bluuebunny/crossref_metadata_2025_split huggingface dataset:
The chemistry of D‐gluconic acid derivatives. Part II1: The formation of (R)‐O‐isopropylideneglyceraldehyde from D‐glucono‐1,5‐lactone
Authors: Chittenden Gordon J. F. 
Published: September 2010

AbstractReaction of D‐glucono‐1,4‐lactone, obtained from the 1,5‐lactone by a modified procedure, with 2,2‐dimethoxypropane‐tin(II) chloride yields the corresponding 5,6‐O‐isopropylidene derivative. The preparation of the title compound from this acetal by periodate oxidation together with the characterisation of products and intermediates is described.
Tetrahedral intermediates formed during the nucleophilic addition‐elimination reaction of carbonyl‐containing compounds in the gas phase. Part II
Authors: van der Wel H. , Nibbering N. M. M. 
Published: September 2010

AbstractThe structures of adduct ions formed between the nucleophiles HO− and CH3O− and various carbonyl compounds, such as aldehydes, esters and amides, have been probed in the gas phase by studying their proton affinity, collision‐induced dissociation pathways and chemical reactivity, using Fourier‐Transform Ion‐Cyclotron‐Resonance (FT‐ICR) Mass Spectrometry.Most of the generated adduct ions are shown to have stable, often proton‐bound, loosely associated structures as well as stable, covalently bound, tetrahedral structures.
Sulfonation and sulfation of 1,3‐dihydroxybenzene and its methyl ethers in concentrated sulfuric acid
Authors: Cerfontain Hans , Koeberg‐Telder Ankie 
Published: September 2010

AbstractThe homogeneous sulfonations of 1,3‐dihydroxybenzene (1), its monomethyl (2) and dimethyl ether (3) in concentrated aqueous sulfuric acid at 25°C have been studied and isomer distributions and rate coefficients for the sulfonation of 1–3 and their monosulfonic acids are reported. The initial process, upon dissolution of the reactants, is protonation at C(4) and C(6). The subsequent sulfonation of the symmetrical reactants 1 and 3 yields the 4‐sulfonic acids and that of 2 the 4‐ and 6‐sulfonic acids, the ratio of which is 0.8 + 0.1 at 73.5% H2SO4. The sulfonation of the 4‐sulfonic acid of 1 (1‐4‐S) yields a mixture of 2,4‐ and 4,6‐disulfonic acids, that of 2‐4‐S and 3‐4‐S yields the 4,6‐S2 and that of 2‐6‐S gives a mixture of 2,6‐ and 4,6‐S2. The disulfonic acids 1‐2,4‐S2 and 2‐2,6‐S2 both slowly isomerize to yield the 4,6‐disulfonic acid isomers. At acid concentrations ≥ 82.8% H2SO4, the disulfonic acids of 1 slowly yield 1‐2,4,6‐S3, whereas those of 2 and 3 are not further sulfonated. The absence of 2‐2,4‐S2 from 2‐4‐S and of 2‐2,4,6‐S3 and 3‐2,4,6‐S3 is discussed in terms of conformer populations of the precursory sulfonic acid substrates.
Photochemical reactivities of cyclic α‐phenyl‐β,γ‐enones. Singlet 1,3‐acyl shift, decarbonylation and unquenchable oxa‐di‐π‐methane reactions upon direct irradiation
Authors: Koppes Margareth J. C. M. , Cerfontain Hans 
Published: September 2010

