Fused s-triazino heterocycles. XV. 13H-4,6,7,13a,13c-pentaazabenzo[hi]chrysene, 13H-4,7,13a,13c-tetraazabenzo[hi]chrysene,and 7H-3,7,10,10b-tetraazacyclohepta[de]naphthalene,three new ring systems

The reaction of N-cyano-N′-(6-amino-2-pyridyl)acetamidine ( 5a ) and homophthalic anhydride followed by ring closure of the 2-[2-(carboxymethyl)phenyl]-5-methyl-1,3,4,6,9b-pentaazaphenalene intermediate ( 4a ) gave 5-methyl-13-oxo-13H-4,6,7,13a,13c-pentaazabenzo[hi]chrysene ( 8a ). An analogous series starting with 3-N-(6-amino-2-pyridyl)amino-2-cyano-2-butenenitrile ( 5b ) in place of 5a gave in two steps 5-methyl-13-oxo-13-H-4,7,13a,13c-tetraazabenzo[hi]chrysene-6-carbonitrile ( 8b ). Elemental analysis, ir and pmr spectra of 8a , 8b and several new model compounds aided in confirming the structures of 8a and 8b. The synthesis of one of these model compounds for 5b and phenylacetic anhydride led surprisingly to 2-methyl-9-phenyl-7H-3,7,-10,10b-tetraazacyclohepta[de]naphthalene ( 10 ) in addition to the expected 2-benzyl-4-cyano-5-methyl-1,3,-6,9b-tetraazaphenalene ( 7b ).     

Fused s-triazino heterocycles. XVI. 13H-1,3,7,8,12a, 13c-hexaazabenzo[de]naphthacene and 1,3,7,8,11b, 12,14,14d-octaazadibenzo[de,hi]naphthacene,two new ring systems

The reaction of 7,9-dibromo-5-tribromomethyl-2-t-butyl-4-cyano-1,3,6,9b-tetraazaphenalene ( 1a ) with 2-amino-5-picoline is shown to give 4,6-dibromo-2-t-butyl-13-imino-11-methyl-13H-1,3,7,8,12a,13c-hexaazabenzo[de]naphthacene ( 3 ) and the isomeric 7,9-dibromo-2-t-butyl-4-cyano-5N-(5-methyl-2-pyridyl)amino-1,3,-6,9b-tetraazaphenalene ( 2a ). A related annulation reaction of 7,9-dibromo-2-t-butyl-5-chloro-4-cyano-1,3,6,9b-tetraazaphenalene ( 1g ) with 2-amino-6-trimethylacetamidopyridine leads in two steps to 4,6-dibromo-2,13-di-t-butyl-1,3,7,8,11b,12,14,14d-octaazadibenzo[de,hi]naphthacene ( 4a ). The preparation of 1g , 5-azido-7,9-dibromo-2-t-butyl-4-cyano-1,3,6,9b-tetraazaphenalene ( 1c ) and the reaction of the latter with pyrrolidine leading to 7,9-dibromo-2-t-butyl-4-cyano-5-(1-pyrrolidino)-1,3,6,9b-tetraazaphenalene ( 1e ) are also reported. Attempted displacement of the azido-group on 1c by 2,6-diaminopyridine affords surprisingly 5-amino-7,9-dibromo-2-t-butyl-4-cyano-1,3,6,9b-tetraazaphenalene ( 1d ).     

Optisch aktive aromatische Spirane, 13. Mitt.

Several optically active title compounds were obtained from the 4-acetyl-4-carboxylic acid2 or the 4,4-diacetyl derivative4. (–)-2 was accessible by optical resolutionvia its (–)--phenethylamine salts, (+)- and (–)-4 as well as the enantiomeric methylesters3 (of2) were obtained by chromatography on triacetylcellulose in ethanol. The enantiomeric purities were established either from the chromatographic results or from the¹H-NMR spectra of the phenethyl-amine saltes (via the diastereotopic acetyl protons).The chirality (–)-(2R) was deduced for all new compounds from a chemical correlation between (–)-2 and (–)-4 and on the basis of the CD spectra of the latter and of (–)-(2R)-17 of known absolute configuration.From the molar rotations of these 4,4-disubstituted 2,2-spirobiindanes (empirical) ligand parameters were determined which for some cases gave good results in the calculation of the rotations (using the shortened Ansatz). These results are briefly discussed especially in comparison with 5,5-disubstituted 2,2-spirobiindanes.

