bluuebunny/crossref_metadata_2025_split huggingface dataset:
1H‐NMR study and conformational aspects of some bicyclo[3.2.0]heptane derivatives
Authors: De Bruyn André , Termont Daniel , De Keukeleire Denis , Anteunis Marc J. O. 
Published: September 2010

AbstractThe 1H‐NMR parameters of endo 2‐hydroxy‐bicyclo[3.2.0]heptan‐6‐one (1), 6,6‐dimethoxy‐bicyclo[3.2.0]heptan‐2‐one (2) and bicyclo[3.2.0]heptane‐2, 6‐dione (3) are discussed, allowing configurational and conformational descriptions. The usual 1H‐nmr criterion based on the observation of one single coupling to state the configuration of the ring annelation in bicyclo[3.2.0]heptane derivatives being not safe, a complete analysis of the ring system seems to be the only alternative as is illustrated for 1. It is found that the five‐membered rings occur in a twist(T)conformation, somewhat more flattened in 2 and 3.
Studies on organophosphorus compounds XX. syntheses of thioketones
Authors: Pedersen B. S. , Scheibye S. , Nilsson N. H. , Lawesson S.‐O. 
Published: September 2010

AbstractSubstituted benzophenones, 2‐benzoylthiophene, 3‐benzoylpyridine, dicyclopropyl ketone, and camphor are converted into the corresponding thioketones after reaction with the dimer of p‐methoxyphenylthionophosphine sulfide, 1. Except for the pyridine derivatives (2‐ and 4‐benzoylpyridines, respectively, gave no thioketones) very high yields are found. Under the same conditions dibenzylketone gave 1,3‐diphenylpropene‐2‐thiol and 1,9‐benzanthr‐10‐one yielded the dimer of 1,9‐benzanthr‐10‐thione. Aromatic thioketones are also obtained by reacting gem‐dichlorides with 2‐methyl‐2‐propane‐thiol in the presence of catalytic amounts of CF3COOH (or AlCl3). A mechanism is suggested based on kinetic measurements. 13C NMR data of the thiocarbonyls of all thioketones are recorded and a function describing the relation between the chemical shifts of CS and CO is found: δCS1.57 δCO=71.45
Studies on organophosphorus compounds XXII The dimer of p‐methoxyphenylthionophosphine sulfide as thiation reagent. a new route to O‐substituted thioesters and dithioesters
Authors: Pedersen B. S. , Scheibye S. , Clausen K. , Lawesson S.‐O. 
Published: September 2010

AbstractSimple alifatic and aromatic esters, such as ethyl, iso‐propyl, and benzyl benzoates, benzyl butanoate, ethyl heptanoate, and ethyl 1‐ and 2‐naphthoate, respectively, react with the dimer of p‐methoxyphenylthiono‐phosphine sulfide 1 in anhydrous xylene at 140°C to give the corresponding 0‐substituted thioesters in nearly quantitative yields. Also simple alifatic and aromatic S‐substituted thioesters, such as S‐phenyl, S‐benzyl and S‐tert‐butyl thiobenzoates, S‐phenyl and S‐benzyl thioacetates, and S‐ethyl thiobutanoate, produced the corresponding dithioesters in nearly quantitative yields upon treatment with 1 in anhydrous toluene at 110°C. 13C NMR data for the carbonyl‐ and corresponding thiocarbonyl carbons, have been recorded and a linear relation between the chemical shifts of CS and CO is found: δ(CS) = 1.75·δ (CO) ‐ 79.6 for 0‐substituted thioesters and δ(CS) = 1.31.δ (CO) ‐ 22.1 for dithioesters. An anomalous reaction has been observed: Thiobenzoic acid, S,S'‐methylene ester 2 reacted with 1 to give 4,5‐diphenyl‐1‐1,3‐dithiol‐2‐thion 3.
Studies on organophosphorus compounds XXIII synthesis of salicylthioamides and 4H‐1,3,2‐benzoxaphoshorine derivatives from the dimer of p‐methoxyphenylthionophosphine sulfide and salicylamides
Authors: Scheibye S. , Pedersen B. S. , Lawesson S.‐O. 
Published: September 2010

