Pyrene-1-acetic acid

Instead of grafting a coordinating chromophore on the macrocyclic framework, which sometimes requires the recourse to relatively comphcated synthetic routes, another strategy was tested, which forms ternary complexes in situ. An example is pyrene acetic acid H34 (fig. 35) which reacts with [Ln(26d)(H20)2] to form kinetically labile ternary complexes [Ln(26d)(34)(H20)x], Ln = Nd, Yb (Faulkner et al., 2004). Metal-centered luminescence occurs upon pyrene excitation. However, according to lifetime measurements for Yb111, 0.72 and 2.52 ps in H2O and D2O, respectively, and the use of eq. (9a), q = 0.9, which suggests that a pyrene acetic acid molecule is coordinated to the metal center expelling one water molecule, but not the second one. That is, the ternary complex does not represent an improvement over [Yb(30a)]. 

Pyridylamine, see 2-Aminopyridine a-Pyridylamine, see 2-Aminopyridine p-Pyrine, see Pyrene Pyrinex, see Chlorpyrifos Pyroacetic acid, see Acetone Pyroacetic ether, see Acetone Pyrobenzol, see Benzene Pyrobenzole, see Benzene Pyrofax, see Butane Pyroligneous acid, see Acetic acid Pyromucic aldehyde, see Furfural Pyropentylene, see Cyclopentadiene Pyrophosphoric acid, tetraethyl ester, see Tetraethyl pyrophosphate... 

In aqueous acetic acid, the disproportionation of the platinum still occurs quite rapidly, and it can be suppressed further by adding mineral acid. Hydrochloric acid is often used, but this has a disadvantage in that the exchange rate is inversely proportional to the chloride ion concentration. Perchloric acid has been found to be more satisfactory (55). The platinum(II) catalyst most used is sodium or potassium tetrachloropla-tinate(II). An aromatic compound added to the reaction mixture also inhibits disproportionation of the platinum(II) complex—benzene, pyrene, and other aromatics have been used. A comparative study of the effect of various aromatics on the H—D exchange in alkanes has been carried out (55). Even under optimum conditions, the disproportionation [Eq. (4)] still takes place, and the catalytic platinum(II) is slowly removed from the reaction mixture. To get useful rates of exchange in alkanes, temperatures of 100° to 120°C have to be used, and the disproportionation rate increases with temperature. 

Phenanthrene and pyrene on treatment with diisopropylcarbodiimide, hydrogen peroxide, and acetic acid in ethyl acetate at room temperature give 1 and 4 in 28% and 27% yields, respectively.17 Similar reaction occurs with dicyclohexylcarbodiimide and cyclohexylbenzylcarbodiimide. The hydrogen peroxide can be either 98% or a 30% aqueous solution. Use of silica gel, Dowex 50W-X8, or diphenylphosphinic acid instead of acetic acid is also permissible. However, because of the sensitivity of arene oxides toward strong acids, hydrochloric, sulfuric, or polyphosphoric acids cannot be used. 

Acetoxyiodination of cyclohexene derivatives is acquired by the oxidative combination NCS/Nal/AcOH427. NBS/AcOH is the common reagent for acetoxybromination428. N-Bromoacetamide in acetic acid or water reacts with 1 l,12-dihydrobenzo[e]pyrene to yield the corresponding bromoacetate and bromohydrine, respectively429. KBr can also be used under oxidative conditions, e.g. coupled with peracid and 18-crown-6430. Iodo enol acetates are obtained by reaction of bis(pyridine)iodo tetrafluoroborate with acetylenes in acetic acid (equation 51)431. 

A solution of 25 g. (0.125 mole) of pyrene (Note 1) in 100 ml. of dimethylformamide (Notes 2 and 3) is treated with a 50% excess of ozone (Note 4). The solution of the ozonide is added at a moderate rate, with stirring, to 500 ml. of 1% aqueous acetic acid. The suspension is allowed to stand overnight (Note 5), and the resulting solid is collected by filtration and washed with water. 

In preparing 5-formyl-4-phenanthroic acid by ozonization of pyrene in dimethyl-formamide, Dessy and Newman stirred the solution of ozonide into 1% acetic acid, collected the solid which separated, and extracted it repeatedly with hot aqueous potassium hydroxide solution. When the dark brown filtrate was treated with potassium hypochlorite solution, let stand overnight, and then heated on the steam... 

Oxidative dimerization 8 [1, 818, before references]. Pyrene (1) is converted into bipyrene (2) by reaction with periodic acid in aqueous acetic acid at 48-51° for 45... 

The gas phase photochemistry of acetic acid has been studied by ab initio methods. The photochemical decomposition of aliphatic amino acids using circularly polarized light has been reported. Many examples were cited. A typical result is shown in Scheme 3 for the decomposition of valine in aqueous HCl solution. Pyrene has been established as the most effective polycyclic arene sensitizer for the photochemical decomposition (irradiation at 366 nm) of N-phenylglycine. The introduction of electron-donating groups into the aryl ring of the glycine also enhances the rate of decomposition. ... 

Arene oxides. The reaction of this carbodiimide (supplier Aldrich) with hydrogen peroxide generates a peroxycarboximidic acid (1) (c/ Payne s reagent 6, 455-456). In combination with acetic acid, 1 converts phenanthrene into the 9,10-oxide (28% yield) and pyrene into the 4,5-oxide (27% yield). Some other carbodiimides can be used in this reaction. ... 

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