bluuebunny/crossref_metadata_2025_split huggingface dataset:
Réactivité des germylamines vis à vis de certains esters. Obtention de dérivés germaniés β‐difonctionnels
Authors: Satgé Jacques , Rivière‐Baudet Monique 
Published: September 2010

AbstractThe action of diethyl malonate and ethyl cyanoacetate on dimethyl(triethylgermyl)amine has been studied. In both cases, competition between two reactions is observed: a cleavage reaction of the germanium‐nitrogen bond by these reagents and an addition reaction on to the carbonyl group of an ester function.The cleavage reaction of the Ge‐N bond leads to the corresponding β‐functional C‐germanium derivatives: ethyl C‐(triethylgermyl)malonate and ethyl C‐(triethylgermyl)cyanoacetate, thermally stable.The addition reactions on the carbonyl group of ester functions lead to new thermally unstable β‐functional α‐aminoalkoxygermanes. These last reactions are compared with those obtained with ethyl acetate or ethylenic esters.The thermal decomposition of β‐functional α‐aminoalkoxygermanes formed in the course of these reactions has been studied, and leads mainly to alkoxygermanes and the corresponding β‐functional amide by an intramolecular decomposition process.
Alkene exchange in chloro‐bridged platinum(II) complexes
Authors: Masters C. , Kramer P.A. 
Published: September 2010

AbstractThe synthesis and characterization of some chloro‐bridged platinum(II) complexes [Pt2Cl4L2], where L = 3,3‐dimethyl‐1‐butene, 3,3‐dimethyl‐1‐pentene, 3,3‐dimethyl‐1‐hexene or partially deuterated 3,3‐dimethyl‐1‐pentene is described. Complexation of these alkenes produces asymmetry within the molecule, which can be seen in the 1H NMR spectra of the complexes. The coordinated alkenes undergo exchange with free alkene in solution. The kinetics of this exchange in benzene and chloroform are reported. It has been found that alkene exchange in these complexes is preceded by a rapid dedimerization of the dimeric species.
On the mechanism of ammoxidation of propene over cerium‐doped bismuth molybdate catalysts
Authors: Giordano N. , Bart J.C.J. 
Published: September 2010

AbstractThe origin of the products of the ammoxidation of propene over cerium‐doped silica supported bismuth molybdates was derived from the effects of temperature (380°‐480°C) on overall conversion and selectivity in fixed‐bed operations. At low (< 80 %) conversion levels, the ammoxidation reaction leads to acrylonitrile at Mo(VI) active sites and to by‐products (HCN, acetonitrile, CO and CO2) at Mo(V) sites; at the highest conversions, by‐products derive from consecutive oxidation of acrylonitrile.
Coordination compounds containing l‐methyl‐2‐pyridone
Authors: Reedijk J. , Schrijver H. , Welleman J. A. 
Published: September 2010

AbstractNew compounds with the general formula M(mepydo)2+n (anion)−2 are described, where M = Mn, Co, Ni, Cu, Zn and Cd, and mepydo = 1‐methyl‐2‐pyridone; the anions being ClO−4, BF−4 and NO−3. The value of n depends upon the particular combination of cation and anion, and reaches 6 for the perchlorates and tetrafluoroborates of Cd, Mn and Ni (all octahedral cations); n can be both 6 and 4 for the perchlorates and tetrafluoroborates of Co(II) and only 4 for Zn and Cu; values for n of 2 and 3 are found for the nitrates.Information on the structure of the compounds was obtained from infrared spectra, ligand‐field spectra and X‐ray powder diagrams. In addition, EPR spectra of Mn(II) and Cu(II) compounds and Mn doped samples of the diamagnetic compounds proved to be very useful in elucidating structures. The strenght of the metal‐ligand bond was studied further with the aid of far‐IR spectra, which showed that no metal‐oxygen vibrations occur in the region above 300 cm−1, except in the case of the copper solvates, where a band at 325 cm−1 is assigned to a Cu‐O stretch.The ligand mepydo appears to be rather similar to the unsubstituted 2‐pyridone, although the steric effect of the methyl group has a dramatic effect upon the coordination number for the small cations, which decreases to four in the case of the Zn(II), Cu(II) and Co(II) ions, and upon the ligand‐field splitting of the Co(II) and Ni(II) ions, which decreases by more than 10% compared with unsubstituted 2‐pyridone. Moreover, the Dq value of Ni(mepydo)2+6 of 760 cm−1 is one of the lowest values sofar observed for a carbonyl group donor ligand.
1H NMR studies of σ‐adducts of pteridine and some of its derivatives in liquid ammonia
Authors: Nagel A. , van der Plas H. C. , van Veldhuizen A. 
Published: September 2010