AbstractBy heating secondary O‐hydroxybenzamides at 110‐120 °C with the dimer of p‐methoxyphenylthionophosphine sulfide, 1, in HMPA, the main product is the corresponding thioamide (15‐51 %) but in addition two phosphorheterocyclic systems are isolated, namely 2,3‐dihydro‐2‐(4‐methoxyphenyl)‐4H‐1,3,2‐benzooxazaphosphorine‐4‐thione 2‐sulfide, 4 (5‐23 %) and the corresponding 2‐oxide, 5 (13‐21 %). Cyclohexylsalicylamide at somewhat elevated temperature (∼ 120°C), only gives one phosphorus containing product besides the thioamide. This product is not a benzoxazaphosphorine derivative but a ring opened phosphonthioamidate, 6. A mechanism is suggested. The structures are determined by 1 H, 13 C, and 31 P NMR spectroscopy, as well as UV, IR, and MS spectrometry, and elemental analyses.
Correlation Corrections to the Molecular Dipole Moment of Closed Shell Molecules via Møller‐Plesset Perturbation Theory
Authors: Figeys H. P. , Geerlings P. , van Alsenoy C. 
Published: September 2010

AbstractUsing Møller‐Plesset perturbation theory a general expression is derived for the second order correlation corrections to the molecular dipole moment obtained via a Spin Unrestricted Hartree Fock procedure. It is shown that this expression can be considerably simplified in the case of a closed‐shell molecule. The final result is computationally attractive.
Regio‐and Stereochemical Effects in the Chemical Ionization Mass Spectra of Isomeric Bicyclo|3, 2, O| Heptan‐2‐One Trimethylsiloxy Derivatives1
Authors: Claeys M. , Matveeva H. , Devreese A. , Termont D. , Vandewalle M. 
Published: September 2010

AbstractIsomers of bicyclo |3, 2, O| heptan‐2‐one trimethylsiloxy derivatives, produced by (π2+π2) photocycloaddition reactions between cyclopent‐2‐enones and trimethylsiloxy alkenes, have been investigated by methane and isobutane chemical ionization mass spectrometry. Head‐to‐head and head‐to‐tail regioisomers and the syn‐and anti‐epimers in each regioisomeric set can be identified by means of these ionization methods. Prominent fragmentation patterns are discussed.
Heterocyclisations with New Fluorinated Reagents from Phosgeniminium Salts(1)
Authors: Gorissen J. , Viehe H. G. 
Published: September 2010

AbstractN,N‐Dimethyl‐Dichloromethyleniminium chloride, in other words: Phosgeniminium chloride (PI) forms 2‐fluoro‐1, 3‐dichlorotrimethine cyanines 1 and 2‐fluorovinylurea dichlorides 6 with tertiary and secondary acetamides, respectively. Further, PI reacts with fluoroacetyl chloride to the 1‐chloro‐2‐fluoro‐2‐chlorocarbonyl enamines 14. These reactive compounds are cyclized to fluorine‐bearing pyrazoles, oxazoles, pyrimidines and a benzodiazepine.
Urey‐Bradley Force Constants of Some Pentafluoride Compounds of Group via Elements
Authors: So S. P. , Li K. K. , Hung L. K. 
Published: September 2010

AbstractThe Urey‐Bradley force constants of SF5O−, SF5Br, SF5Cl, SeF5Cl and TeF5Cl have been determined by least‐squares‐fit method using published fundamental frequencies. Results appear to suggest that some of the reported assignments are questionable.
Benzo‐and Indoloquinolizine Derivatives XVa. Conformational Analysis of 6,7,12,13‐Tetrahydro‐11bH‐Dibenzo[a,f]Quinolizine Derivatives by 1H AND 13C NMR
Authors: Tourwé D. , Van Brandt W. Den , van Binst G. 
Published: September 2010

