Synthese von Diaza-octahydroporphinato-kobalt (III)-Komplexen als Vitamin-B12-Modellverbindungen

Synthesis of Octahydro-porphinato-cobalt(III) Complexes as Vitamin B₁₂ Model Compounds The synthesis of (±)-dibromo[1-hydroxy-2,2,3,3,7,7,8,8,12,12,13,13,17,17,18,18-hexadecamethyl-10,20-diaza-octahydroporphinato]cobalt(III) (2a) is described. The dicyano complex 2b and the corresponding annulene complex 3 have been obtained by exchange of its axial ligands and by elimination of the hydroxy group, respectively.     

The He(Iα) Photoelectron Spectra of the Perfluoroderivatives of Trisannelated Benzenes and Tetrakisannelated Cyclooctatetraenes

The He(Iα) photoelectron (PE) spectra of tris(perfluorocyclobuta)benzene 4 (F)

1 3,3,4,4,7,7,8,8,11,11,12,12-Dodecafluorotetracyclo[8.2.0.0^2,5.0^6,9]dodeca-1,5,9-triene

, tris(perfluorocyclopenta)benzene 5 (F)

2 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-Octadecafluoro-2,3,4,5,6,7,8,9-octahydro-1H-trindene.

, tetrakis(perfluorocyclobuta)cyclooctatetraene 6 (F)

3 3,3,4,4,7,7,8,8,11,1l,l2,l2,l5,15,16,16-Hexadecafluoropentacyclo[12.2.0.0^2,5.0^6,9.0^10,13]hexadeca-1,5,9,13-tetraene.

, and of tetrakis(perfluorocyclopenta)cyclooctatetraene 7 (F)

4 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12-Tetracosafluoro-1,2,3,4,5,6,7,8,9,10,11,12-dodeca-hydrotetracyclopenta[a,c,e,g]cyclooctene.

are reported. A tentative assignment of the PE spectra is derived by empirical correlation with those of relevant reference compounds. The results suggest that 6 (F) retains the D_4h-conformation in the gas phase, i.e. A conformation with a planar cyclooctatetraene ring, as observed in the crystal. All four compounds exhibit a sharp increase of their first ionization energies, relative to the corresponding parent hydrocarbons, due to the perfluoro effect.     

Synthese optisch aktiver Nickel-Komplexe mit porphinoidem Ligandsystem

Synthesis of Optically Active Porphine-type Nickel Complexes Both enantiomers of [1-methyl-8 H-HDP]nickel-perchlorate

1 For nomenclature see footnote 5 in this paper.

( 2a and 2b , respectively) have been synthesized by the following reaction sequence: (a) base induced addition of (?)-( R )-2-octanol to 1 , (b) separation of the two diastereomeric monoadducts 4a and 4b , (c) reaction with methyl magnesium iodide containing an excess of methyl iodide, (d) acid induced elimination of 2-octanol from the diadducts 6a and 6b . By a similar procedure both enantiomers of [1-butyl-8 H-HDP] nickel-perchlorate ( 3a and 3b , respectively) have been prepared. The reaction of 3a with butyl lithium yields in a kinetically controlled addition predominantly the optically active cis -1, 11-dibutyl adduct 8 and in minor quantity the meso - cis -1, 11-dibutyl adduct 9 .     

Conformational analysis of 7,7-dichloro-2,5-dioxabicyclo[4.1.0] heptane by NMR

The ¹H NMR spectra of 7,7-dichloro-2,5-dioxabicyclo-[4.1.0]heptane ( 1 ) were analyzed through the application of programs NMRIT and NMREN2.

1 See Ref. 1.

The half-chair conformation of 1 was obtained from the vicinal coupling constants by the Buys R method.

2 See Ref. 2.

     

Stereochemistry of the Platinum Catalyzed Hydroformylation of Olefins

The deuterioformylation of (Z)- or (E)-2-butene catalyzed by [DIOP]Pt(SnCl₃)-Cl

1 DIOP=2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane.

gives predominantly erythro- or threo-1,3-[²H]₂-2-methylbutanal respectively. Hence, hydroformylation by this catalytic system must take place with cis-stereochemistry.     

Ein einfacher Zugang zu 4-hydroxy-2,5-dimethyl-3(2H)-furanon (furaneol), einem Aromabestandteil von Ananas und Erdbeere

Furaneol®

1 Registered trade mark of Firmenich SA.

[4-hydroxy-2,5-dimethyl-3(2H)-furanone ( 1 )], a flavour component of pineapple and strawberry, has been prepared by a two-step synthesis starting with readily available 3-hexyne-2,5-diol. By the same method 4-hydroxy-5-methyl-3(2H)-furanone ( 2 ) and 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone ( 3a ) have been prepared from 2-pentyne-1,4-diol and 3-heptyne-2,5-diol, respectively.     

