bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of an immunologically active component of the extracellular polysaccharide produced by Aspergillus and Penicillium species
Authors: Veeneman G. H. , van Boom J. H. , Notermans S. , Hoogerhout P. 
Published: September 2010

AbstractThe synthesis of an immunologically active component of the extracellular polysaccharide produced by Aspergillus and Penicillium species, in the form of tetrameric β(1→ 5) interlinked D‐galactofuranoside, is described. Key reactions are the assemblage of a galactofuranosyl donor, having a selective removable protecting group at C‐5, and a stepwise elongation‐deprotection procedure. Furthermore, the synthesis of β(1→ 2), β(1 → 3) and β(1 → 6) D‐galactofuranosyl dimers is reported.
Synthetic approaches to glutinosone
Authors: Banerjee Ajoy K. , Pita‐Boente Maria I. 
Published: September 2010

AbstractThe dienone 4 was converted to ketal ketone 6 by ketalization and reduction with lithium in liquid ammonia. The tosylhyrazone of 6, on treatment with lithium diisopropylamide, afforded the olefin 9 which was converted to the bromohydrin 12 with N‐bromosuccinimide. Oxidation of bromohydrin 12 with lead tetraacetate in benzene afforded the bromo ether 16, whose transformation to epoxy ketone 3 was achieved by heating with tri‐n‐butyltin hydride in methanol followed by deketalization.
Synthesis of three retinal models, including the 10‐s‐cis‐locked retinal, all‐E‐12,19‐methanoretinal
Authors: Groesbeek M. , van der Steen R. , van Vliet J. C. , Vertegaal L. B. J. , Lugtenburg J. 
Published: September 2010

AbstractAll‐E‐12,19‐methanoretinal (1) is distinguished by the presence of the locked 10‐s‐cis conformation in the cyclohexadiene ring in the conjugated chain. 1 has been prepared together with its 13‐Z isomer in an overall yield of 0.5%. 1 and 13‐Z‐1 photochemically interconvert in a clean way. In this system, only photoisomerization around the C13  C14 double bond is observed. In the photostationary state, the 13‐Z isomer is predominant. All‐E‐12‐ethyl‐19‐methylretinal (2) and all‐E‐12‐ethylretinal (3) were prepared in good overall yields (20% and 30%) from β‐ionone using the novel synthon, 3‐methyl‐4‐(diethylphosphono)‐2‐hexenenitrile (11). The photochemistry of these retinal derivatives is very similar to that of retinal. The 9‐Z, 11‐Z and 13‐Z isomers of 2 and 3 were photochemically prepared. The 13C NMR spectra of these new compounds gave information about the structural elements of alkyl groups in conjugated systems and about the conformation of the conjugated chain.
Synthesis of indoles using (N‐arylaminomethyl)diphenylphosphine oxides
Authors: Zorgdrager Jan , Broekhof Nico L. J. M. , van der Gen Arne 
Published: September 2010

AbstractA new route for the synthesis of 1,3‐disubstituted indoles, based on (N‐arylaminomethyl)‐diphenylphosphine oxide (1) chemistry, is described. Adducts 2, obtained by addition of the carbanions from 1 to aldehydes, were treated with p‐toluenesulfonic acid to form the desired indoles 4 in good yields, without isolation of the intermediate amino ketones 3.
Reactions of a series of methyl ethers of the trihydroxybenzenes and three dimethoxyphenyl methanesulfonates with sulfur trioxide. The effect of initial sulfation on the sulfonation product distribution
Authors: Cerfontain Hans , Ansink Harold R. W. , Coenjaarts Norbert J. , de Graaf Erik J. , Koeberg‐Telder Ankie 
Published: September 2010