AbstractThe influence of the nitrogen lone pair delocalisation with the adjacent aromatic ring in the trans‐quinolizidine conformation of the title compound on the proton and carbon‐13 n.m.r. spectral parameters distinguishes the assignment criteria for these compounds from the previously studied benzo‐substituted quinolizidines.
Tricyclo‐Oxy‐and Tricyclo‐Peroxycolupulones
Authors: De Potter Marc , De Keukeleire Denis , De Bruyn André , Verzele Maurice 
Published: September 2010

AbstractFour new tricyclic oxidation products, formed in high yield from colupulone (1) in brewing circumstances, are isolated by preparative‐scale high pressure liquid chromatography. Spectral identification leads to the following structures: the C3‐epimers of 7 ‐(3‐methylbut‐2‐enyl)‐3‐(1‐hydroxy‐1‐methylethyl)‐4, 4‐dimethyl‐9‐(2‐methylpropanoyl)‐tricyclo[5.3.1.o1,5]undeca‐8,10,11‐trione (2 and 3, respectively) and the C3,‐epimers of 7‐(3‐methylbut‐2‐enyl)‐3‐(1‐hydroperoxy‐1‐methylethyl)‐4,4‐dimethyl‐9‐(2‐ methylpropanoyl)‐tricyclo [5.3.1.o1,5] undeca‐8,10,11‐trione (5 and 6, respectively). The reaction mechanism is discussed.
Chemical studies of marine invertebrates. XXXIV(1). Herbadysidolide and herbasolide, two unusual sesquiterpenoids from the sponge dysidea herbacea(2)
Authors: Charles C. , Braekman J. C. , Daloze D. , Tursch B. , Declercq J. P. , Germain G. , van Meerssche M. 
Published: September 2010

AbstractThe isolation and structure determination of the sesquiterpene herbadysidolide (1) and the norsesquiterpene herbasolide (2) from the sponge Dysidea herbacea are described.
Mesure Quantitative de L'Activité de la Desoxyribonuclease Plasmatique et de Son Inhibition Par le Complexe Daunorubicine‐ADN
Authors: Hulhoven R. , Desager J. P. , Zenebergh A. 
Published: September 2010

AbstractA sensitive, fast and quantitative method was described to estimate plasma deoxyribonuclease (DNase) activity. This method was using125I DNA as substrate and the activity of the enzyme was measured by the increase of radioactivity in the TCA‐soluble fraction. The method was enough sensitive to detect the activity of about long of pure DNase I. The coefficient of variation was always lower than 10% at the weakest activity and lower than 2% at higher activities. Experimental results did confirm the weak activity of human plasma DNase, which was about 5‐fold lower than the rabbit's one. In presence of a daunorubicin‐DNA complex with a molar ratio of 20, this activity was inhibited by half.
Negative‐ion mass spectra of organophosphorus compounds containing PO AND PS groups
Authors: Meyer H. J. , Larsson F. C. V. , Lawesson S. ‐O. , Bowie J. H. 
Published: September 2010

AbstractCompounds containing the (XO or S) unit yield negative‐ion spectra, which are dominated by peaks arising by α or ß cleavage to PX.Molecular ions are generally absent in these spectra, except in cases where the molecule contains an additional electron‐capture group (e.g. p‐nitrophenyl). Simple cleavage is accompanied by a characteristic rearrangement reaction for certain compounds containing the ‐C(X)‐Y‐P(S) unit (XO or S, YO, S, or NH); the rearrangement is most pronounced when YNH. Compounds containing the PS moiety are prone to thermal decomposition; such decompositions may be detected by the presence of peaks corresponding to Sn (n=1‐10) in the negative‐ion spectra.
Chemical studies of marine invertebrates. XXXVI(1). Strongylosterol, a novel C‐30 sterol from the sponge strongylophora durissima Dendy (2).
Authors: Bortolotto M. , Braekman J. C. , Daloze D. , Tursch B. 
Published: September 2010