AbstractThe photochemistry of the α‐phenyl‐β,γ‐enones 3–6 has been studied under conditions of direct (λ 300 nm) and triplet‐sensitized irradiation.Upon direct irradiation, 3 exhibits decarbonylation, a 1,3‐acyl shift (1,3‐AS) and an oxa‐di‐π‐methane (ODPM) rearrangement. Under the same conditions, 4, on the other hand, affords only the ODPM product whereas 5 gives the decarbonylation, 1,3‐AS and ODPM products. The formation of the ODPM product of 5 is efficiently quenched by triplet quenchers in contrast to the ODPM products of 3 and 4, the quantum yields of which are not reduced upon the addition of typical triplet quenchers. Triplet‐sensitized irradiation of 5 leads to the ODPM rearrangement, whereas surprisingly 3 and 4 are unreactive. It is suggested that the ODPM rearrangement, upon direct irradiation of 3 and 4, proceeds from the S2(ππ*) state. The ODPM product formed upon direct irradiation of 5 is thought to be formed from the T1(ππ*) state populated by ISC from the S1(nπ*) state.Upon direct irradiation, 6 exhibits a reversible 1,3‐AS and in addition ketene formation via an intramolecular 1,5‐H shift. Under conditions of triplet photosensitization, compound 6 appears to be stable.Given the apparently different photochemical behaviour of these constrained compounds, a general reactivity pattern for the direct and sensitized irradiation cannot be defined.
Preparation of internucleotide phosphate analogues via the corresponding H‐phosphonate diester
Authors: de Vroom E. , Dreef C. E. , van den Elst H. , van der Marel G. A. , van Boom J. H. 
Published: September 2010

AbstractSilylation of a H‐phosphonate diester with N, O‐bis(trimethylsilyl)acetamide or tert‐butyldimethylsilyl chloride affords 3′,5′‐internucleotidic phosphite triester intermediates. Arbusow reaction of the latter compounds with appropriate halogenides gives the corresponding phosphonate derivatives.
Synthesis of two analogues of a fragment of the complex polysaccharide C substance from Streptococcus pneumoniae type 1
Authors: Hermans J. P. G. , Dreef C. E. , Hoogerhout P. , van der Marel G. A. , van Boom J. H. 
Published: September 2010

AbstractThe syntheses of two (spacer‐containing and choline‐phosphate‐deficient) analogues (12e and 12h, Scheme 2) of a fragment of the C substance from S. pneumoniae type 1 are presented. Starting from 1,6:2,3‐dianhydro‐ß‐D‐talopyranose (la), the “building block” 1‐O‐(3,6‐di‐O‐acetyl)‐2‐azido‐4‐O‐benzyl‐2‐deoxy‐ß‐D‐galactopyranosyl)‐2,3,4‐tri‐O‐benzyl‐D‐ribitol (6b) was obtained in six steps (Scheme 1). A second “building block” (9e), containing a protected propanolamine spacer, was prepared in five steps, starting from 2,3,4,6‐tetra‐O‐acetyl‐α‐D‐glucopyranosyl bromide (7). The building blocks 6b and 9e were coupled (Scheme 2) using bis(1‐benzotriazolyl) 2‐chlorophenyl phosphate (10) to give the fully protected phosphotriester derivative 12a. Complete deprotection of compound 12a via two different routes afforded β‐D‐GalNH2p‐(1 ŕ l)‐ribitol‐5‐phosphate‐6‐β‐D–Glcp‐[1 ŕ O‐(CH2)3‐NH2] (12h, an analogue of structure Ia) and its β‐D‐GalNAcp derivative 12e (corresponding to Ib).
Reactions of the dihydroxybenzenes and their methyl ethers with sulfur trioxide. The effect of initial sulfation on the sulfonation product distribution
Authors: Cerfontain Hans , Coenjaarts Norbert J. , Koeberg‐Telder Ankie 
Published: September 2010

