bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photosubstitution and photoreduction of pyrene and 1‐halopyrenes
Authors: Tintel C. , Rietmeyer F. J. , Cornelisse J. 
Published: September 2010

AbstractUpon irradiation, pyrene reacts with cyanide to give 1‐cyanopyrene and with amide to give 1‐aminopyrene. With oxygen nucleophiles no reaction takes place. Irradiation of pyrene in the presence of diethyl malonate anion yields 4,5,9,10‐tetrahydropyrene in high yield, probably via initial electron transfer to excited pyrene. 1‐Fluoropyrene can be photosubstituted with oxygen nucleophiles, leading to 1‐hydroxy‐ and 1‐methoxy‐pyrene, in contrast to 1‐chloro‐ and 1‐bromopyrene, which are converted into a mixture of pyrene and 4,5‐dihydropyrene upon irradiation.
A two‐step synthesis of benzo[e]pyrene via the pyrene dianion
Authors: Tintel C. , Lugtenburg J. , van Amsterdam G. A. J. , Erkelens C. , Cornelisse J. 
Published: September 2010

AbstractReaction of the pyrene dianion with 1,4‐diiodobutane afforded cis‐8b,9,10,11,12,12a‐hexahydrobenzo[e]pyrene, which could subsequently be oxidized by DDQ to give benzo[e]‐pyrene. Thus, benzo[e]pyrene was formed from pyrene in an overall yield of 46%.
The amination of halogeno‐2,7‐ and 1,8‐naphthyridines
Authors: van den Haak H. J. W. , van der Plas H. C. 
Published: September 2010

AbstractThe conversion of 1‐halogeno‐2,7‐naphthyridines into the corresponding 1‐amino compounds with KNH2/NH3, is shown, by the use of deuterated starting compounds, to proceed via an SN(AE)ipso substitution and not via an SN(AE)tele mechanism, even though convincing evidence for the formation of tele σ‐adduct, 8‐amino‐1‐halogeno‐dihydro‐2,7‐naphthyridinide, was obtained. Using the same methods, it is shown that the conversion of 2‐bromo‐1,8‐naphthyridine into 2‐amino‐1,8‐naphthyridine proceeds, to the extent of 40%, via an odd SN(AE)tele pathway.
Solutes in sulfuric acid. Part VIII. Protonation of phenol, 4‐fluorophenol and the 2‐ and 4‐sulfonates of anisole and phenol in concentrated aqueous sulfuric acid; determination of pKa values by means of 13C NMR
Authors: Koeberg‐Telder Ankie , Lambrechts Hans J. A. , Cerfontain Hans 
Published: September 2010

AbstractThe protonation of phenol (2), 4‐fluorophenol (3), phenyl methanesulfonate, potassium phenyl sulfate and the potassium 2‐ and ‐4‐sulfonates of both phenol and anisole in concentrated aqueous sulfuric acid at 30°C has been investigated using 13C NMR spectroscopy. The results show that phenol and 4‐fluorophenol are protonated predominantly on the oxygen atom. This protonation is governed by the H0a acidity function. The pKa of the oxonium ions of 2 and 3 are ‐6.40 ± 0.05 and ‐6.41 ± 0.05, respectively. The protonation of phenyl methanesulfonate occurs at acid concentrations > 100%. Potassium phenyl sulfate in ≥20% H2SO4 hydrolyses very rapidly to give phenol. The 2‐ and 4‐sulfonates of both phenol and anisole are protonated on both the ‐OR (R = H, Me) and the ‐SO3− groups; the sulfuric acid concentrations of half‐protonation have been determined to be between 80.0 and 83.3% H2SO4, corresponding with pKa's of the conjugate acids between ‐6.34 and ‐6.66 based on the H0a scale.
Photochemistry of dienones. Part 12. Photochemistry of (E)‐α‐ and (E)‐β‐damascone
Authors: Visser Cornelis P. , Cerfontain Hans 
Published: September 2010