AbstractThe sulfation and sulfonation of a series of mono‐, di‐ and trimethyl ethers of the trihydroxybenzenes with SO3 have been studied and the product distributions are reported. As for the trimethoxybenzenes, 1,2,3‐trimethoxybenzene (4) yields the 4‐sulfonic acid (4‐4‐S) and, upon further sulfonation, 4‐4,6‐S2. 1, 2, 4‐Trimethoxybenzene (7) yields a mixture of the 5‐sulfonic acid and its anhydride. 1, 3, 5‐Trimethoxybenzene (11) yields the 2‐sulfonic acid and, upon further sulfonation, 11‐2,4‐S2.1, 2‐Dihydroxy‐3‐methoxybenzene (1) with up to 2.0 equiv of SO3 yields the 6‐sulfonic acid. For 2, 6‐dimethoxyphenol (2), the ratio of 3‐ to 4‐sulfonation increases from 1.04 to 7.1 on using 4.0 instead of 0.9 equiv of SO3, due to initial formation of the hydrogen sulfate derivative and subsequent ring sulfonation of that species. 3,4‐Dimethoxyphenol (5), upon sulfonation with both 1.0 and 4.0 equiv of SO3, only yields the 6‐sulfonic acid. 1,3‐Dihydroxy‐5‐methoxybenzene (8), upon sulfonation with 1.0 equiv of SO3, yields 8‐2‐S and 8‐4‐S in a 1:1 ratio in addition to 20% of the hydrogen sulfate of 8. Upon further reaction, a mixture of 8‐2,4(= 2,6)‐S2 and 8‐4,6‐S2 is formed. 3,5‐Dimethoxyphenol (9), upon reaction with 1.0 equiv of SO3, yields 9‐2‐S, whereas with 4.0 equiv of SO3, a 32:68 mixture of 9‐2‐S, 9‐4‐S is obtained. The reactions with SO3 of three dimethoxyphenyl methanesulfonates, as model compounds for the corresponding hydrogen sulfates, which are the initial products formed by sulfation of the corresponding phenols, have also been studied. The observed sulfonic acid product distributions are discussed on the basis of the Curtin‐Hammett principle.
The acetalization of glyoxal by vicinal diols
Authors: Sangsari Farid Hamedi , Chastrette Francine , Chastrette Maurice , Blanc Alain , Mattioda Georges 
Published: September 2010

AbstractThe structure and stereochemistry of products obtained when vicinal diols are allowed to react with glyoxal were established with the aid of 13C NMR structure relationships. Hemiacetalization yields 1,4‐dioxane‐2,3‐diols regardless of the diol reacted. The course of acetalization depends on the structure of the diol: trans‐1,2‐cyclohexanediol and analogs yield only 1,4,5,8‐tetraoxadecalins as acetals, whereas cis‐1,2‐cyclohexanediol and 1,2‐ethanediol yield mixtures containing mostly 2,2′‐bi‐1,3‐dioxolanes. The isomeric distribution of products depends on the reaction conditions.
N, N‐diisopropyl‐bis(4‐chlorobenzyl) phosphoramidite: A versatile phosphitylating agent for the phosphorylation of hydroxy amino acids and preparation of protected phosphopeptides
Authors: de Bont H. B. A. , van Boom J. H. , Liskamp R. M. J. 
Published: September 2010

AbstractN, N‐diisopropyl‐bis(4‐chlorobenzyl) phosphoramidite is an easily accessible phosphitylating agent, which readily phosphorylates Boc‐Ser‐OMe, Boc‐Thr‐OMe and Boc‐Tyr‐OMe in good to high yields after t‐BuOOH or MCPBA oxidation. The Boc‐group can be removed without affecting the phosphate 4‐chlorobenzyl groups and vice versa. Extension of the Boc‐deprotected phosphoamino acids with a subsequent amino acid yields the corresponding protected phosphopeptides
Dioxygen uptake and catalytic activity of some monomeric copper(II) compounds containing an N,S donor ligand. The X‐ray structure of bis[5‐methyl‐4‐(ethylthiomethyl)imidazole]bis(tetrafluoroborato)copper(II)
Authors: Tullemans A. H. J. , Bouwman E. , de Graaff R. A. G. , Driessen W. L. , Reedijk J. 
Published: September 2010

AbstractThe synthesis and characterization of the copper tetrafluoroborate compound containing the bidentate N,S ligand 5‐methyl‐4‐(ethylthiomethyl)imidazole (memi), [Cu(memi)2(BF4)2], is described. The activities of this compound and of [Cu(memi)2(H2O)2](NO3)2 as oxidation catalysts have been determined in the reaction of 2,6‐dimethylphenol with molecular dioxygen to give polyphenylene oxide (PPO) and diphenoquinone (DPQ). For optimum catalysis, an additional base is required in order to dehydronate the phenol. Triethylamine proved to be most useful as a base. Initial reaction rates encountered are between 1 × 10−5 and 6 × 10−5M O2/s and ca. 50% of the phenol was converted after a reaction time of one hour. Less than 10% phenol was converted into DPQ. Both compounds have comparable reactivities.A single crystal of [Cu(memi)2(BF4)2] was used in an X‐ray structure determination: monoclinic space group C2/c, a = 13.844(4) Å, b = 11.251(1) Å, c = 15.753(4) Å, β = 111.39 (2)°, Z = 4 and T = 293 K. The structure was solved using heavy‐atom techniques and refined by least‐squares methods to a residual R value of 0.050. The copper ion is in a centrosymmetric distorted octahedral environment with all chemically identical donor atoms in trans positions. The tetrafluoroborate anions are coordinated to the copper ion with relatively short distances, i.e. 2.55 Å; Cu‐N and Cu‐S distances are 1.93 and 2.41 Å.
Highly active heterogeneous rhodium catalysts for the liquid‐phase hydrogenation of aromatic and other unsaturated compounds under mild conditions
Authors: Timmer Klaas , Thewissen D. Harry M. W. , Meinema Harry A. , Bulten Eric J. 
Published: September 2010

