Potassium In Liquid Ammonia Research Articles

ChemInform Abstract: Enantioselective Birch Reduction and Reductive Alkylations of Chiral 2‐Phenylbenzoic Acid Derivatives. Application to the Synthesis of Hydrofluoren‐9‐ones, Hydrophenanthren‐9‐ones, and (‐)‐(1R,2R)‐2‐Phenylcyclohexanamine.

AbstractThe reductive alkylation of the chiral benzamide (I) is achieved with potassium in liquid ammonia followed by addition of the alkyl iodides (II), producing the cyclohexenecarboxylic amides (III).

ChemInform Abstract: Allyl Substituted Bisphosphines. Synthesis and Reactivity.

AbstractMetalation of trimethylenebisphosphine (I) with potassium in liquid ammonia produces the intermediates (II) or (III) which react with allyl chloride (IV) to give a mixture of 1,3‐bis(allylphosphino)propane (V) and 1,2‐diallyl‐1,2‐diphospholane (VI).

Synthesis of N,N‐[methyl‐14C]‐dimethylhydrazine of high specific activity

AbstractN,N‐[Methyl‐14C]‐Dimethylhydrazine hydrochloride () having a specific activity of 115 mCi/mmol, was synthesized in two steps. Dimethylation of acetophenone hydrazone with 14C‐methyl iodide (specific activity = 58 mCi/mmol) in the presence of potassium in liquid ammonia followed by acid catalyzed hydrolysis of the hydrazone afforded in a yield of 60.0% (>97% radiochemical purity).

Eine neue Synthese von 8‐Hydroxy‐2‐methyl‐1,2,3,4‐tetrahydroisochinolin

A new Synthesis of 8‐Hydroxy‐2‐methyl‐1,2,3,4‐tetrahydroisoquinolineVilsmeier formylation of N‐[2‐(3,5‐dimethoxyphenyl)ethyl]‐trifluoroacetamide (5) yielded the aldehyde 6, which under mild basic conditions was hydrolyzed to 7 and cyclized to 6,8‐dimethoxy‐3,4‐dihydroisoquinoline (3). Methylation of 3 and reduction of the double bond in 10 afforded 6,8‐dimethoxy‐2‐methyl‐1,2,3,4‐tetrahydroisoquinoline (11). The methoxyl group at C(6) was selectively demethylated and the free hydroxyl group in 12 was phosphorylated to give 13. Reduction of the latter with potassium in liquid ammonia yielded 8‐methoxy‐2‐methyl‐1,2,3,4‐tetrahydroisoquinoline (2), which was demethylated to the title compound 1.

Complex cyanides of titanium

The new complex cyanides of titanium(III) Rb 5(CN) 8, Cs 4Ti)CN) 7 and K 3Ti(CN) 6 have been prepared; K 5Ti(CN) 8, Rb 5Ti(CN) 8 and Cs 4Ti(CN) 7 are believed to contain seven coordinated titanium, while K 3Ti(CN) 6 probably contains an octahedral anion. A titanium(II) cyanide, K 2Ti(CN) 4 has been obtained of potassium in liquid ammonia. The extremely reactive titanium(O) cyanide complex K 4Ti(CN) 4 has been prepared by potassium reduction of a mixture of titanium(III) bromide and potassium cyanide in liquid ammonia.

On the mechanism of the reductive cleavage of anti-9-phenyl- cis-bicyclo[6.1.0]nona-2,4,6-triene

Treatment of the title compound ( 1a) with potassium in liquid ammonia at ca −33° immediately afforded the benzylcyclooctatetraene dianion ( 4a) which, upon quenching with iodine-pentane, gave benzylcyclooctatetraene ( 5) as the only isolable product. In contrast, treatment of 1a with potassium amide in liquid ammonia at −69° initially afforded the 9-phenylmethylenecyclooctatrienyl anion ( 6a) as a short-lived intermediate which was then converted to the α-aminobenzylcyclooctatetraene dianion ( 7a). These results, coupled with the observation that cis-bicyclo[6.1.0]nona-2,4-diene ( 12) in potassium amide-liquid ammonia affords the cis-bicyclo[6.1.0]nonadienyl anion ( 8b) which then slowly opens to the methylcyclooctatetraene dianion ( 4b) at −12°, lead to the conclusion that 4a is produced by a reductive cleavage of 1a via a radical anion or dianion.

Velocity of ultrasound in potassium-ammonia solutions: Dilute solutions

New data on the velocity of 10 MHz compressional waves in dulute solutions of potassium in liquid ammonia are presented. These data are not consistent with the existence of the reported volume expansion minimum. Comparison of this data with earlier data on more concentrated solutions shows that the concentration dependence of the sound velocity is quite similar to that exhibited by both the density and viscosity and is consistent with a model of the solutions proposed by Cohen and Thompson.

