bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of salt concentration and counterion on stability of alkali ion-18-crown-6 complexes in aqueous and methanolic solution: A conflicting evidence from potentiometric and sodium-23 NMR studies
Authors: Závada Jiří , Pechanec Václav , Zajíček Jaroslav , Stibor Ivan , Vítek Antonín
Published: September 2010

Contrary to expectation, the title effects observed concurrently by potentiometry with ion-selective electrode and by sodium-23 NMR spectroscopy are completely different. The potentiometric stability constants for the sodium ion-18-crown-6 complex (KISE) exhibit a very pronounced variation with the counterion, KISENaSCN > KISENaCl > KISENaOH, as well as with the sodium salt concentration, the KISENaSCN/KISENaOH ratio being about 1.5, 2.0, 5.0 and 20 in the 0.01, 0.1, 0.5 and 1.0 mol l-1 aqueous and about 2.0, 12, 600 and 2 500 in the 0.01, 0.1, 0.5 and 1.0 mol l-1 methanolic solution, respectively. Whereas, the corresponding spectroscopic stability constants, KNMR, are virtually insensitive to the changes of counterion as well as to the salt concentration the overall spread of the KNMR values being less than 3. Resolution for the conflicting evidence is provided in terms of the activity coefficients γML+, γM+, γL differentiating between the concentration (Kconc) and thermodynamic (Kth) stability constants in the relation Kconc = (γM+ γL : γML+) Kth. At variance with the current opinion it is shown that only KISE are clean concentration constants subjected to the γML+/γM+ γL variation, while KNMR are hybrids between the concentration and thermodynamic constant leaning assumedly to the latter (Kth). Concerning the powerful effect of counterion and salt concentration of KISE, it is attributed to a large variation of γML+. No satisfactory explanation can be, however, offered in customary terms of the Debye-Hückel theory.
Syntheses of piperazines substituted on the nitrogen atoms with allyl, propyl, 2-hydroxypropyl and 3-hydroxypropyl groups
Authors: Kafka Stanislav , Čermák Jan , Novák Tomáš , Pudil František , Víden Ivan , Ferles Miloslav
Published: September 2010

The paper describes synthesis of 1,4-diallylpiperazine (I), 1-allylpiperazine (III), 1-propylpiperazine (IV), 1-(1-piperazinyl)-2-propanol (V), 3-(1-piperazinyl)-1-propanol (VI), 1-allyl-4-propylpiperazine (VII), 1-(4-allyl-1-piperazinyl)-2-propanol (VIII), 3-(4-allyl-1-piperazinyl)-1-propanol (IX), 1,4-dipropylpiperazine (X), 1-(4-propyl-1-piperazinyl)-2-propanol (XI), 3-(4-propyl-1-piperazinyl)-1-propanol (XII), 1,4-bis(2-hydroxypropyl)piperazine (XIII), 3-[4-(2-hydroxypropyl)-1-piperazinyl]-1-propanol (XIV) and 1,4-bis(3-hydroxypropyl)piperazine (XV). Retention indices of I-XV reported and mass spectra of the compounds are discussed.
Isomerization of binor S
Authors: Kafka Zdeněk , Vodička Luděk
Published: September 2010

The isomerization of norbornadiene dimer, heptacyclo[8,4,0,02,12, 03,8,04,6,05,9,011,13]tetradecane (binor S), was studied in the presence of various catalysts. The isomerization resulted in a mixture of hexacyclic olefins (hexacyclo[8,4,0,02,7,03,14,04,8,09,13]tetradec-5-ene and hexacyclo[6,6,0,02,6,05,14,07,12,09,13]tetradec-3-ene), which is an important intermediate product in the five-stage synthesis of triamantane.
Synthesis of some allylic acetoxy derivatives in the steroid series
Authors: Starý Ivo , Kočovský Pavel
Published: September 2010

A synthesis is reported of 1,2- and 5,6-unsaturated cholestane derivatives bearing an acetoxy group in allylic position (i.e. 3 and 7) and containing further functional groups. A simple strategy for synthesis of 3α-substituted 5-cholestenes is devised.
Reduction of 12-oxo derivatives of some bile acids
Authors: Míčková Růžena
Published: September 2010

Methyl ester of 3α-acetoxy-12-oxo-9 (11)-cholenic acid and some other analogous compounds were reduced to the corresponding 9(11)-unsaturated 12-hydroxy derivatives by the action of sodium borohydride in the presence of cerium(III) chloride. A part of our work, viz. preparation of steroid hormones from bile acids, was the reduction of 9(11)-unsaturated 12-oxo derivatives of some bile acids, with the view of obtaining the corresponding 9(11)-unsaturated 12-hydroxy derivatives. Hitherto, the only safe route has been hydrogenation of the starting 9(11)-unsaturated 12-oxo derivatives on platinum at elevated pressures, which, preserving the allyl double bond, yields a mixture of the two isomeric 12-hydroxy derivatives.
Isolation and partial characterization of bovine liver aminopeptidase B
Authors: Blahovec Ján , Bartík Michal , Kasafírek Evžen
Published: September 2010

Aminopeptidase B, specifically hydrolyzing the L-lysine and L-arginine derivatives of p-nitroaniline and β-naphthylamine, was isolated from bovine liver. A multistep purification procedure involving fractionation with ammonium sulfate, gel filtration on Sephadex, ion exchange chromatography on Ecteola-cellulose, and adsorption chromatography on hydroxylapatite, afforded an enzyme whose activity was approximately 240 times higher than the activity of the original material. The molecular weight of the enzyme determined by gel filtration on Sephadex G-200 was approximately 55 000. The Michaelis constant with respect to L-lysyl-p-nitroanilide was 1.2 . 10-3 mol/l.
Effect of activation temperature on acidity of alumina, silica-alumina and cobalt-molybdenum-alumina catalysts
Authors: Vít Zdeněk
Published: September 2010

The effect of surface dehydration on the acidity of silica-alumina and cobalt-molybdenum-alumina catalysts has been studied and compared with alumina. The catalysts were characterized by surface hydroxyl groups concentrations, acid sites concentrations and by catalytic activities in paraldehyde depolymerisation and cumene cracking. It was found that the acidity of alumina and cobalt-molybdenum-alumina catalysts increases significantly with surface dehydration and attains maximum after activation at 500-550 °C. Silica-alumina is strongly acidic even in the hydrated state, the acidity being formed already at relatively low temperature around 100 °C.
Rhodium(I) catalyzed E/Z isomerization of dimethyl butenedioate
Authors: Podlaha Jaroslav , Procházka Miloš
Published: September 2010

