Triphenylmethane , formation

Evidence for this suggestion was obtained by NMR spectroscopy of reacting mixtures which showed that triphenylmethane formation was almost eliminated and a trityl ether unit formed when the reaction systems contained propylene oxide. While this interpretation is consistent with most of the experimental work published, Kuntz and Melchior (25) also report that cocatalysis by propylene oxide can be observed when the latter is added several hours after the start of polymeriza-... 

Hydroxy-2-Naphthalenecarboxylic Acid. l-Hydroxy-2-naphthoic acid is made similarly to the isomer (2-hydroxy-1-naphthoic acid) by reaction of dry sodium 1-naphthalenolate with CO2 in an autoclave at ca 125°C. It has been used in making triphenylmethane dyes and metalli able a2o dyes. Alkylamides and arylamides of l-hydroxy-2-naphthalenecarboxyhc acid are cyan couplers, ie, components used in indoaniline dye formation in color films (see Color PHOTOGRAPHY). 

If the alkyl halide contains more than one, equally reactive C-halogen centers, these will generally react each with one aromatic substrate molecule. For example dichloromethane reacts with benzene to give diphenylmethane, and chloroform will give triphenylmethane. The reaction of tetrachloromethane with benzene however stops with the formation of triphenyl chloromethane 7 (trityl chloride), because further reaction is sterically hindered ... 

Methylsulfinyl carbanion (dimsyl ion) is prepared from 0.10 mole of sodium hydride in 50 ml of dimethyl sulfoxide under a nitrogen atmosphere as described in Chapter 10, Section III. The solution is diluted by the addition of 50 ml of dry THF and a small amount (1-10 mg) of triphenylmethane is added to act as an indicator. (The red color produced by triphenylmethyl carbanion is discharged when the dimsylsodium is consumed.) Acetylene (purified as described in Chapter 14, Section I) is introduced into the system with stirring through a gas inlet tube until the formation of sodium acetylide is complete, as indicated by disappearance of the red color. The gas inlet tube is replaced by a dropping funnel and a solution of 0.10 mole of the substrate in 20 ml of dry THF is added with stirring at room temperature over a period of about 1 hour. In the case of ethynylation of carbonyl compounds (given below), the solution is then cautiously treated with 6 g (0.11 mole) of ammonium chloride. The reaction mixture is then diluted with 500 ml of water, and the aqueous solution is extracted three times with 150-ml portions of ether. The ether solution is dried (sodium sulfate), the ether is removed (rotary evaporator), and the residue is fractionally distilled under reduced pressure to yield the ethynyl alcohol. 

The effect of solvent upon k2 has been reported , and it was concluded that the activated complex is not sufficiently polar to be called ionic . The oxidations of toluene and triphenylmethane exhibit primary kinetic deuterium isotope effects of 2.4 and ca. 4 respectively. No isotopic mixing occurred during formation of the Etard complex from a mixture of normal and deuterated o-nitrotoluene . The chromyl chloride oxidation of a series of substituted diphenylmethanes revealed that electron-withdrawing substituents slow reaction while electronreleasing groups have the opposite effect, the values ofp andp being —2.28 + 0.08 and —2.20 + 0.07 respectively . ... 

Anodic oxidation has been employed for water-soluble triphenyl-methane dyes. It has been shown that the formation of dye is an irreversible two-electron oxidation process.21-23 This method has been used for the oxidation of diamino triphenylmethane leuco compounds containing two to four sulfonic acid groups to obtain food-grade colored materials.24... 

The formation of color from triheteroarylmethanes differs from the methodology employed for triphenylmethane leuco dyes40 (Scheme 4). Dyes are initially formed by alkylation of the pyridyl nitrogen, followed by deprotonation at the central methine carbon. Thus, treatment of the colorless 3,3 -diindolyl-4-pyridylmethane 22 with excess methyl iodide produces colorless compound 23. Subsequent treatment of 23 with hydroxide... 

Pressure-sensitive recording materials are obtained by dissolving a triphenylmethane leuco dye in a solvent composed of paraffin oils. The microcapsules are formed from a water-soluble106 or water-dispersible material.107,108 Leuco dyes dissolved in sunflower oil are microencapsulated in a solution containing a melamine-HCHO precondensate and coated on the back side of a paper sheet. Contact of the microcapsule-coated sheet with an acid-coated receptor sheet allows the color formation to occur. 