AbstractThe photochemistry of (E)‐α‐ and (E)‐β‐damascone has been studied. Upon triplet‐sensitized irradiation, both compounds exclusively undergo (E)‐(Z) isomerization. (E)‐β‐damascone, upon direct irradiation with λ 254, 300 or 350 nm in non‐alcoholic solvents, exhibits only (E)‐(Z) isomerization. However, in an alcoholic solvent, direct irradiation induces cyclization and subsequent solvent incorporation, with formation of exo‐8‐alkoxy‐1,5,5‐endo‐9‐tetramethyl‐cis‐bicyclo[4.3.0]nonan‐7‐one (12).(E)‐α‐damascone, upon direct irradiation, exhibits α‐cleavage with subsequent formation of the 1,3‐acyl shift product, and equal amounts of the dimerization products of the allylic radical, viz. 9 and 10. The 1,3‐acyl shift product again undergoes photo‐α‐cleavage and the only products, upon prolonged irradiation, are the bicyclohexenyls 9 and 10.
Synthesis of 10‐, 11‐, 19‐ and 20‐mono‐13C‐retinal
Authors: Pardoen J. A. , Neijenesch H. N. , Mulder P. P. J. , Lugtenburg J. 
Published: September 2010

AbstractThe 10‐, 11‐, 19‐ and 20‐mono‐13C‐all‐trans‐retinals were synthesized with >98% chemical purity and 92% 13C incorporation from 13C‐labelled acetonitrile and 13C‐labelled methyl iodide. Their 13C‐13C and 13C‐1H NMR coupling constants were measured.
Synthesis and properties of 2,3,17,18‐tetramethyl‐1,19‐[21H,24H]‐bilindione and 2,3,17,18,22,23‐hexamethyl‐23‐hydro‐1,19‐[21H,24H]‐bilindion‐10‐enium trifluoroacetate, two biliverdin model compounds
Authors: de Groot J. A. , van der Steen R. , Lugtenburg J. 
Published: September 2010

AbstractThe biliverdin model compound 1 could be prepared in high yield by acid‐catalyzed condensation of 3,4‐dimethyl‐2,2′‐pyrromethen‐5[1H]‐one (9) with the novel 3,4‐dimethyl‐5′–formyl‐2,2′‐pyrromethen‐5[1H]‐one (11). The biliverdinium model compound 3 could analogously be prepared quantitatively from 1′,3,4‐trimethyl‐2,2′‐pyrromethen‐5[1H]‐one (10) and 5′‐formyl‐1′,3,4‐trimethyl‐2,2′‐pyrromethen‐5[1H]‐one (12).The analytical, chemical, photochemical and photophysical properties of these model compounds have been investigated. The data so obtained are compared with known aspects of the natural biliverdin compounds.
A new and convenient method for the amination of 1,6‐ and 1,7‐naphthyridines using potassium amide/liquid ammonia/potassium permanganate
Authors: Woźniak M. , van der Plas H. C. , Tomula M. , van Veldhuizen A. 
Published: September 2010

AbstractTreatment of 3‐nitro‐1,6‐naphthyridine, its 2‐chloro‐, 2‐ethoxy‐ and 2‐amino derivatives, with liquid ammonia, containing potassium permanganate, gave the corresponding 2‐X‐4‐amino‐3‐nitro‐1,6‐naphthyridines (X = H, Cl, OEt, NH2). From 1H NMR spectroscopy sound evidence for the intermediacy of 2‐X‐4‐amino‐1,4‐dihydro‐3‐nitro‐1,6‐naphthyridine is obtained. Similarly, from 5,8‐dichloro(dibromo)‐1,7‐naphthyridine, the corresponding 2‐amino‐5,8‐dichloro‐(dibromo)‐1,7‐naphthyridines were formed on treatment with liquid ammonia/potassium amide/potassium permanganate. 1H NMR evidence for the intermediary C‐2 σ‐adduct has been obtained.
Ring transformations in reactions of heterocyclic compounds with nucleophiles. The conversion of 5‐nitropyrimidine into pyridine derivatives by CH‐acitve nitriles
Authors: Charushin Valery N. , van der Plas Henk C. 
Published: September 2010