AbstractThe sulfation and sulfonation resulting from the reaction of the dihydroxybenzenes and their mono‐ and dimethyl ethers with SO3 in nitromethane have been studied, and their product distributions are reported. As to the non‐hydroxy‐substituent‐containing substrates, 1,2‐dimethoxy‐benzene (3) yields the 4‐sulfonic acid (3‐4‐S) which, upon further sulfonation, yields a 1:4 mixture of the 3,5‐ and 4,5‐S2. The 1,3‐ (6) and 1,4‐isomer (9) yield initially the 4‐ and 2‐S, respectively, and subsequently exclusively 6‐4,6‐ and 9‐2,5‐S2, respectively.With the substrates containing one hydroxy substituent, the sulfonation isomer distribution is dependent on the SO3 to substrate ratio if the OH and OMe substituents are in ortho or para orientation, due to increasing sulfonation of the corresponding methoxyphenyl hydrogen sulfate. Thus, 2‐methoxy‐ (2) and 4‐methoxyphenol (8) with one equiv of SO3 at 0°C yield a 3:1 mixture of 2‐4‐S and 2‐5‐S and a 9:1 mixture of 8‐2‐S and 8‐3‐S, respectively, but, with ≥4 equiv of SO3, the former reactant yields only 2‐5‐S and the latter only 8‐3‐S. 3‐Methoxyphenol (5) yields initially a 1:1 mixture of the 4‐ and 6‐sulfonic acid. Further sulfonation yields only 5‐O,4,6‐S3 which slowly cyclizes to the 1,3,2, 4‐benzodioxadithiin 2,2,4,4‐tetraoxide derivative 11.As to the dihydroxy‐containing substrates, 1,2‐dihydroxybenzene (1) with 1 equiv of SO3 first yields the hydrogen sulfate 1‐O‐S which rearranges to 1‐4‐S; on using an excess of SO3, the eventual product is l‐O(2),4‐S2. Similarly, the 1,4‐isomer (7) with 1 equiv of SO3 yields initially 7‐O‐S which isomerizes to 7‐2‐S. With 6 equiv of SO3, initially 7‐O,O‐S2 is formed and subsequently its 2‐sulfonic acid, which eventually cyclizes slowly to the 1,3,2,4‐benzodioxadithiin 2,2,4,4‐tetraoxide derivative 12. The 1,3‐isomer 4 with 1 equiv of SO3 yields the 4‐sulfonic acid. With 4 equiv of SO3, initially 4‐O,O‐S2 is formed and subsequently 4‐4, O,O‐S3, which is converted into both 4‐O,O,4,6‐S4 and the cyclization product 10. Eventually, small amounts of 4‐O,2,4,6‐S4 and 14‐2,6‐S2 are formed by transsulfonation.
Observations on the dehydrogenation of α,β‐unsaturated carbonyl compounds with thallium(III) acetate
Authors: Banerjee Ajoy K. , Carrasco María C. , Peña‐Matheud Carmen A. 
Published: September 2010

AbstractDehydrogenation of the α,β‐unsaturated ketones 1, 3 and 5 with thallium(III) acetate yielded the dienones 2,4 and 6, respectively. On similar treatment, the ketone 7 afforded the catechol derivative 12, which, on hydrolysis, yielded the tetralone 13.
Acid hydrolysis of polymers and copolymers of N‐vinyl‐N‐methylacetamide
Authors: Buys H. C. W. M. , Vercauteren F. F. , van Elven A. , Tinnemans A. H. A. 
Published: September 2010

AbstractAcid hydrolysis, under relatively mild conditions (3N HCl, 100°C), of a series of homo‐polymers of N‐vinyl‐N‐methylacetamide, and copolymers thereof with vinyl acetate or methyl acrylate, afforded poly(N‐vinyl‐N‐methylamine), poly(N‐vinyl‐N‐methylamine‐co‐vinyl alcohol) and poly(N‐vinyl‐N‐methylamine‐co‐acrylic acid) in almost quantitative yield. A simple and practical route to poly(N‐vinyl‐N‐methylacetamide‐co‐acrylic acid) and poly(N‐vinyl‐N‐methylacetamide‐co‐vinyl alcohol) has been developed and some kinetic results relating to the hydrolysis step are given. The products were characterized by viscometry, elemental analysis and 13CNMR spectroscopy.
Preparation of 6‐demethoxy‐N‐formyl‐N‐northebaine and its Diels‐Alder reactions with methyl vinyl ketone and nitroethene; novel 8‐nitro‐substituted 6α,14α‐ethenoisomorphinans and 6β,14β‐ethenomorphinans (chemistry of opium alkaloids, part XXVIII)
Authors: Linders J. T. M. , Briel P. , Fog E. , Lie T. S. , Maat L. 
Published: September 2010