Hydride complexes of Rh(I) represent highly effective homogeneous catalysts of the isomerization of (Z)-dimethyl butenedioate (I) yielding (E)-dimethyl butenedioate (II) in benzene at 25 °C. The reaction catalyzed by RhH(P(C6H5)3)4 is first order both in I and in the catalyst, k = 0.51 l mol-1 s-1, Ea = 48 kJ mol-1, ΔS≠ = -46 J mol-1 K-1. At high substrate-to-catalyst ratios the catalyst is inactivated, which consists mainly in deoxygenation and decarbonylation of the E- and Z-esters with formation of methyl 2-butenoate, triphenylphosphine oxide, and carbonylocomplexes of Rh(I). Statistical redistribution of deuterium during the isomerization of equimolar mixture of I and [2,3-2H2]-I and other experimental evidence are consistent with the addition-elimination hydride mechanism of the isomerization involving σ-alkyl rhodium complexes as the intermediates and RhH(P(C6H5)3)2 as the catalytically active species.
Fluorescence properties of some isoquinoline alkaloids
Authors: Kovář Jan , Šimek Karel , Kožoušková Eva , Klukanová Hana , Slavík Jiří
Published: September 2010

The fluorescence properties of 28 isoquinoline alkaloids have been investigated. In most of them the chromophore responsible for fluorescence was the benzene ring with electron-donor substituents containing oxygen. The long-wave excitation peak practically coincides with the long-wave absorption peak of these substances, covering the region from 284 to 293 nm, the maximum emission being in the range 320-332 nm. With alkaloids having a number of conjugated rings, both excitation and emission were observed at higher wavelengths. Only protoberberine alkaloids behaved as hydrophobic probes, i.e. transfer of these compounds into a less polar medium produced a marked hypsochromic shift and a higher intensity of emission. The effect of polarity on the behaviour of tetrahydroprotoberberines, protopines, pavinanes, aporphines and benzophenanthridines was not so pronounced. Changes of pH manifested themselves most markedly in compounds with dissociable hydroxyl groups; the majority of phenolates did not fluoresce.The phenol group pK values of these compounds in the excited state were lower than in the ground state (which ranged between 8.4 and 10.4). The relations between the apparent pK, determined from fluorescence data, and the pK's of these compounds in the ground and the excited states are discussed.
Interaction of ditertiary phosphines with phenyl- and 1-naphthyldithiocarbamatonickel(II)
Authors: Aly Aref A. M. , Mohamed Ahmed A. , Mousa Mahmoud A. , El-Shabasy Mohamed
Published: September 2010

The synthesis of the following mixed ligand complexes is reported: [Ni(phdtc)2(dpm)2], [Ni(phdtc)2(dpe)2], [Ni(phdtc)2(dpp)3], [Ni(1-naphdtc)2(dpm)2], [Ni(1-naphdtc)2], and [Ni(1-naphdtc)2(dpp)2], where phdtc = PhNHCSS-, 1-naphdtc = 1-NaPhNHCSS-, dpm = Ph2PCH2PPh2, dpe = Ph2P(CH2)2PPh2, and dpp = Ph2P(CH2)3PPh2. The complexes are characterised by microanalysis, IR and UV-Vis spectra, magnetic measurements, conductivity, X-ray powder diffraction, and thermal analysis. All the mixed ligand complexes are diamagnetic, and thus a square-planar or square-pyramidal (low-spin) structure was proposed for the present complexes.
4,5-Secoandrostanes by Eschenmoser's reaction
Authors: Kasal Alexander , Kohout Ladislav , Filip Jiří
Published: September 2010

17β-Benzoyloxy-4,5-secoandrost-3-yn-5-one (V), accessible from testosterone in three steps, can be converted both to Δ5-unsaturated alkynes of the type XXV (via axial hydroxy derivative XVII) and to alkynes of the type XXVI (by hydrogenolysis of equatorial methanesulfonate XXIII). These compounds were hydrated and hydrolysed to 17β-hydroxy-4,5-secoandrost-5-en-3-one and 17β-hydroxy-4,5-secoandrostan-3-one (XXX and I respectively). Catalytic hydrogenation of compound XXX with tritium afforded [5,6-3H2]-derivative XXXI.
Synthesis and reactions of trimethylammonium salts of ethylene derivatives of furan
Authors: Végh Daniel , Kríž Miroslav , Kováč Jaroslav , Fulierová Anna , Kada Rudolf
Published: September 2010

The paper deals with direct quaternization of trimethylamine with 5-bromo-2-furylethylene derivatives Ia-Ig which contain strong electron acceptor substituents. New variants are described of the synthesis of 5-N,N-dimethylamino-2-furylethylene compounds III and 5-azido-2-furylethylene derivatives IV.
A study of the mechanism of decay of allyl macroradicals in crosslinked polyethylene
Authors: Bartoš Josef , Klimová Marta , Szöcs František
Published: September 2010

Free radicals were generated in peroxide-crosslinked polyethylene with different gel fraction contents by exposition to a gamma dose of 20 kGy at 293 K. The decay of allyl macroradicals was examined by the ESR method in dependence on the crosslinking concentration. The rate constants of the allyl radical decay decreased with increasing gel content of the samples, and the activation energies, determined from the temperature dependences of the rate constants, increased with increasing extent of crosslinking. The results are discussed from the energy aspect of the conformational motions dominating in the temperature region used and controlling the allyl radical decay in crosslinked polyethylene.
Butaclamol-like neuroleptic agents: Synthesis of 1-(11H-dibenz[b,f]-1,4-oxathiepin-11-yl)methyl-4-isobutylpiperidin-4-ol and of some related compounds
Authors: Šindelář Karel , Holubek Jiří , Svátek Emil , Ryska Miroslav , Valchář Martin , Protiva Miroslav
Published: September 2010