AbstractNitriles R–CH2CN where R is CN, SO2C6H5, C6H4‐NO2‐p, C6H4‐CF3‐m, are effective reagents for converting 5‐nitropyrimidine (1) into 2‐amino‐5‐nitro‐3‐R‐pyridines (7). In reactions of 1 with cyanoacetic acid derivatives (methyl, ethyl, tert‐butyl esters), 3‐cyano‐5‐nitro–2(1H)‐pyridone is formed in addition to 7. Ketonic nitriles, such as 3‐oxobutyronitrile and 3‐oxo–3‐phenylpropionitrile, react with 1 to form 2‐methyl‐ and 2‐phenyl‐5‐nitro‐3‐cyanopyridine, respectively.Plausible mechanisms are discussed. The reaction of 1 with N‐(cyanoacetyl)carbamate provides a facile synthetic route to 1,2,3,4‐tetrahydro‐6‐nitropyrido[2,3‐d]pyrimidine‐2,4‐dione.
Mono alkylation of γ,δ‐unsaturated β‐oxo esters via dianions. Part I
Authors: van den Goorbergh J. A. M. , van der Gen A. 
Published: September 2010

Abstractγ,δ‐Unsaturated β‐oxo esters can be converted into their dianions 6 by reaction with 2 equivalents of lithium diisopropylamide (LDA). Reaction of these dianions with alkyl halides leads exclusively to mono‐γ‐alkylation and affords the unsaturated oxo esters 9 in good yields. Reaction with carbonyl compounds similarly affords the unsaturated δ‐hydroxy β‐oxo esters 10. The regiospecificity of these reactions is discussed in relation to the structure of the dianionic intermediates.
Base‐catalyzed carbon‐carbon bond formation reactions of ω‐hydroxylactams
Authors: Speckamp W. N. , de Boer J. J. J. 
Published: September 2010

AbstractActive methylene compounds such as methyl ketones, 1,3‐dicarbonyl systems and nitromethane condense under the influence of base with ω‐hydroxylactams, thereby forming α‐alkylated nitrogen heterocycles. The ease of alkylation is determined by the position of a tautomeric equilibrium between ω‐hydroxylactam and the open‐chain amide‐aldehyde, which is dependent upon the type of N‐substituent and upon the lactam ring size. Some applications for the products obtained are indicated.
Enantioselectivity in the hydrolysis of esters catalyzed by polyelectrolyte surfactant complexes
Authors: Visser Hendrik G. J. , Nolte Roeland J. M. , Drenth Wiendelt 
Published: September 2010

AbstractA cationic surfactant enhances the enantioselectivity of imidazole containing polymers of isocyanides in the hydrolysis of amino acid 4‐nitro‐phenyl esters.
Synthesis and analysis of tritiated neuropeptides
Authors: Kaspersen Frans M. , van Rooy Fons M. , Wallaart Jan , Funke Carel 
Published: September 2010

AbstractThe synthesis, purification and analysis of three tritiated neuropeptides are described. Org 2766 (an ACTH (4‐9) analogue) and Org GK 78 (des‐Tyr‐γ‐endorphin) were labelled in the aromatic ring of phenylalanine by catalytic deiodination of the (p‐iodophenyl)alanine precursors using 3H2.Org 5878 (des‐enkephalin‐γ‐endorphin) was labelled in the lysine residue by reduction of the L‐2,6‐diamino‐4‐hexynoic acid‐containing analogue with 3H2. The peptides were purified by preparative HPLC using ammonium acetate buffer systems. The chemical purity was determined by 1H NMR, the radiochemical purity was measured by HPLC and the 3H distribution by 3H NMR. Specific activities (as determined by HPLC) were ca. 900 GBq mmol−1 for Org 2766 and Org GK 78 and 1400 GBq mmol−1 for Org 5878.
Syntheses and NMR analyses of deuterated mianserins
Authors: Kaspersen Frans M. , Favier J. S. , Wagenaars Gerard , Wallaart Jan , Funke Carel W. 
Published: September 2010

