bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photocyclisation of Diphenylamine as a Fluorogenic Reaction for Photochemical‐Fluorimetric Analysis
Authors: Fall C. A. T. , Diop A. , Aaron J. J. 
Published: September 2010

AbstractThe photocyclisation reaction of diphenylamine has been studied spectrophotometrically and spectrophotofluorometrically in several organic solvents at room temperature. A two‐step photoreaction takes place, with the formation of carbazole as the main fluorescent photoproduct. In most solvents, the fluorescence intensity of diphenylamine is increased upon UV irradiation, reaching a maximum within 10 to 15 min. Photochemical‐fluorescence enhancement factors range between 3 and 35. Linear log‐log calibration plots are obtained over several orders of magnitude in concentration units. Photochemical‐fluorimetric limits of detection are as low as 20 μg 1−1. The photocyclisation of diphenylamine is shown to be a very useful fluorogenic reaction for its quantitative analysis.
Chemistry of Methyl 1‐Butyl‐Cyclopropene‐3‐Carboxylate: The Role of Transition Metal in Reaction Control: Rhodium‐Catalysed Synthesis of a Bicyclobutane, Coppercatalysed Dimerisation, Selective (Tl+++) Oxidation
Authors: Condé‐Petiniot N. , Hubert A. J. , Noels A. F. , Warin R. , Teyssié Ph. 
Published: September 2010

AbstractSome typical reactions of a cyclopropenecarboxylate(I) were tentatively controlled by the use of transition metal catalysts. The reaction of (I) with methyl diazoacetate (DAM) afforded a dihydropyrazine(III) which was further dehydrogenated photochemically to the pyrazine(IV) whereas, the bicyclobutane(II) was obtained in the presence of rhodium acetate as catalyst. Copper triflate catalysed the ring opening of the cyclopropene ring and a dimer (the octatrienedicarboxylate(V) was thus isolated. Attempts to epoxidize(I) with a peracid (MCPBA) or V0(acac)2 and Mo0(acac)2‐t‐butyl hydroperoxide failed. Up to now, only thallium(III) nitrate afforded satisfactory selective oxidation of (I) (formation of the lactone VII).
Novel Macrocyclic Trichothecenes from Myrothecium Roridum
Authors: Jarvis Bruce B. , Taha Çömezoglu F. , Lee Yin‐Won , Flippen‐Anderson Judith L. , Gilardi Richard D. , George Clifford F. 
Published: September 2010

AbstractAn isolate of Myrothecium roridum (ATCC 60379) produced a series of novel enol ether containing macrocyclic trichothecenes, myrotoxins A‐D, when grown on rice substrate. The stability of the myrotoxins depends strongly on the stereochemistry of the hydroxy group at C12'. In liquid culture, this fungus produced, in addition to myrotoxins A and B, three new macrocyclic trichothecenes, mytoxins A‐C which are related in structure to satratoxins. The myrotoxins and mytoxins are acutely cytotoxic and in vivo toxic agents.
Synthesis and Absolute Configuration of Zonarol. A Fungitoxic Hydroquinone from the Brown Seaweed Dictyoptfris Zonarioides(1)
Authors: Mori Kenji , Komatsu Makoto 
Published: September 2010

AbstractA total synthesis of both the enantiomers of zonarol 1 was accomplished. Measurements of the ORD‐CD spectra of two bicyclic intermediates coupled with direct comparison of the natural and synthetic zonarol 1 established the absolute configuration of the naturally occurring (+)‐zonarol 1 as 1R, 4aR, 8aR.
Diterpenes from a Soft Coral, Minabea SP., from Truk Lagoon
Authors: Ksebati M. B. , Schmitz F. J. 
Published: September 2010

AbstractTen new diterpenoids, minabeins‐1 to −10, possessing the known briarein skeleton have been isolated from a soft coral, Minabea sp., collected from Truk Lagoon, Eastern Caroline Islands. This is the first report of the occurrence of this class of compounds in soft corals. An analysis of the distribution of cembranoids and various cyclized cembranoids among three orders of octorcorals (soft corals, gorgonians, and sea pens) is presented. Structures and relative stereochemistry of the minabeins was determined by extensive1H and13C NMR spectral analysis.
The Chemistry of Lissoclinum Patella
Authors: Sesin David F. , Gaskell Simon J. , Ireland Chris M. 
Published: September 2010