1-(11H-Dibenz[b,f]-1,4-oxathiepin-11-yl)methyl-4-piperidone (XIII), which was obtained from 11H-dibenz[b,f]-1,4-oxathiepin-11-carboxylic acid (VIII) in four steps, was treated with isobutylmagnesium bromide and gave the title compound V in addition to the prevailing quantity of the secondary alcohol VI, i.e. the product of reduction. Synthesis of a series of trisubstituted benzyl phenyl sulfide derivatives XVIII-XXIV, XXVI-XXXI is described; these compounds are potential intermediates in the preparation of 11H-dibenz[b,f]-1,4-oxathiepinacetic acids XVI and XVII. Chloromethylation of 11H-dibenz[b,f]-1,4-oxathiepin (VII) and two further usual steps gave an acid to which structure XVI is assigned. Compound V is an open model of "oxathiaisobutaclamol" and in agreement with this fact it behaves like a neuroleptic agent: it increases the turnover and metabolism of dopamine in the rat brain striatum which is manifested by a significant rise of homovanillic acid level.
Synthesis of several compounds related to 1-(4-methylsulfonylphenacyl)-4-phenylpiperazine and their pharmacological screening
Authors: Vejdělek Zdeněk , Bártl Václav , Svátek Emil , Protiva Miroslav
Published: September 2010

The title compound I was transformed to its oxime II, hydrazone III and semicarbazone IV. 1-(4-Methylsulfonylphenyl)-2-(4-phenylpiperazino)ethanol (V) was esterified by the corresponding acid chlorides in pyridine to give the acetate VI, propionate VII, benzoate VIII, and 4-nitrobenzoate IX. Reactions of 4-(methylsulfonyl)phenacyl bromide, its 4-(ethylsulfonyl), and 4-(2-methylpropylsulfonyl)analogues with diethanolamine afforded instead of the expected substitution products X the hemiacetals XI-XIII, i.e. 2-hydroxy-4-(2-hydroxyethyl)-2-(4-alkylsulfonylphenyl)morpholines. The products were subjected to the pharmacological and microbiological screening; compounds II-IV and VI-IX have more or less the character of tranquillizers, the hemiacetals XI-XIII have some antimicrobial activity in vitro. Compound XIII showed, surprisingly, a positively inotropic effect, and its methiodide XIV a peripheral myorelaxant effect.
An improved synthesis of S-adenosyl-L-homocysteine and related compounds
Authors: Holý Antonín , Rosenberg Ivan
Published: September 2010

5'-Chloro-5'-deoxy-2',3'-O-isopropylideneadenosine reacts with disodium salts of L-homocysteine, L-cysteine or 3-mercaptopropanoic acid in liquid ammonia to afford 2',3'-O-isopropylidene derivatives which are easily desalted by chromatography on octadecyl-silica column. On acid treatment, the high purity preparations of S-adenosyl-L-homocysteine, S-adenosyl-L-cysteine, and 5'-carboxyethylthio-5'-deoxyadenosine are obtained in respectable yields.
CO2 laser photosensitized dehydrobromination of bromoethane and 1-bromopropane. A hot-tube radical-chain reaction with molecular mechanism
Authors: Kubát Pavel , Pola Josef
Published: September 2010

Contrary to the gas-phase hot-tube reaction taking place by a blend of a molecular and radical-chain mechanism, the cw CO2 laser induced dehydrobromination of bromoethane and 1-bromopropane occurs by only a molecular mechanism which is substantiated with reaction rates and products in the absence and the presence of radical-chain inhibitor (propene) and in the presence of chloroethane. The results point out the importance of hot walls for the initiation of radical-chain dehydrobromination.
Stability of molecular aggregates of hydrocarbons with all-trans chains and translation of the molecules
Authors: Gajdoš Ján , Bleha Tomáš
Published: September 2010

Potential energy has been calculated for molecular aggregates formed of all-trans extended hexanes with various arrangements of the central molecule surrounded by the first coordination sphere. Differences in stabilities of the aggregates are connected with biaxial character of asymmetry of the interaction energy of extended paraffins. When investigating the multiparameter interaction potential of the partially ordered systems of hydrocarbon chains, the first step consisted in determination of the energy barriers to longitudinal shifts of the central molecules at various distances of the surrounding molecules. Destabilization of the aggregates with displaced molecules is due to both the mismatch of the central molecule to the matrix and effective shortening of that part of the central molecule which is "immersed" in the aggregate. The energetics of the model aggregates is made use of in elucidating the role of translation of paraffins and cognate molecules in rotational phase, in mesophases, and at a forced shortening of the chains connected with conformational transition.
Stereochemical changes accompanying acid decarboxylation of the Λ-[Co((S)-valinato)2CO3]- isomers
Authors: Jursík František , Ondráčková Jana , Hájek Bohumil
Published: September 2010

Λ-trans(O)-[Co((S)-Val)2CO3]- (Val = valine) reacts with 1M-HNO3) (3 min, 28 °C) to form 90% trans(O) and 10% cis(N)-[Co((S)-Val)2(H2O)2]+. Addition of solid KHCO3 to the reaction mixture containing diaquo species gives 96% (95% Λ) trans(O)- and 4% (56% Λ) C1-cis(N)-[Co((S)-Val)2CO3]- isomers indicating decarboxylation of trans(O) isomer proceeds without change in configuration. Acid decarboxylation of Λ-C1-cis(N)-[Co((S)-Val)2CO3]- leads to the mixture consisting from 65% of cis(N)- and 35% of trans(O)-[Co((S)-Val)2(H2O)2]+. When this reaction mixture is treated with solid KHCO, 61% (92% Λ) of C1-cis(N)- and 39% (95% Λ) of -trans(O)-[Co((S)-Val)2CO3]- isomers are formed. Results show that stereochemistry of acid decarboxylation products depends on the starting isomer geometry suggesting steric and electronic factors contribute to isomer proportions.
The crystal and electron structure of N-(2,2,2-trichloro-1-morpholino-ethyl) formamide
Authors: Vrábel Viktor , Pavelčík František , Kellö Eleonóra , Miertuš Stanislav , Konečný Václav , Lokaj Jan
Published: September 2010

The crystal structure was solved by direct methods and refined by the least squares method in a 9 x 9 block diagonal approximation using the anisotropic temperature parameters. The R-factor was decreased to a final value of 5.6% for 970 observed reflextions. The crystals are monoclinic with a space group of P21/c and lattice parameters of a = 1.1056(11), b = 0.8913(11), c = 1.2023(16) nm, β = 96.32°, and Z = 4. The crystal structure consists of discrete molecules between which hydrogen interactions of the N-H...O and C-H...O type were observed. The lengths of the N1-C3 (0.1432 nm) and C3-O1 (0.1203 nm) bonds and valence angles, C3-N1-C1 (119.9°), N1-C3-O1 (126.5°), indicate considerable delocalization of the π-electrons and participation of the lone electrone pair on N1 nitrogen in the conjugation in the N1-C3-O1 molecular fragment. The CNDO/2 quantum chemical method was used to calculate the electron structure. Calculation for partial optimization of the dihedral angles, φ and ω, indicated that the most stable form is obtained for the values φ = 0°, ψ = 120-150°, 240-270° and ω = 150-210°, 330-30°.
Possible use of chronopotentiometry at the interface between two immiscible liquid phases to the studies of homogeneous chemical reactions
Authors: Makrlík Emanuel
Published: September 2010

