Mono hydroxyl compounds

Among the Ti02 powders, P25, which contains a 30% rutile phase and has a 43 m2/g surface area, showed the highest activity, as shown in Fig. 11.8. In this system, only three kinds of oxidized compounds (2-formylcinnamaldehyde and 1,3- and 1,4-dihydroxynaphthalene) among 10 possible isomers were obtained.81) Furthermore, no mono-hydroxylated compounds, i.e., 1- and 2-naphthol. were detected in the reaction products. Quantum efficiencies of the reactions were determined at around 365 nm. After photoirradiation for 1 h, the quantum efficiencies were determined to be 14.6% and 5.8% for the production of 2-formylcinnamaldehyde and 1,3-dihydroxynaphthalene, respectively. The efficiency was determined on the assumption that 4 holes are necessary to form one oxidized naphthalene molecule. 

In a corresponding manner, the mono-esters of P(III) systems can be produced by controlled reaction of the P(III) halides with the appropriate hydroxyl compound. Significantly better yields are obtained for the aryl esters (from phenols — Equation 4.3) than for alkyl esters (from alcohol), and primary alcohols provide better yields than do secondary alcohols.5 6... 

Anisodamine is a natural derivative of hyoscyamine mono-hydroxylated at the tropane skeleton (Fig. 1). The compound was extracted from traditional Chinese medicine Anisodus tanguticus evoking typical non-specific effects of cholinergic antagonists (spasmolysis, anaesthesia, mydriasis, analgesia) in combination with... 

In 1926, Berl and Bitter studied the action of sodium hydroxide and carbon disulfide upon ethylene glycol, glyceritol, and their methyl ethers, and concluded that, whilst one vacant hydroxyl group is essential for occurrence of esterification, the presence of additional free hydroxyl groups inhibits reactivity. They failed to achieve xanthation of even the mono-hydric compounds in the presence of an equimolar proportion of water, unless activated carbon was also added. By using various 0-methylated celluloses, they were able to demonstrate that, for maximum esterification, two free hydoxyl groups for each D-glucopyranose residue are necessary. 

Over the last decades, large amounts of different man-made chemicals which can act as weak estrogens have been released into the terrestrial and aquatic environment and are distributed world-wide. Classical environmental estrogens are pesticides, such as o,p -DDT, and its metabohtes o,p -DDE and o,p -DDD, methoxychlor and its metabolites, chlordecone (Kepone ), dieldrin, Toxaphene, and endosulfan [126, 135, 136]. It is also known that many chemicals with very weak or no measurable estrogenic activity can be metabolized in organisms especially to hydroxylated compounds which may have much more estrogenic potency than the parent compound. Examples are methoxychlor and its mono- and di-demethylated derivatives [126,127] as well as the alkylphenol... 

As will be seen, only these two mono-hydroxy compounds are possible. Now both of these mono-hydroxy anthraquinones yield alizarin by the introduction of a second hydroxyl group. The only constitution possible for a di-hydroxy anthraquinone obtained from both of these two mono-hydroxy anthraquinones is the 1-2-di-hydroxy compound. As alizarin is thus obtained the two hydroxyl groups in it must be in the 1-2 positions and not in the 2-3 positions. 

The reaction reaches equilibrium rapidly if the hydroxyl group is attached to a reactive radical, as in tertiary alcohols. In such cases, excess of the halogen acid is shaken with the alcohol, and the mono-halogen compound is separated. With primary and secondary alcohols, equilibrium is reached more slowly, and a catalyst (such as zinc chloride in the case of hydrochloric acid, and sulfuric acid in the case of hydrobromic acid) is used. On account of its cost, hy-driodic acid is not used, but iodine and phosphorus, which react as follows ... 

The catalyst selection for blocked isocyanates depends on the nature of the blocking agent, the desired cure temperature, the polyol structure, and the application. Mono-, di- and trialkyltin compounds are effective catalysts for many blocked isocyanate reactions with hydroxyl compounds. In most solvent-borne coatings, DBTDL is used as a catalyst. 

Transglycosylation by glycoside hydrolases (102) is well established and various hydroxyl compounds including mono- and oligosaccharides are known to be acceptors. Jermyn (104) has shown that there is not only high specificity for the substrate, but also for the acceptor and that competition between hydroxyl compounds for the acceptor site can occur. 

The metabolites appeared in the radiochromatograms of various matrices (plasma, urine, etc.) were analyzed by mass spectrometry. Comparison of the fragment ions of metabolites obtained by LC/MS/MS analysis to the ones from the parent compound provide structural information of the metabolite. Typical mass increases such as +16, +32, + 176, +80, +42, +14, —14, —60, and —2 indicate mono-hydroxylation, dihydroxylation, glucuronidation, sulfation, acetylation, methylation, demethylation, deacetylation, and dehydration, respectively. 

The i-butane chemical ionization mass spectra of a number of saturated mono-hydroxylic alcohols have been determined to establish the general patterns of the spectra of this class of compounds. The spectrum of 2-hexanol is given as a typical example in Table X, and it may be seen that the following ion types comprise large fractions of the spectra of alcohols the alkyl ion formed from the hydrocarbon portion of the molecule R ) the ion formed by abstraction of the hydride from the molecule, (M l)" the protonated molecule, (M + 1) the association complex of the molecule with the mje = 39 ion of the i-butane plasma, (M -h 39) the association complex of the molecule with the mje = 57 ion of the /-butane plasma, (M -h 57) and the protonated dimer of the molecule, (2M -h 1). The intensity of this ion in the spectrum of 2-hexanol is so small that it is not included in Table X. 

Two trihydroxy metabolites were also characterized in the extracts from mouse and guinea-pig livers. These were substituted in the same positions as were the dihydroxy acids (22 and 24), namely 6a,7- and either the 2 - or 3 - positions of the side-chain. Their retention times also bore the same relationship to the mono-and dihydroxy metabolites as the dihydroxy acids did to the 7-acid and its mono-hydroxylated derivatives. Both compounds exhibited abundant ions at m/e 560 (loss of TMSOH) (Table 6) and the side -chain fragment ions t m/e 145 (peak 19) and m/e 416 (loss of 144 amu from / M-90 /, peak 21) characterized these triols as 2,6a,7- and 3, 6a,7-trihydroxy-A -THC respectively. 

A considerable variety of biota are capable of metabolizing LCBP up to 6 Cl atoms into polar metabolites. Conjugated and free forms of PCB metabolites have been identified in feces and urine of animals. Present evidence indicates that hydroxylation with the formation of an arene oxide intermediary is the primary metabolic mechanism for the breakdown of PCBs. However, direct hydroxylation of PCBs yielding a single mono-hydroxylated product without the arene oxide intermediary has also been reported (Gardner etal., 1976). Studies on the metabolism of a related compound (biphenyl) by liver microsomal preparations from 11 species of animals showed hydroxylation yielding 2- and 4-hydroxy biphenyls. Species differences with different enzyme systems might account for the variation in results. 

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