AbstractLissoclinum patella is the source of a family of cyclic peptides characterized by the presence of thiazole amino acids. Detailed analysis of 2D COSY 45 NMR data for the Lissoclinum peptides revealed homoallylic coupling between the α‐amino protons both through the peptide bonds and the oxazoline rings. This data was used to reassign the structures of the patellamides A‐C, and to assign structures to three new metabolites prelissoclinamide‐2, prepatellamide‐B‐formate and preulicyclamide.
Reactive Double Bond Systems Via (3+2) Cycloreversion of Heterocycles
Authors: Schaumann Ernst 
Published: September 2010

AbstractAfter deprotonation, saturated five‐membered heterocyclic rings give a facile (3+2) cycloreversion. This approach is employed in syntheses of ketenes, thioaldehydes, thioketones, thioketenes and a thioquinone at low temperature. These highly reactive double‐bond systems are usually trapped in situ using (2+2), (2+3), or (2+4) cycloadditions to give various types of heterocycles.
Performances des Faujasites Échangées Avec des Éléments de la Série des Terres Rares Dans Le Processus de Disproportionnement du Toluene
Authors: Azzouz Abdelkrim , Fourar Mokrane , Berrak Abderrezak 
Published: September 2010

AbstractThe process of toluene disproportionation was carried out using modified Y‐type faujasites. The X‐ray diffraction analysis shows that the cation exchange of the NaY zeolite with La(3+) or Ce(3+) causes 311 plane displacement and affects the crystallinity. This effect was not observed when the faujasites were previously exchanged with NH4(+) cations.The faujasites which have undergone about 73% cation exchange and a programmed calcination gave the best performances. In the temperature range 350–500°C, the toluene conversion was about 20–60 mol. The NaLaY catalysts are slightly more active than those containing cerium, but the latter present a higher selectivity with respect to the main process. Nevertheless, with both types of catalysts the temperature decrease enhances p‐xylene formation.
Effect of Amines on the Kinetics of alkaline Decomposition of Benzyltriphenylphosphonium Chloride in Binary Solvent Mixtures
Authors: Hanna Morcos T. , Khalil Fayez Y. , Beder S. M. 
Published: September 2010

AbstractThe kinetics of decomposition of benzyltriphenylphosphonium chloride by sodium hydroxide was studied in binary aqueous solvent mixtures ranging from pure water to about 70% (v/v) of dipolar aprotic solvents such as DMSO or acetone in presence of a series of aliphatic and aromatic amines. The rate, which is directly proportional to the organic solvent content, was found to increase to a maximum at 0.1 M amine concentration and then to decrease. The small increase in rate due to the addition of amine is explained on the basis of an amine‐water interaction, where the concentration of OH−ions in the solution increases slightly due to the ability of the amines to abstract protons from water molecules in the medium. However, the decrease in rate beyond 0.1 M amine concentration is explained as due to the decrease of hydroxide ion concentration by formation of a weakly ionised quaternary ammonium hydroxide. The observed activation energies, thermodynamic parameters and radii of the activated complex for all solvent compositions are computed. The effect of the bulk dielectric constant on the reaction rate was investigated in the light of the available electrostatic theories.
The Cycloaddition Reaction Between Styrene and 2,3,4,5‐Tetrahydropyridine 1‐Oxide
Authors: Hootelé C. , Ibebeke‐Bomangwa W. , Driessens F. , Sabil S. 
Published: September 2010

AbstractThe cycloaddition of styrene to 2,3,4,5‐tetrahydropyridine 1‐oxide leads, with a high yield, to a 97:3 mixture of the diastereoisomeric isoxazolidines 3c and 4c respectively.
Synthesis and Potential Anticancer Activity for Diaminoalkyl Complexes of Tin Halides
Authors: Eng G. , Engle T. W. 
Published: September 2010

AbstractA series of dimethyltin dihalide bidentate complexes modelled after analogs of cis‐diammine dichloroplatinum, a widely used anticancer drug, were prepared and tested for anticancer activity. An analogous series of pentacoordinated trialkyltin halides were also prepared and tested for comparison. These compounds displayed toxicity too high to make these complexes useful as anticancer agents.
Functionalization of Isophorone Involving Polychlorination. Part I: Heptachlorination Catalyzed by Dimethylformamide Hydrochloride and Solvolysis Induced by Concentrated Sulfuric Acid
Authors: De Buyck L. , Speybrouck J. , Sulmon P. , De Kimpe N. , Verhé R. , Schamp N. 
Published: September 2010