The theoretical potential-time dependence corresponding to the electron transfer reaction proceeding at the interface between two immiscible liquid phases with the redox pairs O1/R1 in the aqueous (aq) phase and O2/R2 in the non-aqueous (non) phase, that is complicated by the reaction R1(aq) + Z(aq) → O1(aq) in the aqueous phase, has been derived under the galvanostatic conditions. Moreover, a method for the determination of the formal rate constant kf for the given homogeneous chemical reaction is proposed.
A study of decay mechanism of alkyl macroradicals in polyisobutylene
Authors: Bartoš Josef
Published: September 2010

The macroradicals generated in polyisobutylene by γ-radiolysis at 77 K have been studied from the point of view of their structure and reactivity with the use of the ESR method and various kinetic models. In the region of 223-243 K a single type of macroradicals is only present, ~C(CH3)2CHC(CH2)2~, these radicals being decayed according to the second order kinetics with effective activation energy of 77.5 kJ mol-1. This result was interpreted within the model of diffusion-controlled reactions using the activation energy approach. Various potential mechanisms of transport of the centres have been tested on the molecular level. Approach of the reactants is controlled by intermolecular hydrogen transfer connected with quasi-crankshaft motions of the chain segments, and at suitable conditions, especially at early stages of the decay, it is possible also to consider a physical mechanism of approach of near-standing reactants with participation of crankshaft motions of the chain segments.
Addition of primary alcohols to 3-chlorononafluoro-1,5-hexadiene and perfluoro-1,3,5-hexatriene
Authors: Dědek Václav , Linhart Igor , Kováč Milan
Published: September 2010

Sodium alkoxide-catalyzed addition of methanol, ethanol and propanol to 3-chlorononafluoro-1,5-hexadiene (I) proceeds at temperatures -35 °C to 8 °C with allyl rearrangement, affording 1,6-dialkoxy-1,1,2,3,4,4,5,6,6-octafluoro-2,4-hexadiene (V) as the principal product, along with 1,6-dialkoxy-1,2,3,3,4,5,6,6-octafluoro-1,5-diene (VI) and trans-1,6-dialkoxy-1,1,2,3,4,4,5,6,6-nonafluoro-2-hexene (VII). The ethers Va-Vc consist of the cis,trans- and trans,trans-isomers in about 3 : 1 ratio, whereas the ethers VIa-VIc have trans,trans-configuration. Ethers Vc and VIc react with concentrated sulfuric acid to give dipropyl 2,3,4,5-tetrafluoro-2,4-hexadienedioate (IX) and dipropyl 2,3,4,4,5-pentafluoro-2-hexenedioate (X), respectively, whereas the ether VIIc affords a mixture of propyl 6-propyloxy-2,3,4,4,5,6-heptafluoro-2-hexenoate (XI) and ester X. Addition of methanol to perfluoro-1,3,5-hexatriene (II) affords 1,1,2,3,4,5,6,6-octafluoro-1,6-dimethoxy-3-hexene (XIII) as the principal product.
Reaction of 3-chlorononafluoro-1,5-hexadiene with diethylamine
Authors: Linhart Igor , Trška Petr , Dědek Václav
Published: September 2010

Reaction of diethylamine with 3-chlorononafluoro-1,5-hexadieae (I) in molar ratio of 1.5 : 1 to 2 : 1 at -30 to -17 °C gives N,N-diethyl-1,1,2,3,4,4,5,6,6-nonafluoro-2,5-hexadienylamine (II) which is easily hydrolyzed to N,N-diethyl-2,3,4,4,5,6,6-heptafluoro-2,5-hexadienamide (III). The same reaction with the molar ratio 4 : 1 at 0-6 °C and at 40 °C produces a mixture of N,N,N',N'-tetraethyl-1,1,2,3,4,5,6,6-octafluoro-2,4-hexadiene-1,6-diamine (IV), N,N,N',N'-tetraethyl-1,1,2,3,4,4,5,6,6-nonafluoro-2-hexene-1,6-diamine (V), and N,N,N',N'-tetraethyl-1,2,3,3,4,5,6,6-octafluoro-1,4-hexadiene-1,6-diamine (VI), which on hydrolysis gives N,N,N',N'-tetraethyl-2,3,4,5-tetrafluoro-2,4-hexadienediamide (VII) and N,N,N',N'-tetraethyl-2,3,4,4,5-pentafluoro-2-hexenediamide (VIII). Reaction of the mixture of diamines IV-VI with methanol or 1-propanol gives dimethyl or dipropyl 2,3,4,5-tetrafluoro-2,4-hexadienedioate (Xa,b), respectively. Stereospecificity of the chlorine substitution in perfluoroallyl grouping and the reaction mechanism are discussed. Conformation of the butadiene skeleton of these compounds is also discussed on the basis of calculation of 19F NMR spectra of trans,trans-2,3,4,5-tetrafluoro-2,4-hexadienedioic acid (IX) and its dimethyl ester Xa.
The crystal and molecular structure of 3-N-pyridylsydnone
Authors: Hašek Jindřich , Beurskens Paul T. , Obrda Jiří , Nešpůrek Stanislav , Schenk Hendrik , Goubitz Kees , Huml Karel , Schagen Jan Dirk
Published: September 2010

The title compound studied for its photochromic properties crystallizes in the monoclinic system, the space group P2/c, a = 734.3(6), b = 933.3(8), c = 2 334(2) pm, β = 117.71(5)°, V = 1.416(2) nm3, Z = 8, measured and calculated density Dm = 1.51, Dx = 1.53 Mg m-3, λ(CuKα) = 154.178 pm, μ = 1.0 mm-1, F(000) = 672, Mr= 163.14, T = 296 K. Final R = 0.084 for 1 511 significant (I > 1.96σI) reflections. The molecules are roughly parallel with the (100) plane and are stacked so that the sydnone ring of the first independent molecule partly overlaps the pyridyl ring of the second independent molecule. This results in the infinite column of partly overlaping pyridyl and sydnone rings in distances 344(4) and 335(4) pm, parallel with the a axis. Symmetrically independent molecules simulate pseudo 21 axis.
Kinetics of dehydration of 1-butanol over zeolites
Authors: Olaofe O. , Yue P. L.
Published: September 2010

