Mono oxidation

On reaction with triflic anhydride, the mono oxides of 2,2 -bis(alkylthio)biphenyl are converted into a dithiadication (48) which spontaneously monodealkylates to give a thiasulfonium salt (49) <96TL667>. 

Regioselective Beckmann rearrangements were used as key steps in the synthesis of phosphonoalkyl azepinones (Scheme 36) [43b] and in a formal total synthesis of the protein kinase C inhibitor balanol (Scheme 37) the optically active azide 197 derived from cyclohexadiene mono-oxide was converted into ketone 198 in several steps. After preparation of the oxime tosylates 199 (2.3 1 mixture), a Lewis acid mediated regioselective Beckmann rearrangement gave the lactams 200 and 201 in 66% and 9% yield, respectively. Lactam 201 underwent a 3-e im-ination to give additional 200, which served as a key intermediate in a balanol precursor synthesis (Scheme 37) [43 cj. 

Another way to describe this non-cyclic phosphino methanide derivatives consists of theuse of monodentate complexes with themono-oxide [203] or monosulfide [204] dppm giving the methanide or methanediide derivatives (14) after addition of the appropriate amounts of [Au(acac)PPh3[. A mixed-valence Au(I)-Au(III) can be isolated by coordination of the fragment AuPPh3 to the free sulfur atom in the mono-oxide starting material [204]. 

The synthesis, structure, and electrochemistry of Ir1 dinuclear complexes [Ir(/i-L)(cod)]2 (L = 2-aminopyridinato (ap) and 2-anilinoj)yridinato (anp)) are reported, in which the square-planar Ir1 centers are 3.0998 A and 3.0681 A apart, respectively.511 Both complexes may be reversibly oxidized to the mixed-valent species. The frozen EPR spectrum of the mono-oxidized anp species shows a rhombic signal with no resolved hyperfine splitting. 

This, the mono-oxide and the 3-amino-6-nitro-2,4-dioxide are all explosives to be... 

When allenyl aldehydes are allowed to react with DMDO, the aldehyde moiety is not oxidized to the acid except for monosubstituted allenes [21]. In all other cases, the carbonyl oxygen participates as a nucleophile in the opening of the intermediate epoxide. From 2,2,5-trimethy]-3,4-hexadienal 67, for example, five different products can be synthesized selectively under different reaction conditions (Scheme 17.22). When p-toluenesulfonic acid (TsOH) is present or DMDO is formed in situ, then the initially formed allene (mono)oxide reacts with the aldehyde moiety to give 68 or 69. In the presence of excess DMDO and the absence of acid, three other products (70-72) can be formed via the spirodioxide intermediate. These reactions, however, seem to be less general compared with similar reactions of allenyl acids and allenyl alcohols. y-Allenylaldehydes 73 can be cyclized to five-membered hemiacetals 74 via the spirodioxide intermediate. 

With hydrogen, the alkali metals form the mono-hydrides MeH, having salt-like properties and a partially ionic, Me H, NaCl-type structure. They are colourless crystalline solids having a fairly negative AH of formation. The mono-hydrides react with water. They may be prepared from hydrogen and the metal (heated at 700-800°C for Li, 350-400°C for the others) or through the reaction of hydrogen with the alkali mono-oxide, nitride, etc. 

In many cases, metal silicides may very well be the catalysts. For example, FeSi2 is being considered to be the catalyst in Fe-assisted nanowire synthesis. This is similar to the silicon mono-oxide case, although it is much easier to understand the mechanisms in the FeSi2 case. It is also possible that during the catalytic processes that silicon diffuses relatively freely through the metal catalyst and consequently, the observed silicides at the end of reaction may be different from those during the catalytic reaction. No direct evidence is available to show whether metal or metal silicide nanoparticles are the tme catalyst. 

A slightly different variation on this concept was developed by Crosby, who used a polymer for selective activation of one alcohol for a supported sulfur based mono-oxidation of heptanediol (Scheme 2.10) [30]. Here the reactant interacts with the support directly (under pseudo high dilution), becoming chemically transformed in the process. 

Fig. 1.42 LC-MS profile of omeprazole metabolites spiked in plasma (A) without mass defect filter, (B) with mass defect filter. Peaks Ml mono-oxidation metabolite [-H6 u, Mass defect (MD) - -5 milliunits], M2 reduction and demethylation (—30 u, MD -HO milliunits), M3 mono-oxidation metabolite (-H6 u, MD —5 milliunits), M4 reduction (—16 u, - -5 milliunits), MS mono-oxidation metabolite (-H6 u, 4-5 milliunits). Adapted with permission from reference [85].

