 8.318(3) Ǻ, β 121.38(3)°, Z 2. The complex cation lies
with the metal atom on a centre of symmetry, the metal being six-coordinate, so
that only one of the tridentate ligands is crystallographically independent.
The geometry about the metal atom deviates only trivially from octahedral,
 within the one ligand being 88.1°.  is 1.982
Ǻ.
The photochemistry of 3β-Acetoxy-6-nitrocholest-5-ene and 6-Nitrocholest-5-ene. The mechanism of photodeconjugation of α,β-unsaturated nitro compounds
Authors: Pinhey JT , Rizzardo E , Smith GC
Published: September 2010

The photochemistry of
3β-acetoxy-6-nitrocholest-5-ene (1) and 6- nitrocholest-5-ene (11) has
been investigated in a number of solvents. It is suggested that for both
compounds the major primary photo-product is the corresponding aci-nitro tautomer, which then undergoes further reactions
depending mainly on the conditions employed. The aci-nitro
compounds are believed to be formed by a 1,5-hydrogen shift from C4 to oxygen,
and their intermediacy is supported by the formation of a mixture of
6α-deutero-6β-nitrocholest-4-ene and 6β-deutero-6α- nitrocholest-4-ene
on irradiation of 6-nitrocholest-5-ene in Me3COD.��� Several other reactions of 3β-acetoxy-6-nitrocholest-5-ene
and 6- nitrocholest-5-ene are described.
Organophosphorus compounds. XXII. The reaction of tertiary phosphonite, phosphinite and mixed phosphite esters with 2-Benzylideneindan-1,3-dione
Authors: Sidky MM , Soliman FM , Shabana R
Published: September 2010

Diethyl phenylphosphonite
and ethyl diphenylphosphinite react with 2-benzylideneindan-1,3-dione(1) to
give colourless addition compounds (6) and (8) respectively. The reaction of
diethyl methyl phosphite and ethyl dimethyl phosphite with (1) leads to the formation
of the corresponding phosphonates (9) and (11). Possible reaction mechanisms
are considered and the structural assignments are based on chemical and
spectroscopic evidence.
A new method of measuring second virial coefficients of condensible vapours
Authors: Couldwell CM , O'Neill SP , Pandya MV , Williamson AG
Published: September 2010

A new method for
determining second virial coefficients of condensible vapours is described
which eliminates contact between the vapour and mercury, and avoids the
necessity for accurate volume calibrations, and which depends on pressure
measurements only. The method has been tested with n-hexane and the results
obtained suggest that the technique is capable of detecting and eliminating
effects due to the contribution of third virial coefficients. New data for the
second virial coefficient are reported.
Crystal structure of Tris(ethane-1,2-diamine)nickel(II) diperchlorate monohydrate
Authors: Raston CL , White AH , Willis AC
Published: September 2010

The crystal structure of
the title compound, [Ni(en)3] (ClO4)2,H2O,
has been determined from single-crystal X-ray diffraction data at 295(1) K and
refined by least squares to a residual of 0.093 for 1400 'observed'
reflections. Crystals are orthorhombic, P bca, a
17.043(7), b 15.922(6), c 13.496(5) Ǻ, Z 8. The precision of the structure
determination is adversely affected by very high perchlorate thermal motion.
 is 2.13 Ǻ.
A versatile spray reagent
Authors: Mills JA
Published: September 2010

A spray reagent is
described, based on the Guyard reaction between MnII and MnVII
ions. It is useful after paper electrophoresis of carbohydrates, polyhydroxy
compounds, hydroxy acids and unsaturated compounds.
Reactions of tricarbonylcyclohexadienyliron cations with nucleosides and nucleoside bases
Authors: Franke F , Jenkins ID
Published: September 2010

The
tricarbonylcyclohexadienyliron cation alkylates the nucleoside bases adenine
and guanine to give both mono- and di-alkylated
derivatives. The nucleoside base cytosine and the nucleosides adenosine and
guanosine are alkylated to give monoalkyl derivatives. The alkylations appear
to be readily reversible. The structures of the alkylated derivatives are
discussed and probable structures assigned.
Acetylenic acids. II. The reaction of sulfur chlorides with phenylpropiolic acid and its methyl ester
Authors: Lok WN , Ward AD
Published: September 2010