AbstractLow temperature 1H NMR spectra of pteridine dissolved in liquid ammonia, indicate that at −60°C a 1: 1 σ‐adduct is formed by addition of ammonia to the C4‐N3 bond in the pyrimidine ring and that at room temperature a stable 2:1 σ‐adduct is obtained by addition of ammonia to the pyrazine ring. The influence of substituents in the pyrimidine and in the pyrazine ring on adduct formation has been investigated. By reaction of pteridine with 15N‐labelled ammonia it was proved that no ring opening ‐ ring closure mechanism in the formation of the adducts is involved.
1H‐NMR study of the complex formation of alditols with multivalent cations in aqueous solution using praseodymium(III) nitrate as shift reagent
Authors: Kieboom A. P. G. , Spoormaker T. , Sinnema A. , van der Toorn J. M. , van Bekkum H. 
Published: September 2010

AbstractComplexation of ten alditols with praseodymium(III) [isosteric with calcium(II)] as the model cation has been studied in aqueous solution by 1H‐NMR. The paramagnetic praseodymium ion shifted the resonances downfield in a regular way and allowed the identification of all the signals and the determination of the coupling constants.The following configurational sequence of tridentate ligands (H‐COH), with respect to complex formation with PrIII has been established: xylo > threo > arabino (lyxo) > glycerol > erythro, ribo. Two major effects appear to be operative: (i) secondary hydroxyl groups show better complexation than primary hydroxyl groups; (ii) gauche butane and 1,3‐dihydroxyl repulsions introduced upon complexation cause a decrease of the complex stability.Conformational data of both the uncomplexed and the complexed state in aqueous solution have been obtained from the vicinal coupling constants.
Conformational preference and rotational barriers in NAD+ model systems. Temperature dependence of NMR spectra for some N‐aralkylpyridinium ions
Authors: Bakker C.J. , de Gee A.J. , Verhoeven J.W. , de Boer Th. J. 
Published: September 2010

AbstractIn pyridinium compounds of the type X‐CH2‐CH(t‐Bu)‐Y (X,Y = substituted aryl or ‐pyridinium), hindered rotation on NMR time scale is observed for Y, even when Y does not carry ortho substituents. For X no hindered rotation is observed and furthermore, only a minor influence of meta‐ and para‐substituents in X or Y on the rotational barrier is found. The barrier appears to be mainly steric in origin and not due to charge transfer interaction. For X = p‐methoxyphenyl and Y = nicotinamidium two unequally populated rotational isomers are observed, pointing to a preferred orientation of the nicotinamidium group relative to the p‐methoxyphenyl group.
Preparation of chloroalkyl alkanedithioates and their conversion into 2‐alkylidene‐1,3‐dithiacycloalkanes
Authors: Meijer J. , Vermeer P. , Brandsma L. 
Published: September 2010

