Ethoxy group

Convincing evidence that ester hydrolysis in base proceeds by the second of these two paths namely nucleophilic acyl substitution has been obtained from several sources In one experiment ethyl propanoate labeled with 0 m the ethoxy group was hydrolyzed On isolating the products all the 0 was found m the ethyl alcohol there was no 0 enrichment m the sodium propanoate... 

The number of ethoxy groups (CH3CH2O-) in an organic compound can be determined by the following sequence of reactions... 

A 36.92-mg sample of an organic compound with an approximate molecular weight of 176 was treated in this fashion, yielding 0.1478 g of Agb How many ethoxy groups are there in each molecule ... 

Cosurfactant requirements can be minimized usiag a surfactant having a short-branched hydrophobe or a branched-alkyl substituent on an aromatic group (232,234) and a long ethoxy group chain (234). Blends of surfactants optimized for seawater or reservoir brine salinity include linear alkyl xylene sulfonate—alcohol ether sulfate mixtures (235). 

Fig. 1. Proposed stmctures for Ti (OC2H )4, where and ° represent titanium and the ethoxy group, respectively.

Polydimethyl siloxane is of moderately high molecular weight. The siHcone is a viscous Hquid. CoUoidal siHca or micronized metal oxides, 5—10 p.m particle size, are added to prepare a paste that is mixed with a tetraalkyl siHcate containing 50% ethoxy groups, eg, commonly tetraethyl orthosiHcate, and 1—2% of an organic tin activator. This type of catalyst has a limited shelf life because of oxidation. 

Substitutions that displace electrons toward the carboxyl group of aromatic acids diminish the rate of the reaction (16). The substitution of fluoromethoxy or ethoxy groups in the ortho position has an accelerating action, whereas iodo, bromo, nitro, or methyl groups produce retardation. The influence of groups in the meta and para positions is not nearly so marked (17). 

There are several examples of replacement of methoxy and ethoxy groups in substituted pyridazine N- oxides, with ammonia or hydrazine producing the corresponding amino and hydrazino compounds. 

However, the ethoxy group of l-ethoxy-2-propylbuta-l,3-diene is no longer present. Evidently the p-toluensulphonyl eyanide (2) undergoes [4-1-2] eyeloaddition to l-ethoxy-2-propylbuta-l,3-diene (/). The resulting dihydropyridine 3 aromatises with 1,4-elimination of ethanol to form 2-p-lo y -sulphonyl-5-propylpyridine (4). 

The observed stereoehemistry of [2jc -I- 2jc] eyeloadditions is in accord with the stereochemieal predietions that ean be made on the basis of this model. For example, E-and Z-2-butene give stereoisomerie products with ethoxyketene. For monosubstituted alkenes, the substituent is vieinal and cis to the ethoxy group in the eyelobutanone product. This is exactly the stereoehemistry predicted by the model in Fig. 11.16, sinee it maximizes the separation of the alkyl and ethoxy substituents in the transition state. 

The addition ratios observed for 46 and 47 can be associated with a wieto-orienting effect of the ethoxy group, analogous to that observed... 

In all 3-nitronaphthyridines with an unsubstituted C-2 position (84a, 84f, and 84j) no traces of the corresponding 2-amino-3-nitro-l,X-naphthyridines (X = 5, 6, and 8) were obtained. As already mentioned, in the aminations of 2-R-3-nitronaphthyridines where R is a chloro or ethoxy group, no amino-dechlorination or amino-deethoxylation was observed. 

MeOH with a Hannovia UV lamp in 1973 (73TL2451). Monitoring with H NMR spectroscopy, only two among many products appeared to contain an ethoxy group. After several separations, 3-ethoxy-2-phenylindole (147, 12%), 2-phenylindole (149, 35%), and an unknown ethoxy-containing 2-phenylindole (unknown 148, 3%) were isolated (Scheme 23). 

In the reaetion of 1-alkoxytryptamines with aqueous HCl, 5-ehlorotryptamines (213), 7-ehlorotryptamines (214), and dealkoxylated tryptamines (53) are pro-dueed, and the results are summarized in Table V. Interestingly, the 1-substituent is an important faetor in governing the yield of 5-ehlorotryptamines (213). As the substituent ehanges in turn from hydroxy to methoxy, l-(2-methoxyearbonyl)ethoxy, and l-(2-methoxyearbonyl-l-methyl)ethoxy groups (entries 1-4), the yield of 213a inereases dramatieally. 

Substitution of the ethoxy group in the 2-ethoxyquinoline derivative 475 with phenacylammonium chloride afforded 2-phenacylaminoquinoline 476 that upon cyclization with HCl gave 477 (98CHE828) (Scheme 80). 

The starting material may be produced by reacting 6-amino-2-methylthiopyrimidine with ethoxymethylene malonic acid diethyl ester. The intermediate thus produced is converted by boiling in diphenyl ether to 6-ethoxycarbonyl-2-methylthio-5-oxo-5,B-dihydropyrido-[2,3-d]pyrimidine. That is hydrolyzed by sodium hydroxide to cleave the ethoxy group and then ethylated with diethyl sulfate to give the starting material. 

Terminally deuterium-labeled phenylacetylene was also used to elucidate the possible mechanism of this reaction. In view of all these results, a rationalization for the loss of the trimethylsilyl and the migration of the ethoxy group from its original position in the complex 96 has been put forward. Due to the contribution of the conjugated diarylcyclopentadiene moiety in 98 and 99, these molecules showed intense fluorescence with a relatively high quantum yield of 46%. 

The analysis of alcohol sulfates has been known for many years. Alcohol ether sulfates are analyzed in a similar way but the presence of ethoxy groups makes the complete procedure longer and more complex. 

An analysis of alcohol and alcohol ether sulfates should determine the anionic active matter, the unsulfated matter, the inorganic sulfate content, the chloride content, and water. Other more precise analysis must determine the alkyl chain distribution of the alcohol and in the case of alcohol ether sulfates the number of ethoxy groups and its distribution, as well as other more specialized determinations, such as the content of 1,4-dioxane and other impurities. 

Ethyl chloroformate obtained from Aldrich Chemical Company, Inc., was distilled, b.p. 93°. The progress of the reaction may be followed by proton magnetic resonance spectroscopy. Aliquots are partitioned between dichloromethane and water, the organic layer is concentrated, and the spectrum is recorded. A quartet from the ethoxy group of the mixed anhydride appears at 8 4.2. Ethyl chloroformate, which exhibits a quartet at 6 4.3, is removed in the concentration step. 

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