AbstractEleven deuterated analogues of mianserin have been synthesized and analyzed by 1H and 13C NMR. Based on these compounds, the aromatic part of the 1H spectrum of mianserin could be interpreted.
Synthesis of alkyloxazoline derivatives of 2‐amino‐2‐deoxy‐D‐glucopyranose via phosphate intermediates
Authors: Oltvoort J. J. , van Boeckel C. A. A. , van der Marel G. A. , van Boom J. H. 
Published: September 2010

AbstractPhosphorylation of 2‐(acylamino)‐3,4,6‐tri‐O‐acetyl‐2‐deoxy‐α/β‐D‐glucopyranose in the presence of triethylamine with 2‐chlorophenyl phosphorodi(1,2,4‐triazolide) gave 2‐alkyl(3,4,6‐tri‐O‐acetyl‐1,2‐dideoxy‐α‐D‐glucopyrano) [2,1 ‐d]‐2‐oxazolines.
Photochemical and Lewis‐acid‐catalyzed rearrangement of 1‐phenyl‐4‐methyl‐3,6‐dioxabicyclo[3.1.0]hexan‐2‐one into its tetronic acid isomer
Authors: Caus Maria J. , Cerfontain Hans , Piniella Juan F. 
Published: September 2010

AbstractThe irradiation of 2 in acetonitrile or methanol with λ 254 nm yields the tetronic acid derivative 3. The (thermal) BF3‐catalyzed rearrangement of 2 yields the same tetronic acid derivative. The structure of the tetronic acid 3 has been determined by means of X‐ray analysis; it forms monoclinic crystals with cell constants a = 10.868, b = 8.320, c = 20.936 Å and β = 90.65°. The space group is P21/n; in the unit cell there are eight molecules which exhibit intermolecular hydrogen bonding.
An approach to the synthesis of liponucleotides
Authors: Oltvoort J. J. , van der Marel G. A. , van Boeckel C. A. A. , van Boom J. H. 
Published: September 2010

AbstractPhosphorylation of 3′‐O‐levulinoylthymidine*** using 2‐chlorophenyl bis‐O‐(1‐benzo‐triazolyl) phosphate, followed by addition of 1‐hexadecanol, afforded in high yield a fully protected triester derivative of thymidine.Similarly, phosphorylation of 1,2‐di‐O‐palmitoyl‐sn‐glycerol with the same reagent and subsequent addition of the above thymidine derivative gave a triester derivative of thymidine in excellent yield. Both triester derivatives were efficiently converted into the corresponding liponucleotides by the removal of the 2‐chlorophenyl and levulinoyl protective groups.
Studies on the synthesis of the protected C‐terminal segment of vasoactive intestinal peptide (VIP) via its 28‐aspartic acid analogue
Authors: Schaaper W. M. M. , Voskamp D. 
Published: September 2010

AbstractA major problem in the synthesis in solution of the gastrointestinal peptide VIP is the solubility of C‐terminal intermediates. Already in the tripeptide stage, the solubility in the usual solvents is very low and gives rise to low coupling yields. The C‐terminal asparagine amide, in combination with leucine and isoleucine, seems to play an important role in this phenomenon. We synthesized the protected C‐terminal segments, VIP(27‐28), VIP(22‐28) and VIP( 14‐28), via the temporary substitution of 28‐asparagine by a β‐tert‐butyl protected aspartic acid. This substitution resulted in a dramatic improvement in solubility. The synthesis could easily be performed via the repetitive excess mixed anhydride method. In the last stage of the synthesis, the β‐tert‐butyl protection of 28‐aspartic acid could be removed selectively. The deprotected aspartic acid was converted into asparagine by amidation using the mixed anhydride or the carbodiimide method.
Reactions of cisoid α‐methoxyimino ketones with N,N‐diethyl‐1‐propyn‐1‐amine. Formation of a γ‐methoxyimino α,β‐unsaturated carboxamide or a 1,4‐benzoxazine
Authors: Elferink V. H. M. , Bos H. J. T. 
Published: September 2010