AbstractChloroalkyl alkanedithioates, R1R2CHC(S)‐S(CH2)nCl, 1 (R1, R2 = H or CH3; n = 2‐4), prepared from Grignard‐reagents R1R2CHMgX, CS2 and Cl(CH2)nBr, are treated with LiNH2 in tetrahydrofuran to form 2‐alkylidene‐1,3‐dithiacycloalkanes 3. On heating the dithioates 1 (R1, R2 = CH3; n = 1‐2) gave the corresponding 2‐alkylidene‐1,3‐dithiacycloalkanes 3. The dithioates 1 (R1, R2 = H; R1, R2 = H, CH3; n =1) cannot be converted into 3 under these circumstances 3.
Photodehydrocyclisations of stilbene‐like compounds XII. Photochemistry of 2‐(2‐benzo[c]phenanthrylethenyl)‐1,6‐methano[10]annulene
Authors: Laarhoven W.H. , Kuin N.P.J. 
Published: September 2010

AbstractOn irradiation of the title compound the methano group is completely eliminated. Benzo‐[m]hexahelicene is obtained as the sole cyclization product.
Oxydation des alcools. I — Choix de l'adamantanol pour déterminer la structure de l'état de transition dans l'oxydation par Cr(VI)
Authors: Durand R. , Geneste P. , Lamaty G. , Roque J.P. 
Published: September 2010

AbstractThe comparison of the rates of chromic oxydation of 2‐adamantanol, bicyclo[3.3.1]nonan‐9‐ol and cis and trans 4‐tert‐butylcyclohexanols shows that the transition state of this reaction is product‐like.It appears that 1,3 diaxial interactions increase, according to the system, in the following order: cyclohexyl < adamantyl < bicyclo[3.3.1]nonane.
Approaches to analogues of anhydrogliotoxin V Syntheses of monodesthio‐secogliotoxin analogues
Authors: Ottenheijm H.C.J. , Hoffmann J.J.M.L. , Biessels P.T.M. , Potman A.D. 
Published: September 2010

AbstractTwo routes for the synthesis of monodesthiosecogliotoxin analogues 4 are described. The addition of suitable N‐protected α‐mercapto α‐amino acids to ethyl 3H‐indole‐2‐carboxylates followed by removal of the amino‐protecting group provides a convenient approach to the title compound. Illustrative of this, the adduct of ethyl 3,3‐dimethyl‐3H‐indole‐2‐carboxylate 8 with 2‐mercapto‐2‐(benzyloxycarbonylamido)propionic acid 11, which was prepared in situ from the mercaptoacetylated precursor 12, gave 17 after deprotection of the amino group.A simple alternative route starts with bromination of the thiazolidinone 13 with N‐bromosuccinimide to yield 29. Substitution of the bromine with an azido group yielded the imino compound 32 directly; this could then be reduced with NaCNBH3 giving the secogliotoxin analogue 4 (RR′H).
Deazapurine derivatives XIV. The synthesis of 1‐deazaguanosine
Authors: Schelling J. E. , Salemink C. A. 
Published: September 2010

AbstractA fusion reaction of 5,7‐dichloroimidazo[4,5‐b)]pyridine (2) with 1,2,3,5‐tetra‐O‐acetyl‐β‐D‐ribofuranose (3) gave, after deacetylation, 5,7‐dichloro‐3‐β‐D‐ribofuranosylimidazo[4,5‐b]pyridine (5). The site of attachment of the ribosyl moiety and the anomeric configuration of 5 were determined by converting it into 3‐β‐D‐ribofuranosylimidazo[4,5‐b]pyridine (6). In a direct condensation of 5‐acetamido‐7‐benzyloxyimidazo[4,5‐b]pyridine (7) with 2,3,5‐tri‐O‐benzoyl‐D‐ribofuranosyl chloride (8) in nitromethane, riboside 9 was formed, which afforded 1‐deazaguanosine (1) upon removal of the protecting groups. The structure of this compound was confirmed by its conversion into 5.
Reactions of hydroxycarbonium ions in strong acids VIII. Cyclization of hydroxyallyl to tetrahydrofuryl ions and related reactions
Authors: Brouwer D. M. , van Doom J. A. , Kiffen A. A. 
Published: September 2010