AbstractThe synthesis of 6‐demethoxy‐N‐formyl‐N‐northebaine (5) and its Diels‐Alder reactions with methyl vinyl ketone and nitroethene are described.N‐Demethylation of 6‐demethoxythebaine (3) with diethyl azodicarboxylate, followed by hydrolysis, gave 6‐demethoxy‐N‐northebaine (4) which was N‐formylated with ethyl formate in DMF to give 5, using “Ketjencat LA‐LPV Steamed” as a catalyst.Reaction of 5 with methyl vinyl ketone using microwave heating gave the expected 7α‐acetyl‐6α,14α‐ethenoisomorphinan 9 by direct crystallization from the reaction mixture. On the other hand, Diels‐Alder reaction of 5 with nitroethene afforded the 7α‐nitro‐6α,14α‐ethenoisomorphinan 12 as a minor product (10%). The major products were 8α‐nitro‐6α,14α‐ethenoisomorphinan (10) (50%) and 8β‐nitro‐6β, 14β‐ethenomorphinan (11) (30%). The structure of the new adducts was elucidated by 1H NMR.Factors which may influence the course of the Diels‐Alder reaction of morphinan‐6,8‐dienes are discussed. The surprising change in selectivity seems to be governed mainly by steric effects.
The chemistry of D‐gluconic acid derivatives. Part IV Synthesis and reactions of some 2‐deoxy‐D‐hexonic acid derivatives, a new synthesis of 2‐deoxy‐D‐arabino‐hexose and some related compounds
Authors: Regeling Henk , Chittenden Gordon J. F. 
Published: September 2010

AbstractTreatment of methyl 3,4;5,6‐di‐O‐isopropylidene‐D‐gluconate (7) with triphenylphosphine/carbon‐tetrachloride/imidazole yields the corresponding 2‐chloro‐2‐deoxy‐D‐mannonate 8. The reduction of 8 under a variety of conditions led to a new synthesis of 2‐deoxy‐D‐glucose and some related acyclic compounds. The characterisation, and some reactions of the intermediate products, leading to chirally defined trihydroxy‐2‐alkenoates is also described.
Synthesis of L‐glycero‐α‐D‐manno‐heptopyranose‐containing disaccharide derivatives of the Neisseria meningitidis dephosphorylated inner‐core region
Authors: Boons G. J. P. H. , van derMarel G. A. , van Boom J. H. , Poolman J. T. 
Published: September 2010

AbstractHydroxymethylation of correctly protected alkyl α‐D‐manno‐hexodialdo‐1,5‐pyranosides with [(isopropoxydimethylsilyl)methyl]magnesium chloride affords the corresponding silane intermediates, the isopropoxydimethylsilyl group of which can be unmasked with hydrogen peroxide. The L‐glycero‐α‐D‐manno‐heptopyranose (L‐α‐D‐Hepp) derivatives thus obtained can be subsequently used for the preparation of the disaccharides β‐D‐Glcp‐(1‐4)‐L‐α‐D‐Hepp‐OMe and β‐D‐Glcp‐(1‐4)‐L‐α‐D‐Hepp‐O‐(CH2)3NH2.
Chirality in pyridoxal
Authors: van Genderen Marcel H. P. , van Lier Pieter M. , Buck Henk M. 
Published: September 2010