The kinetics of catalytic dehydration of 1-butanol have been studied on three commercial types of zeolites varied in cage structures, pore sizes, and acidity at 200 - 300 °C. The dehydration reactions were performed in a continuous stirred gas-solid reactor. Butenes and dibutyl ether were the principal products. Both simple power-law and Hougen-Watson types of rate expressions have been used to model the dehydration reactions kinetics. The former satisfactorily correlates the kinetic data procured over all the zeolites except in the case of dibutyl ether formation over ZNa. The Hougen-Watson type of rate expression adequately fitted the rate of formation of both products. The reaction orders with respect to 1-butanol were approximately equal to zero. The kinetic and adsorption parameters were evaluated and satisfactorily correlated as functions of reaction temperature. Activation energies for the formation of dibutyl ether over zeolites ZNa and 4A are affected by pore diffusion.
Analysis of hydroformylation products of higher n-alkenes by capillary gas chromatography
Authors: Krupčík Ján , Repka Dušan
Published: September 2010

A mixture of alcohols obtained by hydroformylation of C10-C13 n-alkenes was analyzed by capillary gas chromatography using Carbowax 20M stationary phase, and acetates prepared from the alcohols were analyzed on capillary columns using Carbowax 20M and Apiezon L stationary phases. The capillary gas chromatography and gas chromatography-mass spectrometry treatment gave evidence that all of the 24 alcohols that could form by the hydroformylation reaction mechanism were present.
A study of the reaction of copper(II) ions in hydrated y zeolite with sodium 8-mercaptoquinolinate and 8-hydroxyquinolinate
Authors: Plesch Gustáv
Published: September 2010

The reaction of Cu2+ ions from Y zeolite cavities with sodium 8-mercaptoquinolinate (tox) or 8-hydroxyquinolinate (ox) was studied in aqueous solutions by EPR and electronic absorption spectroscopy, X-ray powder diffraction measurements, and scanning electron microscopy. The Cu2+ ions migrate towards the support surface to form [Cu(tox)2] or [Cu(ox)2(H2O)2] complex crystals. Owing to the low solubility of the complex, grains of the [Cu(tox)2] crystallites gradually grow over the support surface. Better soluble than [Cu(tox)2], the [Cu(ox)2(H2O)2] complex crystallizes separately from the carrier in the form of long needles.
13C NMR spectra of sodium naphthalenesulphonates
Authors: Šnobl Dobroslav , Lyčka Antonín , Horyna Jaroslav
Published: September 2010

13C NMR spectra of thirteen sodium naphthalenesulphonates have been measured in deuterium oxide. The 13C chemical shifts have been assigned, and the nJ(13CH) coupling constants have been measured. Effect of SO3(-) group on the 13C NMR parameters is discussed.
Cyclocondensation reactions of 3-aryl-2-benzylidene-3-oxopropanenitriles with acetylaromatic derivatives
Authors: Marchalín Štefan , Kuthan Josef
Published: September 2010

Cyclocondensation of 3-aryl-2-benzylidene-3-oxopropanenitriles Ia and Ib with acetyl aromatic derivatives IIa-IIc in the presence of ammonium acetate affords 2,6-diaryl-4-phenyl-3-cyanopyridines IV and V. Reaction of the nitrile Ib with 1,2-diphenylethanone (III) gave 2-(4-biphenylyl)-4,5,6-triphenyl-3-cyanopyridine (VI). The relation between the structure of the synthesized pyridine derivatives IV-VI and their spectral properties is discussed.
Synthesis of cyano derivatives with diazaquaterphenyl skeleton
Authors: Marchalín Štefan , Kuthan Josef
Published: September 2010

Cyclocondensation of 3-aryl-2-arylmethylene-3-oxopropanenitriles I with 4,4'-diacetylbiphenyl (II) in the presence of ammonium acetate gives para-substituted 4''-acetyl-3,5-diphenyl-2-aza-1:1',4':1''-terphenyls III and 4,4'''-dicyano-3,3''',5,5'''-tetraphenyl-2,2'''-diaza-1:1',4':1'',4'':1'''-quaterphenyls IV. Analogous reaction of the acetyl derivative IIIe with the oxonitriles Ie and Ia afforded the corresponding products IVe and V.
Cyclic amidines derived from benz[c,d]indole and 4,5-dihydro-3H-1-benzazepine including some related compounds: Synthesis and pharmacological screening
Authors: Protiva Miroslav , Šedivý Zdeněk , Holubek Jiří , Svátek Emil , Němec Jiří
Published: September 2010

Reactions of naphthostyril (I) with primary and secondary amines and titanium tetrachloride afforded cyclic amidines III-IX. Hydrogenation of I on Pd-C resulted in the 6,7,8,8a-tetrahydro derivative X which gave by treatment with sodium amide and 3-dimethylaminopropyl chloride the N-(aminoalkyl) compound XI. Reduction of I and its N-methyl derivative II with sodium amalgam in aqueous sodium hydroxide gave the 2a,3,4,5-tetrahydro derivatives XII and XIII. Reaction of XIII with sodium amide and 3-dimethylaminopropyl chloride afforded the 2a-(aminoalkyl) compound XIV. 1,3,4,5-Tetrahydro-1-benzazepin-2-one (XV) treated with primary amines and titanium tetrachloride gave the amidines XVI-XVIII. 3-Methyl-7,8,9,9a-tetrahydro-1H-benz[d,e]isoquinoline (XIX) was reduced with sodium borohydride to compound XX which was alkylated with propargyl bromide to 1-methyl-2-propargyl-2,3,3a,4,5,6-hexahydro-1H-benz[d,e]isoquinoline (XXI). An attempt to prepare the 2-(2-phenylethyl) analogue by treatment of compound XX with phenylacetyl chloride and by the following reduction with lithium aluminium hydride resulted in the open-chain amine XXII. The lactams I, II, X, and XIII showed some discoordinating, hypothermic, peripheral vasodilating, hyperglycaemic, diuretic and antiinflammatory effects. The amidines III-IX and XVI-XVIII had local anaesthetic, slight hypotensive, antiarrhythmic, peripheral myorelaxant, papaverine-like spasmolytic and thiopental potentiating effects.
A study of the medium effect of mixed solvents; The cyclohexane-acetone system
Authors: Bekárek Vojtěch , Nevěčná Taťjana
Published: September 2010

