Hydrolysis rearrangement

In 1900, Gabriel and Colman reported the preparation of phthalimidoyl acetate 4 They had anticipated saponifying 4 with sodium ethoxide and were surprised to find, rather than hydrolysis, rearrangement to 5. The identity of the product was confirmed by hydrolysis of the newly formed ester and concomitant decarboxylation to provide 6, which was hydrogenated to the known isocarbostyril (7). 

Because 2-trimethylsilyloxy sulfides such as 1154 and 1157 are hemiphenyl thioacetals of aldehydes, they are readily hydrolyzed to aldehydes [8-12] or ketones [13]. Thus alkylation of the lithium salt 1162 with cyclohexyhnethylbromide 1163, gives in nearly quantitative yield, the sulfide 1164, which, after oxidation with m-chloroperbenzoic acid and hydrolysis, rearranges in 70% yield to cyclohexylacetal-dehyde 1165 [8] (Scheme 8.2). A more detailed discussion of the formation of aldehydes is given in Section 8.5. 

Hydrolysis/ rearrange- ment 85 2 100 °C pH 2 HCl/MeOH, ClHC, EtOH distillation, recrystallization, evaporation N2/C02 atm. required... 

Lateral chain modifications on QDO and PDO have been well documented in the literature. The described reactions have shown modifications in specific functional group—i.e., acylations, alkylations, decarboxylations, hydrolysis, rearrangements, substitutions—or the production of a new heterocycle, fusioned or not. Examples of the most recent descriptions are depicted in Fig. 6 [64-66],... 

Aspartame (a-L-asparfyl-L-phenylalanine methyl ester) is widely used as an intense sweetener, particularly in diet soft drinks. In colas, Class IV caramel is the predominant ingredient, a typical concentration being 1400 ppm. Such a concentration has been shown to affect the stability of aspartame at the typical pH of 3.0-3.2.202 Thus, at 55 °C, about 90% of the aspartame in a simulated beverage (4 mM phosphate, pH 3.1) has been lost in 27 d by peptide hydrolysis, rearrangement, ester hydrolysis, and cyclisation to the diketopiperazine. The degradation of aspartame was not affected by 250 ppm caramel, but started at 700 ppm. 

More recently, Sherk, Houpt and Brown decomposed phenyl azide in fuming sulphuric acid and isolated phenylhydroxylamine O,m-disulphonic acid (63) which, upon hydrolysis, rearranged to 4-aminophenol-2-sulphonic acid (64). The same product 64 (38%) was obtained in addition to -aminophenol (11%) on heating the azide in a 1 3 (v/v) mixture of sulphuric acid and water. 

Key words Cover a series of predefined terms of importance for the reaction, such as aromatic, oxidation, hydrolysis, rearrangement. 

The difference in reactivity of halosulfonyl isocyanates is shown in equation 84. The reaction of 146 with 2-butyne gave the [2 + 2]adduct in moderate yield, which was hydrolyzed to 163 by treatment with methanol. In contrast, 2 equivalents of fluorosulfonyl isocyanate reacted with 2-butyne to give a six-membered heterocycle, which on hydrolysis rearranged to 16279. 

R Configuration of amine direct hydrolysis Rearrangements H Alkyl CgHj ) Not identified... 

An unusual (although scarcely preparative) variation of using nitrile 647 for the synthesis of quinazolines was described in late 1970s [396]. Compound 647 reacted with organoboron derivatives to give bora-heterocycles 655, which upon hydrolysis rearranged to quinazoline derivatives 656 (Scheme 135). 

Ueberbacher, B.T., Oberdorfer, G., Gruber, K. and Faber, K. (2009) Epoxide-hydrolase-initiated hydrolysis/rearrangement cascade of a methylene-interrupted bis-epoxide yields chiral THF moieties without involvement of a "cyclase". ChemBioChem, 10,1697-1704. 

