Methane derivatives

The cryptophane is typical of the chiral resolution of methane derivatives (eg, CHFClBr) (146) and the basket-shaped host of Figure 23d exhibits extremely high enantioselectivity for various peptides (144). 

Carbanioas derived from the other above mentioned methane derivatives react with alkylboranes, bornic, and boronic esters, providing rich possibihties for the preparation of siagle-carbon iasertion products. Thus 2-aLkyl-l,3,2-dithiaborolanes are converted iato acids or thioacetals by trichloromethyllithium (335). 

Methane, chlorine, and recycled chloromethanes are fed to a tubular reactor at a reactor temperature of 490—530°C to yield all four chlorinated methane derivatives (14). Similarly, chlorination of ethane produces ethyl chloride and higher chlorinated ethanes. The process is employed commercially to produce l,l,l-trichloroethane. l,l,l-Trichloroethane is also produced via chlorination of 1,1-dichloroethane with l,l,2-trichloroethane as a coproduct (15). Hexachlorocyclopentadiene is formed by a complex series of chlorination, cyclization, and dechlorination reactions. First, substitutive chlorination of pentanes is carried out by either photochemical or thermal methods to give a product with 6—7 atoms of chlorine per mole of pentane. The polychloropentane product mixed with excess chlorine is then passed through a porous bed of Fuller s earth or silica at 350—500°C to give hexachlorocyclopentadiene. Cyclopentadiene is another possible feedstock for the production of hexachlorocyclopentadiene. 

The melting ranges and glass transition temperatures of a number of polycarbonates from di-(4-hydroxyphenyl)methane derivatives are given in Table 20.10. 

An important side reaction is the formation of diaryl methane derivatives ArCHaAr. Moreover poly substituted products may be obtained as minor products. Aromatic compounds have been treated with formaldehyde and hydrogen bromide or hydrogen iodide instead of hydrogen chloride. The formaldehyde may be replaced by another aldehyde the term Blanc reaction however stands for the chloromethylation only. 

Lithiumalanat in siedendem Bis-[2-methoxy-athyl]-ather reduziert 1,1-Diaryl-athylene bei gleichzeitiger Me-thylierung durch das Losungsmittel5 (Diphenyl-methan-Derivate werden ebenfalls methyliert6). Natrium-bis-[2-methoxy-athoxy]-aluminiumhydrid reduziert und methyliert selbst 1,1-Diphenyl-athylen (in Kohlenwasser-stoff-Losung)7 und Arene8. 

Dihalogen- und Trihalogen-methan-Derivate werden zu Methanen hydrodehaloge-niert. 

The reaction has not been elucidated. Presumably Michler s thioketone reacts with organomercury compounds to yield intensely colored, mesomer-stabilized diphenyl-methane derivatives. 

Treatment of N, O-acetals 42 in which the para position is unsubstituted, with a twofold excess of the corresponding amine HC1 in boiling 50% aqueous methanol gives rise to the bis(4-aminoaryl)methane derivative.62 43. This method is suitable only for 4-AT,AT-unsubstituted diarylamines (Eq. 5). 

Presumably, 9 is actually formed from carbene 8 in the pyrolysis zone by a P/C phenyl shift, but then apparently succumbs to fast transformation into the thermodynamically stable final products. Formation of the methane derivative 13 should be preceded by a 1,2-phenyl shift to give the shortlived 10, the production of fluorene (14) by the occurrence of diphenylcarbene (II), and the formation of benzophenone (15) by isomerization to the angle-strained three-membered heterocycle 12, which is followed by elimination of phenylphospbinidene. No direct evidence is available for the intermediacy of 10-12. 

The liquid alloy gives mixtures with halocarbons even more shock-sensitive than those with potassium. Highly chlorinated methane derivatives are more reactive than those of ethane, often exploding spontaneously after a delay [1]. Contact of... 

Furylcarbinols with protic acids (fluoroboric acid) may merely give car-benium (furylium) salts.171 Similar cations are accessible via 2-furyldiazo-methane derivatives,172 but in many cases ring opening and prototropic shifts ensue as in Marckwald reactions (Scheme 30).173 A recent development controls solution acidity by using magnesium or zinc ions instead of protons... 