The reactions of
phenylpropiolic acid and methyl phenylpropiolate with thionyl chloride, sulfur
monochloride, sulfur dichloride and sulfuryl chloride have been investigated.
With thionyl chloride the presence of pyridine is necessary for a reaction to
occur with the ester or for the reaction to proceed beyond the acid chloride
stage in the case of the acid. In all cases the Z and E isomers of
2,3-dichlorocinnamic acid or its methyl ester are among the main products that
have been identified. With all but sulfuryl chloride a 3-chloro-1-benzothiophen
system is also formed. Sulfuryl chloride and phenylpropiolic acid form
4-chloro-1-phenylnaphthalene-2,3-dicarboxylic anhydride in low yield. The
structures of other minor products and the pathways leading to all these
products are discussed.
On the oxidation of 2-t-Butyl-p-cresol
Authors: Hewgill FR , Howie GB
Published: September 2010

While oxidation of alkaline
solutions of 2-t-butyl-p-cresol by ferricyanide or silver oxide gives the
ortho-para-coupled Pummerer's ketone (6), ferric
chloride in slightly acid solution gives the ortho- coupled biphenyldiol (5).
With ddq in methanol the cresol is further oxidized,
again through ortho coupling, to the lactone (10), in which one of the aromatic
rings has been cleaved, and to the dibenzo-furan (9). Minor products, both
monomeric and dimeric, in which the methyl group has been oxidized via the quinone
methide, were also identified.
Synthesis of Some Benzopyran Derivatives Related to the Seed Germination Stimulant of Orobanche crenata Forsk. II. 3,4,4a,10b-Tetrahydro-2H,5H-pyrano[3,2-C][1]benzopyrans
Authors: Davis M , Pettett M , Scanlon D , Ferrito V
Published: September 2010

The pyranobenzopyran
derivatives (1a) and (1b) have been prepared by a simple route from m-methoxyphenol.
Oxidation of alkoxyphenols. XXI. Oxidative cross-coupling of phenols to unsymmetrical Biphenyl-2,2'-diols
Authors: Hewgill FR , Howie GB
Published: September 2010

Oxidation of several binary
mixtures of 4-substituted 2-t-butylphenols by potassium ferricyanide gave
unsymmetrical biphenyl-2,2'-diols. The structures of several new oxepino[2,3-b]benzofurans
are reported.
A comparative study of Jones's, Collins's and Corey's reagents in the chromium(VI) oxidation of an epimeric pair of allylic alcohols in the benzo-fused Norbornen-5-ol series
Authors: Warrener RN , Lee TS , Russell RA , Paddon-Row MN
Published: September 2010

A comparison has been made between a series of chromium(VI) oxidizing agents, as well as manganese
dioxide, a bicyclic allylic secondary alcohol, the exo-ol (7), being the substrate. Jones's, Collins's
and Corey's reagents gave, in each case, a mixture of products: the main reactions were epoxidation
to yield (8) and (9), normal ketone formation (10), and ring-fragmentation to form the indanol (11)
and the indanone (12). All reagents yielded substantial amounts of epoxide, which is rare for
Collins's reagent, and unprecedented for Corey's reagent, and varying amounts (13-30 %) of ketone,
while Jones's reagent alone gave significant ring-opened products. A dramatic change in product
composition was observed with the epimeric endo-alcohol (13), where Jones's reagent (only one
studied) yielded the related α,β,-unsaturated ketone (10) in essentially quantitative yield. A discussion
of these results is presented in terms of the current understanding of the mechanism of chromium
oxidations.
A comparison of two empirical pKa(T) equations from 298 to 448 K for 2,9-Dimethyl-1,10-phenanthroline
Authors: Alexander RD
Published: September 2010

The two most commonly used
three-term equation1,2 describing the variation of pKa
with temperature are compared over the range 298-448 K for 2,9-dimethyl-1,10-phenanthroline.
Both equations represent the data equally well over the experimental
temperature range. First-difference calculations and the Σ-plot method are
used to fit the data.
Keto-enol tautomerism. Relative stabilization of enol isomers
Authors: Bouma WJ , Radom L
Published: September 2010

