bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthèse et propriétés physico‐chimiques de trois chloro‐10 tétraméthylphénoxarsines
Authors: Saint‐Ruf G. , Clément M. , Coïc J. P. 
Published: September 2010

Abstract10‐chloro‐2,3,7,8‐tetramethyl‐, 10‐chloro‐2,4,6,8‐tetramethyl‐ and 10‐chloro‐3,4,6,7‐tetramethylphenoxarsines were prepared; the chemical shifts of the protons of these new compounds and those of 10‐chlorophenoxarsine in N.M.R. spectra are reported, as well as the fragmentation patterns noted in their mass spectra.
Excess mixed anhydride peptide synthesis with histidine derivatives
Authors: Beyerman H. C. , Hirt J. , Kranenburg P. , Syrier J. L. M. , van Zon A. 
Published: September 2010

AbstractThe coupling of histidine derivatives by the excess mixed anhydride method was investigated with respect to the yield, the racemization, and the formation of by‐products. The tert‐butyloxycarbonyl‐ (Boc‐), isobutyloxycarbonyl‐ (i‐Boc‐), benzyloxycarbonyl‐ (Z‐), and p‐toluenesulfonyl‐(Tos‐) groups were found to be suitable for protection of the imidazole nucleus.A new way of selective removal of the Nim‐Tos group, with pyridine hydrochloride, is described.
Thermal rearrangements of divinyl disulfides
Authors: Larsson F. C. V. , Brandsma L. , Lawesson S.‐O. 
Published: September 2010

AbstractDivinyl disulfides, obtained by oxidative coupling of anions derived from dithioesters with iodine, have been rearranged to bisdithio esters; these have been converted to derivatives of thiophene by simple heating and by treatment with bases followed by alkylation. Starting from methyl dithiopropionate and methyl phenyldithioacetate these operations led to 2,5‐bis(methylthio)‐3,4‐dimethylthiophene, 2,5‐bis(methylthio)‐3,4‐diphenylthiophene and 2‐mercapto‐5‐(methylthio)‐3,4‐diphenylthiophene, respectively. The divinyl disulfide, obtained from methyl dithioisobutyrate did not undergo thermal rearrangement at elevated temperature.
Ring opening and ring contraction in reactions of some aminobromo‐ and dibromoisoquinolines with potassium amide in liquid ammonia
Authors: Sanders Georgine M. , van Dijk M. , den Hertog H. J. 
Published: September 2010

AbstractReactions of some aminobromo‐ and dibromoisoquinolines with KNH2 in liquid NH3 have been investigated. Compounds with an amino group and a bromo atom in positions α to the heteroatom, show a very fast ring opening, leading to o‐cyanobenzyl cyanide. The 1,4‐substituted aminobromoisoquinolines do not react; 4‐amino‐3‐bromoisoquinoline undergoes ring opening into o‐cyanobenzyl isocyanide, 3‐amino‐4‐bromoisoquinoline ring contraction to 1‐cyanoisoindole. The dibromoisoquinolines react primarily by nucleophilic substitution.
Conformation of non‐aromatic ring compounds ‐ 89 The conformation of 3‐(2,6‐dichlorophenyl)glutaric anhydride studied by dynamic proton magnetic resonance and empirical force field calculations
Authors: Koer F. J. , Faber D. H. , Altona C. 
Published: September 2010

AbstractThe dipole moment and PMR spectra of 3‐(2,6‐dichlorophenyl)glutaric anhydride were measured and interpreted in terms of conformational properties of the anhydride ring and its side chain. Equilibrium compositions in several solvents are derived from vicinal proton couplings. The 2,6‐dichlorophenyl group prefers the equatorial position over the axial one to the extent of 2.1 kcal/mol with a strong rotational preference for the parallel conformational (Epl: Ph//3H). Broadening and collapse of the PMR spectra in the aromatic hydrogen region on lowering the temperature indicates the existence of an appreciable barrier opposing rotation about the sp2‐sp3 carbon‐carbon bond. A full line‐shape analysis gives the activation energy; ΔG≠298: 13.4 ± 0.2 kcal/mol (acetone‐d6) and 13.5 ± 0.2 kcal/mol (dichloromethane‐d2). These values accord well with the barrier height obtained from empirical force field calculations, 14.5 kcal/mol. The transition state is predicted to correspond to the Epr conformation (Ph ± 3H).
Rational synthesis of 4‐hydroxy‐2,5‐dimethyl‐3‐[2H]‐furanone and keto‐enol equilibria of diketone intermediates
Authors: van den Ouweland G. A. M. , Tjan S. B. 
Published: September 2010