Herrn Prof. Dr.O. Hromatka mit den besten Wünschen zum 80. Geburtstag gewidmet.     

Fused s-triazino heterocycles. XIV 8H-1,3,7,8,9,10c-hexaazacyclopenta[a]phenalene, 1,3,7,8,10,11c-hexaazabenz[de]anthracene and 13H-4,6,8,13a, 13c-pentaazabenzo[de]naphthacene,three new ring systems

The synthesis of the title compounds 3,4 and 5 is described, using 7,9-dibromo-5-tribromomethyl-2-t-butyl-4-cyano-1,3,6,9b-tetraazaphenalene 2a as starting material. The key intermediates are 7,9-dibromo-2-t-butyl-4-cyano-5-hydrazino-1,3,6,9b-tetraazaphenalene 2b , 5-benzamidino-7,9-dibromo-2-t-butyl-4-cyano-1,3,6,9b-tetraazaphenalene 2c , and 7,9-dibromo-2-t-butyl-5-(2-carboxyanilino)-4-cyano-1,3,6,9b-tetraazaphenalene 2e.     

13C-NMR.-Spektroskopie von Organolithiumverbindungen bei tiefen Temperaturen. Strukturinformation aus der 13C, 6Li-Kopplung

Low-Temperature ¹³C-NMR. Spectroscopy of Organolithium Derivatives. - ¹³C, ⁶Li-Coupling, a Powerful Structural Information The ¹³C-NMR. spectra of thirteen lithiated hydrocarbons ( 1c–13c . Table 2) and of eighteen a-halo-lithium carbenoids ( 14c–31c , Table 3) have been recorded in donor solvent (R₂O, R₃N) mixtures at temperatures down to ?150°. The organolithium species were generated from singly or doubly ¹³C-labelled precursors by H/⁶Li- or Br/⁶-exchange. - ¹³C, ⁶Li-Coupling was observed of all species but those which supposedly contain contact ion pair C,Li-bonds (benzylic and acetylenic derivatives). The multiplicities of the signals are correlated with the degree of aggregation in solution: the triplets of the halocarbenoids must arise from monomers or heteroatom-bridged oligomers, the quintuplets of butyl-, cyclopropyl-, bycyclo[1.1.0]butyl-, vinyl-, and phenyllithium from dimers with planar arrangement of two Li- and two C-atoms, as known from crystal structures (Scheme 3). All ¹³C, ⁶Li-couplings are temperature-dependent, dynamic processes cause them to disappear above ca. ?70° (Fig. 1–4). - Types of organolithium compounds are categorized according to the change of chemical shift δΔ (H, Li) upon H/Li-substitution, according to the ¹³C, ⁶Li-coupling constants ranging from 0 to 17 Hz, and according to the multiplicities which indicate the aggregation: type A are Li-derivatives of alkanes and cycloalkanes, type B are s?-bonded vinyl, aryl, and alinyl derivatives, type C are a-heterosubstituted (RS, hetero=halogen) organolithium compounds, and type D are π-bonded allylic and benzylic systems (Table 5). The C,Li-distances in the crystal structures of representatives of all four classes are within the small range of 2.18–2.28 Å (cf. Scheme 3). - Some surprising observations and their interpretations and consequences are: (a) butyllithium solutions in THF, THF/TMEDA, and dimethyl ether contain increasing amounts of dimer upon cooling, the equilibrium (tetramer · 4 THF)+4 THF ? 2 (dimer · 4 THF) being shifted to the right (Fig. 1 and Scheme 4); thus, more of a different species is present at low temperatures, with the accompanying changes in reactivity; (b) mixed higher aggregates are formed upon addition of butyllithium to bicyclobutyllithium; these are broken up to dimers upon addition of TMEDA (Tetramethylethylene-diamine) (Fig. 2 and Scheme 5); (c) the solid state, the calculated gas-phase and the solution species of phenyllithium all have dimeric structures, and so do vinyl and cyclopropyl lithium derivatives; the ¹³C-deshielding observed upon replacement of H by Li on sp²- and sp-C-atoms is related to a polarization of the π-electrons (Table 3, Fig. 3 and Scheme 6); (d) the spectra of halo-lithium carbenoids show three striking features as compared to the C,H-compound: deshielding of up to 280 ppm (Table 3), strong decrease of the coupling constant with ¹H- and ¹³C-nuclei attached to the carbenoid C-atom (Table 4), and a structure-independant, almost constant, large ¹³C, ⁶Li-coupling constant of 17 Hz (Table 3); as shown in Scheme 7, these effects might be the consequence of a reduced degree of hybridization of the carbenoid C-atom. - The preparation of the labelled compounds and the generation of solutions of the organolithium compounds for NMR. measurements are described in full detail.     