Wavenumbers of the S-O bond valence vibration of dimethyl sulphoxide, wavenumbers of the longest wavelength band maxima of 3-nitro-N,N-dimethylaniline and 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenoxide and rate constants of the reaction of triethylamine with ethyl iodide measured in mixtures of cyclohexane and acetone were correlated with functions of relative permittivity and refractive index of these media and mutually with each other.
Cleavage of 3,3,4-trifluoro-2,2-dimethyloxetane by mineral acids
Authors: Dědek Václav , Veselý Ivan
Published: September 2010

Cleavage of 3,3,4-trifluoro-2,2-dimethyloxetane (I) in an aqueous solution of sulphuric acid, phosphoric acid, hydrogen chloride, or hydrogen bromide gave a mixture of 2,2-difluoro-3-methyl-3-butenal (II) and 5,5-difluoro-2-(1,1-difluoro-2-hydroxy-2-methylpropyl)-4-hydroxy-6,6-dimethyl-1,3-dioxane (VIa); in the cleavage effected by hydrochloric or hydrobromic acid the mixture also contained 3-chloro- or 3-bromo-2,2-difluoro-3-methyl-1,1-butanediol (Vb or Vc). In alcoholic solutions of the mineral acids the cleavage afforded the corresponding acetals of butenal II and 2,2-difluoro-3-hydroxy-3-methylbutanal (IIIa). The action of sulphuric acid in the presence of acetyl chloride or acetanhydride led to 1-chloro-2,2-difluoro-3-methyl-3-butenyl acetate (IVd) or 2,2-difluoro-3-methyl-3-butenylidene diacetate (IVe), as the main product. Butenal II was a sole product of the cleavage of oxetane I by polyphosphoric acid at 150-160 °C in the gaseous phase. At temperatures above 180 °C there were also formed (in addition to butenal II) 1,1,5,5-tetrafluoro-2,6-dimethyl-1,6-heptadiene-4-ol (IX) and its formate (X).
Synthesis of 3,5-dicyano-4-phenyl-2,6-bis(4-p-terphenylyl)-1,4-dihydropyridine. An attempt at extending the Hantzsch synthesis
Authors: Marchalín Štefan , Kuthan Josef
Published: September 2010

The 3-oxopropanenitrile IIIc, prepared from 4-acetyl-p-terphenyl (IV) by the sequence IV → V → VI → IIIc, reacts with benzaldehyde and ammonium acetate in acetic acid to give the Hantzsch 1,4-dihydropyridine VIIc and the corresponding pyridine derivative VIIIc. The alternative cyclocondensation of benzylidene derivative IIc and 3-oxopropanenitrile IIIc in the presence of ammonium acetate exclusively gives the pyridine derivative VIIIc. Rate of thermal and oxidative aromatizations of the 1,4-dihydropyridine derivatives, VIIa → VIIc → VIIIa → VIIIc, decreases in the order VIIc > VIIb > VIIa. Mechanism of these transformations and spectral characteristics of compounds VIIc and VIIIc are discussed with regard to their molecular structure.
Photo-induced rearrangement of isoxazolines - A pathway to 2,4,5,8-tetrahydro-1,3-dioxa-5-azocine derivatives
Authors: Fišera Lubor , Oremus Vladimír , Štibrányi Ladislav , Timpe Hans-Joachim , Máťušová Alena
Published: September 2010

4-R-Substituted-8-X-phenyl-3,5,10-trioxa-9-azabicyclo[3,5,0]dec-8-enes (X = H, 4-CH3, 4-OCH3, 4-Cl, 4-Br, 4-F, 3-NO2, 3-Cl, 3-Br) have been prepared by cycloaddition of substituted benzenenitriloxides with 2-R-substituted 1,3-dioxep-5-enes (R = H, CH3, C6H5). A mixture of the endo and exo adducts is formed, if R is CH3 or C6H5. Their irradiation produces high yields of the title compounds as the single products. High selectivity of the photo-rearrangement is due to resonance stabilization of the biradical with p electrons of the oxygen atom. The quantum yields of the photoreaction vary from 0.02 to 0.04 depending on the substituent X. An unexpected dependence has been found between the quantum yield of the photo-rearrangement and stereochemical arrangement of the 4-R-substituent: exo derivatives exhibit higher values than the endo derivatives. Also different are UV spectra of the endo and exo derivatives. A new synthesis principle is described enabling preparation of (n + 1)-membered heterocycles from n-membered heterocycles.
Reaction of 1,6-anhydro-4-O-benzyl-2-deoxy-2-isothiocyanato-β-D-glucopyranose; Preparation of 2-amino-1,6-anhydro-2,3-dideoxy-2,3-dideoxy-β-D-ribo-hexopyranose
Authors: Elbert Tomáš , Černý Miloslav
Published: September 2010

1,6-Anhydro-4-O-benzyl-2-deoxy-2-isothiocyanato-β-D-glucopyranose (IV), prepared from 2-amino-1,6-anhydro-4-O-benzyl-2-deoxy-β-D-glucopyranose (I) by reaction with carbon disulfide followed by oxidation with iodine, was converted into the 3-O-p-toluenesulfonate VII. This was cyclized to give either the 2,3-epimino derivative X or the thiazoline XII. 2-Acetamido-3-S-acetyl-1,6-anhydro-4-O-benzyl-2-deoxy-3-thio-β-D-glucopyranose (XVI), obtained from compound XII, was desulfurized with Raney nickel to afford 2-acetamido-1,6-anhydro-2,3-dideoxy-β-D-ribo-hexopyranose (XVII). The isothiocyanato group was not affected upon acetylation of compound IV and acetolysis of the 1,6-anhydride bond with acetic anhydride and trifluoroacetic acid.
A contribution to the problem of partial condensation of a binary vapour mixture
Authors: Kolář Václav , Červenka Jan
Published: September 2010

An empirical approach has been proposed to solve the problem of partial condensation of a binary vapour mixture. The approach accounts for the effect of the intensity of cooling on the composition of the streams existing from a partial condenser at constant composition of inlet vapours.
Analysis of the system precipitation reactor-separator. Effect of crystal growth mechanism on the filtration properties of a suspension produced in a continuous reactor
Authors: Söhnel Otakar
Published: September 2010

