bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron diffraction by gases: The molecular structure of bicyclo[2.2.1]heptane
Authors: Dallinga G. , Toneman L. H. 
Published: September 2010

AbstractThe structure of bicyclo[2.2.1]heptane has been investigated by means of electron diffraction of the vapour. The results are compared with other electron measurements, with X‐ray singlecrystal work on derivatives, and with theoretical calculations. Some interesting facts emerge, but a complete, accurate and unambiguous structure is not produced by the diffraction techniques.
Electron diffraction by gases: The molecular structure of bicyclo[2.2.1]hepta‐2,5‐diene
Authors: Dallinga G. , Toneman L. H. 
Published: September 2010

AbstractThe structure of bicyclo[2.2.1]hepta‐2,5‐diene has been investigated by means of electron diffraction of its vapour. The results are compared with those of other electron diffraction and X‐ray investigations and with theoretical calculations. It appears that in this molecule the sp2‐sp3 and the sp3‐sp3 carbon‐carbon bonds are very nearly equal.
Aromatic sulfonation 20: The sulfonation of some chlorobenzenes with sulfur trioxide in nitromethane as solvent
Authors: Bosscher J. K. , Cerfontain H. 
Published: September 2010

AbstractThe sulfonation of chlorobenzene andp‐dichlorobenzene with sulfur trioxide in nitromethane as solvent has been studied. The main reaction products are arenesulfonic anhydride and probably arenepyrosulfonic acid. Withp‐dichlorobenzene as substrate the amount of diaryl sulfone is undetectably small; with chlorobenzene it is < 1‐mole % relative to the converted substrate. The sulfonation is of the first order with respect to the substrate and of the second order with respect to sulfur trioxide. For each mole of converted substrate two moles of sulfur trioxide are consumed. The sulfonation ofp‐dichlorobenzene proceeds without a primary kinetic isotope effect of hydrogen.It is suggested that the sulfonation proceeds via 1‐arenonium‐1‐sulfonate and 1‐arenonium‐1‐pyrosulfonate as the subsequent reactive intermediates, with the formation of the latter intermediate as the rate‐limiting step. The kinetics of the formation of 4,4′‐dichlorodiphenyl sulfone are compatible with a mechanism in which the speciesp‐ClC6H4S3O9H is the effective sulfonylating entity.The literature on aromatic sulfonation with sulfur trioxide in aprotic solvents is critically reviewed.
Electron diffraction by gases: The molecular structure of spiropentane
Authors: Dallinga G. , van der Draai R. K. , Toneman L. H. 
Published: September 2010

AbstractThe molecular structure of spiropentane has been redetermined from electron diffraction by the vapour. The difference of 0.05 Å found between the two non‐equivalent carbon‐carbon bond lengths is in agreement with the expectation based on the results of an MO calculation.
Natural coumarins. Part X.: Isoimperatorin, a further constituent of the fruits of Ammi Majus L
Authors: Abu‐Mustafa E. A. , El‐Bay F. K. A. , Fayez M. B. E. 
Published: September 2010

AbstractIn addition to the previously known coumarin constituents (xanthotoxin, imperatorin, bergapten, isopimpinellin and marmesin) of Ammi majus L. fruits, a further product has been isolated. On the basis of chemical and physical evidence, the new component was proved to be isoimperatorin (VII).
Reactions of organometallic compounds with terminal epoxides. Part I. Reaction of various magnesium compounds with propylene oxide
Authors: Schaap A. , Arens J. F. 
Published: September 2010

AbstractThe reaction of propylene oxide with Mg‐compounds has been investigated systematically. Variations involved alkyl group, halide, presence of salts, solvent, ratio of reactants, reaction period and temperature.
Some reactions with 1,1‐bis(alkylthio)‐2‐alkynes
Authors: Wildschut G. A. , van Boom J. H. , Brandsma L. , Arens J. F. 
Published: September 2010