AbstractPolychlorination of isophorone (1), catalyzed by dimethylformamide hydrochloride, under drastic conditions afforded mainly 2,2,4,6,6‐pentachloro‐3‐dichloromethyl‐5,5‐dimethyl‐3‐cyclohexenone (3) (35‐45% isolated). Moderate conditions (below 90°C, excess DMF) permitted the isolation of 2,6,6‐trichloro‐3‐dichloromethyl‐5,5‐dimethyl‐2‐cyclohexenone (2) in 45‐55% yield. Selective solvolysis induced by concentrated sulfuric acid was used in the purification of 2 and for synthesis of 6,6‐dichloro‐3‐formyl‐5,5‐dimethyl‐1,2,4‐cyclohexanetrione (4) (45‐58% yield from 3). Side products containing a 3‐trichloromethyl group were converted into carboxylic acids.
The Reactivity of Selenium Dioxide Towards Aromatic Aldehydes Hydrazones, Azines and Phenylhydrazones: Carbonyl Regeneration and a New One‐Pot Oxidation of Aldehydes to Aromatic Acids
Authors: Dekova B. Y. , Evers M. J. , Christiaens L. R. , Guillaume M. R. 
Published: September 2010

AbstractSelenium dioxide is a mild oxidizing reagent able, in hot D. M. F. solution, to regenerate arylaldehydes from their hydrazones and azines. The same experimental conditions in the case of phenylhydrazones of aromatic aldehydes yield the corresponding substituted benzoic acids. In this respect the behaviour of SeO2 differs from that of benzeneseleninic anhydride.
Synthesis and Thermal Decomposition of 4‐Azidoisoxazoles
Authors: L'abbé Gerrit , Godts Prançoise 
Published: September 2010

AbstractThe diazonium salts derived from 1a, b decompose at 0°C to give α‐cyanodiazoketones 3a, b and, in the case of 1b, also the N‐hydroxytriazole 4. The azides 2a, b were prepared from the diazonium salts at ‐15°C. The diazonium salt from 1c is more stable and can be converted into the azide 2c at 0°C, along with formation of 5 as a side product. Kinetic measurements have been carried out for the thermal fragmentation of 2a, c which indicated that the reactions occur by a concerted mechanism.
Relationship Between the pH‐Dependence of the Half‐Wave Potential and the Limiting Current in Second Reduction Waves of CE Mechanisms
Authors: Muñoz E. , Camacho L. , Avila J. L. , Heras A. M. , Ruiz J. J. 
Published: September 2010

AbstractElectrode processes involving chemical stages prior to and subsequent to the electric transfer allow the theoretical and experimental separation of the influence of both reactions on the half‐wave potential. This paper contributes a new example to the study of processes corresponding to second reduction wave coupled to CE mechanisms.
Oxydation d'Amines Aromatiques Primaires en Présence du Radical Tritertiobutyl‐2,4,6 Phénoxyle
Authors: Hedoyatullah Mir , Thevenet Francis 
Published: September 2010

AbstractThe trapping of onilino radicals generated by a mild dehydrogenetion of primary aromatic amines, at 20°C, in homogeneous medium or in two‐phase system, by 2,4,6‐tritertiobutylphenoxy radical is carried out and the structures of the corresponding C‐N or C‐C coupling products are established by spectral data (IR, UV, RMN 1H).
Potentiometric Investigation of the Dissociation of α‐Hydroxyisobutyric Acid in Aqueous Sodiumperchlorate Solutions of Unit Ionic Strength at 25°C
Authors: Vantomme Paul , Bouserie Frank L. G. , Thun Harry P. 
Published: September 2010

AbstractFrom emf measurements in titrations at constant ligand concentration (cL) the formation function nH is calculated for aqueous solutions of α‐hydroxyisobutyric acid of I=1 at 25°C. From cL = 0.2 M on these functions grow separate, keeping only one cross‐over point in common. Considering then the presence of associated forms a reasonably good agreement was obtained with the experiment. However, after correction of the emf data for all effects leading to a changed activity coefficient of the measuring electrolyte and for the consequent changes in the formal dissociation constant, the data again can best be described by a normal monoprotic dissociation behaviour.
Crystal Structure and Conformation of Short Linear Peptides: Part IV: Glycyl‐Glycyl‐L‐Isoleucine Monohydrate Methanol Solvate
Authors: Wu S. , Tinant B. , Declercq J. P. , van Meerssche M. 
Published: September 2010