AbstractHighly active heterogeneous rhodium hydrogenation catalysts ‐ rhodium on support ‐ have been prepared by pyrolysis of commercially available Rh4(CO)12, highly dispersed on a suitable support, e.g. SrTiO3, TiO2‐anatase, TiO2‐rutile, BaTiO3 or SrZrO3. The inactive materials initially obtained were activated by exposure to air at room temperature. The activities of these catalysts were determined in the liquid‐phase hydrogenation of aromatic compounds at atmospheric pressure and at low temperatures (max. 70 °C). They appear to be at least twice as active as catalysts prepared from impregnated RhCl3 or [RhCl(CO)2]2 on SrTiO3 or a commercially available catalyst (5% Rh on Al2O3).The gas‐phase hydrogenation of benzene at room temperature takes place exothermally. Very high activities were also found in the liquid‐phase hydrogenation of alkenes and alkynes, whereas low activities were shown in the hydrogenation of nitriles. Almost no activity was observed in the liquid‐phase hydrogenation of nitro compounds and ketones.Catalysts, prepared from Rh6(CO)16, showed lower activities as compared with those prepared from Rh4(CO)12. Hardly any activity was found using Ir4(CO)12 as starting carbonyl cluster and no activity was observed when Ru3(CO)12, Co4(CO)12, Os3(CO),2 or Fe3(CO)12 was used.
Study of the promotion effect of inorganic oxides on Pt catalysts for the epoxidation of 1‐octene with hydrogen peroxide
Authors: Strukul Giorgio , Zanardo Andrea , Pinna Francesco , Schmidt Manfred , Goor Gustaaf 
Published: September 2010

AbstractThe promotion effect of a variety of inorganic oxides on the catalytic epoxidation of 1‐octene with hydrogen peroxide catalyzed by (cis‐Ph2PCH = CHPPh2)Pt(CF3)X (X = CH2Cl2, ·OH) in the liquid phase is reported. Catalysts were prepared either by mixing the oxides directly in the reaction medium or by impregnation of the oxides with the complexes prior to catalysis. A significant increase in the catalytic activity is obtained under certain experimental conditions and this is interpreted as a cooperation effect taking place at the interface between solid support and solution.
Steric and electron‐withdrawing effects of substituents governing chemical stability and catalytic activity of Mn(III)‐tetraarylporphyrins in HOCl/ClO− alkene expoxidations
Authors: Banfi S. , Montanari F. , Quici S. 
Published: September 2010

AbstractMn(III)‐tetrakis(2,4,6‐trimethyl‐3,5‐dihalogenophenyl)porphyrins 5‐7 (halogen = Cl, Br, I) have been synthesized and their catalytic activity has been tested in HOCl/ClO− alkene epoxidations. These porphyrins are characterized by structural separation of the two parameters governing chemical stability towards the oxidants: the steric protection of both the metal centre and of the meso positions of the porphyrin ring; and the electron‐withdrawing effect of substitutents (methyl groups and halogen atoms in the o,o′ and m,m′ positions, respectively, of the meso‐aromatic rings). The stability of 5–7 towards oxidative degradation is similar to that of Mn(III)‐tetrakis(2,6–dichlorophenyl)porphyrin (1). Catalytic activities of the porphyrins 5‐7 and 1 are optimized under quite different conditions. This behaviour can be explained in terms of mono‐ (K1) and bis‐coordination (β2) constants of porphyrins 1, 5 and 6 with the axial ligand, 1‐hexylimidazole, which account for the concentration of the mono‐ligated species Mn(P)L and of the free ligand at the equilibrium.
Ab‐initio calculations on oxomanganese porphyrin chloride. II. An explanation of its reactions with alkenes
Authors: den Boer D. H. W. , Zwaans R. , van Lenthe J. H. , van der Made A. W. 
Published: September 2010