Abstract4‐Hydroxy‐2,5‐dimethyl‐3‐[2H]‐furanone was prepared in an overall yield of 40% via a new route from acetone and ethyl lactate. The percentages of the enol‐keto tautomers of a number of intermediate 2,4‐diketones have been determined by PMR analyses.
Insertion of phenyl isocyanide into ethanol catalysed simultaneously by copper(I) and base
Authors: Knol D. , van Os C. P. A. , Drenth W. 
Published: September 2010

AbstractThe insertion of phenyl isocyanide into ethanol under the influence of base and Cu(PhNC)4BF4 is investigated mechanistically. In pre‐equilibria the BF4⊖ anion is exchanged for ⊖OC2H5. By intramolecular nucleophilic attack of ⊖OC2H5 on coordinated isocyanide an [(ethoxy)‐(phenylimino)methyl]copper intermediate is formed. The substituent effect supports this conclusion. In a rapid reaction with ethanol the intermediate decomposes and the insertion product, ethyl N‐phenylformimidate, is formed. It reacts slowly to give N,N′‐diphenylformamidine, which is precipitated at the end of the reaction as a copper complex.
[3,3]‐Sigmatropic rearrangement of 1‐alkenyl allenyl sulfides. Synthesis of γ,δ‐acetylenic aldehydes and ketones
Authors: Brandsma L. , Verkruijsse H. D. 
Published: September 2010

AbstractThermal rearrangement of the sulfides magnified image (R1 ‐ R4 is H or alkyl) at 125−135° in a mixture of dimethyl sulfoxide and water gives, γ,δ‐acetylenic aldehydes (R3 = H) or ketones (R3 = alkyl) magnified image in moderate yields.
The chemistry of small ring compounds. Part 29: Synthesis and stereochemistry of some arylcyclopropanone methyl hemiacetals and their acetates
Authors: Bakker B. H. , Steinberg H. , de Boer Th. J. 
Published: September 2010

AbstractSome mono‐aryl substituted 1‐methoxycyclopropanols (cyclopropanone hemiacetals) with the following aryl groups, C6H5‐, p‐CH3C6H4‐ and p‐ClC6H4‐, have been prepared in 80‐85 % yield by passing ketene at −70°C into a solution of aryldiazomethane in CFCl3 or CCl4, containing an excess of methanol, which adds to the intermediate arylcyclopropanone. It appears that the addition of methanol to the carbonyl group in the arylcyclopropanone takes place preferentially at the least hindered side of the cyclopropyl ring as is shown by structure elucidation (NMR) of the more stable acetates derived from the hemiacetals.
A novel method for the synthesis of specifically substituted cycloheptatrienes
Authors: van Tilborg W.J.M. , Smael P. , Visser J.P. , Kouwenhoven C.G. , Reinhoudt D.N. 
Published: September 2010

AbstractA novel method has been developed for the synthesis of substituted cycloheptatrienes, involving the cycloaddition of substituted cyclopropenes to substituted thiophene 1,1‐dioxides followed by expulsion of sulfur dioxide from the cycloadduct. The scope and limitations of the reaction have been investigated and its mechanism is discussed. Attempts to extend this reaction principle to the synthesis of 1‐heterocycloheptatrienes were unsuccessful.
Formation of new ring systems by addition of hydrogen sulfide, selenide, telluride, water and primary amines to cyclohexyl‐ or phenyl‐ di(1‐alkynyl)phosphine oxides and alkyl di(1‐alkynyl)phosphinates under nucleophilic conditions
Authors: Naaktgeboren A. , Meijer J. , Vermeer P. , Brandsma L. 
Published: September 2010

AbstractInteraction between di‐1‐alkynylphosphine oxides or di‐1‐alkynylphosphinates and disodium disulfide, sodium selenide, sodium telluride, water and primary amines in solvents like water, methanol, dimethylformamide, liquid ammonia gives the new six‐membered heterocyclic systems 2–6.
Aromatic lead(IV) compounds VII. The plumbylation of aromatic compounds
Authors: de Vos D. , van Barneveld W.A.A. , van Beelen D.C. , van Der Kooi H.O. , Wolters J. , van Der Gen A. 
Published: September 2010

