Hydrolysis and subsequent

The thiazolium is not acidic enough for observing directly solvation of the molecule (or an hydrolysis and subsequent cleavage of the ring) (24) without adding a base, as it is the case for benzoxazolium or benzothiazolium. With the same dilution (10 mole liter ), it is necessary to add sodium ethylate to the solution of 2-methyl-4.5-diphenylthiazolium to observe the equilibrium described above. A new band appears in the UV spectrum at 320 nm that is attributed to the ethoxy derivative by analogy to what has been observed with other benzothiazoliums (26),... 

Hydrolysis and subsequent oxidation by air of benzoylated selenazolidines gives N.N -diben20vlbis(2-aminoethyl)diselenide (Scheme 73)... 

High quahty SAMs of alkyltrichlorosilane derivatives are not simple to produce, mainly because of the need to carefully control the amount of water in solution (126,143,144). Whereas incomplete monolayers are formed in the absence of water (127,128), excess water results in facile polymerization in solution and polysiloxane deposition of the surface (133). Extraction of surface moisture, followed by OTS hydrolysis and subsequent surface adsorption, may be the mechanism of SAM formation (145). A moisture quantity of 0.15 mg/100 mL solvent has been suggested as the optimum condition for the formation of closely packed monolayers. X-ray photoelectron spectroscopy (xps) studies confirm the complete surface reaction of the —SiCl groups, upon the formation of a complete SAM (146). Infrared spectroscopy has been used to provide direct evidence for the hiU hydrolysis of methylchlorosilanes to methylsdanoles at the soHd/gas interface, by surface water on a hydrated siUca (147). 

Hydrolysis and subsequent oxidation of 2-methyl-4,6,7,l Ifi-tetra-hydro[l,3]oxazino[2,3-n]isoquinoline-4-one (42) afforded ring opened product 43 (99TL8269). 

The reasonable mechanism outlined above has not yet been rigorously proven in every detail, but is supported by the fact that a 1 1-intermediate 5 has been isolated." The ester groups are essential for the Weiss reaction because of the /3-keto ester functionalities however, the ester groups can be easily removed from the final product by ester hydrolysis and subsequent decarboxylation. 

Subsequently it was found140 that ethyl 2-alkyl-1//-azepine-1-carboxylates can be isolated from a mixture of isomeric 1//-azepines by stirring the mixture with potassium hydroxide in ethanol at room temperature. Apparently, this method, which is limited to 2-alkylated azepines, depends on the slower rate of hydrolysis (and subsequent decomposition of the resulting 1H-azepine-l-carboxylic acid) of the sterically hindered 1-(ethoxycarbonyl) group. Although the yields of l//-azepines are poor (4-7%, vide supra), the method provides access to otherwise difficult to obtain, isomerically pure 2-alkyl-1//-azepines. Under the basic hydrolysis conditions aryl 2-alkyl-l//-azepine-1-carboxylates undergo transesterification to the l-(ethoxycarbonyl) derivatives. 

Caution Hydrazoic acid, which is used in Part C of this procedure, is very toxic. Consequently, the conversion of methyl cycloundec-l-enecarboxy-late to cycloundecanone by the Schmidt degradation, including hydrolysis and subsequent steam distillation, should be conducted in a well-ventilated hood. 

For the oxidative formation of a quinoxalinequinone, it appears that the precursor must have at least one appropriately placed substiment that can be oxidized directly (—OH or tautomeric =0) or that can suffer hydrolysis and subsequent oxidation (e.g., OMe or NH2). This stipulation is illustrated in the following examples. 

Note This indirect process proceeds by hydrolysis and subsequent decarboxylation. 

Two types of sulfoximinocarboxylates (analogous to sulfinylcarboxylates 16), namely 5 -aryl-5 -methoxycarbonylmethyl-A(-methyl sulfoximine 36 and -methyl-5 -phenyl-A(-ethoxycarbonyl sulfoximine 37, were subjected to hydrolysis in the presence of PLE in a phosphate buffer. As a result of a kinetic resolution, both the enantiomerically enriched recovered substrates and the products of hydrolysis and subsequent decarboxylation 38 and 39, respectively, were obtained with moderate to good ees (Equations 20 and 21). Interestingly, in each case the enantiomers of the substrates, having opposite spatial arrangement of the analogous substituents, were preferentially hydrolysed. This was explained in terms of the Jones PLE active site model. ... 