Ab initio molecular orbital
theory is used to examine the effect of simple π-electron-accepting
substituents (Li, BeH, BH2) on the keto-enol equilibrium in the acetaldehyde-vinyl alcohol system.
The enol-keto energy difference is increased slightly
by α-Li substitution and decreased to a near-zero value by a BH2
substituent. The results are rationalized in terms of geminal interactions. The
conformational preferences of substituted acetaldehyde systems (XCH2CHO;
X = Li, BeH, BH2, CH3, F) are
discussed. Three classes of rotational potential functions are distinguished on
the basis of the σ-electron-donating or -accepting nature of the
substituent.
Isolation of cyclodepsipeptides from plant pathogenic fungi
Authors: Deol BS , Ridley DD , Singh P
Published: September 2010

The cyclodepsipeptide
beauvericin and a mixture of the cyclodepsipeptides, enniatin A1,
enniatin B1, enniatin B and enniatin A, have been isolated from
plant pathogenic fungi. Previously, beauvericin has only been isolated from the
unrelated entomopathogenic fungi.
Molecular orbital calculations for a series of Tri- and Tetra-N-heterocyclic aromatic amines and their protonated analogues
Authors: Ellerton NF , Jordan DO
Published: September 2010

Molecular orbital
calculations have been carried out by means of the Huckel
approximation for a series of amino-benz[a]-, -benz[b]- and- benz[c]-acridine
molecules and ions, and for the aminoacridine ions. The results are discussed
with reference to the antisymmetric stretching frequencies, pKa
values and ultraviolet and visible spectra of several of the molecules.
Reduction by dissolving metals. XXIII. Conversion of aromatic amines into cyclohexadienamines
Authors: Birch AJ , Dyke SF
Published: September 2010

N-(m-Methoxyphenyl)morpholine
and the o-isomer have been reduced by the metal-ammonia system to dienamines
and some cycloaddition reactions have been attempted.
Conformational analysis of coordination compounds. VIII. 1H N.M.R. study of diamagnetic five-membered amino alcohol chelate rings
Authors: Hawkins CJ , Palmer JA
Published: September 2010

The proton magnetic
resonance spectra of tetraamminecobalt(III) complexes with a series of amino
alcohols have been analysed and the coupling constant data utilized to
calculate the conformational populations for the various complexes. When
substitution occurred at the carbon adjacent to the amine group, the equatorial
orientation of the substituent was not markedly preferred over the axial.
However, when substitution occurred adjacent to the alcohol group, the
substituent was found to be exclusively in the equatorial orientation.
Quinazolines. XXIII. The synthesis of 3,5-Diazatetracyclo[7,3,1,17,11,01,6]tetradecanes (Adamantano[2,1-d]pyrimidines)
Authors: Armarego WLF , Tucker PG
Published: September 2010

The syntheses of
3,5-diazatetracyclo[7,3,1,17,11,01,6]tetradecan-4-iminium
(3) sulfate, 3,5-diazatetracyclo[7,3,1,17,11,01,6]tetradecan-4-one
(4), 3,5-diazatetracyclo[7,3,1,17,11,01,6]tetradecane (5)
dipicrate,3,5- diazatetracyclo[7,3,1,17,11,01,6]tetradeca-2,4-dione
(6), 3-oxa-4-azatetracyclo[6,3,1,16,10,01,5]tridec-4-en-2-one
(15) and 3,4-diazatetracyclo[6,3,1,16,10,01,5]tridec-4-en-2-one
(16) are described.
By-product formation in the synthesis of chromium(III) chelates of β-diketones
Authors: Dilli S , Robards K
Published: September 2010

A comparison is made of
three common synthetic methods in the preparation of the chromium(III)chelate
of 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dine. One of these methods,
involving homogeneous reaction with urea, is limited in general use by the
possibility of reaction between urea and certain β-diketones to form
insoluble, substituted pyrimidinones. Some specificity is demonstrated in the reaction,
notably with pentane-2,4-dione and 4,4,4-trifluoro-1- pentafluorophenylbutane-1,3-dione.
Electrophilic substitution. II. Friedel-Crafts type nitration using acetone cyanohydrin nitrate
Authors: Narang SC , Thompson MJ
Published: September 2010