AbstractA novel sterol, strongylosterol, has been isolated from the sponge Strongylophora durissima. It has been demonstrated to be 3β‐hydroxy‐24°‐ethyl‐27‐methylcholesta‐5, 25(26)‐diene (1).
Some applications of the empirical force field method to stereochemistry
Authors: Mislow Kurt , Dougherty Dennis A. , Douglas Hounshell W. 
Published: September 2010

AbstractThe empirical force field (or molecular mechanics) method has become increasingly popular as a computational tool in chemistry. Examples are adduced from work in our laboratories to illustrate some of the power and scope of this method as applied to problems in static and dynamic stereochemistry.
The 1H NMR spectra of the strychnos alkaloids retuline isoretuline, and their N‐deacetyl compounds.
Authors: Tavernier D. , Anteunis M. J. O. , Tits M. J. G. , Angenot L. J. G. 
Published: September 2010

AbstractThe 300 MHz 1H NMR spectra of the title compounds are discussed. The vicinal coupling constants 3J H2, H16 and H16, H15 are about 10 Hz and 4 Hz in the iso series, and about 7 Hz and 1 Hz for 1 and 2. In isoretuline, the piperidine ring (ring D) has a chair conformation, but in retuline a boat conformation, with C21 in the tip position, prevails. This conclusion is based on the pattern of allylic and homoallylic couplings around the double bond, and rests also on comparison with the spectrum of strychnine. Evidence is presented for a hydrogen bond between the C17 hydroxymethyl and the Nl‐COCH3, group in isoretuline.
Stereochemical aspects of proton chemical shifts. VII‐4‐fluoro‐prolines. A FURTHER CASE OF VIOLATION OF THE “SYN‐UPFIELD” RULE IN1H‐NMR.
Authors: Anteunis M. J. O. , Cuypers P. , Liberek Bogdan , Kolodziejczyk A. 
Published: September 2010

AbstractIt is reported that, as previously also found for ‐N°Me3groupings, the “syn‐upfield” effect caused by F fails for 4‐F‐prolines and their derivatives.
Chemical studies of marine invertebrates. XXXVII(1). Three novel meroditerpenoids from the sponge strongylophora durissima(2).
Authors: Braekman J. C. , Daloze D. , Hulot G. , Tursch B. , Declercq J. P. , Germain G. , van Meerssche M. 
Published: September 2010

AbstractThree novel meroditerpenoids, strongylophorine‐1 (1), ‐2 (2) and ‐3 (3) have been isolated from the sponge Strongylophora durissima, Strongylophorine‐1 and ‐3 possess structure 1 and 3 respectively, as established by their spectral properties, hemisynthesis and chemical intercorrelation. The structure of strongylophorine‐2 has been shown to be 2 by X‐ray diffraction analysis on its monoacetylderivative (13).
On The Mechanism of the Conversion of α‐Cyanoenamines into Amides
Authors: Kimpe Norbert De , Verhé Roland , Buyck Laurent De , Schamp Niceas 
Published: September 2010

AbstractThe conversion of α‐cyanoenamines into N‐monosubstituted carboxylic acid amides by means of hydrogen chloride in various alcohols under strictly anhydrous conditions was shown to occur with incorporation of the alcohol‐oxygen atom into the final amides. α‐Cyanoenamine hydrochlorides were obtained as stable salts by reaction of α‐cyanoenamines with hydrogen chloride in benzene.
6,6‐Dimethoxy Bicyclo[3.2.0]Heptan‐2‐One: An Intermediate for Prostanoid Synthons
Authors: Keukeleire Denis De , de Wilde Hugo , Verzele Frank , Wyffels Wilfried , Vandewalle Maurits 
Published: September 2010

