3- ethyl, tables

Generally the most abundant sterol in higher plants is sitosterol which has a 24a-ethyl (Table 1), which accounts for about 50 to 80% of the total amount of plant sterols [16]. However, only seven species of 39 plants hitherto examined have been known to contain BRs with a 24a-ethyl and these are not major BRs except in the green alga Hydrodictyon reticulatum [18] (Tables 1 and 2). Furthermore, immature seed of Phaseolus vulgaris contains sitosterol as the major sterol (56% of the total sterol), however, corresponding BRs (28-homocastasterone and related BRs) were detected at very low levels [19]. On the other hand, campesterol and 24-methylene-25-methylenecholesterol each accounts for only about 3% of the total sterols. However, castasterone and 25-methyldolichosterone (and related BRs), which structurally correspond to these sterols, respectively, are major... 

For ethyl alcohol, two volumes of dicycZohexyl are mixed with one volume of the alcohol, a thermometer is introduced, and the mixture heated until it becomes clear. The solution is then slowly cooled, with constant stirring, and the temperature is determined at which the opalescent solution suddenly becomes turbid so that the immersed portion of the mercury thread of the thermometer is no longer clearly visible. This is the C.S.T. The water content may then be evaluated by reference to the following table. 

Ethyl salicylate. Use 28 g. of salicylic acid, 84 g. (106 ml.) of absolute ethyl alcohol and 8 ml. of concentrated sulphuric acid. Reflux the mixture for at least 5 hours. The yield of ethyl salicylate (a colourless liquid), b.p. 231-234°, is 26 g. It is more convenient in practice to distil the liquid under reduced pressure the boiling points under various pressures are given in Table II, 19. 

Ingold and his co-workers used the competitive method in their experiments, in which nitration was brought about in acetic anhydride. Typically, the reaction solutions in these experiments contained o-8-I 4 mol of nitric acid, and the reaction time, depending on the reactivities of the compounds and the temperature, was 0-5-10 h. Results were obtained for the reactivities of toluene, > ethyl benzoate, the halogenobenzenes, ethyl phenyl acetate and benzyl chloride. Some of these and some later results are summarized in table 5.2. Results for the halogenobenzenes and nitrobiphenyls are discussed later ( 9.1.4, lo.i), and those for a series of benzylic compounds in 5,3.4. 

Another category Ic indole synthesis involves cyclization of a-anilino aldehydes or ketones under the influence of protonic or Lewis acids. This corresponds to retro.synthetic path d in Scheme 4.1. Considerable work on such reactions was done in the early 1960s by Julia and co-workers. The most successful examples involved alkylation of anilines with y-haloacetoacetic esters or amides. For example, heating IV-substituted anilines with ethyl 4-bromoacetoacetate followed by cyclization w ith ZnClj gave indole-3-acetate esterfi]. Additional examples are given in Table 4.3. 

Indoles can also be alkylated by conjugate addition under alkaline conditions. Under acidic conditions, alkylation normally occurs at C3 (see Section 11.1). Table 9.1 includes examples of alkylation by ethyl acrylate, acrylonitrile, acrylamide and 4-vinylpyridine. 

A traditional method for such reductions involves the use of a reducing metal such as zinc or tin in acidic solution. Examples are the procedures for preparing l,2,3,4-tetrahydrocarbazole[l] or ethyl 2,3-dihydroindole-2-carbox-ylate[2] (Entry 3, Table 15.1), Reduction can also be carried out with acid-stable hydride donors such as acetoxyborane[4] or NaBHjCN in TFA[5] or HOAc[6]. Borane is an effective reductant of the indole ring when it can complex with a dialkylamino substituent in such a way that it can be delivered intramolecularly[7]. Both NaBH -HOAc and NaBHjCN-HOAc can lead to N-ethylation as well as reduction[8]. This reaction can be prevented by the use of NaBHjCN with temperature control. At 20"C only reduction occurs, but if the temperature is raised to 50°C N-ethylation occurs[9]. Silanes cun also be used as hydride donors under acidic conditions[10]. Even indoles with EW substituents, such as ethyl indole-2-carboxylate, can be reduced[ll,l2]. 