AbstractMinimal‐basis‐set gradient‐SCF calculations on oxomanganese porphyrin chloride in which the oxygen atom bridges a metal‐nitrogen bond (Cs structure) are reported. In comparison with the earlier reported results of similar calculations on a C4v structure, a lower energy is found for the Cs structure. Electronic and steric arguments are brought forward to explain available experimental information on the reactions of the complex with alkenes.
Reduction of 1‐(5‐uracilylmethyl)pyridinium salts by thiols to thymine derivatives. A model of the thymidylate synthase reaction
Authors: Vega Erwin , de Waard Eduard R. , Pandit Upendra K. 
Published: September 2010

Abstract1‐(5‐uracilylmethyl)pyridinium salts react with 9, 10‐dihydrophenanthridine, Hantzsch ester or thiols (RSH, R = p‐nitrobenzyl, t‐butyl) to form thymine derivatives. The mechanisms of the reactions are discussed.
On the mechanism of formation and fragmentation of [8]paracyclophane in the gas phase
Authors: Kraakman Paulus A. , Eeken Paulus J. K. M. , de Wolf Willem H. , Bickelhaupt Friedrich 
Published: September 2010

AbstractRegiospecifically labelled 3‐[(13C)methylene]spiro[5.7]trideca‐1,4‐diene (2a′) and (1‐13C)‐dispiro[2.2.6.2] tetradeca‐4,13‐diene (7a′) were prepared. By flash vacuum thermolysis (FVT) at 600°C, 2a′ was converted into [8]paracyclophane (1a′) in 95% yield. The label in 1a′ was found at the benzylic position(s). At 750°C, 1a′ fragmented by cleavage of the homobenzylic bonds finally yielding (after extrusion of one or more molecules of propene or ethene) p‐ethyl‐ (4e′) and p‐propyl‐(4d′) styrene. The styrenes were labelled at both benzylic carbon atoms. The product spectrum obtained by FVT of 7a′ was more complex. At 600°C, 1a′, 7a′ and 3‐ vinylspiro[5.6]undeca‐4,13‐diene (11a′) were found. Compound 1a′ was labelled at both the benzylic and homobenzylic positions, whereas 11a′ was labelled only at the two carbon atoms of the vinyl group. At 750 °C, the p‐(n‐alkyl)styrenes 4a′, 4d′ and 4e′, the p‐(sec‐alkyl)styrenes 14d′ and 14e′ and p‐divinylbenzene (15′) were found. Compound 4a′ was labelled only on both carbon atoms of the vinyl group, 4d′ and 4e′ also at the benzylic carbon atom of the alkyl group and 4e′ at the terminal methyl group. The p‐(sec‐alkyl)styrenes 14d′ and 14e′ were labelled exclusively at the benzylic carbon atom and the sec‐methyl group of the sec‐alkyl chain. The distribution of the label in the pyrolysis products is in line with the previously suggested routes for their formation. A full explanation for the (low‐percentage) incorporation of label at some unexpected positions will only be available after further investigation.
A practical route toward the preparation of 4,5:7,8‐di‐O‐isopropylidene KDO ethyl ester
Authors: Boons G. J. P. H. , van der Klein P. A. M. , van der Marel G. A. , van Boom J. H. 
Published: September 2010

AbstractCondensation of 2,3: 5,6‐di‐O‐isopropylidene‐D‐mannopyranose with (ethoxycarbonylmethylene)triphenylphosphorane afforded the expected Wittig product. Reaction of the latter with chlorotrimethylsilane followed by methyl methanethiosulfate, in the presence of I. DA and after removal of the trimethylsilyl and unmasking of the dimethyl thioketal function, gave the title compound in a good overall yield.
Enantioselective syntheses of isotopically labelled α‐amino acids. Preparation of (ϵ‐13C)‐L‐α‐aminoadipic acid and five isotopomers of L‐lysine with 13C, 15N and 2H in the δ‐ and ϵ‐positions
Authors: Raap J. , van der Wielen C. M. , Lugtenburg J. 
Published: September 2010