8-Methxlcorxpallihe and its O-Metbzlzzher: A Facile Sxhthesis of 8-Methxl Substituted-6, 7- Dimethoxy Tetrahsdroisoquxnolines

Abstract The optically active B-Methy1 substituted tetrahydroisoquinoline (−)− 1 is a major reaction product in the cleavage of the bisbenzylisoquinoline alkaloid repanduline with potassium in liquid ammonia.1 A synthesis of (±) − 1 by a rather lengthy procedure has been reported.2 In this connection we now wish to report a simple and efficient method of introducing an 8-methyl substituent into a 7-hydroxy-6- methoxy tetrahydroisoquinoline. This approach, which has probably wider applications, is exemplified by the synthesia of 8-methylcorypalline 4 and its O-methylether 5 and involves the thiomethylation reaction of poppeladorf and Holt3 followed by reductive desulfurization of the phenyl thiomethyl intermediate.

Thermoelectric Power of solutions of Sodium and Potassium in Liquid Ammonia

AbstractWe have extended the experimental study of the thermoelectric power of metal‐ammonia solutions to the intermediate concentration range.We have also determined the temperature coefficients of the thermoelectric powers.Abnormal behaviors show up between 1 and 2.5% MPM (mole fraction of metal). They are interpreted by the formation of isolated unstable clusters within the bulk of the solution. These clusters become interconnected between 2.5 and 4%, and, beyond 4%, they provide entirely interconnected metallic paths for the transfer of electrons.

Solvation Number of the Electron in Liquid Ammonia. A Nitrogen Magnetic Relaxation Study

The high resolution proton magnetic resonance spectrum of a dilute solution of potassium in liquid ammonia shows a large contribution to the line shape from 14N spin–lattice relaxation through magnetic dipolar interaction with unpaired electrons. The predominant 14N-electron interaction occurs through Fermi contact. From total line shape analyses of the proton spectra recorded at 60 MHz and 100 MHz values were obtained for both τ(e−), the average lifetime of a given 14N in a given electron–ammonia complex, and for N, the average solvation number of the electron. The lifetime varies from approximately 1–2 × 10−12 sec over the concentration and temperature range studied. The solvation number ranges from approximately 20 to 40. These results are most consistent with the lattice vacancy model of the solvated electron.

Viscosities of Solutions of Potassium in Liquid Ammonia and Deuteroammonia

The viscosities of solutions of potassium in liquid ammonia and deuteroammonia have been measured with an Ostwald viscosimeter at − 33.6, 0.0, and + 20.0°C over a concentration range from zero to approximately 1.5 mole liter−1. The methods of measurement and the experimental results are given. The viscosities η of the pure liquids, measured in centipoise, are least-squares fitted by the relations logeη = −4.677 +1.577/RT for ammonia and logeη=−4.676+1.670/RT for deuteroammonia, in which R is the gas constant and T is the Kelvin temperature. (The standard deviations are given in parentheses.) The viscosities of the solutions have been discussed previously.

Conditioning polytetrafluoroethylene surfaces for use in vascular prostheses

AbstractPolytetrafluoroethylene surfaces have been treated to reduce thrombogenicity in order to make them suitable for use in prosthetic devices that come in contact with blood. This was done by first etching the surface with potassium in liquid ammonia to produce double bonds and then using these double bonds as sites for grafting on polyacids or as sites for chemical reactions. Tubes so treated were tested for thrombo‐genetic activity by implantation in the thoracic aorta or inferior vena cava of dogs. These tests showed that the thrombogenicity of a polytetrafluoroethylene surface can be reduced by attaching negatively charged groups provided the surface concentration of these groups is not too high (order of 1–2 × 10−6 equivalent per cm2 geometric area) and provided the distribution of these groups is uniform. Sulfonic acid groups obtained by chlorosulfonation and carboxyl groups attached by grafting tert‐butyl crotonate and hydrolyzing to crotonic acid were effective. Long chains of poly(acrylic acid), poly‐(ethylenesulfonic acid), and poly(vinyl alcohol) sulfate were less effective.

Knight Shifts in Potassium–Ammonia Solutions Doped with Potassium Iodide

A relatively large Knight shift of 127I in solutions of potassium in liquid ammonia with added potassium iodide has been observed. The effect was investigated from M = 0.12 mole liter−1 of potassium to M = 0.95 at 300°K and a concentration of KI equal to 0.03 mole liter−1. At M = 0.95 the shift k = 380 ppm to lower magnetic field; k increases monotonically with increase in M at fixed concentration of KI. At M(K) = 0.44 and M(KI) = 0.14, k increases with increase in temperature from 9 ppm at 211°K to 176 ppm at 300°K similar to that of 23Na in sodium–ammonia solutions. An approximate fit of the data is made in which it is proposed that the species KI− is formed. Self-consistent field calculations were performed for the system electron, iodide ion, and solvent. A weakly bound state is obtained but this species is deemed to be of minor importance. Spin-density calculations are performed for the species KI−. The lifetime of KI− is calculated to be less than 10−11 sec.

