Potassium derivatives

Shibata, S. Omima, Y. Matsui, and S. Motegi, Bull. Chem. Soc. Japan, 1975, 48, 2516. 

Phase transitions in potassium (T = 334 K) and rubidium (T = 320 K) acrylates have been established by wide-line n.m.r. and differential scanning calorimetry. Transitions were not observed for Li and Na salts. The i.r. spectrum of HCO2K in KBr discs is variable. The spectra obtained all proved to be superpositions of two spectra, one due to the original solid, and the other to a transformation product, formed when pressure was applied. 

Electron microscopy of and a study of electron dilBfraction by a thin film of the complex formed between copper phthalocyanine and potassium have revealed a unique crystalline structure/ The electron micrographs showed that an island film structure existed, with single crystals of the complex being up to 1 /utm in diameter. The films were stable in vacuo, but on exposure to air they degraded over a period of 24 hours, after which only traces of the ordered structure were observable by electron diffraction. 

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Picrates of p-naphthyl alkyl ethers. Alkyl halides react with the sodium or potassium derivative of p-naphthol in alcoholic solution to yield the corresponding alkyl p-naphthyl ethers (which are usually low m.p. solids) and the latter are converted by alcoholic picric acid into the crystalline picrates ... 

Syntheses of Nicotine. Pictet and Cr pieux found that 3-aminopyridine mueate on dry distillation yielded l-(3-pyridyl)pyrrole (I), and this, in accordance with the usual behaviour of such pyrrole derivatives, transfers its pyridyl substituent from the 1- to the 2-position at a red heat giving 2-(3-pyridyl)pyrrole (II), which is nomieotyrine. The potassium derivative of this reacts with methyl iodide to form l-methjd-2-(3-pyridyl)-pyrrole methiodide, which is identical with nieotyrine methiodide (III), and on distillation with lime yields nieotyrine (IV Cl — CH). For a re-investigation of this synthesis see Spath and Kainrath. ... 

Oxyacanthine contains three methoxyl groups, and one phenolic hj droxyl group is indicated by the preparation of an 0-benzoyl derivative, a potassium derivative and a methyl ether (identical with trilobamine methyl ether, p. 357) yielding a hydroehloride,. 2HC1, m.p. 

The alkynylation of estrone methyl ether with the lithium, sodium and potassium derivatives of propargyl alcohol, 3-butyn-l-ol, and propargyl aldehyde diethyl acetal in pyridine and dioxane has been studied by Miller. Every combination of alkali metal and alkyne tried, but one, gives the 17a-alkylated products (65a), (65c) and (65d). The exception is alkynylation with the potassium derivative of propargyl aldehyde diethyl acetal in pyridine at room temperature, which produces a mixture of epimeric 17-(3, 3 -diethoxy-T-propynyl) derivatives. The rate of alkynylation of estrone methyl ether depends on the structure of the alkyne and proceeds in the order propar-gylaldehyde diethyl acetal > 3-butyn-l-ol > propargyl alcohol. The reactivity of the alkali metal salts is in the order potassium > sodium > lithium. 

The easiest access to most benzyllithium, -sodium, or -potassium derivatives consists of the deprotonation of the corresponding carbon acids. Hydrocarbons, such as toluene, exhibit a remarkably low kinetic acidity. Excess toluene (without further solvent) is converted into benzyllithium by the action of butyllithium in the presence of complexing diamines such as A. Af.Af.jV -tetramethylethylenediamine (TMEDA) or l,4-diazabicyclo[2.2.2]octane (DABCO) at elevated temperatures1 a procedure is published in reference 2. 

Thus, the allyllithium, -sodium or -potassium derivatives are the ones which are most easily generated (Section D.1.3.3.3.1.1.), but they are of limited value in stereoselective carbonyl addition reactions. Usually these reagents need to be tuned" in their reactivity by metal exchange prior to application in order to achieve high selectivities. 

Unsubstituted or alkyl-substituted 2-alkenyllithium, -sodium and -potassium derivatives are of little value in stereoselective carbonyl addition reactions. In general, these reagents exhibit high... 

Investigation of the configurational stability of allylmetals 2a, prepared by means of Rieke metals from geometrically pure l-chloro-2-decenes 1 a in THF, showed that the (Z)- and (ZT)-lithium, -sodium, and -potassium derivatives preserve the configuration of the precursors to a preparatively useful extent below — 90°C, — 50°C, and >0°C, respectively. For the pairs of 3,7-dimethyl-2,6-octadienyl derivatives (Z)- and ( )-2b, which differ less in their thermodynamic stability, the respective temperatures are — 60 °C, — 40 °C and >0°C124. 