Abstract1,1‐Bis(alkylthio)‐2‐alkynes RCH2CCCH(SC2H5)2 (I) (with R  H or alkyl) can be metallated with alkali metal amides in liquid ammonia or with butyllithium in ether or tetrahydrofuran. Subsequent hydrolysis affords a mixture of 1 and a 1,1‐bis(alkylthio)‐1,2‐alkadiene RCH2CH  CC(SC2H5)2 (II); a similar result is obtained starting from II. The ratio of I and II depends on the metallating agent and on the solvent. Sodium ethoxide in liquid ammonia or in ethanol converts I into II completely.Alkylation of metallated I or II with alkyl iodides gives the products RCH2C  CC(R′)(SC2H5)2 (IV) and traces of RCH2C(R′)CC(SC2H5)2(V).Reaction with allyl bromide or with chloromethyl ethyl ether leads to the formation of RCH2CCC(CH2CH CH2)(SC2H5)2 (VI) and RCH2CCC(CH2OC2H5)(SC2H5)2 (VII). Acetone reacts to give the carbinol RCH2CCC[C(CH3)2OH](SC2H5)2 (VIII) as the sole product.
Charge fluctuations in isoionic protein solutions. Determination of the quantity S = (¯z2)½ by means of conductivity measurements and hydrogen ion titrations
Authors: de Bruin S.H. , van Os G.A.J. 
Published: September 2010

AbstractOn theoretical grounds it must be expected, that the electrical charge of protein molecules fluctuates around a mean value. In this paper the determination of the standard deviation of the charge from this; mean value in isoionic protein solutions is described. The standard deviation was measured in two independent ways, viz. from conductivity measurements and from the slope of the hydrogen ion titration curves. The proteins investigated were bovine carboxy‐hemoglobin, bovine methemoglobin, horse heart metmyoglobin and bovine serum albumin.
Synthesis and stereochemistry of spiro‐dihydropyran derivatives derived from bicyclo[2.2.1]heptane
Authors: de Boer Th. J. , van Velzen J.C. , Kruk C. 
Published: September 2010

AbstractThe addition of acrolein to norcamphene leads to an exo‐oxa spiro compound (Scheme 1, VIa). The corresponding endo‐isomer VIb can be obtained from norbornanone X and methoxybutenyne XIII via the sequence of reactions outlined in Scheme 2. Because the steric course in some crucial steps is known, the endo structure of VIb can be established.An alternative route leading to the exo‐oxa. spiro compound IXa, starting with norbornanone is given in Scheme 3. Another route to predominantly endo‐oxa compounds from norbornanone is given in Scheme 4.
Dialkylethynylphosphine oxides; synthesis and reactions
Authors: Hagens W. , Bos H.J.T. , Voskuil W. , Arens J.F. 
Published: September 2010

AbstractDimethyl‐ and dibutyl‐ethynylphosphine oxide R2P(O)C ≡ CH with R = CH3 and n‐C4M9, respectively, have been prepared from the corresponding dialkylphosphinic chlorides.Reactions of (C2H5)2NH, (CH3)2NH2, NaOCH3, NaOC2H5, NaSC2H5, HCl and HI with these ethynylphosphine oxides afforded 1: 1 adducts of the general formula R2P(O)CH = CHY. With the exception of alkoxide the addition occurred in the trans fashion yielding the cis compounds, but several adducts thermally rearranged to the trans isomers.As a side reaction with Na OC2H5, nucleophilic substitution at the phosphorus atom was observed.The stereochemistry of the reactions was established by NMR spectroscopy. The influence of substituents on coupling constants was studied.
The β‐pinene‐acrolein adduct and its acid‐catalysed cyclization
Authors: Kruk C. , Velzen J. C. V. , de Boer Th. J. 
Published: September 2010