AbstractThe plumbylation of a large number of aromatic compounds is reported and a route for the preparation of the novel compounds ArAr′PbX2 is described. The course of the plumbylation reaction is discussed and its selectivity is explained in terms of differences in reactivity of aryllead(IV) compounds with halogen substituted acetic acids.
Approaches to analogues of anhydrogliotoxin IV Syntheses and reactions of 2‐mercapto‐2‐aminopropionic acid derivatives
Authors: Ottenheijm H.C.J. , Potman A.D. , van Vroonhoven T. 
Published: September 2010

AbstractSeveral S,N‐protected‐2‐mercapto‐2‐aminopropionic acid derivatives (3a‐g Table I) have been prepared by the reaction of thiols with the corresponding N‐protected 2‐hydroxy‐2‐amino‐propionic acid derivatives 8, prepared from the corresponding amides 7 and pyruvic acid. Recent controversies in the literature regarding this method are discussed. Selective removal of the sulfur‐protecting group in 3b and 3e afforded the 2‐mercapto‐2‐acylamidopropionic acids 11, R2 = H and C6H5 respectively. Reaction of 3e with thionyl chloride afforded 4‐methyl‐4‐(acetylthio)‐2‐phenyl‐2‐oxazolin‐5‐one 10. Under these conditions 3g gave the Leuchs' anhydride 14.
Stereoselectivity and proton binding in some transition‐metal complexes of N‐(o‐hydroxybenzyl)alanine
Authors: Ritsma J. H. 
Published: September 2010

AbstractStability constants and stereoselective effects are presented for some transition‐metal complexes of the new legand, N‐(o‐hydroxybenzyl)alanine, H2(oHBAl). The preparation of DLH2(oHBAl) and optically pure LH2(oHBAl), by hydrogenation of the salicylaldimine of alanine, is described. The M‐oHBAl systems studied are complicated by the presence of protonated species [M = Co(II), Ni(II), Cu(II) and Zn(II)] or a hydroxylated species [M = Zn(II)]. From comparison of competition constants it is concluded that the proton in the protonated complexes is bound to the phenoxy atom (CoHA2, NiHA2, NiHA and CuHA) or, possibly, to the secondary nitrogen atom (CuHA2, ZnHA2) of (oHBAl)2−, A. Appreciable stereoselective effects, in favour of the “racemic complex” {M(LA)2 + M(DA)2}, are found for the cobalt and nickel bis‐complexes. In the copper bis‐complexes no stereoselectivity was found.
A 15N‐study of the conversion of 3‐(methylthio)‐1,2,4‐triazine with potassium amide in liquid ammonia at ‐ 75°C
Authors: Rykowski A. , van der Plas H. C. 
Published: September 2010

AbstractTreatment of 3‐(methylthio)‐1,2,4‐triazine with potassium amide in liquid ammonia gives 3‐amino‐1,2,4‐triazine, 3,3′‐bis(methylthio)‐5,5′‐bi‐1,2,4‐triazine and 3‐amino‐3′‐(methylthio)‐5,5′‐bi‐1,2,4‐triazine. In the 3‐amino compound formed from 3‐(methylthio)‐[4‐15N]‐1,2,4‐triazine, 93% of the 15N is present in the exocyclic nitrogen of the amino group. A SN(ANRORC) mechanism is proposed for this amino‐de(methylthio)lation reaction.
A 13C‐NMR study of squalene some aspects of the selective terminal oxidation of squalene
Authors: van Dommelen Marianne E. , Wilson Arnold R. N. , de Haan Jan W. , Buck Henk M. 
Published: September 2010

Abstract13CNMR data (shifts and relaxation times) show that the conformational equilibrium and the intramolecular mobility of squalene are very similar in media of different polarity. This is inconsistent with one of van Tamelen's original proposals explaining the selective terminal epoxidation in terms of tight coiling of squalene in polar media. MINDO/2′ calculations predict that terminal epoxidation is favoured over internal epoxidation by ∼1.5 kcal/mole.
Synthesis of substituted cis‐8,cis‐11,cis‐14‐eicosatrienoic acids, precursors of correspondingly substituted prostaglandins
Authors: Heslinga L. , van Der Linde R. , Pabon H. J. J. , van Dorp D. A. 
Published: September 2010