AbstractPyridoxal and its iminium derivatives form cyclic compounds via an intramolecular nucleophilic attack. This results in a configurational chirality on C4′ which can be related to out‐of‐plane orientations around the C4C4′ bond in the open forms. 1H‐ and 13C‐NMR structural studies of the cyclic compounds were performed in solution and in the solid state (13C NMR only). It was found that the presence of an additional chiral centre in the iminium moiety gives rise to an excess of one of the diastereomers for the cyclic aminal. This indicates a preference for one of the axially chiral C4‐C4′ conformers prior to ring closure. The present results may be of relevance with respect to the function of the coenzyme pyridoxal phosphate, which forms iminium compounds with l or d amino acids. Axial chirality in these systems has been proposed by us as a mechanism for the stereospecificity of enzymatic amino acid transformations.
Discrimination between polarity and mobility effects on the charge‐transfer fluorescence of Fluoroprobe in organic matrices
Authors: Jenneskens L. W. , van Houwelingen G. D. B. , van Ramesdonk H. J. , Verhey H. J. , Verhoeven J. W. 
Published: September 2010

AbstractThe fluorescence of Fluoroprobe, a molecule with an extremely polar excited state, is studied in matrices consisting of (macro)molecules which contain repeating units of different polarity. In matrices of low molecular weight Fluoroprobe displays its typical bathochromic shift with increasing contribution of polar groups, but an hypsochromic shift is observed in viscous or solid matrices of high molecular weight. This remarkable phenomenon is attributed to loss of mobility, which allows fluorescence of the probe to occur prior to full relaxation of the surrounding matrix sites.
X‐Ray absorption spectroscopic studies on iron in soybean lipoxygenase: A model for mammalian lipoxygenases
Authors: Feiters M. C. , Boelens H. , Veldink G. A. , Vliegenthart J. F. G. , Nolting H.‐F. , Hermes C. , Navaratnam S. , Allen J. C. 
Published: September 2010

AbstractX‐ray absorption spectroscopy studies are contributing both to the refinement of the geometry of metal sites already known from crystallographic studies and the elucidation of the coordination sphere in metal sites in metalloproteins where only limited information was available. Specific problems in the analysis of coordinating imidazoles can be overcome by applying multiple‐scattering simulations. The model for the lipoxygenase iron site derived from the EXAFS study, a coordination sphere predominated by imidazoles, may require some adjustment in view of the possibility of coordination by water, and has received independent confirmation from studies of amino acid sequence homologies and the interaction with catechols.The spectroscopy of lipoxygenase is not consistent with the presence of the organic cofactor, PQQ, nor with its coordination to iron, but would be consistent with the presence, but not the coordination to iron, of the carboxy‐hydroxy‐indoloquinone‐glutamic acid cofactor, CHIQG. From the observed amino acid sequence homologies it is concluded that plant lipoxygenases can be good models for the studies of mammalian lipoxygenases.
Interactions between carbonyl‐containing compounds and bismuth trihalides. A spectroscopic investigation
Authors: Delaviz Yadollah , Cabasso Israel , Smid Johannes 
Published: September 2010

AbstractThe high solubility of bismuth tribromide and bismuth trichloride in methyl methacrylate, propylene carbonate and other carbonyl‐containing compounds and polymers results from the interaction between bismuth and the carbonyl moiety. It was established by infrared, 1H‐ and 13C‐NMR measurements that in all these systems a 1:1 complex is formed. The bismuth trihalides are potentially useful as compatible X‐ray contrast additives for carbonyl‐containing polymers.
A comparative study of the liquid‐crystalline behavior of three homologous series of 1,2‐propanediol derivatives
Authors: van Doren Henk A. , van der Geest Ralph , Kellogg Richard M. , Wynberg Hans 
Published: September 2010