The structural investigations have been extended to potassium derivatives of the "super" formamidine HC(NC6H3Pr2-2,6)(NHC6H3Pr2-2,6) ( = HDippForm). Treatment of the free formamidine with KN(SiMe3)2 yielded the formamidinate species [K(DippForm)2K(THF)2l (THF) , which exhibits a macromolecular structure of alternating fj -arene f/ -amidinate bound potassium di-amidinate and potassium di-THF units in a one-dimensional polymeric array (Figure 5). Addition of a further equivalent of HDippForm afforded hydrogen-bonded [K(DippForm)(THF)3](HDippForm). ... 

Such representation with a formal Sn-Sn bond order of 1.5 and highly trans-btrA substituents is suggestive of the diminished Sn-Sn hybridization resulting from the poor 5p -5p -orbitals overlap to form weak tt-bonds. The anion radical sodium salt 51-Na, prepared similarly by the reaction of chlorostannylene 52 with sodium an-thracenide in THF, exhibited structural and spectral features identical to those of the above-described potassium derivative 51-K (Scheme 2.39). ... 

Bis and tris(pyrazolyl)hydroborato ligands are generally prepared as the potassium derivatives by the direct reaction of KBH4 with the appropriate pyrazole (RR pzH), as illustrated in Scheme 1 for the parent system (13). The reaction is extremely general and has been applied to a number of different derivatives, which have included the incorporation of chiral (14, 15) and tethered (16) substituents. However, if the alkyl substituents of the pyrazole are inequivalent (i.e., R + R ), a potential problem may be encountered with the formation of isomeric products, in which either of the R and R substituents may occupy the 3-position of the poly(pyrazolyl)borato ligand. Nevertheless, if the difference in steric demands of R and R is large, there is a strong... 

The potassium derivatives obtained from the reaction mixture are typically not isolated in pure form, and the crude products are often converted directly to the thallium complexes by metathesis with either thallium nitrate or thallium acetate [Eqs. (1) and (2)]. 

It has long been recognized that anionic poly(pyrazolyl)borato derivatives may be readily monoprotonated to give the neutral acids (lb). For example, [pzTp]H, [Tp]H, and [Bp]H derivatives can be obtained by acidification of the appropriate potassium derivative with glacial acetic acid, (lb, 123, 200). Similarly, [Bp]H has also been obtained by acidification of K[Bp] with HCl(aq). The structures of [(Me2pz)TpMe2]H (201) and [Bp]H (117) have been determined by x-ray diffraction. Mono-... 

When the potassium derivative was allowed to stand in ammonia, single crystals of the diammoniate K2[Zn(C2Fl)4]-2NFl3 63 separated.120 A low-temperature, single crystal X-ray analysis of 63 showed it to consist of tetrahedral [Zn(C2H)4]2 ions, which feature almost linear Zn-C-C units. The zinc-carbon bonds (2.053(3) A) are slightly longer than those in 64, while the carbon-carbon bonds are identical (1.203(4) A) in length. 

The reaction of KSb(SiMe3)2 with Me3SiP=C(But)(OSiMe3) gives the potassium derivative of the diphospha-stibolyl 2,39 which reacts in the presence of FeCl3 with the formation of cage 4.40 The stibindolyl anion 3 is formed in a one-pot synthesis from trimesitylantimony and potassium.41... 

This remarkable reaction occurs because alkalis (potassium hydroxide) convert benzoin partly into the di-enol form, i.e. into the potassium derivative of stilbenediol C6H5.COK COK.CgHg.1... 

In the synthesis due to Heumann and Pfleger the fusion yields the potassium derivative of indoxyl, which is dehydrogenated to indigo even by atmospheric oxygen at the same time hydrogen peroxide is produced (see p. 175). 

The next example deals with an effect of ferrous chloride addition (Galli and Gentili 1993). Phenyl iodide reacts with the potassium derivative of l,l-dimethyl-butan-2-one (pinacolin) in DMSO according to the following equations ... 

The use of KN(SiMe3)2 as metalating reagent enabled us to prepare the dimeric potassium derivative [(Cy7Si70i2)2Kg(DME)4] (18) as a crystalline solid, which was structurally characterized by X-ray diffraction (Scheme 7). Here again a box-shaped KgOg polyhedron forms the central structural unit. Four potassium ions are coordinated by DME (1,2-dimethoxyethane) ligands. ... 

A-Lithium and A-potassium derivatives of A-Boc 0-p-tosylhydroxylamines have been also reported to react rapidly with organoboranes to give A-Boc protected primary amines in modest to good yields (Scheme 28) . 

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