AbstractThe cyclization of hydroxyallyl ions (protonated 3‐alken‐2‐ones) to tetrahydrofuryl ions in a series of strong acids (HF, H2SO4, FSO3H) and superacids (FSO3HSbF5, HFSbF5) has been studied, together with some related reactions. The rates of cyclization of hydroxyallyl ions increase with substitution of alkyl groups at the C(5) carbon; they pass through a maximum if the acidity of the solvent is increased. It is concluded that the cyclizations involve concerted reactions, the formation of any distinct (short‐lived) intermediates taking place only when particular combinations of acidity of the solvent and structure of the starting ion are present.Rate constants are also reported for the cis/trans isomerization of protonated 3‐penten‐2‐one. Protonated 4‐penten‐2‐one isomerizes to the hydroxyallyl ion, via solvent addition products as long‐lived intermediates, but protonated 4‐hexen‐2‐one gives the cyclized ion even under conditions of kinetic control. The acid‐catalysed ionization of protonated 5‐chloropentan‐2‐one gives a hydroxyallyl ion as the first product. All these reactions, too, involve concerted processes.
Structure analysis of the reaction products of 1′,3′,3′‐trimethylspiro[2H‐1‐benzopyran‐2,2′‐indolines] with 1,1‐bis[4‐(dimethylamino)phenyl]ethylene and related compounds
Authors: van Den Bogaert H.M. , Zwanenburg D.J. , Maas Th. A. M. M. 
Published: September 2010

AbstractReaction of 1′,3′,3′‐trimethylspiro[2H‐1‐benzopyran‐2,2′‐indolines] with 1,1‐bis[4‐(dimethylamino)phenyl]ethylene can give two types of isomeric products, 2,2‐bis[4‐(dimethylamino)‐phenyl]‐4‐{2‐methylidene‐1,3,3‐trimethylindoline}chromans (2a–e) and 1′,3′,3′‐trimethyl‐4‐{2,2‐bis[4‐(dimethylamino)phenyl]vinyl}‐spiro[chroman‐2,2′‐indolines] (3a–d).These products and related compounds have been analysed by spectroscopic methods. The conformation of the dihydropyran ring and the chemical shift differences in the pairs of isomeric adducts are discussed.
(2 + 2)‐Cycloaddition of 9,10‐phenanthrenequinone to alkyl‐substituted aminoacetylenes. Isomerisation of the adducts via photochemical γ‐hydrogen‐abstraction and via base‐catalysis. Preparation of some phenanthro(9,10‐b]furan‐2‐one derivatives
Authors: Mosterd A. , Bos H.J.T. 
Published: September 2010

AbstractPhenanthrenequinone (1) reacts with 1‐dialkylamino‐1‐alkynes 2 via (2 + 2)‐cyclo‐addition to γ‐oxo‐α,β‐unsatutrated amides 3E of the quinone methide type.These adducts isomerise under the influence of base to α,β‐unsaturated hydroxyamides 4. Irradiation of the adducts 3E in benzene affords the same α,β‐unsaturated hydroxyamides 4 via intramolecular hydrogen‐abstraction.Treatment of 3E with boron trifluoride gives 3‐alkyl‐3‐dialkylamino‐2,3‐dihydrophenanthro[9,10‐b]furan‐2‐ones 6 in good yields. With hydrochloric acid in acetic acid, the unsaturated hydroxyamides 4 afford 3‐alkylidene‐2,3‐dihydrophenanthro[9,10‐b]furan‐2‐ones 7. Similar reactions have been performed starting from 3,5‐di‐tert‐butyl‐o‐benzoquinone.
NMR studies on σ‐adducts of heterocyclic systems with nucleophiles (Part VII). 1H‐NMR investigations on σ‐adduct formation of pyridazine, of pyridazine 1‐oxide and some of its derivatives with ammonia. A new substitution mechanism
Authors: Klinge D. E. , van Der Plas H. C. 
Published: September 2010