AbstractThe known 6,6‐dimethoxy bicyclo [3.2.0]heptan‐2‐one, obtained by (π 2 + π 2) photocycloaddition of 2‐cyclopentenone and 1, 1‐dimethoxyethene, is an adequate precursor for prostanoid synthons. Its conversion into intermediates for the 11‐desoxyprostaglandin (PG) series and for PGC2 is described.
New Members of the hop anti iso‐α‐Acids Series
Authors: Taeye Leo De , Keukeleire Denis De , Verzele Maurice 
Published: September 2010

AbstractTwo new compounds, 4‐hydroxy‐5‐(3‐methylbutanoyl)‐2‐(3‐methyl‐2‐butenyl) furan(2H)‐3‐one(5) and 2‐(3‐methyl‐2‐butenyl)‐4‐ethanoyl‐3,4‐dihydroxy‐5‐(2‐methylpropylidene)‐2‐cyclopentene‐1‐one (12) have been isolated from isomerisation reaction mixtures of humulone (1). As both formation mechanisms show, the compounds are rearranged derivatives of the hop anti iso‐α‐acids.
A novel structure for substituted dithiooxamide Pd(II) and Pt(II) complexes
Authors: Dommisse R. A. , Aarts A. J. , Desseyn H. O. , Alderweireldt F. C. 
Published: September 2010

AbstractAs a part of our study on the spectral properties of N, N′‐dialkyldithiooxamide Pd(II) and Pt(II) complexes, their 1H‐ and 13C‐NMR spectra were studied. The structure formerly proposed in the literature cannot be maintained (1, 2). It is shown that these complexes exist with coordination to both sulfur atoms.
Structure de la Dibenzyl‐4,4′Diphényl‐2,2′ [Biimidazoline‐4:4′] Dione‐5,5′
Authors: Tinant B. , Germain G. , Declercq J. P. , van Meerssche H. 
Published: September 2010

AbstractThe crystal and molecular structure of the title compound, C32H26N4O2, has been determined by direct methods from diffractometer intensities. The structure is that of a racemic formed by dl dimers.Crystal data are as follow: monoclinic, P21/c, a = 9.991 (2), b = 13.709 (6), c = 18.961 (8) Å, β = 96.89° (3), Z = 4, Dx = 1.28 Mg m−3
A Re‐Investigation of the Conformational Behaviour of CIS‐D‐Allo‐Hydroxyproline in Solution
Authors: Anteunis Marc J. O. , Cuypers Paul , Buďêsínský Milos 
Published: September 2010

AbstractThe 1H NMR spectral changes observed at 300 MHz during titration in D2O of cis‐D‐allohydroxyproline (aHyp) allow to define the approximate ring conformation in solution and the rotational behaviour of the carboxyl around Cα‐C′. The cationic species is characterized by ring conformers close to the envelopes with Cγ‐endo and Cδ‐exo as the flap. The carboxyl plane is in the direction of Cδ/Cγ (Ψ = 60‐90°), allowing for an interaction with the quasi‐axial γ‐OD. During titration of the carboxylic group this plane rotates nearer to γ‐OD. The latter picture is consistent with observations reported in the literature for the behaviour in Pro and trans‐Hyp2, 4. When the amine function is titrated (pD > 10) the carboxylate group becomes coplanar with D‐N‐Cα (Ψ ∼ 0°). In conjunction the ring escapes into a form best defined by a twist having Cδ exo and N endo. The possibility for intramolecular hydrogen bonding (e.g. between the carboxylic group and the hydroxyl function in the cation and zwitterion or between the same group on the amine function in the anion) contributes little to the inherent pyrrolidine ring conformation, although a restriction of conformational freedom to δ+ in D2O for the zwitterionic state could be revealed by comparison to DMSO‐d6, where concomitantly the γ− form also is present.
Chemical Studies of Marine Invertebrates. XL. Δ9 (12)‐Capnellene‐2β, 5α, 8β, 10α‐Tetrol, a New Sesquiterpene Alcohol from the Soft Coral Capnella Imbricata
Authors: Kaisin M. , Tursch B. , Declercq J. P. , Germain G. , van Meerssche M. 
Published: September 2010