AbstractThe synthesis of the following groups of acids is described: (a) 3‐Methyl‐c‐2,c‐8,c‐11,c‐14‐, and 3‐methyl‐t‐2,c‐8,c‐11,c‐14‐eicosatetraenoic acid and 3‐methyl‐c‐8,c‐11,c‐14‐eicosatrienoic acid, (b) c‐8,c‐11,c‐14‐eicosatrien‐5‐ynoic acid, (c) c‐2,3‐methylene‐,t‐2,3‐methylene‐,3,3‐dimethyl‐ and 4,4‐dimethyl‐c‐8,c‐11,c‐14‐eicosatrienoic acid, (d) 18‐methyl‐, (S)‐18‐methyl‐ and 19‐methyl‐c‐8,c‐11,c‐14‐eicosatrienoic acid. They were obtained via coupling of (a) c‐7,c‐10,c‐13‐nonadecatrien‐2‐one with ethoxycarbonylmethylenetriphenylphosphorane and c‐7,c‐10,c‐13‐nonadecatrien‐2‐yl methane sulfonate with diethyl malonate, (b) l‐bromo‐c‐2,c‐5,c‐8‐tetradecatriene with 5‐hexynoic acid, (c) 1‐bromo‐2,5‐undecadiyne with the appropriately substituted 8‐nonynoic acids and (d) from the correspondingly substituted 1‐bromo pentanes, using standard procedures.
Proton bonding to 1,8‐bis(dialkylamino)naphthalenes
Authors: de Groot R. L. , Sikkema D. J. 
Published: September 2010

AbstractProton NMR spectra of 1,8‐bis(dimethylamino)naphthalene and 1,8‐bis(diethylamino)‐naphthalene (MPS and EPS) solutions to which acetic acid or trifluoroacetic acid (TFA) has been added exhibit several characteristic features caused by proton exchange phenomena. In the presence of less than one mole of TFA per mole of diamine the protonated and unprotonated forms can be observed separately. The proton in the protonated amine resonates at unusually low field (∼20 ppm). When more TFA is added another proton signal at low field, between 18 and 12 ppm down field from TMS, is observed. The nature of the latter proton resonance is discussed. The proton in the amine is probably in a bridge between the two nitrogen atoms, since no magnetic inequivalence is observed for the four methyl or ethyl groups attached to the nitrogen. In the presence of acetic acid instead of TFA the proton in the amine molecule changes places with the other protons in the solution. From the temperature‐dependence of the spectra the activation energy for the exchange of D+ between amine molecules has been estimated. The possible use of MPS as a probe for the investigation of hydrogen bonding phenomena in carboxylic acid solutions in non‐aqueous solvents is indicated.
Didehydrohetarenes (XXXVII). On the existence of 4,5‐didehydropyridazine
Authors: Klinge D.E. , van der Plas H.C. 
Published: September 2010

AbstractReaction of 4‐chloro‐3,6‐diphenylpyridazine with potassium amide in liquid ammonia gives 4‐amino‐3,6‐diphenylpyridazine and imino‐4,4′‐bis(3,6‐diphenylpyridazine). Starting with 4‐chloro‐3,6‐diphenylpyridazine‐[5‐13C], it was proved by quantitative 13CNMR measurements that both products are formed via the intermediacy of 4,5‐didehydro‐3,6‐diphenylpyridazine.
The synthesis of bis‐endo‐2‐(hydroxymethyl)‐5‐(4‐imidazolylmethyl)‐bicyclo[2.2.2]octane and the corresponding cyclohexane analogue
Authors: Hora J. 
Published: September 2010

AbstractA synthesis of bis‐endo‐2‐(hydroxymethyl)‐5‐(4‐imidazolylmethyl)bicyclo [2.22]octane and cis‐1‐(hydroxymethyl)‐4‐(4‐imidazolylmethyl)cyclohexane is reported. Two sequences of reactions representing the formal replacement of halogen by the 4‐imidazolyl group have been developed.
The addition of hydrogen bromide to syn‐7‐methoxybicyclo[2.2.1]hept‐2‐ene
Authors: Boerhorst E. , Klumpp G.W. 
Published: September 2010

AbstractFree radical addition of hydrogen bromide to syn‐7‐methoxybicyclo[2.2.1]hept‐2‐ene (1) yields mixtures of exo‐ and endo‐2‐bromo‐syn‐7‐methoxybicyclo[2.2.1]heptanes (2 and 3). Under ionic conditions products of skeletal rearrangements (4 and 5) are formed besides 2. No indications of 4‐MeO participation were found.
Esters β‐thiocétoniques cyclaniques N° 3 Thio‐réarrangement de Claisen
Authors: Morin L. , Paquer D. , Smadja S. 
Published: September 2010