Inductive Charge Dispersal in Quinuclidinium Ions. Polar Effects,Part 13

Inductive charge dispersal to the α- β- and γ-positions of the solvated quinuclidinium ion has been examined by comparing the pK_a and the derived inductivities ρ_I of several 2- 3- and 4-substituted quinuclidinium perchlorates 4, 5 , and 6 , respectively. The same inductivity is observed at the practically equidistant β- and γ-positions. It, therefore, appears that polar substituent effects are transmitted directly through the molecule. As expected, inductivity is considerably higher at the α-positions where through-bond and direct induction coincide. The fact that the pK_a of all three series of salts correlate linearly with each other points to the common nature of these inductive electron displacements.     

Carbene chemistry. Part 13 [1]. Preparation of sole fluoroallenes by a carbene route,and the reaction of allenes with halogenocarbenes

Fluoroallene and 1, 3-difluoroallene are prepared in good overall yield by the addition of dichlorocarbene to vinyl fluoride and 1, 2-difluoroethylene respectively, followed by pyrolysis of the dichlorocyclopropanes and treatment of the resulting dichloropropenes with zinc. Pyrolysis of 1, 1-dichloro-2-fluorocyclopropane over zinc gives fluoroallene directly.The reaction of allene with 2, 2, 3-trifluoro-3-trifluoro- methyloxiran at 180°C as a source of difluorocarbene gives both 1, 1-difluoro-2-methylenecyclopropane and its rearrangement product 1-(difluoromethylene)cyclopropane, the latter reacting more readily with a second difluorocarbene to give 2, 2, 3, 3- tetrafluorospiropentane. In an analogous way, fluoroallene reacts with dichlorocarbene, generated from trifluoro(trichloromethyl) silane at 140°C, to give $\text{E}$- and $\text{Z}$-1, 1-dichloro-2- (fluoromethylene)cyclopropane, 1-(dichloromethylene)-2-fluorocyclopropane, and 2, 2, 3, 3-tetrachloro-4-fluorospiropentane.     

Die Acylierung von 5-Amino-1 H-1, 2, 4-triazolen. Eine 13C-NMR.-Studie

The Acylation of 5-Amino-1 H-1,2,4-triazoles. A ¹³C-NMR. Study The acylation of 3-substituted-5-amino-1 H-1,2,4-triazoles (1) with methyl chloroformate or dimethylcarbamoyl chloride yielded mainly 1-acyl-5-amino-1,2,4-triazoles ( 2 and 3 ). Acylation of 3-methyl-, 3-methoxy- and 3-methylthio-5-amino-1 H-1,2,4-triazole ( 1b , 1c and 1d ) with methyl chloroformate gave up to 10% of the 1-acyl-3-amino-1,2,4-triazoles. For the unsubstituted 5-amino-1,2,4-triazole (1a) , a (1:1)-mixture of the 3- and 5-isomers 2a and 4 was obtained in dioxane in the presence of triethylamine. No 4-acylated product was detected in contrast to earlier reports. The structures of the reaction products were determined with the aid of proton coupled ¹³C-NMR. spectra using the corresponding N-methyl-1,2,4-triazoles as reference compounds.     