Reexamination of the reactions of triethyl- and trimethylboron with sodium and potassium in liquid ammonia

Reexamination of the reactions of triethyl- and trimethylboron with sodium and potassium in liquid ammonia

Heats of Solution of Alkali Metals in Ammonia

The heats of solution of sodium and potassium in liquid ammonia are examined in terms of the redox model which has been proposed for the composition of these solutions. The heats of solution are shown to vary in an essentially linear manner with the spin paramagnetic susceptibility of the solutions, as expected from the model. Analysis of the data yields enthalpy changes for the redox equilibrium M++2S−⇌M−+2S,which are in reasonably good agreement with those obtained from the temperature variation of spin paramagnetic susceptibility. A temperature-dependent enthalpy is indicated for the redox equilibrium.

Reactions of aliphatic halides with solutions of alkali metals in liquid ammonia v. Experiments with trans‐1‐chloro‐2‐butene and 3‐chloro‐1‐butene

AbstractThe reaction of trans‐1‐chloro‐2‐butene with solutions of lithium, sodium, or potassium in liquid ammonia yields mainly trans‐2‐butene, 2,6‐octadiene, and 3‐methyl‐1,5‐heptadiene. Under the same conditions 3‐chloro‐1‐butene yields mainly trans‐ and cis‐2‐butene (in a ratio of about 2 : 1), 3‐methyl‐1,5‐heptadiene, and 3,4‐dimethyl‐1,5‐hexadiene. The composition of the “bibutenyls” provides strong evidence that these products are formed in an SN2 reaction between carbanion and chloride.

Synthesis of (�)-D-homoestrone, (�)-8-iso-D-homoestrone, and the corresponding estradiols

1. By the selective and exhaustive hydrogenation of (±)-8,14-didehydro-D-homoestrone (I) we obtained (±)-8-dehydro-D-homoestrone (II) and (±)-8-iso-D-homoestrone (III), respectively. By the reduction of (±)-8-dehydeo-D-homoestrone 3-(tetrahydropyran-2yl) ether (IV) with potassium in liquid ammonia with subsequent hydrolysis we synthesized (±)-D-homoestrone (VI). (±)-D-Homoestrone (VI) was also prepared in good yield by the demethylation of (±)-D-homoestrone 3-methyl ether (VII). 2. The reduction of the ketones (I), (II), (III), and (VI) with lithium aluminum hydride led stereospecifically and in high yields to the corresponding 17α,β-hydroxy compounds.

Reactions of aliphatic halides with solutions of alkali metals in liquid ammonia IV. Experiments with optically active 1‐phenylethyl halides

AbstractOptically active 1‐phenylethyl chloride or bromide when treated with a solution of lithium, sodium, or potassium in liquid ammonia yields optically active 2,3‐diphenylbutane. It is concluded that the formation of the “biaralkyl” proceeds via carbanions.The absolute configurations of (+)‐ and (‐)‐2,3‐diphenylbutane are deduced.

Electron Spin Relaxation in Metal-Ammonia Solutions

The electron spin resonance relaxation times (T1 and T2) for solutions of lithium, sodium or potassium in liquid ammonia have been measured by transient methods for a resonant frequency of 9340 Mc/s over the temperature range -75 °c to 80 °c. T1 and T2 are equal except for potassium for which T2 is shorter than T1 by an almost constant amount over the whole temperature range. From the equality of T1 and T2 an upper limit on the correlation time of the electron spin interaction with 14N nuclei of 3.5 × 10-12 sec at -33.3 °c is established. An estimate is made of the effective number of 14N nuclei in interaction with the electron spin which excludes the `cavity' model for these solutions. For the dilute solutions of lithium, ζT1, where ζ is the shear viscosity of pure liquid ammonia, is independent of temperature whereas for sodium ζT1/T is about constant.

Heat Conduction in Metal—Ammonia Solutions

The thermal conductivity of solutions of lithium, sodium, or potassium in liquid ammonia has been measured as a function of temperature and concentration. The conductivity shows a strong dependence on concentration and rises with increasing concentration to values of 30–60 mW/cm deg at saturation. Pure ammonia has a conductivity of 5 mW/cm deg. Two modes of heat transport, molecular and electronic, may be invoked to interpret the data. The molecular term follows a semiempirical equation often used for insulating liquids. The electronic heat conductivity obeys a Wiedemann—Franz law, with a Lorenz number about 75% of the free-electron value.