AbstractAlicyclic β‐thioxo esters react with alkyl halides and ethyl chloroacetate to give S‐alkylated compounds.Thioclaisen rearrangement is observed with allyl bromide, crotyl bromide, and propargyl bromide.
Chemistry of sulfines. Part 32. Synthesis and reactions of (phenylsulfonyl)ketene dimethyl dithioacetal monoxide
Authors: Veenstra G.E. , Zwanenburg B. 
Published: September 2010

AbstractOxidation of methyl (phenylsulfonyl)dithioacetate (1) with m‐chloroperbenzoic acid gave the sulfine C6H5SO2CH2C(SO)SCH3 (2).Deprotonation of 2 with TlOEt and subsequent S‐alkylation of the thallium(I) salt with methyl iodide gave (phenylsulfonyl)ketene dimethyl dithioacetal moxonide (5). When other bases were used in the deprotonation step deoxygenated products, viz. C6H5SO2CHC(SCH3)2 were obtained. Evidence is presented that oxygen is lost by an intramolecular redox reaction of an initially formed vinylsulfenic ester.The new ketene dithioacetal monoxide 5 reacts with malonate anions in an additon‐elimination reaction in which the phenylsulfonyl group serves as the leaving group.
Magnetic measurements, electron spin resonance and far‐infrared spectra of manganese(II) urea compounds
Authors: Barbier J.P. , Hugel R.P. , van Der Put P.J. , Reedijk J. 
Published: September 2010

AbstractCompounds Mn(ur)n(anion)2 [ur is urea (U), N,N′‐dimethylurea (DMU) and N,N′‐diethylurea (DEU), n = 2, 3, 4, 6, 10, and anion = Cl−, Br−, I− and ClO−4] have been studied by ESR, far‐IR and low‐temperature magnetic susceptibility. With U as the ligand, anion = Cl, Br and n = 2 halogen‐bridged linear‐chain compounds are formed, with oxygen‐bonded U in the axial positions. The Mn atoms in the chain are antiferromagnetically coupled with J/K values of −0.6 K (Br) and −1.0 K (Cl).Compounds Mn(U)4X2 appear to be tetragonally coordinated with the anions in the axial positions. The zero‐field splittings of the ground state have been determined as 0.11 and 0.18 cm−1 for X = Cl and Br, respectively. The octahedral cations Mn(ur)2+6 have been studied by ESR and far‐IR spectra, and were found to be barely distorted. Mn‐O vibrations occur in the 200‐235 cm−1 region. Compounds with n = 3 found for ur = DEU should be described as Mn(DEU)6MnX4 (X = Cl, Br). A new type of compound (n = 3; ur = DMU; X = Cl, Br, I) all of which are nearly isomorphous, is believed to be monomeric and contains two kinds of DMU ligands.
Addition of oxygen nucleophiles to alkyldicyanamides
Authors: Benders P.H. 
Published: September 2010

AbstractOxygen nucleophiles such as water, alcohols and phenols, have been reacted with alkyldicyanamides (1). Selective addition to one of the cyano groups only was effected by a careful control of the reaction conditions. The reactions have been employed for the synthesis of a number of novel 1‐alkyl‐1‐cyanoureas (2), 1,2‐dialkyl‐1‐cyanoisoureas (5) and 1‐alkyl‐2‐aryl‐1‐cyanoisoureas (7). The reactivity of the cyano group in 1 has been explained in terms of a relatively “soft” electrophilic carbon atom. Proof of structure for the novel compounds was obtained by chemical transformations and with the help of IR and PMR spectroscopy.
Effect of the ensemble size in the hydrogenation of benzene on Pt and Pt‐Au catalysts
Authors: Puddu S. , Ponec V. 
Published: September 2010

AbstractHydrogenation of benzene and cyclohexene has been studied on Pt and four Pt‐Au alloys. The overall behaviour −‐ activity, selfpoisoning and regeneration was similar to that of Ni−Cu alloys. The surface of the two‐phase Pt−Au alloys had, according to the kinetic data a composition of the β‐alloy (Au‐rich phase). Hydrogenation of benzene was 103 to 104 times slower than the hydrogenation of cyclohexene. The most dilute alloys are active in cyclohexene hydrogenation but they are completely inactive in the low temperature hydrogenation of benzene. The main effect of alloying is the decrease in the pre‐exponential term of the rate. The effect is explained in geometric terms: activation of a benzene molecule for the low temperature hydrogenation requires larger ensembles than those for cyclohexene activation and the larger ensembles are missing on the surface of the most dilute alloys.
Chemistry of crown ethers: Synthesis of crown ethers derived from α,γ‐and α,δ‐bis(halomethyl)‐ or α,γ‐bis(hydroxymethyl)‐substituted aromatics
Authors: Gray R.T. , Reinhoudt D.N. , Smit C.J. , Veenstra I. 
Published: September 2010