AbstractΔ9(12)‐Capnellene‐2β,5α,8β,10α‐tetrol [1], a new sesquiterpene of the capnellene sesquiterpene class has been isolated from the alcyonarian Capnella imbricata. Its structure and relative configuration were determined by X‐ray diffraction analysis.
The Crystal Structure of 1‐{2,4‐Dichloro‐β‐ [(2,4‐Dichloro‐Benzyl)Oxy] Phenethyl} Imidazole Hemihydrate: Miconazole. 1/2 H2O
Authors: Peeters O. M. , Blaton N. M. , De Ranter C. J. 
Published: September 2010

AbstractThe structure of the title compound has been investigated as part of a general study on the chelating properties of therapeutically active imidazole derivatives. The compound crystallizes in the monoclinic system, space group P21/n, with lattice parameters a = 14.614(5), b = 33.206(12), c = 8.062(3) Å, β = 91.24(3)°, Z = 8 and Dm = 1.42, Dc = 1.44 Mg m−3. The structure was solved by direct methods and refined to a final R‐value of 0.086. The asymmetric unit contains two miconazole molecules linked by the water molecule.
Spectres R.M.N.‐13C D'Hydroxy‐5 Isoflavones et de Diméthyl‐2,2 Phénylacetyl‐6 Chromènes
Authors: Vilain C. , Jadot J. 
Published: September 2010

Abstract13C NMR assignments previously given for A‐nuclei (C‐5, 6, 7, 8, 9, 10) of 5‐hydroxy‐isoflavones (Ie, IIe, IIIb) have been reconsidered on the basis of the proton‐coupled spectrum of 5‐hydroxy‐7, 4′‐dimethoxyisoflavone (Ie) (cf:Bull. Soc. Chim. Belg., 76 n°6/473, 1977).Furthermore, in order to generalize the method employed to predict resonances of the aromatic carbons of the 2,2‐dimethylchromene ring, we have recorded and fully analysed the spectra of the model compound (IV) and of the 2,2‐dimethylphenylacetyl‐6‐chromenes (V) and (VI).
Hydrogenolysis of Alkanes on Alumina Supported Platinum Kinetic Study and Effect of the Hydrocarbon Structure
Authors: Leclercq G. , Leclercq L. , Maurel R. 
Published: September 2010

AbstractThe kinetics of the hydrogenolysis of some light saturated hydrocarbons has been studied and the results have been rationalized by using a rate expression derived from the kinetic scheme originally proposed by CIMINO, BOUDART and TAYLOR for ethane hydrogenolysis.magnified imageThis kinetic study leads to the conclusion that the influence of the structure of the hydrocarbon on its reactivity is mainly due to change in its adsorption equilibrium constant rather than to changes in the reactivity of the adsorbed species. Those results are in a good agreement with Anderson's conclusions on the involvement of 1, 2 and 1, 3 diadsorbed species in the hydrogenolysis of saturated hydrocarbons on platinum.The effect of the hydrocarbon structure on its reactivity and on the selectivity of its reactions with hydrogen have been investigated. This study confirms our previous conclusions since they emphasize the influence of the neighbor carbon atoms of the C‐C bond to be broken on its reactivity. Our results cannot all be rationalized by a single reaction mechanism but support the view that 1, 2‐, 1, 3‐, 1, 4‐ and 1, 5‐ diadsorbed species can all play a role in reactions between hydrogen and hydrocarbons on platinum.
Études dans la Série des Pyrano [2,3‐c] Pyrazole‐3(2H)‐Ones
Authors: Maquestiau A. , van Haverbeke Y. , Vanden Eynde J. ‐J. 
Published: September 2010