AbstractThermal addition of acrolein to β‐pinene leads mainly to the unsaturated aldehyde I and, in small amount, to the spiro compound II. Heating of I with dilute acid yields 6‐isopropyltetralin (IV) and the tricyclic diol V, the latter being favoured at very low acid concentrations. Oxidation of this diol yields the ketol VI with a negative Cotton‐effect and the diketone VII with a positive Cotton‐effect, both in accordance with the suggested stereo‐structure.
On the synthesis of cephalosporin antibiotics (III). α, β‐substituted butenolides and α,β‐substituted γ‐butyrolactones via Erlenmeyer condensations
Authors: Tan H. S. , Reinhoudt D. N. , Beyerman H. C. 
Published: September 2010

AbstractA synthesis of α, β‐substituted butenolides and of α, β‐substituted γ‐butyrolactones, starting from 1, 3‐dihydroxyacetone and a number of N‐acylglycines, by an Erlenmeyer condensation is described.The scope and limitations of the condensation were studied.
Synthesis and antifungal activity of some carbohydrate and amino acid derivatives of dimethyldithiocarbamic acid and of pyridine‐2‐thiol 1‐oxide
Authors: Pluijgers C. W. , Berg J. , Thorn G. D. 
Published: September 2010

AbstractThe synthesis of a number of carbohydrate and amino acid derivatives of dimethyldithiocarbamic acid and of pyridine‐2‐thiol 1‐oxide is described. The antifungal activity of the compounds and their activity against cucumber scab (Cladosporium cucumerinum) are given in tabular form.
Vibrational‐Spectra of some indium compounds
Authors: Brinkmann F. J. J. , Gerding H. 
Published: September 2010

AbstractSolid state Raman‐spectroscopic results are communicated for: In2Cl3, In5Cl9, InCl2, InCl3, InCl3 · PCl51, InCl3 · NH4Cl, InCl3 · N(C2H5)4Cl, InCl3 · 3 NH4Cl and InCl3 · 3 TlCl.The melt of InCl2 has been studied too.Infrared absorption spectra, mostly in the range 240‐700 cm−1, have been determined for the majority of the compounds mentioned above.A detailed study of the binary system In ‐ InCl3 in the range InCl1.75 to InCl2.10 has been made.
Chemistry and spectroscopy in strongly acidic solutions. Part XXV: Formation and properties of 1,2,3,4,5,6‐hexamethylcyclohexenyl cations
Authors: Hogeveen H. , Gaasbeek C. J. , Volger H. C. 
Published: September 2010

Abstract1,2,3,4,5,6‐Hexamethylcyclohexenyl cations are obtained on protonation of 1,2,3,4, 5endo, 6endo‐hexamethylbicyclo[2.2.0]hexene and of cis‐1,2,3,4,5,6‐hexamethylcyclohexa‐1,3‐diene. The structure of the ions was proved unambiguously by the chemical shifts and coupling constants of the NMR signals, by deuterium labelling experiments and by their chemical reactivity.The mechanism of the formation of the ions is discussed.
Isomerization reactions occurring on alkylation of benzene with some branched long‐chain 1‐alkenes
Authors: Nooi J. R. , Muller J. J. , Testa M. C. , Willemse S. 
Published: September 2010

AbstractBenzene was alkylated successively with a mixture of 2‐methyl‐1‐octene and 2‐methyl‐2‐octene, with 2‐butyl‐1‐octene, 3,7‐dimethyl‐1‐octene, 10‐methyl‐1‐undecene and 3,3‐dimethyl‐1‐undecene, using sulfuric acid and aluminium chloride as catalysts. In some cases, a considerable methide shift occurred.With sulfuric acid, there is a considerable preference for the formation of tertiary alkylbenzenes, even if the tertiary carbon atom is far removed from the double bond.Under the conditions used, aluminium chloride shows less preference for the formation of tertiary alkylbenzenes. The yields are low when, in the early stage of the reaction, a tertiary carbonium‐ion type intermediate is formed. Particularly tertiary alkylbenzenes are unstable under alkylation conditions in the presence of aluminium chloride: dealkylation and isomerization to secondary alkylbenzenes occur.
The chemistry and fungicidal and phytotoxic properties of arylsulfonyl‐, arylsulfinyl‐, and arylthio‐alkyl thiocyanates
Authors: Dolman H. , Tempel A. , Koopman H. , Wellinga K. , Hamminga D. 
Published: September 2010