As noted above, the presence of Met(O) in proteins would go undetected after acid hydrolysis and subsequent amino acid analysis. Thus, since this method of hydrolysis is most commonly used, it is impossible to ascertain from the literature the abundance of Met(O) residues normally present in proteins. However, a number of studies have reported the presence of Met(O) residues in various proteins using one of the appropriate procedures described above. It has been found that Met(O) residues comprise 30% of the total Met in proteins isolated from bovine glomerular basement membranes and anterior lens . Other investigators have reported that the levels of Met(O) in proteins of the trabecular meshwork of human eyes increased with the age of the donor . The amount of Met(O) detected ranged from 15% (10 years old) to 55% (79 years old) of the total methionine content found in the tissue samples. Other studies have shown that in certain species of clams the proteins of the hinge ligament contain only Met(0) residues and no Met . In addition, it has also been reported that as much as 18% of the Met residues in pea seed proteins is in the form of Met(O) . Lastly, Met(O) residues have been found in... 

It should be pointed out that the diglyceryl silane is a solid compound [113,138,139] thus sol-gel processing with its participation is performed through dissolution of the precursor in an aqueous solution. This leads, as shown experimentally in Ref. [140], to the hydrolysis and subsequent sol formation in accordance with Equations (2)-(4). The important consequence is that the diglyceryl silane can be involved only in the two-stage immobilization procedure shown schematically in Figure 3.3. 

Danishefsky s diene also reacted with 130a at 130 °C to give phenol derivatives 132, which might arise from the initially formed adduct 131 through hydrolysis and subsequent aromatization. 

Conversion of lignocellulose into transportation fuels via pyrolysis and subsequent oil upgrading [72], via gasification and subsequent Fischer-Tropsch or methanol synthesis [3], via hydrolysis and subsequent fermentation to ethanol or subsequent conversion into ethyl levulinate [45, 46, 73]. 

In a related reaction arylacetonitriles are nitrated to the corresponding a-nitronitriles, which on alkaline hydrolysis and subsequent acidification, yield arylnitromethanes. This method has been used to convert phenylacetonitrile to phenylnitromethane in 70 % overall yield without the need for intermediate purification. 

Boiling an ethanolic solution of 4//-pyridazino[6,l-fl]isoquinoline (42) in the presence of KOH for 6 h gave the 4-unsubstituted derivative 53, which was A-acylated with benzoyl chloride (83JOC1084). Heating the A-benzoyl derivative 54 in boiling ethanol in the presence of KOH for 36 h afforded the 2-hydroxy derivative 55, which was also prepared from 56 by basic hydrolysis and subsequent acylation with benzoyl chloride. A decarboxylation-oxidation product 50 was also isolated from the reaction mixture. 

Analogous oxidation of methyl 4,6-dihydrothieno[3,4-i]thiophene-2-carboxylate (134) leads to the 5,5-dioxide (135) (70%) hydrolysis and subsequent oxidation with sodium metaperiodate at 0° (cf. Leonard and Johnson ) results in 2-carboxy-4,6-dihydrothieno[3,4-i]thiophene-5-oxide (91) (74%). ... 

Amination of AT-alkylpyridinium salts with amide ions, which in principle should be easier than the reaction with the parent pyridine, has been little studied. The main reason for this is that solvent selection is difficult. Metal amides are only soluble in liquid ammonia (with which pyridinium salts react easily, vide infra), and pyridinium salts are soluble in solvents that are not suitable for use with metal amides. The A/ -methylacridinium cation undergoes direct imination to give (153) in 35% yield by treatment with potassium amide and iron (III) nitrate in liquid ammonia. Two other products (154) and (155) are also formed, probably by hydrolysis and subsequent disproportionation (Scheme 90). One might question whether sodamide is necessary to the above transformation in light of the fact that quin-olinium, isoquinolinium and certain pyridinium ions give cr-complexes (156), (157) and (158) in liquid ammonia alone at 0 °C (73JOC1949). 

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