AbstractAddition of 2‐(methoxyimino)acenaphten‐1‐one 1 and 10‐(methoxyimino)phenanthren‐9‐one 3 to N,N‐diethyl‐1‐propyn‐1‐amine gives the γ‐methoxyimino α,β‐unsaturated carboxamides 2 and 4 via a (2 + 2)‐cycloaddition reaction with the carbonyl group, followed by an electrocyclic ring opening. Reaction of 4,6‐di‐tert‐butyl‐2‐(methoxyimino)‐3,5‐cyclohexadien‐1‐one 5 with N,N‐diethyl‐1‐propyn‐1‐amine gives rise to formation of 1,4‐benzoxazine 6, presumably via addition of the ynamine to the C = N group, followed by 1,3‐rearrangement of methoxide and subsequent ring closure of the 0CCNCC system.
Electrophilic additions to (dimethylamino)allene
Authors: Klop W. , Klusener P. A. A. , Brandsma L. 
Published: September 2010

Abstract(Dimethylamino)allene reacts with alcohols, thiols and aliphatic secondary amines without the addition of a catalyst to give the adducts H2C=CH−C(Y)NMe2 (Y = OR, SR or NR2). The reactions are slowed down or do not proceed if bases (KOH, t‐BuOK) are present. Under the influence of H⊕ (H2O, NH4Cl or acid alumina), the adducts rearrange to the enamines Y‐CH2CH=CH−NMe2 (100% trans). If Y = SR or NR2, the enamines are obtained in good yields, but with Y = OR, the rearrangement proceeds much more slowly and cannot be forced to completion without formation of resinous material.
Deuterium isotope effects in mianserin
Authors: Kaspersen Frans M. , van Acquoy Jan , van de Laar Gerrit L. M. , Wagenaars Gerard N. , Funke Carel W. 
Published: September 2010

AbstractIsotopic fractionation in HPLC can be observed for mianserin when deuterated in the piperazine ring, except on position 14b. This isotope effect is caused by an increase in basicity upon introduction of deuterium. No effects of deuteration on the conformation of the molecule could be detected.
Synthesis of imidazole‐containing poly(iminomethylenes). Choice of N(Im)‐protecting group
Authors: van der Eijk J. M. , Richters V. E. M. , Nolte R. J. M. , Drenth W. 
Published: September 2010

AbstractFour imidazole‐containing isocyanides having different N(Im)‐protecting groups at the tele as well as at the pros position have been synthesized. These isocyanides include Nτ(Im)‐tosyl‐Nα‐carbylhistamine (4a), Nτ(Im)‐benzyl‐Nα‐carbylhistamine (4b), Nπ(Im)‐benzyl‐Nα‐carbylhistamine (4c) and Nτ,Nπ(Im)‐dibenzyl‐Nα‐carbylhistamine bromide (4d). Compounds 4a and 4d polymerize in the presence of nickel(Il) ions, whereas compounds 4b and 4c do not. This result is explained by the type of nickel complex that is formed, viz. a tetrahedral or square‐planar complex with general formula Ni(CNR)42+ in the case of 4a and 4d, and an octahedral complex with general formula Ni(CNR)32+ in the case of 4b and 4c. In the latter complexes, not only the isocyano groups but also the imidazole groups coordinate to the nickel. Thus, the imidazole groups block the coordination sites which are required for polymerization of the isocyano functions.
A new enzymatic chlorination of barbituric acid and its 1‐methyl and 1,3‐dimethyl derivatives
Authors: Franssen M. C. R. , van der Plas H. C. 
Published: September 2010

