Oxo compounds

The cationic dinuclear complex [/ -0(TcOCl(terpy))2] was synthesized by reaction of excess terpyridine with [TcOCU] in refluxing ethanol. The blue-violet chloride precipitate is soluble in DMF and DMSO. IR absorptions at 679 and 936 cm arc ascribed to v(Tc-O-Tc) and v(Tc=0), respectively [185]. 

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Naphthalene hydrocarbons halogen compounds, nitrogen compounds. (1949.) hydroxy compounds. (l950.) oxo-compounds except quinones. (1950.) quinones. (1962.)... 

Ketenes are oxo compounds with cumulated carbonyl and carbon—carbon double bonds of the general stmcture R R2C—C—O, where and R2 may be any combination of hydrogen, alkyl, aryl, acyl, halogen, and many other functional groups. Ketenes with R = sometimes called aldoketenes,... 

Amino-6-chloro-4-methyl- and 3-amino-6-chloro-5-methyl-pyridazine and 3-amino-6-methylpyridazin-4(l//)-one are transformed with sodium nitrite in the presence of acid into the corresponding oxo compounds. If concentrated hydrochloric acid is used, in some instances the corresponding chloro derivatives are obtained as side products. On the other hand, 3-, 4-, 5- and 6-aminopyridazine 1-oxides and derivatives are transformed into stable diazonium salts, which can easily be converted into the corresponding halo derivatives. In this way 3-, 4-, 5- and 6-bromopyridazine 1-oxides, 5-chloropyridazine 1-oxide, 3,4,5-trichloropyridazine 1-oxide and 6-chloropyridazine 1-oxide can be obtained. 

Amino groups a to nitrogen are hydrolyzed to the corresponding oxo compounds (as in the purines and pteridines) in bo h acid and alkaline conditions. Schiff bases are reduced to benzylamino derivatives with borohydride. 

In some cases oxo compounds have been converted directly to the corresponding thiones with phosphorus pentasulfide. 

The 6- and 7-quaternary salts of pyrido[2,3-d]pyridazine are reduced by borohydride with subsequent air oxidation to 5,6- and 7,8-dihydro oxo derivatives respectively (77BSF919), whilst the [3,4-d] analogues give the corresponding 1,2- and 3,4-dihydro oxo compounds 72CR(C)(275)1383). ... 

These substances contain the -C=NH group and, because they are strong, unstable bases, they are kept as their more stable salts, such as the hydrochlorides. (The free base usually hydrolyses to the corresponding oxo compound and ammonia.) Like amine hydrochlorides, the salts are purified by solution in alcohol containing a few drops of hydrochloric acid. After treatment with charcoal, and filtering, dry diethyl ether (or petroleum ether if ethanol is used) is added until crystallisation sets in. The salts are dried and kept in a vacuum desiccator. 

This oxidation state is sparse in the case of Mn but is important in the pharmaceutical applications of Tc, and an extensive chemistry has been developed. Some fluoro complexes of Tc and Re such as the salts of [MFe] are known, but oxo compounds predominate and, in [MOCls] and [MOX4] (X = Cl, Br, I) for instance, other halides are also able to coordinate. [MOX4] is square pyramidal with apical M=0 and the moiety is reminiscent... 

Alkylation of these mercapto compounds in alkaline solution gives only the S-methyl derivatives. Of the four isomeric A-methyl derivatives, the 4-thioquinazolines, (28) and (29), have been obtained from the corresponding oxo compounds with phosphorus pentasulfide but the corresponding 2-thio derivatives (30) and (31) are not known. However, derivatives of substance (31) with methyl replaced by... 

Dihydroquinazolines are normally stable compounds but they deteriorate on long standing. Some examples are known to oxidize to the corresponding 4(3H)quinazolinones. 3-Methyl-3,4-dihydroquin-azoline is converted to the 4-oxo compound after three recrystallizations from light petroleum. The most remarkable example is 3,4-dihydro-6-fluoro-3(p-fluorophenyl)quinazoline [(44), R = F] which oxidizes at its melting point (137°-I38°C), Other halogenated derivatives of (44) are more stable. ... 

Caffeine (128) and dimethyl sulfate in nitrobenzene give the fully methylated dioxo compound 129. In the same way that 2,4-dialk-oxypyrimidines give unstable quaternary salts which decompose to the N-alkyl oxo compounds even at room temperature, the action of... 

The formation of quaternary salts by attack at an oxygen atom is only achievable in certain special cases. Most of the attempts to effect reactions of this type with N-alkyl-a-oxo derivatives have failed. Until recently it might have been assumed that 2-alkoxy-quaternary salts were unobtainable, the usual product from reactions with the alkoxy derivatives being the N-alkyl-oxo compounds (see Section IV,C). Recently, however, Meerwein and his co-workers found that triethyloxonium borofluoride and a number of N-methyl-a-oxo... 

The above method is unsatisfactory when hydration takes place at two alternative sites in the molecule, although one hydrate is usually present in only a very small proportion, at equilibrium. Which oxo compound is preferentially formed in such a case depends on the rates of oxidation at the different sites and on the rate of isomerization of the water molecule from one position to the other, hence this method does not indicate which is the thermodynamically more stable hydrate. 

Occasionally it happens that the oxo compound, produced by oxidation, forms a hydrate which is further oxidized to a dihydroxy compound. Attention must be given to the possibility (so far unreported) that when the hydrated species is in equilibrium with a trace of the ring-opened structure a sufficiently fast oxidation rate of the amino-aldehyde (i.e. the acyclic structure) could lead to the incorrect conclusion that the original material was not cyclic. 

The spectra of 1,3,5-, 1,3,7-, and 1,3,8-triazanaphthalerie cations revealed that they were predominantly hydrated, and mild oxidation to the corresponding 4-oxo compounds indicated that hydroxylation took place on C-4. Ring-chain tautomerism in the cation was excluded, at least during the first 45 min after mixing, because negative aldehyde tests were obtained with p-nitrophenylhydrazine. 1,3,6-Triazanaphthalene, under the same conditions, gave a yellow precipit-... 

Aryl-6-carboethoxy(and 6-carboxy)-4-oxo-2-thioxo-l,3,8-triaza-naphthalenes are converted (100°, 3 hr) 7 7 7b to 2-oxo compounds with chloroacetic acid (cf. 136 and 237). The 4-oxo group is replaced (96°, 1 hr) by hydrazine along with ring-closure involving the 6-carboethoxy group in the 2-thioxo compounds, this substituent is simultaneously converted to an oxo group. 

Iron in the oxidation state + III in dimeric p-oxo compounds 5 can be reduced to iron + II, leading to monomeric phthalocyanines 6.351... 

Sequential O-deacetylation, 0-isopropylidenation, and acetylation transformed 80 into compound 81. O-Deacetylation of 81, and ruthenium te-traoxide oxidation of the product, gave the 2-oxo compound 82, which was converted into 83 by hydrogenation over a platinum catalyst and acetylation. ... 

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