Asymmetric Total Synthesis of (11R, 12S, 13S, 9Z, 15Z)-9, 12, 13-Trihydroxyoctadeca-9, 15-dienoic Acid,a self-defensive agent against rice-blast disease

The Diels-Alder adduct of furan and 1-cyanovinyl (1′R)-camphanate was converted into methyl [(tert-butyl)-dimethylsilyl 5-deoxy-2, 3-O-isopropylidene-β-L -ribo-hexofuranosid] uronate ((+)- 4 ). Reduction with diisobutyl-aluminium hydride gave the corresponding aldehyde which was condensed with the ylide derived from triphenyl-(propyl)phosphonium bromide to give (1R, 2S, 3S, 4S)-1-[(tert-butyl)dimethylsilyloxy]tetrahedro-2, 3-(isopropyl-idenedioxy)-4-[(Z)-pent-2′ -enyl]furan ((+)- 7 ). Removal of the silyl protective group gave a mixture of the corresponding furanose that underwent Wittig reaction with the ylide derived from [8-(methoxycarbonyl)-octyl]triphenylphosphonium bromide to yield methyl (11R, 12S, 13S, 9Z, 15Z)-13-hydroxy-11, 12-(isopropylidene-dioxy)octadeca-9, 15-dienoate ((?)- 9 ). Acidic hydrolysis, then saponification afforded (11R, 12S, 13S, 9Z, 15Z)-11, 12, 13-trihydroxyoctadeca-9, 15-dienoic acid ( 1 ).     

RSR13, a potential athletic performance enhancement agent: detection in urine by gas chromatography/mass spectrometry.

RSR13 (2-[4-[[(3,5-dimethylanilino)carbonyl]methyl]phenoxyl]-2-methylpropionic acid) is a synthetic allosteric modifier of hemoglobin that is currently in a phase III clinical trial as a radio-enhancing agent. RSR13 has been shown to increase maximum oxygen uptake (VO(2max)) in a canine skeletal model, which makes it a potential performance-enhancing agent for endurance athletes, since VO(2max) is an index of aerobic capacity. In this study we present a method for the detection of RSR13-bis-TMS in human urine by gas chromatography/electron impact ionization mass spectrometry (GC/EI-MS) suitable for doping control laboratories. The presence of RSR13 is detected by monitoring the ions m/z 485 ([M](+.)) and 470 ([M - CH3](+)). The limit of detection (LOD) is less than 2 ng/mL in urine. Urine samples collected from clinical trial subjects immediately prior to receiving an infusion of RSR13 showed no evidence of RSR13, whereas post-infusion urine samples contained up to 1181 microg/mL. A urine sample collected 36 h after administration of a small dose (10 mg/kg) and diluted 100-fold showed a signal 80 times higher than the LOD. Urine samples obtained from 100 randomly selected athletes in our routine testing program did not show any traces of RSR13. Sport authorities may wish to add RSR13 to the list of prohibited substances.     

Alkaloids of Arundo donax L. 13. The structure of a new dimeric indole alkaloid,arundanine

The structure of a new dimeric indole alkaloid, named arundanine, isolated from the roots of Arundo donax L. (Poaceae), was elucidated. Arundanine was identified as 3-(N,N-dimethylaminoethyl)-4-[3-(N,N-dimethylaminoethyl)indole-1-yl]-5-hydroxyindole on the basis of spectroscopic data and the transformation into the known alkaloid, arundamine.     