AbstractA number of pyrano [2,3‐c] pyrazole‐3(2H)‐ones are obtained by reaction of 3‐hydroxypyrazolin‐5‐one with β‐dicarbonyl compounds.The position of the substituents on the 6‐membered ring of these bicyclic derivatives is determined by 1H NMR.The orientation of the cyclocondensation is discussed.
Un Nouvel Exemple de Migration D'Hydrogène Intramoleculaire Dans Un Radical Vinylique: Addition Radicalaire de l'Acétone À l'Octyne‐1
Authors: Gardrat C. , Montaudon E. , Lalande R. 
Published: September 2010

AbstractAddition of acetonyl radicals to 1‐octyne leads to the formation of 1/1 adducts. Besides the normal product, appear two kinds of cyclic derivatives. Formation of the latter is explained by hydrogen shifts in the transient vinyl radical. 1,5‐hydrogen shift is predominant, but 1,6‐hydrogen shift is evidenced for the first time in such a radical.
Rearrangement of 1‐aryl‐2,2‐Dichloro‐1‐Alkanones and 1‐Aryl‐2,2‐Dichloro‐1‐Alkanols with Methylmagnesium Iodide
Authors: de Kimpe Norbert , Verhé Roland , de Buyck Laurent , Schamp N. 
Published: September 2010

Abstract1‐Aryl‐2,2‐dichloro‐1‐alkanones were shown to rearrange with methyl magnesium iodide in ether under reflux into highly sterically hindered alkohols. The mechanism proceeds by a pseudo pinacol type rearrangement of the initially formed carbonyl adduct. The mechanism of the rearrangement was proven by the synthesis of authentic reaction intermediates. The rearrangement was also extended to 1‐aryl‐2,2‐dichloro‐1‐alkanols which behaved analogously towards methylmagnesium iodide.
Force field studies of some XY3 planar molecules and ions
Authors: Jothi A. , Shanmugam G. 
Published: September 2010

AbstractRedington and Aljibury's parametric method has been applied to study the force fields of some XY3 planar molecules and ions. Interatomic force constants and interaction force constants were calculated. Other molecular constants like coriolis coupling constants, mean amplitudes of vibration and centrifugal distortion constants were calculated and found to agree with the available literature values.
Enzymatic “in vitro” Reduction of ketones. I. Kinetics of coupled‐substrate coenzyme recycling systems
Authors: Lemière G. L. , van Osselaer T. A. , Lepoivre J. A. , Alderweireldt F. C. 
Published: September 2010

AbstractThe kinetics of the coupled‐substrate coenzyme recycling system, which is a very useful enzymatic method for preparative purposes, are studied. A full steady‐state rate equation and a much more useful initial rate equation are elaborated. These equations are built up with kinetic constants from the two composing single reactions. This enables synthetists to predict rate and equilibrium of recycling systems from the kinetic constants of the single reactions.
Enzymatic “In Vitro” Reduction Of Ketones. V. (1) Reduction of 1‐alkyl‐4‐piperidones in an ethanol ‐ NAD+ ‐ HLAD ‐ system
Authors: van Luppen J. J. , Lepoivre J. A. , van Osselaer T. A. , Lemière G. L. , Alderweireldt F. C. 
Published: September 2010

AbstractIn a previous paper (2) the coupled‐substrate coenzyme recycling system ketone‐ethanol‐NAD+‐HLAD has been described as an excellent tool for the reduction of alicyclic ketones. Now we report similar reductions for a series of 1‐alkyl‐4‐piperidones.Although it is generally known that nitrogen heterocycles (3) are very effective inhibitors of HLAD, these products are readily reduced. However the rates of reduction of these products are much smaller than those of the corresponding cyclohexanone derivatives (4, 5) (e.g. the reduction rate of 1‐n‐butyl‐4‐piperidone is 40x lower than that of cyclohexanone). This is mainly reflected in an increase of the enthalpy of activation. Detailed results will be published soon.