AbstractC10H19N3O4. 1/2CH3OH. H2O, Mr = 279.31, orthorhombic, P212121, a = 35.826 (15), b = 9.793(3), c = 8.969(2)Å, V = 3146(2)Å3, Z = 8, Dx = 1.18 gcm−3, Cukα, λ = 1.5418 Å, μ = 8.10 cm−1, F(000) = 1208, T = 291K, R = 0.072 for 3508 observed reflections. The two molecules have rather different conformation in the main chain. The side chains take a sterically unfavorable conformation characterized by (X11, X12, X2) of (60°, ‐67°, 170°) for molecule A and of (67°, ‐61°, 162°) for molecule B with the ethyl group gauche to both the carbonyl group and the N atom. Three of four 0 atoms of the carboxylate groups accept two H‐bonds. The crystallization conditions ‐ pH and temperature ‐ seem to affect strongly the conformation of peptide in this case.
Application of Cinnamyloxycarbonyl (Coc) Protection During the Synthesis of Coc‐Pro‐MePhe‐MeAla‐OMe. Chain Rupture of the Tripeptide on Chromatography
Authors: Sharma N. K. , Anteunis M. J. O. 
Published: September 2010

AbstractThe preparation of 1‐(cinnamyloxycarbonyloxy)benztriazole (Coc‐OBt), as reported in literature, results in a mixture of 50% Coc‐OBt (6) next to 13%. of 1‐(cinnamyloxy)benztriazole (7). The reagent 6 is stable for several months in the fridge. Coc‐protection of Pro can be obtained in an improved yield by a slightly modified procedure.Coc‐Pro‐MePhe‐MeAla‐OMe was prepared in good yields using BOP‐Cl as the activator for coupling. In an attempt to isolate the tripeptide by chromatography on SiO2 we found it to decompose into Coc‐Pro and the cyclic dipeptide (DKP) c(MePhe‐MeAla). The same DKP is formed from the dipeptide ester salt Tfa. MePhe‐MeAla‐OMe on standing in COCl3. These findings stress the ease of chain rupture of peptides caused by acidic agents when they possess a triad of N‐alkylated amino acids (3).
Synthesis and Reactions of 3‐Phenyl‐3,4‐Dihydro‐1, 4‐Quinoxalin‐2 (1H) ‐One and its Heterocyclic Analogues
Authors: Olagbemiro T. O. , Nyakutse C. A. , Lajide L. , Agho M. O. , Chukwu C. E. 
Published: September 2010

AbstractThe lactams quinoxalinone 3a, benzothiazinone 3b and benzothiazinone 3c were synthesized by reactions of methyl 2‐bromo‐2‐phenylethanoate 1 with orthosubstituted arylamines 2a ‐ 2c. Subsequent reductive alkylation of the lactams with sodium hydride and iodomethane afforded only the N‐alkylated quinoxalinone 4a and benzothiazinone 4b. Lithium aluminium hydride reduction of the lactams 3a‐3c gave the dihydro‐derivatives 5a, 5b and 5c while similar reduction of the N‐alkylated lactams 4a and 4b yielded the unsaturated quinoxaline 6a and benzothiazine 6b respectively. Lead tetraacetate oxidation of the quinoxalinone 3a furnished the unsaturated quinoxalinone 9 which was N‐alkylated using sodium borohydride in formic acid to give 10. Treatment of the lactams 3a, 3b and 3c with phosphorus pentasulphide produced only the quinoxalinethiol 11 and benzothiazinethione 12. Compounds 11 and 12 were alkylated with iodomethane and sodium ethoxide to give the S‐alkylated products 13 and 14 respectively.
ESR Studies of Some Copper (II) Complexes
Authors: Bhoopathy T. J. , Payami Feridoun , Mohan S. 
Published: September 2010

AbstractThe ESR and optical absorption spectra of four transition metal complexes, copper (II) dichloroacetate, copper (II) trichloroacetate, copper (II) cyanoacetate, and copper (II) N‐acetyl methioninate were recorded at room temperature in powder and solution, and at liquid nitrogen temperature (LNT) in frozen solution with DMF or DMSO as solvent. The g‐parmeters and hyperfine constants were obtained from the spectra. Using optical and ESR data, the covalency factor has also been calculated.
Trans 8‐Tert‐Butyl‐2‐Oxaspiro [4. 5] Decan‐3‐One C13H22O2
Authors: Tinant B. , Declercq J. P. , van Meerssche M. , Picard Ph. , Moulines J. , Lecoustre M. 
Published: September 2010