The filtration properties of a suspension of a sparingly soluble substance produced in a MSMPR (mixed suspension mixed product removal) crystallizer with a mean residence time tz have been studied as a function of the crystal growth mechanism. The slope, n, of the log α vs log tz plot, where α is the specific mass filtration resistance, takes values of 0, 1, and 2 for the mononuclear, diffusion, and screw-dislocation mechanisms, respectively. If solid phase coagulation occurs, n takes values below 2. For the size-dependent growth, n may become greater than 2.
Relationships among structure, reactivity towards thiols and basicity of phenylhydrazonopropanedinitriles
Authors: Šturdík Ernest , Antalík Marián , Sulo Pavol , Baláž Štefan , Ďurčová Edita , Drobnica Ľudovít
Published: September 2010

Data required for characterization of reactivity of ortho-, meta-, and para-substituted derivatives by first and second order rate constants were obtained from spectrophotometric investigation of reaction kinetics of phenylhydrazonopropanedinitriles with model thiols. The reactivity has been found to be linearly dependent on Hammett constants of substituents. Similar dependence revealed the basicity characterized by pKa values determined spectrophotometrically. Whilst reactivity and basicity of meta- and para-substituted derivatives is dependent, ortho-substituted derivatives did not obey any simple relation between reactivity and basicity. This finding is important for utilization of ortho-derivatives of phenylhydrazonopropanedinitrile when studying the uncoupling effect of these substances upon oxidative and photosynthetic phosphorylation.
Synthesis and reactions of β-substituted derivatives of furan
Authors: Jurášek Adolf , Žvak Vladimír , Kováč Jaroslav , Rajniaková Oľga , Štetinová Jarmila
Published: September 2010

The 1,4-cycloaddition reaction of 4-phenyl-1,3-oxazole to 2-propinyl benzoate and dimethyl butinedioate afforded the respective 3-furylmethyl benzoate (I) and 3,4-bis(methoxycarbonyl)furan (II). These compounds served for the synthesis of 3-chloromethylfuran and 3,4-bis(chloromethyl)furan, which afforded via Wittig reaction 3-(β-arylvinyl)furans III (aryl = 5-nitro-2-furyl (IIIa), 5-nitro-2-thienyl (IIIb), 1-methyl-4-nitro-2-pyrrolyl (IIIc), and 4-nitrophenyl (IIIe)) and 3,4-bis(β-arylvinyl)furans IV (aryl = 5-nitrofuryl (IVa), 5-nitro-2-thienyl (IVc), and 4-nitrophenyl (IVd)). According to spectral evidence (1H NMR, IR, UV spectra), compound IIIa and IIIb originated as E isomers, whilst the remaining products are a mixture of E and Z isomers; some couples were succeded to separate.
Design of a continuous flow immobilized-cell reactor for biosynthetical production of L-aspartic acid
Authors: Zahradník Jindřich , Fialová Marie , Škoda Jan , Škodová Helena
Published: September 2010

An experimental study was carried out aimed at establishing a data base for an optimum design of a continuous flow fixed-bed reactor for biotransformation of ammonium fumarate to L-aspartic acid catalyzed by immobilized cells of the strain Escherichia alcalescens dispar group. The experimental program included studies of the effect of reactor geometry, catalytic particle size, and packed bed arrangement on reactor hydrodynamics and on the rate of substrate conversion. An expression for the effective reaction rate was derived including the effect of mass transfer and conditions of the safe conversion-data scale-up were defined. Suggestions for the design of a pilot plant reactor (100 t/year) were formulated and decisive design parameters of such reactor were estimated for several variants of problem formulation.
Infrared spectroscopic study of the YPO4-YCrO4 system
Authors: Muck Alexander , Šantavá Eva , Hájek Bohumil
Published: September 2010

The infrared spectra and powder X-ray diffraction patterns of polycrystalline YPO4-YCrO4 samples are studied from the point of view of their crystal symmetry. Mixed crystals of the D4h19 symmetry are formed over the region of 0-30 mol.% YPO4 in YCrO4. The Td → D2d → D2 or C2v(GS eff) correlation is appropriate for both PO43- and CrO43- anions.
Structures of hexa-O-acetylsucroses formed by deacetylation of sucrose octa-O-acetate
Authors: Čapek Karel , Vydra Tomáš , Ranný Mojmír , Sedmera Petr
Published: September 2010

A fraction corresponding to hexa-O-acetylsucrose was isolated in 34% yield from the reaction mixture after deacetylation of sucrose octa-acetate by aluminium oxide impregnated by potassium carbonate. Its subsequent reaction with p-toluenesulfonyl chloride in pyridine provided crystalline 1',2,3,4,6,6'-hexa-O-acetyl-3',4'-di-O-p-toluenesulfonylsucrose (III). With triphenylphosphine-diethyl azodicarboxylate reagent, 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-D-lyxo-hexulofuranoside (VI) was obtained. Treatment of ditosyl derivative III with sodium methoxide followed by acetylation gave besides the anhydro derivative VI also the anhydro derivative V with ribo configuration. The same reaction carried out with mother liquors after crystallization of ditosyl derivative III yielded in addition to anhydro derivatives V and VI the crystalline 1',2-anhydro(3,4,6-tri-O-acetyl-α-D-glucopyranosyl 6'-O-acetyl-3',4'-anhydro-β-D-ribo-hexulofuranoside) (VII). From these results and the analysis of NMR and mass spectra of the hexa-O-acetylsucrose, it follows that the deacetylation of sucrose octa-acetate is highly regioselective, providing the mixture of 1',2,3,4,6,6'-hexa-O-acetylsucrose (I) and 2,3,4,4',6,6'-hexa-O-acetylsucrose (XIII) with markedly prevailing the former component. The structure of dianhydro derivative VII (except the oxirane ring configuration) was determined by NMR spectroscopy. The configuration of this ring follows from the fact that the treatment of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 6-O-acetyl-3,4-anhydro-1-O-methanesulfonyl-β-D-lyxo-hexulofuranoside (IX) with sodium methoxide followed by acetylation does not give the dianhydro derivative VII. However, this compound is formed from the anhydro derivative V by its partial deacetylation, mesylation, reaction with sodium methoxide, and acetylation.
The density and viscosity of concentrated solutions of silver nitrate in dimethyl sulphoxide
Authors: Kodejš Zdeněk , Špalková Hana , Sláma Ivo
Published: September 2010