AbstractA new chlorination procedure, involving as reagent the system chloroperoxidase/hydrogen peroxide/potassium chloride was developed for converting barbituric acid, 1‐methylbarbituric acid and 1,3‐dimethylbarbituric acid into their 5,5‐dichloro derivatives. It could be proved that the corresponding 5‐mono‐chlorobarbituric acids are intermediates in the reaction.
The interaction of bacterioopsin with 11,14‐bridged retinals: The synthesis of 13‐demethyl‐11,14‐imino‐, 13‐demethyl‐N‐methyl‐11,14‐imino, 13‐demethyl‐11,14‐thio‐, 13‐demethyl‐11,14‐etheno‐, 11,14‐imino‐retinal and their binding with bacterioopsin
Authors: Muradin‐Szweykowska M. , Peters A. J. M. , Lugtenburg J. 
Published: September 2010

AbstractThe synthesis of the all‐trans and 9‐cis isomers of 11,14‐imino‐retinal, 13‐demethyl–11,14‐imino‐retinal, 13‐demethyl‐N‐methyl‐11,14‐imino‐retinal, 13‐demethyl‐11,14‐thio‐retinal and 13‐demethyl‐11,14‐etheno‐retinal is described.The interaction of these retinals with bacterioopsin has been investigated. The all‐trans isomers bind to bacterioopsin to form complexes with λmax values around 430 nm. These complexes are stable and do not convert into bacteriorhodopsin analogues. In these complexes the aldehyde group is still present and can be reduced in situ using NaBH4.The fact that these bridged retinals do not form bacteriorhodopsin analogues must be due either to the steric hindrance or to the electronic perturbations of the system caused by the bridging group.
Photochemistry of 4,5‐dihydro‐8‐hydroxygermacrene B
Authors: Fransen Harrie R. , Dormans Guido J. M. , Bezemer Gerrit J. , Buck Henk M. 
Published: September 2010

AbstractIrradiation of two racemates of 4,5‐dihydro‐8‐hydroxygermacrene B (2, 3) results, in addition to E‐Z isomerization, in the occurrence of a [1,3]‐C shift. Conformational differences between the diastereoisomers are reflected in a highly stereospecific photoreaction.
P(V) trigonal bipyramidal phosphoranes as model compounds for the description of cAMP‐catalyzed reactions
Authors: van Ool Peter J. J. M. , Buck Henk M. 
Published: September 2010

Abstract13C NMR low‐temperature investigations have revealed that the dioxaphosphorinane ring, trans‐annelated with a cyclopentane ring (3), prefers an equatorial‐apical alignment in trigonal bipyramidal phosphoranes. However, the 13C NMR low‐temperature investigations of the model compound, in which the dioxaphosphorinane ring is trans‐annelated with a tetrahydrofuran ring (4), have shown that the ligand exchange (pseudorotation) in this compound is very fast on the NMR time scale, even at low temperatures. These results are in fairly good agreement with quantum‐chemical calculations.
Synthesis of retinals labelled at positions 14 and 15 (with 13C and/or 2H)
Authors: Pardoen J. A. , Winkel C. , Mulder P. P. J. , Lugtenburg J. 
Published: September 2010

AbstractEight retinals labelled at positions 14 and 15 with 13C and/or 2H were obtained with >98% chemical purity, 92% 13C incorporation, 95% 2H incorporation at position 14 and 99% 2H incorporation at position 15. (14‐13C)retinal, (15‐13C)retinal and (14,15‐13C2)retinal were synthesized from (2‐13C)‐, (1‐13C)‐ and (1,2‐13C2)acetonitrile, respectively, while for the synthesis of (14‐2H)retinal, C2H3CN was used. Via a three‐step process these retinals were transformed into (14,15‐2H2)retinal, (14‐13C,15‐2H)retinal, (15‐13C,15‐2H)retinal and (14,15‐13C2,15‐2H)‐retinal. Their 13C–13C, 13C‐2H and 13C‐1H NMR coupling constants were determined.
Conformational analysis of 3‐oxo 5(10)‐unsaturated steroids. Single‐crystal X‐ray structure analysis of 17‐hydroxy‐7α‐methyl‐19‐nor‐17α‐pregn‐5(10)‐en‐20‐yn‐3‐one (Org OD 14)
Authors: Declercq J.‐P. , van Meerssche M. , Zeelen F. J. 
Published: September 2010