The Curtius rearrangement in acetic anhydride of the azide (8) prepared from 4-carboxythiazole yields 4-acetamidothiazole (Scheme 8) (47). The same reaction starting with ethyl-2-methyl-4-thiazolyl carboxy-late, failed to give the 4-aminothiazole (48). Heterocyclizations are more convenient synthetic methods (Chapter II. Table 40). 

The barriers to rotation about the N-C bond have been determined b dynamic nuclear magnetic resonance for A -isopropyl (80. 81). propanoic acid (74). A -ethyl (82). N-benzyl. and A -neopentyl substituents (82). Selected values of these barriers are given in Tables VII-6 and VII-7. 

Various 4-, 5-, or 4,5-disubstituted 2-aryIamino thiazoles (124), R, = QH4R with R = 0-, m-, or p-Me, HO C, Cl, Br, H N, NHAc, NR2, OH, OR, or OjN, were obtained by condensing the corresponding N-arylthiourea with chloroacetone (81, 86, 423), dichloroacetone (510, 618), phenacyichloride or its p-substituted methyl, f-butyl, n-dodecyl or undecyl (653), or 2-chlorocyclohexanone (653) (Method A) or with 2-butanone (423), acetophenone or its p-substituted derivatives (399, 439), ethyl acetate (400), ethyl acetyl propionate (621), a- or 3-unsaturated ketones (691), benzylidene acetone, furfurylidene acetone, and mesityl oxide in the presence of Btj or Ij as condensing agent (Method B) (Table 11-17). 

The N,N-disubstituted thioureas (135) condensed with a-halocarbonyl compounds give 2-disubstituted aminothiazoies (136) but in lower yields (30 to 70%) (Scheme 65 and Table 11-20) (518). For example, N,N-dialkylthioureas condensed with chloroacetaldehyde or dibromoether lead to Ar,At-dialkyl-2-aminothiazoles in 136, Ri=R2 = methyl (342, 404, 436, 637), ethyl (343, 436), n-propyl (518), n-butyl (518), ally] (518), and benzyl (26, 29). When chloroacetone and dichloroacetone are the carbonyl reactants the corresponding 4-methyl (518) and 4-chloromethyl derivatives (572) were obtained. 

As the table indicates C—H bond dissociation energies m alkanes are approxi mately 375 to 435 kJ/mol (90-105 kcal/mol) Homolysis of the H—CH3 bond m methane gives methyl radical and requires 435 kJ/mol (104 kcal/mol) The dissociation energy of the H—CH2CH3 bond m ethane which gives a primary radical is somewhat less (410 kJ/mol or 98 kcal/mol) and is consistent with the notion that ethyl radical (primary) is more stable than methyl... 

Included in the table are all compounds for which information was available through the C, compounds. The mass number for the five most important peaks for each compound are listed, followed in each case by the relative intensity in parentheses. The intensities in all cases are normalized to the w-butane 43 peak taken as 100. Another method for expressing relative intensities is to assign the base peak a value of 100 and express the relative intensities of the other peaks as a ratio to the base peak. Taking ethyl nitrate as an example, the tabulated values would be... 

Pure adiponitrile is a colorless Hquid and has no distinctive odor some properties are shown in Table 5. It is soluble in methanol, ethanol, chloroalkanes, and aromatics but has low solubiUty in carbon disulfide, ethyl ether, and aUphatic hydrocarbons. At 20°C, the solubiUty of adiponitrile in water is ca 8 wt % the solubiUty increases to 35 wt % at 100°C. At 20°C, adiponitrile dissolves ca 5 wt % water. 

Ben2onitri1e [100-47-0] C H CN, is a colorless Hquid with a characteristic almondlike odor. Its physical properties are Hsted in Table 10. It is miscible with acetone, ben2ene, chloroform, ethyl acetate, ethylene chloride, and other common organic solvents but is immiscible with water at ambient temperatures and soluble to ca 1 wt% at 100°C. It distills at atmospheric pressure without decomposition, but slowly discolors in the presence of light. 