Über die Synthese von 1-Aryl-und 1-Alkyl-2, 3-dimethyl-chinoxalinium-perchloraten. 2. Mitteilung. Synthese und 1H-NMR.-Spektren von 2,3-Dimethyl-1-phenyl-6-X-chinoxalinium-perchloraten

On the Synthesis of 1-Aryl- and-1-Alkyl-2, 3-dimethyl-quinoxalinium Perchlorates. 2nd Communication

1 1. Mitt.: [1].

. Synthesis and ¹ H-NMR. Spectra of 2, 3-Dimethyl-1-phenyl-6-X-quinoxlinium Perchlorates The synthesis of the title compounds ( 5 ) which have been useful as precursors for a lot of conventional and new-type dyes [2-8] has yet been limited to examples with X?H [2] [3] [11] [15] and with electron-donating [4] [12] or at best slightly electron-accepting [1] [6] substituents X and R. We now describe a method suitable even for compounds 5 with strongly electron-accepting substituents: N-monosubstituted o-phenylendiamines 4 , were condensed with 2, 3-butanedione and perchloric acid in mixed solvents containing an excess of diethyl ether. The products - mostly substituted at position 6 of the quinoxalinium ring - are chracterized by ¹H-NMR. spectra, elemental analyses and in most cases by isolation of the corresponding bases 6 . Correlations of chemical shifts with Hammett's σ_p [18] are given by equations (1)-(5).     

Nachbargruppeneffekte in der Gas-Phase: Intramolekulare Deacetalisierung von Hydroxyacetalen unter den Bedingungen der chemischen Ionisation

Neighboring-Group Participation in the Gas Phase: Intramolecular Deacetalization of Hydroxyacetals under the Conditions of Chemical Ionization

1 Herrn Prof. Dr. Christoph Tamm zum 70. Geburtstag gewidmet

Under the conditions of chemical ionization (NH₃, isobutane, ND₃), hydroxyacetals do not show the expected [M + H⁺] signal, but the peak corresponding to the loss of the alcohol component of the acetal. This reaction is dependent on the presence of the OH group in the vicinity of the acetal and on the ring size of the heterocycle being formed. M^+· is detected to a small extent as a consequence of charge exchange during chemical ionization.     

Chemie von α-Aminonitrilen. 12. Mitteilung. Sondierungen über thermische Umwandlungen von α-Aminonitrilen

Chemistry of α-Amino Nitriles

1 11. Mitteilung: [1].

. Exploratory Experiments on Thermal Reactions of α-Amino Nitriles The paper extends a previously published report [4] on chemical properties of α-amino nitriles and of members of the C₃H₄N₂ ensemble (Scheme 1) as observed in experiments carried out under non-aqueous conditions. The reactions investigated and the observations made are summarized in some detail in the English footnotes (*) referring to Schemes 1–17 and Fig. 1.     

Reactions of the Carbonyl Group in Fluorinated Ketones

The chemistry of polyfluorinated ketones has recently received a great deal of attention.

1 A. Ya. Yakoubovich, Usp. Chim. 25, 3 (1956).

2 H. P. Braendlin and E. T. McBee in: Advances in Fluorine Chemistry. Butterworths, London 1963, Vol. 3, p. 1.

3 The review by Braendlin and McBee [2] does not deal only with perfluorinated ketones; moreover, though published in 1963, it is already outdated. The papers discussed in [1,2] will not be reviewed in the present article.

. The carbonyl and imino groups of the fluorinated ketones and their imines react in many different ways. In particular, the electron-attracting perfluoroalkyl groups intensify the electrophilic properties and weaken the nucleophilic properties of the carbonyl group. The perfluoroalkyl group also hinders the heterolytic removal of the hydroxyl group from adducts by reducing the stability of the carbonium ion . The increased electrophilicity of the carbonyl group and the increased stability of the addition products leads not only to a change in reactivity in the characteristic ketone reactions, but also to numerous new reactions which are not observed with non-fluorinated ketones. Thus it is possible to synthesize a wide variety of fluoroorganic compounds from perfluorinated ketones.

4 We have been concerned mainly with hexafluoroacetone, since in addition to being the most readily available and simplest perfluorinated ketone, this is also a typical representative of this class of compounds.

.     