AbstractThe synthesis and fungicidal and phytotoxic properties of a large number of arylsulfonyl‐, arylsulfinyl‐, and arylthio‐alkyl thiocyanates are described and discussed.
Nitromethane as a ligand. Part I: Complexes with some divalent metals and the hexachloroantimonate anion
Authors: Driessen W. L. , Groeneveld W. L. 
Published: September 2010

AbstractA series of new complexes is reported with nitromethane as a ligand: viz. [M(CH3NO2)6]2+[SbCl6]2− where M is Mg(II), Ca(II), Sr(II), Mn(II), Fe(II), Co(II), Ni(II), and Zn(II).The compounds have been identified by chemical analysis and with the aid of physical measurements.No shift in the N → O stretching frequencies has been observed. The NO2 rocking mode (B1) shifts to higher frequencies.Ligand field spectra for the Co(II) and Ni(II) compounds are investigated. Values for Dq and B are reported and the ligand is placed in the spectrochemical and nephelauxetic series.It is concluded that complexes of nitromethane can serve as precursors of coordination compounds of other weakly nucleophilic ligands.
Extraction of platinum group metals by high molecular weight amines (H.M.W.A.): A study of Pt(IV)‐HCI system
Authors: Khattak M. A. , Magee R. J. 
Published: September 2010

AbstractThe distribution of Pt(IV), between aqueous hydrochloric acid solutions and various High Molecular Weight Amines in organic solvents has been studied and the effects of HCl concentration, the type of amine and various organic solvents investigated. Spectrophotometric studies were carried out on the aqueous Pt(IV) solution in hydrochloric acid solution and on the extracted species in the organic phase. Diffuse reflectance studies on the complexes were also carried out and evidence is presented to support the conclusion that the extracted species is the hexachloroplatinate(IV) ion.
Mechanism of reactions of α‐ diazosulfones. Part V. Substituent effects in the acid‐catalysed hydrolysis of arenesulfonyldiazomethanes
Authors: Engberts J.B.F.N. , Zuidema G. , Zwanenburg B. , Strating J. 
Published: September 2010

AbstractThe synthesis of the α‐diazosulfones m‐XC6H4SO2CHN2 (X = CH3O, CH3, Cl, CF3 and NO2) by the method of van Leusen and Strating is described. The pseudo first order rate constants for the acid‐catalysed hydrolysis of these a‐diazosulfones and those of p‐XC6H4SO2CHN2 (X = CH3O, CH3, H, Cl, NO2) in 40% (v/v) dioxane‐water at 25° have been correlated by the Hammett qσ equation. The deviation found for the p‐CH3O‐derivative is discussed. A linear correlation has been found between the logarithm of the rate constants and the frequencies of the infrared absorption of the diazo group at about 2100 cm−1. This relationship between rate data and infrared frequencies can be extended to the acid‐catalysed solvolysis of other types of aliphatic diazo compounds.
Complexes with ligands containing nitrile groups Part XI: The formation of chloromercurate(II) anions with mono‐ and di‐valent cations in acetonitrile
Authors: Reedijk J. , Groeneveled W.L. 
Published: September 2010