AbstractMr = 210.32, monoclinic, P21/a, a = 41.943(7), b = 6.410(2), c = 10.161 (3) Å, β= 114.42 (2)°, V = 2487.4(11) Å3, Z = 8, Dx = 1.12 gcm−3, MoKα, λ = 0.71069 Å, μ = 0.79 cm−1, F (000) = 928, T = 291K, R = 0.058 for 2248 observed reflections. The trans configuration is observed. The two independent molecules of the asymmetric unit have a similar geometry with perfect chair and envelope conformations for respectively the 6‐ and 5‐membered rings.
Preparation of (S)‐2‐Methylbutylamine and Synthesis of Chiral Isoleucine and Alloisoleucine
Authors: Anteunis M. J. O. , Callens R. , De Nitte M. , Reyniers M.‐F. , Spiessens L. 
Published: September 2010

AbstractA four‐step synthesis (45% total yield) of a mixture of chiral pure L‐isoleucine and D‐alloisoleucine is reported, via a route comprising anodic oxidation of suitable acylamide precursors. Efficient preparations for (s)‐2‐ methylbutylamine from the cheap parent (s)‐alcohol are described.
Synthesis and Crystal Structure of Bis [1,2,3] Triazolo [1,5‐a:4′,5′‐d] Pyrimidin‐9‐Ones
Authors: L'abbé Gerrit , Godts Françoise , Toppet Suzanne , Meervelt Luc Van , King Geoffrey S. D. 
Published: September 2010

AbstractThe reactions of 5‐azido‐4‐alkoxycarbonyl‐1,2,3‐triazoles with active methylene nitriles (phenylacetonitrile, malononitrile) yield bis‐[1,2,3] triazolo [1,5‐a:4′,5′‐d] pyrimidinones 7 instead of the previously reported3 bis[1,2,3] triazolo[1,5‐a:4′,5′‐e] pyrimidinones 6. The structures were established by 1H and 13C NMR analyses and confirmed by a crystal structure determination of a selected derivative obtained by methylation.
Effet des Substitutants Aromatiques en RMN du Carbone‐13: Extension du Modèle de Smith et Proulx aux Composés Hétérocycliques et Analyse Statistique des Résultats
Authors: Faure Robert , Llinares Jeanine , Elguero Jose , Goya Pilar 
Published: September 2010

AbstractThree new Q* parameters have been calculated for dimethylamino, amino and tert‐butyl substituents, thus completing a set of fifteen substituents for which F, R and Q* are well characterized. The substituent carbon‐13 chemical shifts of several aromatic heterocycles have been analyzed using the model Δδ=aF+bR+cQ*+d. The set of fifteen substituents (three variables, natural or coded) has been submitted to two statistical treatments. In the first one, with the Fedorov type exchange algorithms it has been possible to select the most significant substituents. In the second one, the possibility to reduce the number of variables has been considered and rejected.
Crystal Structure of 2 ‐(2‐ Amino ‐ 4 ‐ Thiazolyl ‐ 5 ‐ Chloro ) ‐ 2 ‐Z‐Methoxyimino N‐ Methyl Acetamide, C7O2N4 S Cl H9
Authors: Laurent Guy , Norberg Bernadene , Durant Francois 
Published: September 2010

AbstractMr = 248.70, dx = 1.53 Mgm−3, C2/c, Z = 8, a = 15.704(1), b = 7.623(1), c = 18.659(4) Å, β = 104.83(1)°, V = 2159.3 Å3, λ CuKα = 1.54178 Å, μ = 46.91 cm−1, F(000) = 1024, T = 293 K, final R value = 0.043, 2190 independent reflections, 1971 considered as observed (I ≥ 2.5 σ (I)) collected on a Enraf‐ Nonius CAD‐4 diffractometer.The chlorine substitution on the aminothiazol nucleus does not induce any conformational change by comparison with the unsubstituted analogue. This could explain the identical biochemical activity of cefotaxime, a third generation cephalosporin, and its chloro analogue.
Chemoselective Intramolecular Nitrone‐Olefin Cycloaddition : An Efficient Route to Functionalized Cis Hydrindane Systems
Authors: Stanssens Dirk , Keukeleire Denis De , Vandewalle Maurits 
Published: September 2010