Nitration of activated
aromatic systems has been studied by using acetone cyanohydrin nitrate with boron
trifluoride etherate in catalytic amounts. Products of typical electrophilic
nitration were formed under non-oxidizing conditions.
The stereochemistry of organometallic compounds. XVIII. Tricarbonylchromium complexes of cis- and trans-1,3-Dimethylindan-5-amine
Authors: Ashraf CM , Jackson WR
Published: September 2010

cis- and
trans-1,3-Dimethylindan-5-amines have been prepared and allowed to react with hexa-carbonylchromium. The stereochemistry of the
tricarbonylchromium complexes so obtained is discussed.
Conformational calculations of some azobilirubin isomers
Authors: Cetina R , Rubio M , Salmon M , Bernal J
Published: September 2010

A theoretical
conformational analysis of one benzeneazodipyrromethene isomer of bilirubin in
both the E and Z forms was performed by the PCILO method. The Z arrangement in
its planar conformation showed the highest stability for this type of
configurations.
Crystal structure of Tris(N,N-diethyldithiocarbamato)thallium(III)
Authors: Kepert DL , Raston CL , Roberts NK , White AH
Published: September 2010

The crystal structure of
the title compound, [Tl(S2CNEt2)3],
has been determined by single-crystal X-ray diffraction methods at 295 K and
refined by full-matrix least squares to a residual of 0.050 for 2517 'observed'
reflections. Crystals are monoclinic, with space group A2/a, a 14.789(7), b
10.428(4), c 18.207(9) Ǻ, β 118.11(4)°, Z 4, and are isostructural
with those of the previously determined gallium and indium analogues, the molecule
having 2 symmetry with  2.666
Ǻ. As in the dimethyl/thallium analogue, the departure of the TlS6
core symmetry from 3 is large and is examined in terms of electron-pair
repulsion theory.
Studies of Australian soft corals. VIII. A chemical and crystallographic study of a novel bicyclic diterpene alcohol with a rearranged skeleton from an unknown species of soft coral
Authors: Bowden BF , Coll JC , Mitchell SJ , Stokie GJ , Blount JF
Published: September 2010

The structure of a novel
bicyclic diterpene alcohol is reported and shown to be (3Z,5E,9E,1R*,-7R*,12aR*)-1-isopropyl-6,10,12a-trimethyl-
1,2,4,7,8,11,12,12a-octahydrocyclopentacycloundecen-7-ol(1a). It is
structurally related to the known diterpene (2) from Dollabella californica.
However, in (1a), there has been a methyl migration resulting in a rearranged
isoprenoid skeleton. The structure was solved by single-crystal X-ray analysis,
after spectroscopic analysis failed to yield an unambiguous structure.
Insect Moulting Hormones: Possible Intermediates in the Metabolism of Cholesterol to Ecdysteroids in an Insect
Authors: Kinnear JF , Martin MD , Chong YK , Faux A , Horn DHS , Wilkie JS
Published: September 2010

The possible ecdysteroid
precursors 3β,5,14x-trihydroxy-5α-cholest-7- en-6-one (12) and
3β,14α-dihydroxycholesta-4,7-dien-6-one (19) have been synthesized
and the metabolism of the corresponding 3α-tritium- labelled compounds
studied in Calliphora stygia
at the time of ecdysteroid biosynthesis. Labelled 20-hydroxyecdysone was
isolated in both cases and the compounds may thus be ecdysteroid precursors.
However, confirmation of these results with substrates labelled in another
position is necessary.
Nucleophilic alkenes. V. Formation of a naphthalenic system by addition of 1,1-Dimethoxyethene to 2-Acetyl-1,4-benzoquinone and subsequent transformation
Authors: Cameron DW , Feutrill GI , Sefton MA
Published: September 2010

2-Acetyl-1,4-benzoquinone
underwent rapid 1 : 1-addition of 1,1- dimethoxyethene at position 3 to give a
2,3-dihydro-2,2- dimethoxybenzofuran derivative (2).
Ring opening of this cyclic orthoester and subsequent ring closure onto the
acetyl group gave a naphthalene derivative incorporating the 1,3-dioxygenation
pattern found in many polyketides.