AbstractTwenty new compounds of the general formula M(CH3CN)mn+(anion)n− are described. In this formula M = (C2H5)4N, Li, Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn, n = 1 or 2, m = 0‐8, and the anions are (HgpCl2p+q)q−, in which p = 1‐5 and q = 1 or 2.These compounds are prepared by chloride‐ion transfer reactions between MCln and HgCl2 in acetonitrile. The process is followed conductometrically for some cases.The compounds are identified and characterized by chemical analyses, ligand‐field spectra, infrared spectra, and Raman spectra. Both tetrahedral and linear coordinated chloromercurate(II) anions are found to be present in the solid compounds.
Isomerization of cyclic olefins in basic media. Part 2: The degradation of [14C]‐cyclopentene, [14C]‐cyclohexene and [14C]‐cycloheptene
Authors: Tjan S.B. , Steinberg H. , de Boer Th. J. 
Published: September 2010

AbstractVarious methods of selective degradation of [14C]‐cyclopentene, [14C]‐cyclohexene and [14C]‐cycloheptene are described, which render it possible to determine the specific activity of each ring carbon atom. The synthesis of [1‐14C]‐cycloheptene from [l‐14C]‐cyclohexanone is described.
The synthesis of substituted bicyclo[3.2.1]octa‐2,6‐dienes
Authors: Klumpp G. W. , Barnick J. W. F. K. , Veefkind A. H. , Bickelhaupt F. 
Published: September 2010

AbstractBicyclo[3.2.1]octa‐2,6‐diene‐ax‐ and ‐eq‐4‐carboxylic acids (IIIa) have been prepared via Knoevenagel condensation of bicyclo[3.1.0]hex‐2‐ene‐6‐endo‐carbaldehyde (Ia). Synthesis and properties are reported of endo‐4‐t‐butoxy‐bicyclo[3.1.0]hex‐2‐ene‐6‐endo‐carbaldehyde (Ib). This aldehyde has been converted to endo‐8‐t‐butoxybicyclo[3.2.1]octa‐2,6‐diene (IIIb) and to endo‐8‐t‐butoxybicyclo[3.2.1]octa‐2,6‐diene‐ax‐ and ‐eq‐4‐carboxylic acids (IIIc) respectively via Wittig methylenation and Knoevenagel condensation.
Acid‐catalyzed ring closure of 1‐methoxy‐ or 1‐methylthio‐1‐(α‐ or β‐hydroxyalkyl)allenes: Formation of 3,8‐dimethoxy‐1,6‐dioxacyclodeca‐3,8‐dienes and 4‐methylthio‐5,6‐dihydro‐2H‐pyrans
Authors: Hoff S. , Brandsma L. 
Published: September 2010

AbstractTreatment of 1‐(α‐hydroxyalkyl‐1‐methoxyallenes CH2CC(OCH3)C(OH)R1R2 (I, with R1 and R2H, alkyl or (CH2)5‐) with a catalytic amount of p‐toluenesulfonic acid in tetrahydrofuran gives 3,8‐dimethoxy‐1,6‐dioxacyclodeca‐3,8‐dienes (VI) in low to moderate yield.The same treatment of 1‐(β‐hydroxyethyl)‐1‐methylthioallenes RCH = C=C(SCH3)CH2CH2OH (IX, with R = H or n‐C3H7) produces 4‐methylthio‐5,6‐dihydro‐2H‐pyrans (X and XI) in good yields.Addition of gaseous hydrogen chloride to methoxypropadiene gives ClCH2CHCHOCH3 (VIII).
Alkyl 1,1‐dialkoxy‐alkane‐ and ‐arene‐carboxylates. Part III: Mixed orthoformates
Authors: Scheeren J. W. , Stevens W. 
Published: September 2010

AbstractThe reaction of ROH and RSH (R = alkyl or aryl) with methyl diethoxyacetate leads to an easy synthesis of mixed orthoformates. In view of the contradictory results reported in the literature the disproportionation of mixed orthoformates was also studied.
A stereospecific synthesis of 4‐oxo‐2trans‐hexenal
Authors: Ward J. P. , van Dorp D. A. 
Published: September 2010