Rhodium (I)-katalysierte Reaktionen der [2+4]-Cycloaddukte aus 3,4-Dimethoxyfuran und Acetylendicarbonsäure-estern

[2+4]-Cycloaddition Products of 3,4-Dimethoxyfuran with Acetylenedicarboxylates and Their Transformations under the Influence of Rhodium(I) Catalysts 3,4-Dimethoxyfuran ( 1 ) readily reacts with acetylenedicarboxylates ( 2 ) at room temperature in a [2+4]-cycloaddition to give a mono-( 3 ) and several di-addition products. 90% of the latter consists of the endo-exo compound 4 . Under the influence of catalytic amounts of [Rh(CO)₂Cl]₂ the mixture of mono- and di-adducts in methanolic solution is smoothly transformed into endo-5,5,6-trimethoxy-7-oxabicyclo [2.2.1]hept-2-ene-2,3-dicarboxylate

1 Alle Verbindungen sind racemisch. Die Formeln stellen jeweils nur ein Enantiomeres dar.

(5) , 3-hydroxy-4,5-dimethoxyphthalate ( 6 ) and (I R *, 2 S *, 4 R *, 5 R *, 7 R *, 11 R *, 12 R *) -5,8,8,9,12-pentamethoxy-3,6-dioxatetracyclo [5.3.1.1 ^2,5 . 0 ^4,11 ]dodec-9-ene-1,11-dicarboxylate ( 7 ).     

Über Reaktionen oxygenierter Kobalt(II)-Komplexe. IX. Oxydative Eigenschaften von Tetrakis(äthylendiamin)-μ-peroxo-μ-hydroxo-dikobalt(III)

Reactions of oxygenated cobalt(II) complexes. IX. Oxidative properties of tetrakis(ethylenediamine)-μ-peroxo-μ-hydroxo-dicobalt(III)

1 VIII s. [1].

[(en)₂Co(O₂, OH)Co(en)₂]³⁺ ( a ) reacts with I^? in acidic aqueous solution according to: Co^III(O₂, OH)Co^III + 21^? + 5H⁺ ? 2Co^III + 3H₂O + I₂. Using I^? in excess first order rate constants are obtained which, to a first approximation, are independent of [I^?]. Comparison with kinetic data of deoxygenation of [(en)₂Co(O₂, OH)Co(en)₂]³⁺ under analogous conditions suggests that both reactions have the same rate determining step. The singly bridged species [(en)₂(H₂O)CoO₂Co(H₂O) (en)₂]⁴⁺ is shown to be the reactive intermediate in the iodide oxidation (Schema 2).     

Comment on the Estimation of the Dimerisation Constant of Caffeine

Reasons for the low reliability of the

1 Compare e.g. former results cited in [3][4] with our results in [3].

H-NMR estimation of the dimerisation constant of caffeine in D₂O are discussed. The main reasons are (1) strong influence of small variations in the monomer shifts δ₀ which are to be determined by extrapolation, and (2) disturbance by the formation of higher oligomers. The dilemma ist that attempts to minimize errors from (1) increase the influence of (2) and vice versa.     

Structure et synthèse de la damascénone (triméthyl-2,6,6-trans-crotonoyl-1-cyclohexadiène-1,3), constituant odorant de l'essence de rose bulgare (rosa damascena Mill.

Damascenone

1 DORICENONE (trade mark applied for by Firmenich & Cie, Geneva).

an odoriferous ketone isolated in minute amounts from Bulgarian rose oil (Rosa damascena Mill.) is shown to be trans-2,6,6-trimethyl-1-crotonoyl-cyclohexa-1, 3-diene (I). A synthesis starting from beta;-cyclocitral is described for this conspicuous constituent of rose oil, which displays a powerful fragrance. The synthesis of four related, more saturated ketones, damascones

2 DORINONE (trade mark applied for by Firmenich & Cie, Geneva).

, is also described.     

Identification de la damascénone et de la β-damascone dans le tabac Burley

The successful identification of damascenone (I)

1 DORICENONE (trade mark of Firmenich & Cie, Geneva).

and β-damascone (III)

2 DORINONE (trade mark of Firmenich & Cia, Geneva)

in Burley tobacco oil was achieved through the use of an efficient vapour phase chromatography/mass spectrometry combination. Thus, the occurrence of β-damascone in nature and the presence of damascenone in an essential oil not related to rose oil were demonstrated.     

Kinetics of fluorine atom reactions using resonance absorption spectrometry in the far vacuum ultraviolet reactions F + HCl,CH4, CHCl3 CHCl2F,and CHClF2

Atomic resonance absorption spectrometry with a nonreversed fluorine resonance lamp (～95 nm) has been used to study the kinetics of elementary reactions of ground state F²P_J atoms in a discharge-flow system. The following rate constants (in cm³/molec·sec)

1 All rate constants are given with 1.5 σ.

were determined at 298° K: The reaction F ₂P_J + HCl(1) was found to give J-excited Cl ₂P_1/2 atoms with a product branching ratio [Cl ₂P_1/2]/[Cl ₂P_3/2] = 0.10.     