AbstractIsoxazolidines 5a‐c and 8 were obtained via chemoselective nitrone‐olefin cycloaddition in suitably modified 1,4‐cyclohexadienes 1a‐c: 5a and 5c were transformed to highly functionalized cis‐hydrindanes.
Transformation of Quinolines and Anilines Over NiMo‐Al2O3 Catalysts
Authors: Perot G. , Brunet S. , Canaff C. , Toulhoat H. 
Published: September 2010

AbstractThe decomposition of nitrogen‐containing compounds : 1,2,3,4 tetrahydroquinoline, 6‐methylquinoline, decahydroquinoline, orthopropylaniline and 2,6‐diethyl, l‐aniline, was studied at 623 K, 7 MPa in a continuous flow microreactor over two commercial nickel‐molybdenum‐alumina catalysts, (HR346 and HR348, Procatalyse). Decahydroquinoline was found to react very rapidly under the conditions of 1,2,3,4‐tetrahydroquinoline hydrodenitrogenation. The simultaneous transformations of quinoline and anilines showed that the aniline transformation was inhibited by the quinolines. However the inhibiting effect was much less significant with HR348 which also happens to be more active in aniline transformation.
An Exafs Study on Carbon‐Supported Mo and Co‐Mo Sulfide Hydrodesulfurization Catalysts
Authors: Bouwens S. M. A. M. , Koningsberger D. C. , De Beer V. H. J. , Prins R. 
Published: September 2010

AbstractThe structure and dispersion of the active phase present in sulfided Mo/C and Co‐Mo/C catalysts are studied by means of Mo K‐edge EXAFS. EXAFS measurements were carried out at liquid N2 temperature on freshly sulfided catalysts in situ. Due to a high signal‐to‐noise ratio of the experimental data, detailed information about the structural parameters of the active phase can be obtained. The Mo/C and Co‐Mo/C catalysts consist of very small MoS2‐like particles, which contain on average 5 to 6 Mo ions (Mo/C), and 7 to 8 Mo ions (Co‐Mo/C). There are indications for the presence of a Mo‐C interaction in Mo/C and Co‐Mo/C. The Mo‐C coordination distance is estimated to be 1.9 ± 0.1 Å. There are also indications for the presence of a Mo‐Co interaction. The Mo‐Co coordination distance was estimated to be 2.8 ± 0.1 Å.
Crystal structure of 3‐methyl‐4‐pyrimidonium picrate
Authors: Kasende Okuma , King Geoffrey S. D. , Zeegers‐Huyskens Thérèse 
Published: September 2010

AbstractCrystal structure analysis of the 1:1 complex of 3‐methyl‐4‐pyrimidone with picric acid has shown that the proton from the picric acid is attached to the pyrimidone N(1) to form an O−.....H+‐N bond rather than to the carbonyl group. The complex crystallizes in the space group C2/c with a = 22.357 (5), b = 9.022 (3), c = 13.882 (4) A, B = 98.85 (2) and Z = 8.
Functionalization of isophorone involving polychlorination part IV: Synthesis of 2, 5‐cyclohexadienones related to filicinic acid
Authors: De Buyck L. , De Pooter H. , Schamp N. 
Published: September 2010

AbstractCyclohexadienone 2 was obtained in 90% yield from heptachloroisophorone 1 by selective dechlorination and hydrolysis in 90% methanol containing iodide and bisulfite. Reaction of 2 with methanolic sodium methoxide allowed isolation of aldehyde 4 (95% yield) or the intermediate acetal 3 in 65‐75% yield. Substitution of all chlorine atoms with methoxide occurred after conversion of 2 into the methyl enol ether 5, resulting in acetal 8 (55% yield) or aldehyde 9 (55%). Using potassium carbonate in boiling methanol one chlorine atom in 5 was left, resulting in acetal 6 (62%) or aldehyde 7 (95%). Careful hydrolysis of the acetals left the enol ethers intact and yielded the aldehydes 10, 11 and 12 which all show remarkably large geminal coupling constants (2J 13C‐CH=O=22 to 23 Hz). Analogous substitution reactions were performed on the chloromethyl analog 18. The resulting methyl enol ethers with methoxymethyl side chain were exceptionnally resistant to acidic hydrolysis.