Abstract4‐Oxo‐2trans‐hexenal is an odoriferous substance secreted by certain arthropods and it has also been described as present in soyasauce. It was synthesized as follows: reaction of propanal with the Grignard derivative of 1,1‐diethoxy‐2‐propyne to give 1,1‐diethoxy‐4‐hydroxy‐2‐hexyne, and reduction of the acetylenic bond with sodium in liquid ammonia to 1, 1‐diethoxy‐4‐hydroxy‐2trans‐hexene; oxidation with active manganese dioxide and acid hydrolysis gave the title compound in 96% purity (GLC). This synthesis offers a useful alternative to that described in the literature, which gives a mixture of the cis and trans isomers.
C‐Nitroso compounds: Part. XI. Trans‐azodioxycyclohexane (dimeric nitrosocyclohexane) by photochemical nitrosation of cyclohexane with alkyl nitrites
Authors: Mackor A. , Veenland J. U. , de Boer Th. J. 
Published: September 2010

AbstractThe photonitrosation of cyclohexane by tertiary butyl nitrite has been studied as a model system for the photochemical reaction between alkyl nitrites and hydrocarbons. The products are trans‐azodioxycyclohexane (trans‐dimeric nitrosocyclohexane) and a minor amount of cyclohexanone oxime, together in 81 % yield.Most of the trans‐dimer is formed via the cis‐dimer, which can be isolated at low temperature. It is shown that optimal conditions for this reaction involve the use of a tertiary alkyl nitrite in low concentration, wavelengths around 400 nm and temperatures slightly below room temperature.The free radical mechanism of this reaction is supported by electron spin resonance spectroscopy.
Synthesis of methyl DL‐13‐hydroxy‐9cis‐octadecenoate and methyl DL‐19‐hydroxy‐allcis‐8,11,14‐eicosatrienoate
Authors: Ward J. P. , van Dorp D. A. 
Published: September 2010

AbstractWhen methyl vernolate was treated with BF3 etherate in benzene and the reaction product chromatographed on silica gel, the first eluted product contained methyl 13‐oxo‐9cis‐octadecenoate, contaminated with some dimers and polymers. Reduction with NaBH4 and re‐chromatography produced pure methyl DL‐13‐hydroxy‐9cis‐octadecenoate.Methyl DL‐19‐hydroxy‐all cis‐8,11,14‐eicosatrienoate was prepared by extension of the carbon chain of 5‐chloro‐2‐pentanone, as acetal, by two 2‐propynyl units to 10‐oxo‐2,5‐undecadiynol. The corresponding bromo‐compound was acetalized and coupled with the di(bromomagnesium) derivative of 8‐nonynoic acid. Methyl 19‐oxo‐8,11,14‐eicosatriynoate was hydrogenated with Lindlar's catalyst and the oxo‐trienoate obtained was reduced with sodium borohydride. The disproportionation of 2‐(2‐hydroxyethoxy)tetrahydrofuran, a by‐product at one stage, is also described.
Isomerization of the bicyclo[5.1.0]octadienyl anion: (Short communication)
Authors: Kloosterziel H. , Zwanenburg E. 
Published: September 2010

AbstractNMR spectroscopy has revealed that the bicyclo[5.1.0]octadienyl anion 2 isomerizes by opening of the three‐membered ring and a 1,2 shift of hydrogen to the 1,6‐methanoheptatrienyl anion 3. The symmetry‐forbidden electrocyclic ring opening of 2 to the cyclo‐octatrienyl anion 5 does not occur. Experiments with cyclo‐octa‐1,3,5‐triene showed that 5 is unstable relative to disproportionation into cyclo‐octatriene and cyclo‐octatetraenyl dianion.
Action of potassium amide on 6‐substituted derivatives of 2‐bromopyridine in liquid ammonia
Authors: Streef J. W. , den Hertog H. J. 
Published: September 2010