The tri(azulenyl)methane derivative 24+ including a 6-azulenyl group was prepared by the reaction of azulene 6b with diethyl 6-formylazulene-l,3-dicarboxylate. Synthesis of 24+ was accomplished by hydride abstraction with DDQ. Cation 24+ was isolated as a hexafluorophosphate salt by treatment with aqueous HPF6. The new salt is a stable, deep-green colored crystals, that can be... 

The quantity measured in the experimental work on the methane derivatives was the rotation of the Na D-line in ethanol solution (sometimes it was necessary to use another solvent, in which case a correction was applied). The sum (5), as well as its separate terms, was evaluated for 13 different choices of the set of ligands a,b,c,d,x. For eleven of these, the observed sum was less in absolute value than its statistical average calculated from the absolute values of the separate terms. For the other two (as well as for some of the eleven), the mixture contained molecules for which one would expect large deviations from T,rsymmetry, and/or dimerization. For those mixtures for which the sum (5) was small, a least-square fit was made to the data with a function of the form (2). This best fit was interpreted as the T -component, the remainder as the result of deviation from T -symmetry for each molecule. A fit was also made with functions of the form (1), with less quantitative success. 

Of the synthetic reactions of the alkyl halides that with potassium cyanide, which enabled H. Kolbe to synthesise acetic acid from a methane derivative, has already been mentioned (cf. the preparations on pp. 137 and 254). Of the simpler syntheses that of Wiirtz may be mentioned here. Metallic sodium removes the halogen from two molecules and the two radicles combine. Thus, in the simplest case, ethane is formed from methyl bromide ... 

The formation of the acid dye bmzaurin takes place in a quite analogous manner. p-Tetramethyldiaminobenzophenone (Michler s ketone), which is prepared technically from dimethylaniline and phosgene, can, like benzaldehyde, be condensed with dimethylaniline in the presence of phosphorus oxychloride. In this case, however, it is not a methane derivative, a leuco-compound, which is obtained, but, as the equation shows, the carbinol stage is at once reached. As will soon be shown, however, this stage in acid solution is equivalent to the formation of the dye. 

Substitution of elements or groups of elements ("radicals") into the molecular type became the explanation for the production of compounds that then could be understood as, say, ammonia or methane "derivatives"... 

Individual substituent effects of phenyl groups in substituted methanes and ethanes are not additive either (278), but decrease with progressive substitution In methane derivatives the first a-SCS (144) is 23.5, file second (144 — 145) 20.7, and the third (145 — 146) 14.7 (278). Although these values differ markedly from those of corresponding methylated compounds (methyl instead of phenyl) (169), the tendencies are in good qualitative agreement in both cases. 

Upfield shifts of multiply heterosubstituted carbon atoms are well known in the 13C NMR literature. Some representative examples are shown in Figure 9 and Table 16, where the actual l3C chemical shifts and individual a-SCSs, respectively, for each newly introduced substituent in methane derivatives are compiled. The ICSs can be calculated by subtracting any a-SCS from its respective predecessor within a given row in Table 16. The general trend is toward a distinct decrease of a-SCS with progressive substitution that is, all the ICSs are negative. 

Table 6.15 shows the product mixture from an unstirred (silent) reaction in which the only mixing is by convection, an arrangement not normally used in electrosynthesis. (All electrosyntheses are normally agitated mechanically in some way and therefore still conditions cannot practically be achieved.) For these conditions, the major product was the isomeric mixture of diphenyl methane derivatives. This was similiar to the product mix obtained at 800 kHz. Thus the use of high frequency ultrasound... 

Dittman EC, Etschenberg E. 1973. Endoanesthetic and narcotic activity of halogenated methane derivatives. Eur J Pharmacol 24 389-398. 

In Table 3.3, data are given for some polysubstituted methane derivatives. Here it is possible to judge the effects of sequential additions of the same substituent. The... 

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