The technical preparation of crystal violet and of its methyl-free parent substance, parafuchsine, almost the oldest of the triphenylmethane dyes, is not so easily explained. As is well known, in this process aniline and p-toluidine are united by oxidation in an acid melt. (In the preparation of fuchsine itself, which contains a methyl group attached to one of the benzene rings, o-toluidine is an additional ingredient.) Although all the phases of this important synthesis have not yet been experimentally established, we may nevertheless explain it on the basis of a dehydrogenation similar to that involved in the formation of malachite green. Moreover, the union of several molecules of base proceeds exactly according to the principle on which indamines are formed (p. 321) (Bucherer). 

An alternative route to phenolate-like EGBs is through the cathodic reduction of quinonemethides, (36), [82, 83]. The advantage of these PBs is that they are reduced at modest potentials, which allow EGB formation to take place in situ, and they are ultimately converted into phenols that are easily reoxidized to (36) either by air or by anodic oxidation (60-70% yield) [82]. The radical anion (36a) is expected to have basicity similar to that of (35) , whereas the pK of the conjugate acid of the dianion formed by further reduction can be assumed close to that of triphenylmethane, 30.6. 

Addition of triphenylmethane (PhsCH) to photolysis mixtures led to an increase in the product ratio 136h/134h from ca. 1.3 in the absence of Ph CH to ca. 9 at [PhsCH] > 0.15 M. The dimeric product 137 (Scheme 56) was isolated in these experiments, but no PhsCOH was detected. The generation of 137 is consistent with formation of PhsC-, but not Ph3C. ... 

The enthalpy of formation for the solid triphenylmethane is from Reference 5. The enthalpy of fusion, 22.0 kJ mol at 365 K, is taken from Reference 8. 

Product formation was interpreted in terms of transalkylation of substituted triphenylmethanes. Protonation at the ipso position of the substituted phenyl ring to form arenium ion 64 followed by the C—C bond breaking yields the diphenylmethyl cation, which alkylates benzene or is stabilized by hydride transfer (Scheme 5.30). The protonated intermediate 64 is highly unstable when the ring has an electron-withdrawing substituent. Consequently, its transformation is extremely slow and the primary product triphenylmethane can be isolated. 

The amide ions are powerful bases and may be used (i) to dehydrohalogenate halo-compounds to alkenes and alkynes, and (ii) to generate reactive anions from terminal acetylenes, and compounds having reactive a-hydrogens (e.g. carbonyl compounds, nitriles, 2-alkylpyridines, etc.) these anions may then be used in a variety of synthetic procedures, e.g. alkylations, reactions with carbonyl components, etc. A further use of the metal amides in liquid ammonia is the formation of other important bases such as sodium triphenylmethide (from sodamide and triphenylmethane). 

Certain aliphatic aldehydes which have no hydrogen atoms on the a-carbon atom undergo cleavage under the influence of alkali. The conversion of a trihaloacetaldehyde to the haloform and the alkali formate is the best-known example. Triphenylacetaldehyde undergoes a similar cleavage, yielding triphenylmethane and the alkali formate.38 Aldehydes in which the a-carbon atom is part of an ethylenic or acetylenic system do not give the normal Cannizzaro reaction their behavior is discussed on p. 102. 

Ortho-adduct formation is an unlikely complication in transfer of hydride to substituted 9-phenylfluoren-9-yl cations from triphenylmethane, or 4,4 -dimethoxydiphenylmethane (Bethell et al., 1981). The log of the rates correlated with a+ constants, giving p-values of 2.44 when triphenylmethane is the donor and 3.02 when the diphenylmethane was the" donor. They also correlate with the difference in pA R+ between the product and acceptor carbocation. There does not seem to be a simple pattern of reactivity in the... 

Such a self-sorting process can also lead to the formation of structurally well-defined assemblies of the dendrimer type [66], We have demonstrated this in a first example, using the dimerization of tri-ureas 26 derived from triphenylmethanes [67]. It has been shown that this dimerization is independent of the dimerization of tetra-urea calix[4]arenes. It is neither disturbed by tetra-ureas nor does it disturb their dimerization. In addition, Figure 5.20 even shows that the dimerization of rigidified tetra-ureas 25 also occurs independently [68]. 

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