Thiazolo[3,2-c]pyriinidiiies [C8NS-C4N2].— 2,3-Dihydro-6-(ethoxycarbonyl)thia-zolo[3,2-fl]pyrimidin-5-one undergoes hydrolysis, rearrangement, and decarboxylation to give 2,3-dihydrothiazolo[3,2-c]pyrimidin-5-one on treatment with hydrochloric acid. ... 

The Curtms rearrangement has been used to prepare 5-aminothiazole (11) (60.61), 4-methyl-5-aminothiazole. 2-chloro-5-aminothiazole (58), and 2.4-dimethyl-5-aminothiazole (62) (Scheme 11). Heating the corresponding azides yield carbamates that resist hydrolysis but react with acetic anhydride to give the 5-acetylaminothiazoles. 

Rearrangement to an open chain imine (165) provides an intermediate whose acidity toward lithiomethylthiazole (162) is rather pronounced. Proton abstraction by 162 gives the dilithio intermediate (166) and regenerates 2-methylthiazole for further reaction. During the final hydrolysis, 166 affords the dimer (167) that could be isolated by molecular distillation (433). A proof in favor of this mechanism is that when a large excess of butyllithium is added to (161) at -78°C and the solution is allowed to warm to room temperature, the deuterolysis affords only dideuterated thiazole (170), with no evidence of any dimeric product. Under these conditions almost complete dianion formation results (169), and the concentration of nonmetalated thiazole is nil. (Scheme 79). This dimerization bears some similitude with the formation of 2-methylthia-zolium anhydrobase dealt with in Chapter DC. Meyers could confirm the independence of the formation of the benzyl-type (172) and the aryl-type... 

Additional evidence for carbocation intermediates in certain nucleophilic substitutions comes from observing rearrangements of the kind normally associated with such species For example hydrolysis of the secondary alkyl bromide 2 bromo 3 methylbutane yields the rearranged tertiary alcohol 2 methyl 2 butanol as the only substitution product... 

Why does the carbocation intermediate in the hydrolysis of 2 bromo 3 methylbutane rearrange by way of a hydride shift rather than a methyl shift ... 

Step 3 Hydrolysis of the rearranged mine gives l alanine and a ketoglutarate O2CCH3CH2 COj" "OjCCHjCHj... 

Propylene oxide-based glycerol can be produced by rearrangement of propylene oxide [75-56-9] (qv) to allyl alcohol over triUthium phosphate catalyst at 200—250°C (yield 80—85%) (4), followed by any of the appropriate steps shown in Figure 1. The specific route commercially employed is peracetic acid epoxidation of allyl alcohol to glycidol followed by hydrolysis to glycerol (5). The newest international synthesis plants employ this basic scheme. 

Hydroxynaphthalenesulfonic acids are important as intermediates either for coupling components for a2o dyes or a2o components, as well as for synthetic tanning agents. Hydroxynaphthalenesulfonic acids can be manufactured either by sulfonation of naphthols or hydroxynaphthalenesulfonic acids, by acid hydrolysis of arninonaphthalenesulfonic acids, by fusion of sodium naphthalenepolysulfonates with sodium hydroxide, or by desulfonation or rearrangement of hydroxynaphthalenesulfonic acids (Table 6). 

The rearrangement is self-cataly2ed by the organosulfonic acid that is already present or acid from hydrolysis of the mixed anhydride product. If the... 

Phosphorus—Hydrogen Bond. A hydrogen bound to phosphoms has Httie acidic or hydric character. Most of the reactions the bond undergoes are those of a reducing agent. P—H bonds are formed by hydrolysis of active metal phosphides or phosphoms haUdes, by the rearrangement of P—O—H or P—S—H linkages, or by the hydrolysis of P—P bonds (6,17). 

AEyl compounds, depending on the stmcture of substituents, can undergo other reactions such as rearrangements, hydrolysis, and additions. Such reactions that may affect polymerization and have health considerations have been closely studied only with important industrial compounds (1). 

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