AbstractThree series of novel crown ethers have been prepared in which polyether rings of various sizes are linked to a benzene ring through the 1,3‐ or 1,4‐positions or to a furan ring through the 2,5‐positions. They were synthesized from the corresponding α,γ‐ or α,δ‐bis(halomethyl)‐substituted aromatics by reaction with polyethylene glycol disalts or from the disalts of bis(hydroxymethyl)‐substituted aromatics by reaction with polyethylene glycol ditosylates. Both 1:1 (2−67 % yield) and 2:2 (6−30% yield) cyclic reaction products were formed.The fact that the above compounds, which may contain up to 31 ring atoms, are obtained in such high yields without operating at high dilution is connected with the relationship between the chain length of the polyethylene glycol and the diameter of the cation used in the synthesis (template effect).
Studies on polypeptides XVIII Solid‐phase synthesis of RNase S‐peptide analogues with high S‐protein activating ability; replacement of histidine‐12 by L‐homohistidine
Authors: van Batenburg O.D. , Raap J. , Kerling K.E.T. , Havinga E. 
Published: September 2010

AbstractAs part of a structure‐activity relationship study of ribonuclease, focussing on the role of histidine‐12 in the active centre, the following polypeptides have been synthesized by the solid‐phase method and tested for S‐protein activating ability: bovine RNase S‐peptide 1−14, [Ile13]‐ S‐peptide 1−14 and the corresponding analogues in which histidine‐12 is replaced by L‐homohistidine. Whereas their binding tendency is considerably lower the [Hhi12] analogues show a remarkably high ability to generate enzymatic activity when combined with S‐protein in the presence of yeast RNA as a substrate.
Electronic spectra and magnetic susceptibilities of some eight‐coordinated complexes of molybdenum(IV) and tungsten(IV)
Authors: Nieuwpoort A. , Steggerda J.J. 
Published: September 2010

AbstractThe electronic spectra and magnetic susceptibilities of some complexes of the type Mo(R2dtc)4 (R2dtc = R2NCS2−; R = Me, Et, i‐Pr, Ph; R2 = Tm, Pm, MeBz; Tm = (CH2)4; Pm = (CH2)5) and M(Rdta)4 (M = Mo, W; Rdta = RCS2−; R = Tol, Naf; Tol = p‐toluoyl, Naf = 2‐naphthoyl) are reported. In contrast to literature data, the R2dtc complexes are diamagnetic, like the Rdta compounds. This is in agreement with a Ligand Field calculation for this type of compound, which shows, that for a moderate reduction in the electronic repulsion parameter B, diamagnetic behaviour is to be expected.Extended Hückel calculations show that the lowest unoccupied MO in Mo(Rdta)4 has ligand character, in contrast to Mo(R2dtc)4. This is in agreement with the charge‐transfer character of the absorption near 12 kK found in the electronic spectra of Mo(Rdta)4, while the Mo(R2dtc)4 compounds show a d‐d absorption at 10.8 kK.
On the N‐ethylation of 4‐alkoxy‐ and 4,6‐dialkoxypyrimidines with triethyloxonium tetrafluoroborate
Authors: Oostveen E. A. , van der Plas H. C. 
Published: September 2010

AbstractReaction of 4‐alkoxy‐(1–4) or 4,6‐dialkoxypyrimidines (5–9) with 1 equivalent of triethyloxonium tetrafluoroborate yields 4‐alkoxy‐N‐ethyl (13–15) or 4,6‐dialkoxy‐N‐ethylpyrimidinium salts (10–12), respectively. With two or more equivalents of this reagent, rearrangement of N‐ethylalkoxypyrimidinium salts into 1‐ethyl‐3‐alkyl‐1,4(3,4)‐dihydro‐4‐oxopyrimidinium salts (16–22) takes place. These rearrangements can also be performed by heating. The mechanism of these rearrangement reactions is discussed.