AbstractAn asymmetric synthesis of the six‐carbon α‐amino acids (ϵ‐13C)‐L‐α‐aminoadipic acid and various isotopomers of L‐lysine is described. The synthesis is based on a general method starting from the bis‐lactim ether of cyclo(D‐Val‐Gly) and simple labelled reagents like K13CN, K13C15N, 13CH3CN and LiAl2H4. Using this route (ϵ‐13C)‐L‐α‐aminoadipic acid was prepared in 31% yield based on the labelled potassium cyanide. Five different isotopomers of L‐lysine were prepared in high overall yield (45% based on the labelled starting compound): (ϵ‐13C)‐L‐lysine, (ϵ‐13C,ϵ‐15N)‐L‐lysine, (δ‐13C)‐L‐lysine, (ϵ‐2H2)‐L‐lysine and (ϵ‐13C,ϵ‐2H2)‐L‐lysine. The isotopomers were characterized using various spectroscopic techniques, e.g., 1H NMR, 2H NMR, 13C NMR, 15N NMR and mass spectrometry. The 31.2‐ppm and the 27.6‐ppm peak in the 13C NMR spectrum of lysine could be unambiguously assigned to the β‐ and δ‐carbons, respectively. This means that the assignment previously reported is incorrect.
Photoreduction of aryl ketones by amides, lactams and various nitrogen‐containing heterocycles
Authors: Gramain Jean‐Claude , Remuson Roland , Jeandrau Jean‐Pierre , Lemaire Jacques 
Published: September 2010

AbstractBenzophenone is photoreduced by amides and lactams. The hydrogen atom α to the nitrogen atom is abstracted regioselectively; coupling of the two resulting radicals leads to adducts with a 1‐phenylethanolamide structure. The use of this general reaction in synthetic reactions is demonstrated: adducts of benzophenone with amides, lactams, 2,4‐imidazolinediones tetrahydro‐2H‐1,3‐oxazin‐2‐one and 2‐oxazolidinone, and of dibenzosuberone, 9H‐xanthenone, 9H‐thioxanthenone and α‐tetralone with 1‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide and N,N‐diethylacetamide are described. Kinetic parameters for dibenzosuberone and 9H‐thioxanthenone are given. Knowledge of the rate constants of photoreduction (kr) and autodeactivation (kaT) allows optimization of the experimental procedure to provide adducts in good yields.
Gas‐phase oxygenation of benzene derivatives around 300 K with O(3P) atoms produced by microwave discharge of N2O. Part 2. Kinetic H/D isotope effects
Authors: Sol Veronica M. , Louw Robert , Mulder Peter 
Published: September 2010

AbstractThe possible pathways for the formation of (chloro)phenol, following the addition of O(3P) to (chloro)benzene, have been examined using deuterated substrates: C6D6 (also in admixture with C6H6) and p‐deuterochlorobenzene. Whereas with O‐C6H6 adduct biradicals, loss of H\documentclass{article}\pagestyle{empty}\begin{document}\[^\bullet\]\end{document} to give phenoxy radicals predominates, only one‐third of the O‐C5D6 intermediates undergo the corresponding reaction. Phenoxy radicals lead to phenol by transfer of an H(D) atom from cyclohexadienyl‐type radicals, formed from H\documentclass{article}\pagestyle{empty}\begin{document}\[^\bullet\]\end{document} (D\documentclass{article}\pagestyle{empty}\begin{document}\[^\bullet\]\end{document}) and substrate.Analogously, in reactions of p‐deuterochlorobenzene, loss of H is a major reaction after addition of an oxygen atom to a meta position, whereas loss of D (to give p‐chlorophenol) occurs only with 35% of the corresponding O(3P) adduct biradicals. The isotopic composition of phenol formed from p‐DC6H4Cl (via p‐DC6H4O\documentclass{article}\pagestyle{empty}\begin{document}\[^\bullet\]\end{document}; generated by ipso substitution) revealed that H transfer to phenoxy radicals primarily gives the keto tautomers as major products. Isomerization of (chloro)‐benzene‐O(3P) adduct biradicals to the corresponding phenols also appears to involve mainly, keto tautomers.The reaction of O(3P) with p‐deuterochlorobenzene showed a slight change in the o/m/p distribution; this can be explained by the absence of a net secondary H/D kinetic isotope effect for O(3P) addition to the para site and a normal secondary isotope effect for meta addition.
Intramolecular amine coordination versus NMe C‐H Activation: The stereoselective synthesis of a tantala(V)azacyclopropane complex
Authors: Abbenhuis Hendrikus C. L. , Grove David M. , van Mier Guido P. M. , van Koten Gerard , Spek Anthony L. 
Published: September 2010