AbstractIn the reaction of 6‐chloro‐3‐methoxy‐4‐nitropyridazine 1‐oxide with methanolic ammonia and with liquid ammonia, amino‐demethoxylation occurs. By using 1H‐NMR spectroscopy we observed that with ammonia a σ‐adduct at C(5) is formed. The unusual substitution reaction at C(3) is proposed to take place in this σ‐adduct. This new substitution mechanism is discussed.
The structure of erythromycin A cyclic carbonate
Authors: Slawinski W. , Bojarska‐Dahlig H. , Glabski T. , Dziegielewska I. , Biedrzycki M. , Naperty S. 
Published: September 2010

AbstractThe cyclic carbonate of erythromycin A, a compound with higher antibacterial activity than the parent antibiotic, is the 11,12‐carbonate derivative. The cyclic carbonate exhibits a hydroxy ketone/hemiacetal tautomerism in which the hemiacetal is the more stable form.
A derivative of (4‐imidazolyl)acetaldehyde of proven structure
Authors: Kivits G. A. A. , Hora J. 
Published: September 2010

Abstract2‐[(4‐Imidazolyl)methyl]‐5,5‐bis(hydroxymethyl)‐1,3‐dioxane has been prepared by acetalization of (4‐imidazolyl)acetaldimide salt with pentaerythritol. The literature discrepancies on (4‐imidazolyl)acetaldehyde are discussed.
Specificity in the enzymic conversion of substituted cis‐8, cis‐11, cis‐14‐eicosatrienoic acids into prostaglandins
Authors: van Dorp D. A. , Christ E. J. 
Published: September 2010

AbstractThe enzyme specificity in the biosynthesis of prostaglandins has been investigated by incubation of a particulate fraction of sheep vesicular glands with substituted cis‐8,cis‐11,cis‐14‐eicosatrienoic acids. Conversions were always lower than with the unsubstituted acid (20:3). In the 2‐substituted series, a conversion of up to 50% was found for 2‐methoxycarbonyl‐ ; 2‐methyl‐ ; 2‐hydroxymethyl‐ ; 2‐butyl‐ ; 2‐methoxy‐ ; 2‐methoxymethylene‐ ; 2‐fluoro‐ ; 2‐bromo‐ ; 2‐cyano‐ ; and 2‐phenyl‐20:3. No conversion was found for 2‐hydroxycarbonyl‐ ; 2‐heptoxycarbonyl‐ ; 2‐amino‐ ; and 2‐acetamido‐20:3. In some cases, a slight preference of the enzymes for the R configuration (2‐phenyl‐ ; 2‐methyl‐20:3) was noted.For di‐substituted acids, yields of up to 70% were found for 2‐cyano‐2‐butyl‐ ; 2,3‐cis‐ and 2,3‐trans‐methylene‐ ; 3,3‐dimethyl‐20:3, but 4,4‐dimethyl‐20:3 was not converted. However, 5‐yne‐20:3 was again a substrate (25% conversion).Substitution at the methyl end of the precursor acid resulted in 34% conversion with 19‐methyl‐20:3, but 18‐methyl‐20:3 was not converted.Biological activities of substituted prostaglandins were, in general, much less than those of PGE1, but for 19‐methyl‐PGE1, smooth muscle‐stimulating activity was 1.6 times that of PGE1. For some substituted prostaglandins (2‐fluoro‐ ; 2‐cyano‐PGE1), an appreciable activity in one biological test system was found but very little in others.
Synthesis of 2‐substituted cis‐8,cis‐11,cis‐14‐eicosatrienoic acids, precursors for 2‐substituted prostaglandins
Authors: van Der Linde R. , van Der Wolf L. , Pabon H. J. J. , van Dorp D. A. 
Published: September 2010