AbstractHomologous series (R = n‐hexyl to n‐tetradecyl) of 3‐(alkylamino)‐, 3‐(alkylthio)‐ and 3‐alkoxy‐1,2‐propanediols have been synthesized and their thermal behavior studied by thermomicroscopy and differential‐scanning calorimetry. The occurrence of liquid‐crystalline behavior was found to be strongly dependent on both the alkyl‐chain length and the hetero‐atom that links the alkyl chain to the 1,2‐propanediol moiety.No thermotropic liquid‐crystalline behavior could be observed for 3‐alkoxy‐1,2‐propanediols; 3‐(heptylamino)‐ through 3‐(nonylamino)‐1,2‐propanediol exhibit a transient smectic A phase on supercooling of the isotropic liquid, whereas 3‐(hexylthio)‐1,2‐propanediol through 3‐(nonylthio)‐1,2‐propanediol form smectic phases that are quite stable. Although the thermal behavior in the pure form differs considerably, all three classes of compounds are capable of lyotropic mesophase formation in the presence of water.
Synthesis and ligand exchange reactions of (pentamethylcyclopentadienyl)lanthanum aryloxides
Authors: Heeres H. J. , Teuben J. H. 
Published: September 2010

AbstractCp*La(OAr)2 (Cp* = η5‐C5Me5)1 is easily accessible by the reaction of La(OAr)3 with Cp*Li. Addition of THF yields the adduct Cp*La(OAr)2(THF)2. Both compounds disproportionate in solution with formation of equilibrium mixtures with comparable amounts of Cp*La(OAr)2, La(OAr)3 and Cp*2LaOAr. The equilibria were studied at various temperatures and thermodynamic parameters were determined from the temperature dependence of the equilibrium constants.
Reversal of an enzymatic decarboxylation: Thiamin mediated carboxylation of acetaldehyde into pyruvic acid
Authors: Foppen Marie‐Anne E. , de Lange Yvonne M. , van Rantwijk Fred , Maat Leendert , Kieboom Antonius P. G. 
Published: September 2010

AbstractAcetaldehyde has been converted into pyruvic acid (42% yield) via the reaction of 2 ‐(1‐hydroxyethyl)thiamin (3) with carbon dioxide at 50 atm. (DMF, 20 C).
Synthesis of novel morphinan peptides based on ethenoisomorphinans and enkephalin residues containing L‐ and D‐phenylalanine; conformational analysis and preliminary pharmacology (Chemistry of opium alkaloids, Part XXXIII)
Authors: Cappon J. J. , Lie T. S. , Maat L. 
Published: September 2010

AbstractThe morphinan peptidesN‐(4,5α‐epoxy‐3,6‐dihydroxy‐17‐methyl‐6α,14α‐ethenoisomorphinan‐7α‐carbonyl)‐L‐phenylalanine ethyl ester (4),N‐(4,5α‐epoxy‐3,6‐dihydroxy‐17‐methyl‐6α,14α‐ethenoisomorphinan‐7α‐carbonyl)‐D‐phenylalanine ethyl ester (5) andN‐[N‐(4.5α‐epoxy‐3.6‐dihydroxy‐17‐methyl‐6α,14α‐ethenoisomorphinan‐7α‐carbonyl)glycinyl]‐L‐phenylalanine ethyl ester (6) have been prepared from 4,5α‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6α,14α‐ethenoisomorphinan‐7α‐carboxylic acid (7) and the protected amino acids. The morphinan moiety was coupled to the peptide residue via the acid chloride of 7, after which the morphinan peptides wereO‐demethylated with the aid of hydrogen bromide in glacial acetic acid. The dipeptideN‐glycinyl‐L‐phenylalanine ethyl ester was synthesized via the Excess Mixed Anhydride method (EMA). The new morphinan peptides have been characterized by1H and13C NMR spectroscopy. For conformational analysis, the relative stabilities of two possible hydrogen bonds around the C7‐C20 bond have been calculated on a model compound11, using molecular mechanics.
Competitive hemiacetalization and acetalization: Cross‐linking of cellulose by glyoxal
Authors: Sangsari Farid Hamedi , Chastrette Francine , Chastrette Maurice , Blanc Alain , Mattioda Georges 
Published: September 2010