AbstractA stereoselective C‐H activation reaction of a NMe group of [Ta{C6H4CH(Me)NMe2−2}‐(CH2Ph)2Cl2 (1b) affords toluene and a species which was isolated as the new pentagonal bipyramidal Ta(V) tetrahydrofuran (THF) adduct [Ta{C6H4(CH(Me)N(Me)CH2)‐2}(CH2Ph)Cl2‐ (THF)] (2). The chirality of the arylamine leads to a single structurally characterized diastereoisomer in which intramolecular coordination of the modified amine group produces a triangular Ta‐CH2‐N unit.
The influence of substituents on the geometry of the cyclopropane ring. IV. The molecular and crystal structure of 1‐amino‐1‐phenylcyclopropane
Authors: de Boer J. S. A. M. , Stam C. H. 
Published: September 2010

AbstractCrystals of 1‐amino‐1‐phenylcyclopropane, C9H11N, grown from the liquid are mono‐clinic, space group P21/n, a = 27.565(5), b = 6.047(6), c = 18.024(4) Å, β = 96.76(2) = (110 K). Z = 16. The final R for 4086 independent observed reflections is 0.057. The 4 molecules in the asymmetric unit have the bisecting conformation for the phenyl group and the s‐trans pyramidal conformation for the NH2 group. The average distal bond length in the cyclopropane ring is 1.503(4) Å; the average vicinal length is 1.520(3) Å (corrected for libration).
Crown‐ether‐substituted phthalocyanines. Control of supramolecular organization by monovalent and divalent metal salts
Authors: Sielcken Ot E. , Drenth Wiendelt , Nolte Roeland J. M. 
Published: September 2010

AbstractAggregation of crown‐ether‐substituted phthalocyanines with monovalent metal ions (K+, Rb+, and Cs+) results in cofacially ordered phthalocyanine stacks. Aggregation with Ba2+ leads to the formation of phthalocyanine networks.
Two‐step chemo‐enzymatic synthesis of octyl 6‐O‐acyl‐α‐D‐glucopyranoside surfactants from glucose
Authors: de Nijs M. P. , Maat L. , Kieboom A. P. G. 
Published: September 2010

AbstractThree novel carbohydrate surfactants were synthesized by lipase‐catalyzed transesterification of octyl 2‐D‐glucopyranoside, obtained from the acid‐catalyzed reaction of glucose and octanol. The 6‐OH was regioselectively acylated with ethyl octanoate, ethyl acetoacetate and diethyl succinate as acyl‐donating agents. Several lipases have been investigated as biocatalysts. For each esterification, various combinations of lipase, ester and cosolvent were studied, from which a preparative‐scale synthesis was developed. The new compounds were tested for physical properties (melting behaviour, surface tension and CMC): it appears that all 6‐acyl derivatives have surfactant characteristics. The 6‐octanoyl derivative was also found to have liquid‐crystal properties.
The synthesis of polyhydroxycarboxylates. Part 6. N‐Alkylation of amino compounds by a Michael‐type addition with maleate
Authors: van Westrenen J. , van Haveren J. , Alblas F. J. , Hoefnagel M. A. , Peters J. A. , van Bekkum H. 
Published: September 2010

AbstractThe N‐alkylation of aminopolyols and amino acids by a Michael‐type addition with maleate or fumarate in aqueous medium occurs readily at 90°C. Maleate reacts faster than fumarate by virtue of the higher free energy of the ground state. For a series of amino compounds, the second‐order rate constants are related to the nucleophilicity of the nitrogen and the steric hindrance involved. Subsequent N‐alkylation of aminohydroxyl compounds and LaIII‐ion‐catalyzed O‐alkylation of hydroxyl groups with maleate is shown to be a promising way to synthesize new chelating agents.
Photochemical behaviour of cyclic s‐cis α‐oxo oxime ethers. Ab‐initio investigation on ethanedial monooxime as model compound
Authors: Stunnenberg Frank , Rexwinkel Roel , Cerfontain Hans , Sevin A. 
Published: September 2010

AbstractWith the objective of understanding the photodissociation of cyclic s‐cisoid α‐oxo oxime ethers upon irradiation at λ 254 nm, an ab‐initio study has been performed using s‐cis‐ethanedial monooxime as model compound. In accordance with previously presented experimental observations, the calculations demonstrated (i) that the initial step in the photodissociation is NO homolysis and (ii) that NO scission takes place with the (E), but not with the (Z) isomer, due to the presence of a relatively low‐lying doubly excited (nπ*)(nπ*) state with the (Z) isomer, causing this isomer to decay via Z‐E isomerization.