13C-NMR-spektroskopische und stereochemische Untersuchungen. XXIII.—Konformationen, 13C-NMR-Verschiebungen- und 13C?1H- Kopplungen bei Pinanverbindungen

¹³C NMR shifts of bicyclo[3.1.1]heptanes are discussed on the basis of geometries which are largely obtained by application of a molecular mechanics force field. For the basic hydrocarbon chair geometry minima are observed; their interconversion, however, is so fast [ΔH*～0.6 kcal (2.51 kJ) for fully relaxed molecular states] that an average flat Y form should be assumed for the ground state. In pinanes bearing equatorial substituents approximate chair geometries are obtained which, upon introduction of axial groups, appear very much flattened. In cosequence, conformationally transmitted substituent induced shieldings are observed, which can reach, e.g. + 7.45 ppm deshielding for a γ-methyl substituent. One bond ¹³C—¹H coupling constants, obtained in some cases from {¹H} off-resonance decoupled ¹³C spectra, are compared to calculated hybridization of C? H bonds. Their values of up to 145 Hz\documentclass{article}\pagestyle{empty}\begin{document}$ \buildrel \wedge \over = $\end{document}29% s for the cyclobutane part of pinanes are also useful for ¹³C signal assignments. Some literature assignments have to be revised, also on the basis of measurements with specifically deuterated compounds.     

Cyclization and rearrangement of diterpenoids. VI. Products of dehydration of (1R,2S,7S,10S,12S,13S)-2,6,6,10,12-pentamethyltetracyclo[10.2.1.01,10.02,7]pentadecan-13-ol by phosphorus oxychloride

It has been established that on the dehydration of (1R,2S,7S,10S,12S,13S)-2,6,6,10,12-pentamethyltetracyclo[10.2.1.0^1,10.0^2,7]pentadecan-13-ol with phosphorus oxychloride in pyridine a mixture of six substances is formed, from which three previously undescribed hydrocarbons have been isolated and identified: (1R,2S,7S,10S,11R,12S,13S)-2,6,6,10,12-pentamethylpentacyclo[10.2.1.0^1,10.0^2,7.-0^11,13]pentadecane, (1R,2S,7S,10S,12R)-2,6,6,10,13-pentamethyltetracyclo[10.2.1.0^1,10.0^2,7]pentadec-13(14)-ene, and (1R,2S,7S,10S,12R)-2,6,6,10-tetramethyltetracyclo[10.2.1.0^1,10.0^2,7]pentadec-13(16)-ene, these being based on two new carbon skeletons.Institute of Chemistry, Institute of Applied Physics, MSSR Academy of Sciences, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 203–211, March–April, 1988.     

α- und β-Phenylazo-styrole Oxidationsprodukte von Arylhydrazon-Verbindungen, 13. Mitt.

The reaction of phenylhydrazones of phenyl- and benzylketones2 with I₂ in pyridine followed by alkali treatment yields - and -phenylazo-styrene derivatives4 and5 respectively. The increasing bulkiness of an additional hydrocarbon substituent attached to the olefinic moiety affects the stereochemistry of the heterodiene system of these compounds as evidenced by their spectra.

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12. Mitt.:J. Schantl, Mh. Chem.105, 427 (1974).     

Synthetic, spectroscopic, computational and structural studies of some 13-vertex ruthenacarboranes

Reduction of 1,2-closo-C2B10H12 followed by treatment with [RuCl2(p-cymene)]2(p-cymene = C6H4MeiPr-1,4) affords the 13-vertex ruthenacarborane 4-(p-cymene)-4,1,6-closo-RuC2B10H12, characterised both spectroscopically and, in two crystalline forms, crystallographically. Although asymmetric in the solid state, having a docosahedral cage architecture with cage C atoms at vertices 1 and 6, this species clearly has Cs symmetry on the NMR timescale at room temperature. However, the fluctional process in operation can be arrested at low temperature, and an activation energy of 43.1 kJ mol(-1) is estimated. A computational study of the related species 4-(eta-C6H6)-4,1,6-closo-RuC2B10H12 reveals that the fluctionality is due to a double diamond-square-diamond process, first suggested by Hawthorne et al for the analogous CpCo species. These calculations yield an activation energy of 40.4 kJ mol(-1), in excellent agreement with that derived from experiment. Reduction of 1,2-Ph(2)-1,2-closo-C2B10H10 followed by treatment with [RuCl2(eta-C6H6)]2 or [RuCl2(p-cymene)]2 yields the analogous species 1,6-Ph2-4-(eta-C6H6)-4,1,6-closo-RuC2B10H10 and 1,6-Ph2-4-(p-cymene)-4,1,6-closo-RuC2B10H10, respectively. These C,C-diphenyl compounds were again studied spectroscopically and crystallographically, the p-cymene species again showing two crystalline modifications. In contrast to their CpCo and Cp*Co analogues all three ruthenacarboranes do not undergo isomerisation in refluxing toluene.     