AbstractThe mechanism of cross‐linking of cellulose by glyoxal has been investigated using various alcohols as models for cellulose. Competitive hemiacetalizations of glyoxal show that vicinal diols are much more reactive than isolated alcohols. With a catalyst, both kinds of alcohols react with the hemiacetals, but the isolated alcohols are the most reactive. The main products of acetalization are mixed dioxane bisacetals. Methyl 4‐O‐methyl‐α‐glucoside, considered as a monomeric unit of cellulose, reacts in the same way. The cross‐linking of cellulose by glyoxal is thought to proceed according to the same pattern. The pathways of cross‐linking in the presence of ethylene glycol and diethylene glycol, currently used as co‐reactants of glyoxal, are discussed.
Reductive double alkylation of anthracene with lithium bromoacetate; synthesis of cyclopent[hi]aceanthrylene, a novel dicyclopenta‐fused hydrocarbon
Authors: Boere Ben B. , Mulder Patrick P. J. , Cornelisse Jan , Lugtenburg Johan 
Published: September 2010

AbstractThe synthesis and characterization of cyclopent[hi]aceanthrylene, a novel dicyclopenta‐fused polycyclic hydrocarbon, are described. The key step is the reductive double alkylation of anthracene by lithium bromoacetate in liquid ammonia giving cis‐9,10‐dihydroanthracene‐9,10‐diacetic acid in good yield. Lithium bromoacetate is a better alkylating agent than the sodium iodoacetate formerly used.
Synthesis of a spacer‐containing trimeric fragment of the capsular polysaccharide from Escherichia coli K100
Authors: Elie C. J. J. , Muntendam H. J. , van der Marel G. A. , van Boom J. H. , Hoogerhout P. , van de Werken G. 
Published: September 2010

AbstractStereoselective β‐glycosidation of 1,3,4‐tri‐O‐benzyl‐5‐O‐pivaloyl‐D‐ribitol, prepared from L‐ribose, with 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranose gave, after protecting‐group manipulations, the properly protected terminal and non‐terminal units. Elongation (2 ×) of the terminal unit with the incoming non‐terminal unit could be accomplished using the bifunctional phosphorylating reagent, bis(l‐benzotriazolyl) 2‐chlorophenyl phosphate. The trimeric unit thus obtained was condensed, using the same phosphorylating reagent, with the spacer N2‐(benzyloxycarbonyl)‐N1‐(3‐hydroxypropyl)glycinamide, to give, after complete deblocking, the spacer‐containing trimeric unit of Escherichia coli K100.
(S)‐2‐Chloropropanoyl chloride. A convenient reagent for the determination of the enantiomeric composition of α‐substituted α‐hydroxy acids
Authors: Moorlag Henk , Kruizinga Wim H. , Kellogg Richard M. 
Published: September 2010

Abstract(S)‐2‐Chloropropanoyl chloride reacts cleanly with α‐substituted α‐hydroxy acids (or esters) to give O‐acyl derivatives, which can be used for the establishment of optical purities of the acids or their esters.
“Tert‐amino effect” in heterocyclic synthesis. Synthesis of thieno[3,2‐e]indolizines and thieno[2,3‐c]quinolizines
Authors: Verboom W. , Verboom C. , Eissink I. M. , Lammerink B. H. M. , Reinhoudt D. N. 
Published: September 2010

AbstractA new and convenient route for the synthesis of the thieno[3,2‐e]indolizines 4a,b,d, the thieno[2,3‐c]quinolizine 4e and their [1]benzothieno analogues 9a,b is presented. Reaction of the (dialkylamino)thiophenes 1, 5 and 7 with (methoxymethylene)malononitrile (2) gives the Michael adducts 3, 6 and 8. Heating of 3 and 8 in refluxing 1‐butanol gives the cyclized products 4 and 9. This cyclization proceeds via a 1,5 hydrogen shift, followed by an intramolecular addition of the carbanion to the iminium double bond in the intermediate 10 formed. The scope and limitations of this approach are discussed.