Regioselectivity of the Diels-Alder Additions of 2-Substituted 5,6 Dimethylidenenorbornanes and-bicyclo[2.2.2]octanes

The cycloadditions of methyl propynoate and methyl vinyl ketone to 5,6-dimethylidene-2-norbornanone ( 6 ) are para′-regioselective

1 “Para” (p) designs in this paper the 4, 9-disubstituted tricclo[6.2.1.0^{2, 7}] undecane- and 4, 9-disubsstituted tricycle[6.2.20^2,7] dodecane derivatives, “meta” (m) design the corresponding 4, 10-disubstituted compounds.

. A smaller para -regioselectivity is observed for the addition of methyl propynoate to 5,6-dimethylidene-2bicyclo[2.2.2]octanone ( 10 ). No regioselectivity is observed with 5,6-dimethylidene-2exo-norbornyl alcohol ( 3 ), acetate ( 5 ) and 5,6-dimethylidene-2exo-bicyclo[2.2.2]octanol ( 9 ). PMO arguments based on the shape of the HOMO's and subHOMO's of the dienes allow to rationalize these observations. Unpredictable para′- or ‘meta’regioselectivities are found for the Diels,-Alder additions of 5,6-dimethylidene-2endo-norbornyl alcohol ( 2 ), acetate ( 4 ) and 5,6-dimethylidene-2endo-bicyclo[2.2.2]octanol ( 8 ). The carbonyl group of β,γ unsaturated ketones such as 6 and 10 can act as an electron donating homoconjugated substituent. The n(CO) ? σ[C(1), C(2)] ? π[C(5), C(6)] hyperconjugative interaction can override the usual electron-withdrawing effect of this function.     

The very low-pressure pyrolysis of phenyl ethyl ether,phenyl allyl ether,and benzyl methyl ether and the enthalpy of formation of the phenoxy radical

A value of the enthalpy of formation of the phenoxy radical in the gas phase, ΔH°_,298K (?O·, g) = 11.4 ± 2.0 kcal/mol, has been obtained from the kinetic study of the unimolecular decompositions of phenyl ethyl ether, phenyl allyl ether, and benzyl methyl ether

1 Trivial names for ethoxy benzene, 2-propenoxy (allyloxy) benzene, and α-methoxytoluene, respectively

at very low pressures. Bond fission, producing phenoxy or benzyl radicals, respectively, is the only mode of decomposition in each case. The present value leads to a bond dissociation energy BDE(?O—H) = 86.5 ± 2 kcal/mol,

2 1 kcal = 4.18674 kJ (absolute)

in good agreement with recent estimates made on the basis of competitive oxidation steps in the liquid phase. A comparison with bond dissociation energies of aliphatic alcohols, BDE(RO—H) = 104 kcal/mol, reveals that the stabilization energy of the phenoxy radical (17.5 kcal/mol) is considerably greater than the one observed for the isoelectronic benzyl radical (13.2 kcal/mol). Decomposition of phenoxy radicals into cyclopentadienyl radicals and CO has been observed at temperatures above 1000°K, and a mechanism for this reaction is proposed.     

Die stereospezifische Reduktion von (1R)-3-endo-Aminocampher zu (1R)-3-endo-Aminoborneol

The highly stereospecific reduction of (1R)-3-endo-aminobornan-2-one ( 2 ) to [1R]-3-endo-amino-2-endom-bornanol ( 1 ) is described. This reaction is achieved by using alkylaluminumdichlorides, a new group of reducing agents for the reduction of the ketone 2 to the secondary alcohol 1

1 Diesc Reduktion ist Gegenstand van Patcntanmeldungen, z. B. [l].

     

(Perhalogenmethylthio)heterocyclen. XII. Herstellung von Perfluoroalkylsulfonylharnstoff-Derivaten sowie CCl3−nFnX-substituierten Heterocyclen und deren biologische Wirkung

(Perhalomethylthio)heterocycles XII. Preparation of Perfluoroalkylsulfonylurea Derivatives as well as CCl_3?nF_nX-Substituted Heterocycles and Their Biological Activity

1 XI, Mitt., s.[1]

In the presence of CF₃SO₃H (chlorodifluoromethylthio)thiophene 1 reacts with CClF₂SCl to give the 2,5-disubstituted thiophene 2a which on oxidation with 30% H₂O₂-solution yields the corresponding sulfonyl compound 2b · R¹SO₂NCO adds amines to give R¹SO₂NHC(O)NHR 3a – g . Some biological properties of these compounds were investigated.