Synthesis, structure, and reactivity of 13-vertex carboranes and 14-vertex metallacarboranes

Syntheses, properties, and synthetic applications of 13-vertex closo- and nido-carboranes are reported. Reactions of the nido-carborane salt [(CH2)3C2B10H10]Na2 with dihaloborane reagents afforded 13-vertex closo-carboranes 1,2-(CH2)3-3-R-1,2-C2B11H10 (R = H (2), Ph (3), Z-EtCH=C(Et) (4), E-(t)BuCH=CH (5)). Treatment of the arachno-carborane salt [(CH2)3C2B10H10]Li4 with HBBr2.SMe2 gave both the 13-vertex carborane 2 and a 14-vertex closo-carborane (CH2)3C2B12H12 (8). On the other hand, the reaction of [C6H4(CH2)2C2B10H10]Li4 with HBBr2.SMe2 generated only a 13-vertex closo-carborane 1,2-C6H4(CH2)2-1,2-C2B11H11 (9). Electrophilic substitution reactions of 2 with excess MeI, Br2, or I2 in the presence of a catalytic amount of AlCl3 produced the hexa-substituted 13-vertex carboranes 8,9,10,11,12,13-X6-1,2-(CH2)3-1,2-C2B11H5 (X = Me (10), Br (11), I (12)). The halogenated products 11 and 12 displayed unexpected instability toward moisture. The 13-vertex closo-carboranes were readily reduced by groups 1 and 2 metals. Accordingly, several 13-vertex nido-carborane dianionic salts [nido-1,2-(CH2)3-1,2-C2B11H11][Li2(DME)2(THF)2] (13), [[nido-1,2-(CH2)3-1,2-C2B11H11][Na2(THF)4]]n (13a), [[nido-1,2-(CH2)3-3-Ph-1,2-C2B11H10][Na2(THF)4]]n (14), [[nido-1,2-C6H4(CH2)2-1,2-C2B11H11][Na2(THF)4]]n (15), and [nido-1,2-(CH2)3-1,2-C2B11H11][M(THF)5] (M = Mg (16), Ca (17)) were prepared in good yields. These carbon-atom-adjacent nido-carboranes were not further reduced to the corresponding arachno species by lithium metal. On the other hand, like other nido-carborane dianions, they were useful synthons for the production of super-carboranes and supra-icosahedral metallacarboranes. Interactions of 13a with HBBr2.SMe2, (dppe)NiCl2, and (dppen)NiCl2 gave the 14-vertex carborane 8 and nickelacarboranes [eta5-(CH2)3C2B11H11]Ni(dppe) (18) and [eta5-(CH2)3C2B11H11]Ni(dppen) (19), respectively. All complexes were fully characterized by various spectroscopic techniques and elemental analyses. Some were further confirmed by single-crystal X-ray diffraction studies.     

13C-NMR. Spectra of 4-Substituted Quinuclidines. Polar effects,Part V

¹³C-NMR. sepctra of 37 4-substituted quinuclidinium perchlorates, 15 4-substituted quinuclidines and the corresponding 1-methylquinuclidinium iodides have been measured. The chemical shifts δ for all compounds lie in the expected range. No correlation is found between δ and the inductive substituent constant σ of the substituent. Abnormal shift differences between quinuclidines bearing a nucleofugal group and the corresponding protonated or N-methylated quinuclidinum salt are observed for the bridgehead carbon C(4). These differences are ascribed to incipient fragmentation, i.e. C, C-hyperconjugation in the ground state.     