AbstractTwo crystallographically independent molecules with differing half‐chair conformations of ring A were found in the analysis of Org OD 14. These results are compared with published X‐ray structure analyses and Westheimer‐type calculations of related steroids. It is concluded that the energy differences between the half‐chair and envelope conformations of ring A of 3‐oxo 5(10)‐unsaturated steroids are small.
Biomimetic total synthesis of steroids VIII. Stereospecific synthesis of B‐homo‐19‐norsteroids
Authors: Groen M. B. , Zeelen F. J. 
Published: September 2010

AbstractCationic cyclization of 2‐[7‐(3‐methoxyphenyl)‐(E)‐3‐heptenyl]‐3‐methyl‐2‐cyclopentenol (7) gave mainly tetracyclic products via Ar1‐6 and/or Ar2‐7 participation. The major product, 3‐methoxy‐17‐methyl‐B‐homo‐1,3,5(10),13(17)‐gonatetraene (9), was converted in two steps into B‐homoestrone methyl ether 20. High‐resolution 1H NMR spectra indicated that the seven‐membered ring in 9 occurs mainly in a boat‐like conformation whereas in its 1‐methoxy isomer 8 it occurs in an unsymmetrical twist‐boat conformation. In 20, the B‐ring probably occurs both in chair and boat conformations.
Synthesis and photooxidation of furylthymines; chemiexcitation model studies
Authors: Feringa Ben L. , Dannenberg W. 
Published: September 2010

AbstractA method for the synthesis of 1‐(5‐methyl‐2‐furoyl)thymine (7) and 1‐(5‐methyl‐2‐furyl)thymine (8) is described. Trimethylsilyliodide catalysed addition of 5‐methyl‐2,4‐bis(trimethylsilyloxy)pyrimidine (9) to 2‐methyl‐2,5‐dihydro‐2,5‐dimethoxyfuran yielded the new thymine derivative 13. Photooxidations of 7 and 8 gave not the expected addition products but furan endoperoxides and hydroperoxides and the novel rearrangement product 1‐(3‐keto‐1‐butenyl)thymine.
Coal liquefaction ‐ entrapment of bitetralyls and other products from tetralin
Authors: de Vlieger J. J. , de Leeuw J. W. , Kieboom A. P. G. , van Bekkum H. 
Published: September 2010

AbstractSmall scale coal liquefaction experiments are often carried out with tetralin as a model hydrogen donating solvent1–4. Tetralin was thought for a long time to be selectively converted into naphthalene. Recently, however, we have found substantial cracking and isomerization of tetralin under common coal liquefaction conditions, in particular at prolonged reaction times5. The present paper describes further studies of the behaviour of tetralin during coal liquefaction at 400°C, whereby special attention is given to the formation of bitetralyls. Entrapment of these relatively low‐volatile compounds strongly influences data obtained for the coal derived product. This means that the common procedures used to separate coal product and donating solvent are highly insufficient. The structure of the entrapped dimer tetralin compounds has been determined and the mechanism of dimerization is discussed.
sp3‐Carbon detosylations by Dibal‐H≠: Model studies
Authors: Janssen Cornelus G. M. , Hendriks Adrianus H. M. , Godefroi Erik F. 
Published: September 2010

Abstractα‐ And β‐tosylated alkenylaromatic systems 5c, d and 9a‐c are cyclized to 6c, d and 10a‐c in FSO3H‐containing SO2 in synthetically useful processes. Dibal‐H treatment of α‐substituted 6c, d brings about rapid, high‐yield detosylation to 7c, d; the β‐tosylated isomers 10a‐c give, with Dibal‐H, after 18 h in refluxing toluene, mainly unreacted sulfones together with minor amounts of sulfides 11a‐c. Ring‐disrupted congeners 15a‐d and 18a‐c behave likewise, with α–tosylated 15a‐d being rapidly detosylated by Dibal‐H to 16a‐d and their β‐substituted isomers undergoing low‐yield reductions to sulfides 19a‐c. Dibal‐H mediated detosylation appears to be limited to benzylic substrates.