Oxidation of -hexane with Co AlPO-18 with 10% rather than 4% of the framework AP ions replaced with Co resulted in a dramatic enhancement in the formation of adipic acid [65]. It was argued that in these catalysts two Co ions are ideally separated by 7-8 A on the inner wall of the zeolite, allowing both methyl groups unfettered access to catalytically active sites. Furthermore, it was demonstrated that 1,6-hexanediol and 1,6-hexanedial served as precursors to the adipic acid. On the other hand, 1-hexanol, hexanoic acid, and hexanal, which were also formed in the reaction, did not serve as precursors for the adipic acid. It is tempting to suggest that the mono-oxidized hexane products were produced in regions of the zeolite where simultaneous access to two catalytically active sites was not possible. 

Iodide is oxidized rapidly, " bromide slowly, " by the mono-oxidized form of fi-oxo-di-iron(III) bis-tetraphenylporohyrin. The latter reaction occurs in three kinetically distinct steps the first, with 293 = 738dm mol s , AH = 59 kJ mol , and A5 = +9 J K mol leads to the formation of Br2 as intermediate. Cyanide reduces iron(III) porphyrins, probably by rate-limiting nucleophilic attack, at least in DMSO (in which CN has a very high chemical potential). " ... 

Fel3, first isolated in the pure state as recently as 1988 as a black, fairly stable solid (though unstable in solution), reacts with iodide to give the previously characterized complex [Fel4]. Iodide appears stable coordinated to iron(III) in ternary porphyrin complexes such as (12,17-diethoxycarbonyl-2,3,6,7,ll,18-hexamethylcorrphycenato)-iodo-iron(III), where Fe — I = 2.600 A, though it is oxidized by the mono-oxidized form of /.t-oxo-di-iron(III) bis-tetra-phenylporphyrin. " Remarkably, iodide has been reported coordinated to iron(V), in [Fe(313)I]. ... 

Oxidation of the thiadiazole sulfur to its mono-oxide (3) causes a loss in aromatic character which... 

Metal centers are usually mono-oxidized at mild potentials (e.g., at potentials less positive than + 2.00 V versus SCE). However, at more positive potentials a successive oxidation, leading to a formally M,v metal center, can also occur. This has been particularly investigated by using liquid S02 as solvent, as this special medium allows... 

Interestingly, metal-metal interaction appears to be dependent on the oxidation state of the system. This is clearly evidenced by the results obtained for Os2 in liquid SO2 at —70°C, in that in these experimental conditions both the first and the second oxidation of each metal center can be seen (Fig. 5.4 Table 5.1).15 Potential splitting for the first oxidation process is 370 mV, whereas potential splitting for the second oxidation process is 150 mV. This result confirms the electron transfer pathway for the superexchange interaction once mono-oxidized, the Os(III)-based orbitals are stabilized and their interaction with the bridge-based LUMO orbitals decreases. A similar result has been recently obtained in molecular grids based on similar polypyridine ligands.25... 

Oxidation at the sulfur atom of thiadiazole to the mono-oxide (157) causes a loss in aromatic character which can be seen by X-ray analysis and by the 33 kcal mol1 inversion barrier of the pyramidal sulfur which agrees with the calculated barrier (31.9 kcal mol-1) (82JA1375). 

Because of the mildness of Fetizon s reagent and its sensitivity to minor structural features, this oxidant is particularly well-suited for the mono oxidation of symmetric diols7 and for the oxidation of 1,2-diols in which one of the alcohols is tertiary.8... 

The azo coupling just mentioned is accompanied by the conversion of one of the nitro groups into the hydroxyl group. Hence, the radical product is stabilized by elimination of the nitrogen monoxide radical. All the radicals are prone to stabilize, expelling a small radical particle. This is the case too. And nitrogen mono-oxide was established as a gas-phase product of the reaction (Todres, Hovsepyan, Ionina 1988). 

The heteroelement diatomic molecules CO [3-5,11,13,48,93-98], CS [11,13,99,100], and NO [11,13,101 104] are widely found as ligands in modern coordination chemistry. Formation of complexes having the structures 62 >5 has been proved for carbon mono-oxide [3 5,13] ... 

Finally, Boezio and Charette have shown that Me-DuPhos in combination with Cu(OTf)2 is effective in the enantioselective addition of dialkylzinc reagents to A-diphenylphosphinoylimines 76 to provide phosphinoylamines 77 with high selectivities (Scheme 13.28).73 Further study revealed that a bis(ligand)-Cu catalyst containing the mono-oxide of Me-DuPhos, and not Me-DuPhos itself, was responsible for the high enantioselectivities observed in this process.74... 

Furthermore, observe that not only are there these four stable oxides of carbon, there also exist various unstable carbon oxides [16], such as C03, C20, C203, C30, C40 and C60. In particular, note that the geometry of the mono-oxides, such as C40 ( C=C=C=C=0 ) are nearly linear triplets [17] which would be named as ... 

Oxidation of the neutral tetravalent cerium OEP double-decker into its mono-oxidized form results in the appearance of a new absorption peak at 1240 nm in the near-IR... 

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