Carbon-13 as a tool for the study of carbohydrate structures, conformations and interactions

The application of 13C-NMR spectroscopy to problems involving the structures and interactions of carbohydrates is described. Both 13C-enriched and natural abundance compounds were used and some advantages of the use of the stable isotope are described. Carbon-carbon and carbon-proton coupling constants obtained from 1-13C enriched carbohydrates were employed in the assignment of their chemical shifts and to establish solution conformation. In all cases studied thus far, C-3 couples to C-1 only in the beta-anomers while C-5 couples to C-1 only in the alpha-anomers. C-6 and C-2 always couple to C-1 in both anomeric species. The alkaline degradation of glucose [1-13C] to saccharinic acids was followed by 13C-NMR. The conversion of glucose [1-13C] to fructose-1, 6-bisphosphate [1, 6-13C] by enzymes of the glycolytic pathway was shown as an example of the use of 13C-enriched carbohydrates to elucidate biochemical pathways. In a large number of glycosyl phosphates the 31P to H-1 and 31P to C-2 coupling constants demonstrate that in the preferred conformation and phosphate group lies between the O-5 and the H-1 of the pyranose ring. The influence of paramagnetic Mn2 + ions on the proton decoupled 13C-NMR spectra of uridine diphosphate N-acetylglucosamine indicates that the Mn2 + interacts strongly with the pyrophosphate moiety and with the carbonyl groups of the uracil and N-acetyl groups.     

Crystallographic Studies of Synthetic Corrinoids. I. Nickel(II)-1, 8, 8, 13, 13-pentamethyl-5-cyano-trans-corrin chloride

The crystal and molecular structure of nickel(II)-1, 8, 8, 13, 13-pentamethyl-5-cyano-trans-corrin chloride has been determined by X-ray analysis. The shape and dimensions of the corrin nucleus are discussed in some detail.     

Reaction of Cl atoms with C6F13CH2OH, C6F13CHO, and C3F7CHO

The Cl atom initiated oxidation of C(6)F(13)CH(2)OH, C(6)F(13)CHO, and C(3)F(7)CHO was investigated at 298 K and 1000 mbar pressure of air in a photoreactor using in situ Fourier transform infrared (FTIR) analysis. The rate coefficient for the reaction Cl + C(6)F(13)CH(2)OH (reaction 2) was measured using a relative method: k(2) = (6.5 +/- 0.8) x 10(-13) cm(3) molecule(-1) s(-1). C(6)F(13)CHO was detected as the major primary product, while CO and CF(2)O were found to be the major secondary products. A fitting procedure applied to the concentration-time profiles of C(6)F(13)CHO provided a production yield of (1.0 +/- 0.2) for this aldehyde in reaction 2, and the rate coefficient for the reaction Cl + C(6)F(13)CHO (reaction 4) was k(4) = (2.8 +/- 0.7) x 10(-12) cm(3) molecule(-1) s(-1). A high CO yield observed in the oxidation of C(6)F(13)CH(2)OH, (52 +/- 1)%, is attributed to the Cl atom initiated oxidation of C(6)F(13)CHO. High CO yields, (61 +/- 2)% and (85 +/- 5)%, were also measured in the Cl atom initiated oxidation of C(3)F(7)CHO in air and nitrogen, respectively. These high CO yields suggest the occurrence of a decomposition reaction of the perfluoroacyl, C(6)F(13)CO, and C(3)F(7)CO radicals to form CO which will compete with the combination reaction of these radicals with oxygen to form perfluoroacyl peroxy radicals in the presence of air. The latter radicals C(n)F(2)(n)(+1)CO(O)(2) (n = 6-12), through their reaction with HO(2) radicals, are currently considered as a possible source of persistent perfluorocarboxylic acids which have been detected in the environment. The consequences of the present results would be a reduction of the strength of this potential source of carboxylic acids in the atmosphere.