Densities and viscosities of silver nitrate-dimethyl sulphoxide solutions have been measured at 5, 25, and 60 °C over the range of salt mole fractions from 0.05 to 0.5. The dependence of viscosity on the salt concentration has been expressed by an empirical equation and compared with analogous dependences obtained for aqueous solutions of silver nitrate and solutions of other salts in dimethyl sulphoxide.
Dipole moments and conformation of α-disulphones. The gauche effect
Authors: Exner Otto , Jehlička Václav
Published: September 2010

The dipole moments of substituted diphenyl disulphones I-III were measured in benzene solution and interpreted by the previously described graphical method. The results suggest an equilibrium of the ap and sc conformations in the ratio 3 : 1, at variance with various empirical rules and theories of the so-called gauche effect. A statistical treatment of X-ray data of various sulphonyl derivatives revealed essentially two preferred conformations: the more stable sc, with a broadened dihedral angle, and the less stable ap.
Preparation of (Z) and (E)-9-dodecenyl acetates
Authors: Körblová Eva , Romaňuk Miroslav
Published: September 2010

The sexual pheromones (Z)-9-dodecenyl acetate (IXa) and (E)-9-dodecenyl acetate (IXb) were synthesized using facile preparation of the acetylenic precursor, 9-decyn-1-ol (IV), from tetrahydrofurfuryl chloride (I). Hydroxyl groups of intermediates in the subsequent steps were protected by the ethoxyethyl group.
Alkaloids from Corydalis solida (L.) SW. mass spectrometry of quaternary benzylisoquinoline alkaloids
Authors: Slavík Jiří , Dolejš Ladislav , Slavíková Leonora
Published: September 2010

From the strongly polar fraction from the tubers of Corydalis solida (L.) SW., a new quaternary alkaloid, (+)-N-methyllaudanidinium iodide, was isolated after conversion to iodides. Mass spectrometric behaviour of this type of quaternary alkaloids is described. In the tubers (0.37% of alkaloids) the main alkaloid component is (+)- and (±)-tetrahydropalmatine; other dominant alkaloids include protopine, (+)-corydaline, allocryptopine, dehydrocorydaline and jatrorrhizine. (±)-Corybulbine, (+)-corypalmine, (-)-isocorypalmine, (-)-scoulerine, (-)-stylopine, corysamine, palmatine, (+)-N-methyllaudanidinium hydroxide, (-)-cis-N-methylcanadinium hydroxide and cis-N-methylstylopinium hydroxide represent minor alkaloids. The last three mentioned were isolated in the form of iodides. Bulbocapnine, coptisine, berberine and columbamine were detected in trace amounts. The main alkaloid of the aerial parts of the plant (0.35% of alkaloids) is berberine, accompanied by coptisine, (-)- and (±)-canadine, (-)-stylopine, isoboldine, protopine, columbamine and (-)-cis-N-methylcanadinium hydroxide (isolated in the form of iodide) as significant components. Among minor alkaloids allocryptopine, (-)-isocorypalmine, (+)-corypalmine, (±)- and (-)-tetrahydropalmatine, corysamine, dehydrothalictricavine, palmatine and cis-N-methylstylopinium hydroxide (as iodide) were isolated and trace amounts of jatrorrhizine and bulbocapnine were detected.
Extraction of three-ion-associative complexes of Nb(V) with polyphenols and 2-(4'-iodophenyl)-3-(4''-nitrophenyl)-5-phenyl tetrazolium chloride
Authors: Alexandrov Alexander , Kostova Stefka , Navrátil Oldřich
Published: September 2010

Article in Russian
Modelling of catalyst pellet deactivation
Authors: Brunovská Alena , Buriánek Ján , Ilavský Ján , Valtýni Ján
Published: September 2010

The diffusion and the shell progressive models of deactivation caused by irreversible chemisorption of a catalytic poison are presented for a single catalyst pellet. The method for solution of the model equations is proposed. The numerical results are compared with experimental data obtained by measuring concentration and temperature changes due to thiophene poisoning in benzene hydrogenation over a nickel-alumina catalyst.
Equation-oriented simulation of technological systems
Authors: Kohlert Wolfgang , Siegismund Barbara , Hartmann Klaus , Vrba Josef
Published: September 2010

The paper presents general notions and methods of the equation-oriented simulation of complex technological systems and introduces a computer-coded simulator of this type.
A polymer analog of DMSO: Interactions of alkali metals picrates with polymers containing bound sulfoxide groups
Authors: Janout Václav , Hrudková Hana , Čefelín Pavel
Published: September 2010

The equilibria of interactions of alkali metals (Li(+), Na(+), K(+)) picrates with a polymer analog of dimethyl sulfoxide derived from crosslinked polystyrene were investigated in an aqueous medium in order to obtain quantitative information on the complex-binding properties of sulfoxide groups covalently bound to the polymer. By using the spectrophotometric analysis, the binding constants and stoichiometry of the complex-forming process were determined as a function of the cation size, the degree of crosslinking of polystyrene, and the degree of its functionalization with sulfoxide groups. The values of the binding constants of alkali picrates reflect the structurally different character of the polymer the more the larger the alkali metal cation. The stoichiometric ligand-cation ratio lies in the range between 6 and 9.
Ground state molecular parameters of phosphine, PH3, from the simultaneous analysis of the high-resolution infrared, microwave and submillimeterwave spectra
Authors: Přádná Soňa , Papoušek Dušan , Kauppinen Jyrki , Belov Sergei P. , Krupnov Andrei F. , Scappini Flavio , Di Lonardo Gianfranco
Published: September 2010

Fourier transform spectra of the ν2 band of PH3 have been remeasured with 0.0045 cm-1 resolution. Ground state combination differences from these data have been fitted simultaneously with the microwave and submillimeterwave data to determine the ground state spectroscopical parameters of PH3 including the parameters of the Δk = ± 3n interactions. The correlation between the latter parameters has been discussed from the point of view of the existence of two equivalent effective rotational operators which are related by a unitary transformation. The ΔJ = 0, +1, ΔK = 0 (A1 ↔ A2, E ↔ E) rotational transitions in the ν2 and ν4 states have been measured for the first time by using a microwave spectrometer and a radiofrequency spectrometer with acoustic detection.