AbstractVarious 2‐substituted all‐cis‐8,11,14‐eicosatrienoic acids have been prepared via coupling of all‐cis‐6,9,12‐octadecatrienyl methanesulfonate with diethyl malonate, substituted diethyl malonates, ethyl cyanoacetate or ethyl 2‐cyanohexanoate. The substituents are: COOH, COOCH3, COOC4H9, COOC7H15, CH2OH, CH3, C4H9, C6H5, CH2OCH3, NHCOCH3, NH2.HCl, F, OCH3, CN and both CN and C4H9.
Reductive substitution of chlorosulfines withp‐toluenesulfinate
Authors: Veenstra G. E. , Zwanenburg B. 
Published: September 2010

AbstractThe reaction of chlorosulfines [R‐C(Cl)SO with R beingp‐CH3C6H4S, Cl andp‐ClC6H4] withp‐toluenesulfinate leads to products in which the CSO function is replaced by a CH2group. The first step in the reaction is a substitution of chlorine by sulfinate. Subsequent attack of the sulfinate at the sulfine sulfur atom produces sulfinyl sulfones which upon hydrolysis provide the apparent reduction products. Substantiation of the suggested reaction sequence was achieved by reaction of a sulfone sulfine with sulfinate and isolation of one of the proposed intermediates.
Copper(I) bromide promoted reaction of grignard compounds with propiolaldehyde diethyl acetal. An efficient synthesis of allenic ethers and α,β‐ethylenic aldehydes
Authors: Tadema G. , Vermeer P. , Meijer J. , Brandsma L. 
Published: September 2010

AbstractInteraction between ethereal solutions of Grignard compounds RMgBr and propiolaldehyde diethyl acetal I in the presence of copper(I) bromide gives allenic ethers, III. Acid hydrolysis affords trans‐α,β‐ethylenic aldehydes, IV, in good to excellent yields.
[2 + 2] Cycloaddition reactions of heterocyclic compounds with ynamines
Authors: Reinhoudt D.N. , Kouwenhoven C.G. 
Published: September 2010

AbstractTwo possible routes have been investigated for the synthesis of 1‐heterocycloheptatrienes starting from annulated cyclobutene derivatives. The first approach comprised a [2 + 2 + 2] cycloreversion of tetracyclic compounds prepared from 2,3‐bis(methoxycarbonyl)‐7‐oxa‐ or −7‐azabicyclo‐[2.2.1]hepta‐2,5‐diene by a [2 + 2] cycloaddition with ynamines followed by a cycloaddition reaction with a 1,3‐dipolar reagent However, upon flash‐vacuum pyrolysis of these compounds, a retro‐1,3‐dipolar addition rather than a [2 + 2 + 2] cycloreversion occurred, yielding 2,4,6‐trimethylbenzonitrile oxide. The second approach comprised the synthesis and isomerization of [2 + 2] cycloadducts of ynamines with electron‐deficient heteroaromatics. Both 3‐nitrobenzo[b]thiophene and 4‐nitro‐isothiazole yielded [2 + 2] cycloadducts and as the by‐product nitrones. Attempts to convert the [2 + 2] cycloadducts into benzo[b]thiepins or 1,2‐thiazepines were unsuccessful.
Base‐induced ring‐opening and ring‐transformation of acetylenic epoxides and episulfides
Authors: Schreurs P. H. M. , de Jong A. J. , Brandsma L. 
Published: September 2010

AbstractEpoxides magnified image, in which R can represent the groupings magnified image magnified imageare converted by KO‐t‐C4H9 in dimethyl sulfoxide into derivatives of furan or dihydrofuran and/or alcohols with the enyne system CCCCCOH. The analogous episulfides (magnified image) give, in low yield, the expected thiophene derivatives.
Kinetics of the reactions of aromatic amines and acid chlorides in hexamethylphosphoric triamide
Authors: Borkent G. , Tijssen P. A. T. , Roos J. P. , van Aartsen J. J. 
Published: September 2010

