Substitution oxidative

Other reactions taking place throughout the hardening period are substitution and addition reactions (29). Ferrite and sulfoferrite analogues of calcium monosulfoaluminate and ettringite form soHd solutions in which iron oxide substitutes continuously for the alumina. Reactions with the calcium sihcate hydrate result in the formation of additional substituted C—S—H gel at the expense of the crystalline aluminate, sulfate, and ferrite hydrate phases. 

Pyridazine 1-oxides substituted at position 3 or positions 3 and 6 afford the corresponding 5-nitro derivatives. A methyl group at position 6 (a with respect to the iV-oxide group) is frequently converted into the cyano group, and a methoxy group at position 6 is demethy-lated by benzoyl chloride/silver nitrate. For example, 3-substituted 6-methylpyridazine 1-oxides give the 5-nitro derivatives (96) and the 6-cyano-5-nitro derivatives (97), whereas... 

Oxidative substitutions at ring junction positions in various tetrahydro-5-deaza-pterins (79JA6068) and -flavins (77JA6721) have been studied, e.g. to give (13), and the oxidation-reduction reactions of 5-deazaflavins (e.g. 78CL1177, 80CPB3514) across the 1,5-positions, e.g. (19) (20), are involved in their co-enzymic role in enzymic oxidations (see Section... 

Deazaflavin, 5-amino-synthesis, 3, 222 5-Deazaflavin, tetrahydro-oxidative substitutions, 3, 205 Deazaflavinium salts synthesis, 3, 228 5-Deazaflavinoids, 3-aryl-synthesis, 3, 219 Deazaflavins... 

Hintner J-P, T Reemtsma, A Stolz (2004) Biochemical and molecular characterization of a ring fission dioxygenase with the ability to oxidize (substituted) salicylate(s) from Pseudaminobacter salicylatoxidans. J Biol Chem 279 37250-37260. 

On the other hand, the oxidation of the alkyl substituent in alkyl aromatic compounds can be carried out by various methods efficiently. For example, CAN has been used to oxidize substituted toluene to aryl aldehydes. Selective oxidation at one methyl group can be achieved (Eq. 7.19).44 The reaction is usually carried out in aqueous acetic acid. 

Tc2[(CH3)3CCOO]4 C12. The first binuclear d4-d4 technetium complex was obtained by Cotton and Gage [45] by oxidative substitution of the chloride ions in the coordination sphere of [Tc2Cl8]3 by trimethylacetate ions. The substitu-... 

Oxidative Substitution of Monodentate Ligands by Bidentate Ligands... 

Various diphenylphosphine oxide-substituted seven-membered rings 2-200, including also hydroazulenes, were synthesized by a Michael addition of 2-198, obtained from 2-197, and 2-199 followed by a Wittig reaction as developed by Fujimoto and coworkers (Scheme 2.47) [114]. 

A similar (but somewhat less obvious) dichotomy results in the simultaneous ring and sidechain substitution of durene. Thus in this charge-transfer nitration, the addition of N02 to the cation radical DUR+- (72) occurs in competition with its deprotonation (73), in which the pyridine has been shown to act as a base (Masnovi et al., 1989) (Scheme 15). [Note that deprotonation of DUR+- also leads to aromatic dimers via the subsequent (oxidative) substitution of the benzylic radical formed in (73) (Bewick et al., 1975 Lau and Kochi, 1984).]... 

Above experience in PVC modification was recently applied to PECH which seems to have more labile (reactive) primary chlorine atom. PECH would be useful in the preparation of poly(propylene oxide) substitut-... 

Since Figure 17 is constructed only with calculations on Mn oxides substituted with one other 3d metal, it is not clear whether using Figure 17 to predict the valence of two or more non-Mn 3d TM ions coexisting in an oxide would be valid. However, with additional calculations on non-Mn TM oxide compositions perhaps Figure 17 can be expanded to address combinations of non-Mn TM ions. 

Table 4.7. Poly(ethylene oxide)-substituted phosphine ligands in rhodium-catalyzed...

Ni(02)(CNBu )2] reacts with a variety of compounds and the reactions which are outlined in Scheme 5 can be classified as either atom transfer redox reactions, atom transfer oxidation reactions, oxidative substitution reactions or metal assisted peroxidation reactions. An i.r. study of [Ni( 02)(CNBu )2]... 

Oxide Substitution No. of samples Surface area m g" Dissolving medium TfC) Model Reaction rate Activation energy (kj mot ) Author... 

In a different study, anthracene, phenanthrene, perylene 93 (Fig. 31), and 2,7-di-tert-butylpyrene underwent regioselective oxidative-substitution reactions with iodine(III) sulfonate reagents in dichloromethane to give the corresponding aryl sulfonate esters. The use of [hydroxy(tosyloxy)iodo]benzene, in conjunction with trimethylsilyl isothiocyanate, led to thiocyanation of the PAH nucleus. 

Recently, the preparation of metallosilicates with MFI structure, which are composed of silicone oxide and metal oxide substituted isomorphously to aluminium oxide, has been studied actively [1,2]. It is expected that acid sites of different strength from those of aluminosilicate are generated when some tri-valent elements other than aluminium are introduced into the framework of silicalite. The Bronsted acid sites of metallosilicates must be Si(0H)Me, so the facility of heterogeneous rupture of the OH bond should be due to the properties of the metal element. Therefore, the acidity of metallosilicate could be controlled by choosing the metal element. Moreover, the transition-metal elements introduced into the zeolite framework play specific catalytic roles. For example, Ti-silicate with MFI structure has the high activity and selectivity for the hydroxylation of phenol to produce catechol and hydroquinon [3],... 

A more efficient method for converting the oxide (258) to 2-azaquinolizinium bromide is by refluxing it in phosphorus tribromide (Scheme 129) <67JCS(C)2391>. Deoxygenation by use of phosphorus trichloride or tribromide proved effective (7lJCS(C)86l) with a number of 2-azaquinolizinium 2-oxides substituted in positions 1 and 3, although the 1-methyl oxide offered some resistance. 

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