AbstractIn continuation of previous studies on the reactions of 2‐bromo‐6‐ethoxy‐, 2‐bromo‐6‐methyl‐ and 2,6‐dibromopyridine with potassium amide in liquid ammonia, aminations of twelve other 2‐bromopyridines substituted at the 6‐position, i.e. 6‐amino‐, 6‐anilino‐, 6‐amidocarbonyl‐, 6‐(N‐methylanilino)‐, 6‐phenyl‐, 6‐(2′‐pyridyl)‐, 6‐phenoxy‐, 6‐(p‐ethoxyphenoxy)‐, 6‐(m‐ethoxy‐phenoxy)‐, 6‐(p‐fluorophenoxy)‐, 6‐chloro‐ and 6‐nitro‐2‐bromopyridine were investigated.The following reaction types were observed:
Substitutions producing 2‐amino derivatives (from all starting substances except 6‐amino‐, 6‐bromo‐, 6‐chloro‐ and 6‐nitro‐2‐bromopyridine).
Cine‐substitutions producing 4‐amino derivatives (from 6‐methyl‐, 6‐ethoxy‐, 6‐phenoxy‐, 6‐(p‐ethoxyphenoxy)‐, 6‐(m‐ethoxyphenoxy)‐ and 6‐(p‐fluorophenoxy)‐2‐bromopyridine).
Ring transformations yielding 6‐substituted 2‐methylpyrimidines by fission of the 3,4‐carbon bond (from 6‐phenyl‐, 6‐(2′‐pyridyl)‐, 6‐phenoxy‐, 6‐(p‐ethoxyphenoxy)‐, 6‐(m‐ethoxyphenoxy)‐, 6‐(p‐fluorophenoxy)‐ and 6‐chloro‐2‐bromopyridine; from 2,6‐dibromopyridine).
Replacement of the 6‐substituent producing the 6‐amino compound (from 2‐bromo‐6‐nitropyridine).
Ring fission yielding 1, 3‐dicyanopropene by cleavage of the N —C6 bond (from 6‐amino‐2‐bromopyridine).
The mechanisms of the reactions studied are discussed. In this connection the aminations of 2,6‐dichloro‐, 2,6‐difluoro‐ and 2‐amino‐6‐fluoropyridine were examined too.
Conformation of non‐aromatic ring compounds: Part 56. The conformational properties of cis‐2‐halogeno‐4‐t‐butylcyclohexanones
Authors: Buys H. R. , Giesen M. T. , Havinga E. 
Published: September 2010

AbstractThe dipole moments and vicinal coupling constants of cis‐2‐bromo‐, cis‐2‐chloro‐ and cis‐2‐fluoro‐4‐t‐butylcyclohexanone have been determined in several solvents, in order to investigate the conformational homogeneity of these compounds. The dipole moments show a small solvent‐dependence, which is not reflected in the coupling constants. The results can be explained satisfactorily on the assumption that in the solutions only the chair form (with an equatorially oriented halogen atom) occurs.
N,N′‐disubstituted‐5,5′‐diamino‐3,3′‐bi‐1,2,4‐oxadiazoles
Authors: Witteveen A. J. , Trompen W. P. , Hackmann J. Th. 
Published: September 2010

AbstractThe preparation of some N,N′‐disubstituted‐5,5′‐diamino‐3,3′‐bi‐1,2,4‐oxadiazoles from dichloroglyoxime diacetate and 1,1,3,3‐tetrasubstituted guanidines is described. Evidence for the structure is given by spectroscopic data and an independent synthesis.
C‐nitroso compounds. Part XIII: Monomeric nitroso compounds by photochemical nitrosation of branched‐chain hydrocarbons with tert‐butyl nitrite
Authors: Mackor A. , de Boer Th. J. 
Published: September 2010

AbstractThe photochemical nitrosation with t‐butyl nitrite of some branched‐chain hydrocarbons, containing tertiary hydrogen atoms leads to the formation of monomeric nitroso compounds in yields up to 78%, when a special Soxhlet technique is employed. The use of wavelengths around 400 nm is essential for this reaction.