AbstractThe kinetics of the reaction between aromatic amines and aromatic acid chlorides in hexamethylphosphoric triamide (HMPT) have been studied by stopped‐flow spectrophotometry using an acid‐base indicator to follow the change in H⊕ during the reaction.Measurements on bifunctional amines and acid chlorides, e.g. p‐phenylenediamine (PPD) and terephthaloyl dichloride (TDC) have shown that the NH2 groups in PPD react approximately 12 times as fast as the NH2 group in the intermediate product, while the acid chloride groups in TDC and intermediate product have equal reactivities.It has been found for all reactions studied that protonation of the NH2 groups by the H⊕ produced is very important.The influence of substituents could be analysed by two Hammett relations. The reaction of substituted anilines with benzoyl chloride could be described by the relation log kR = −1.4σ+R + 2.10 and the reaction of substituted benzoyl chlorides with aniline by the relation log kR = 3.4σR + 2.10.
The preparation of diribonucleoside monophosphates containing 4‐thiouridine via the phosphotriester approach
Authors: van Boom J. H. , Burgers P. M. J. , den Hartog J. , van der Marel G. 
Published: September 2010

AbstractA new procedure for the synthesis of 2′‐ketals of 4‐thiouridine (1c), N4‐methylcytidine (2a) and N4,N4‐dimethylcytidine (2b), starting from the. easily accessible 3′,5′‐di‐O‐acetyl‐2′‐O‐(methoxytetrahydropyranyl)uridine (1b), has been devised. Modified dinucleoside monophosphates i6Aps4U (7a) and s4UpU (7b)N, Y, nucleoside moiety. NpY, nucleotidyl‐(3′‐5′)‐nucleoside; s4U, 4‐thiouridine; i6A, N6‐(Δ2‐isopentenyl)adenosine. See also: Pure Appl. Chem. 40, 277 (1974).
have been prepared, in satisfactory yields, by appropriate internucleotide bond formation between (1c) and the corresponding 5′‐ester (1d) with 2′,5′‐dieO‐(methoxytetrahydropyranyl)‐N6‐(Δ2‐isopentenyl)adenosine (3) and 2′,3′‐O‐methoxymethylideneuridine (4), respectively.
On the occurrence of the SN(ANRORC) mechanism in the amination of substituted 1,3, 5‐triazines
Authors: Simig Gy. , van der Plas H. C. , Landheer C. A. 
Published: September 2010

AbstractAmination of 2‐X‐4, 6‐diphenyl‐1,3,5‐triazines (X = H, Cl, SCH3) with KNH2 in liquid NH3 at −33° yields 2‐amino‐4, 6‐diphenyl‐1,3,5‐triazine. 2‐Chloro‐4, 6‐diphenyl‐1,3,5‐triazine can also be aminated by liquid NH3 at −33° to give the corresponding 2‐amino compound.It is proved using 15N‐labelled triazines that i. the amination of 2‐(methylthio)‐4,6‐diphenyl‐1. 3,5‐triazine proceeds to the extent of about 100% by an SN (ANRORC) mechanism; ii. the amination of 2‐chloro‐4,6‐diphenyl‐1,3,5‐triazine with liquid NH3 and of 2,4‐diphenyl‐1,3,5‐triazine with KNH2 occurs by an Sn(AE) process; iii. both mechanisms occur in the amination of 2‐chloro‐4,6‐diphenyl 1,3,5‐triazine with KNH2 in liquid NH3, the ratio depending on the KNH2 concentration. PMR‐spectroscopic evidence is presented for a covalent addition of the amide ion at C‐6 of 2,4‐diphenyl 1,3,5‐triazine.
Stereochemistry of the reduction of ethyl 3,3‐dimethyl‐2,4‐dioxocyclopentanecarboxylate
Authors: Plantema O. G. , de Koning H. , Huisman H. O. 
Published: September 2010

AbstractSeveral isomeric hydroxycyclopentanone and dihydroxycyclopentane derivatives were obtained from the reduction of ethyl 3,3‐dimethyl‐2,4‐dioxocyclopentanecarboxylate. The relative configurations of the isomers were determined by spectroscopic and chemical methods.