Table 11. Some Physical Properties of Cyanoacetic Acid and Methyl and Ethyl Esters ...

Vinyl Ethers. The principal commercial vinyl ethers are methyl vinyl ether (methoxyethene, C H O) [107-25-5], ethyl vinyl ether (ethoxyethene, C HgO) [104-92-2], and butyl vinyl ether (1-ethenyloxybutane, C H 20) [111-34-2]. (See Table 8 for physical properties.) Others such as the isopropyl, isobutyl, hydroxybutyl, decyl, hexadecyl, and octadecyl ethers, as well as the divinyl ethers of butanediol and of triethylene glycol, have been offered as development chemicals (see Ethers). 

Table 4 lists a variety of aLkoxypropionaldehydes and certain of thek properties (67). Alcohols up to -butyl have been added to acroleki ki this fashion. Methyl, ethyl, and aHyl alcohols react with ease, while the addition of hexyl or octyl alcohol proceeds ki low yields. Although the aLkoxypropionaldehydes have found only limited kidustrial utiUty, it is anticipated that they will find use as replacements for more toxic solvents. Furthermore, the aLkoxypropionaldehydes may readily be reduced to the corresponding alkoxypropanols, which may also have deskable properties as solvents. 

Mechanical and Thermal Properties. The first member of the acrylate series, poly(methyl acrylate), has fltde or no tack at room temperature it is a tough, mbbery, and moderately hard polymer. Poly(ethyl acrylate) is more mbberflke, considerably softer, and more extensible. Poly(butyl acrylate) is softer stiU, and much tackier. This information is quantitatively summarized in Table 2 (41). In the alkyl acrylate series, the softness increases through n-octy acrylate. As the chain length is increased beyond n-octy side-chain crystallization occurs and the materials become brittle (42) poly( -hexadecyl acrylate) is hard and waxlike at room temperature but is soft and tacky above its softening point. 

Table 10. Chain-Transfer Constants to Common Solvents for Poly(ethyl acrylate) ...

The physical properties of the monomers must be discussed along with those of the cured polymers because consideration of one without the other presents an incomplete picture. The 2-cyanoacryhc ester monomers are all thin, water-clear Hquids with viscosities of 1 3 mPa-s(=cP). Although a number of the esters have been prepared and characterized, only a relative few are of any significant commercial interest, and, of those, the methyl and ethyl esters by far predominate. The physical properties of the principal monomers are included in Table 1. 

The Brominated Flame Retardants Industry Panel (BFRIP) was formed ia 1985 within the Flame Retardant Chemicals Association (FRCA) to address such concerns about the use of decabromodiphenyl oxide. Siace 1990 the BFRIP has operated as a Chemical Self-Funded Technical Advocacy and Research (CHEMSTAR) panel within the Chemical Manufacturers Association (CMA) (64). As of 1993, members of BFRIP are Ak2o, Amerihaas (Dead Sea Bromine Group), Ethyl Corp., and Great Lakes Chemical. Siace its formation, BFRIP has presented updates to iadustry on a regular basis (65,66), and has pubhshed a summary of the available toxicity information on four of the largest volume brominated flame retardants (67,68) tetrabromo bisphenol A, pentabromodiphenyl oxide, octabromodiphenyl oxide, and decabromodiphenyl oxide. This information supplements that summarized ia Table 11. 

Cha.ra.cter Impa.ct Items. The character impact item is a chemical or blend of chemicals that provide the principal portion of a flavor s sensory identity, ie, when tasted and/or smelled, the item is reminiscent of the named character, eg, vanillin is the character impact item for vanilla flavors (Table 6). A character item for one flavor can contribute to another flavor in a different way, for example, ethyl oenanthate is a character item for the grape flavor of the Vinus vinifera type and is a contributor to the flavor of the concord grape, ie, the labmska-type grape. 

Several 3-fiuoropyridine derivatives are employed to produce enoxacia, tosufioxacia, and other naphthyridine antibacterials (Table 14). Examples of such iatermediates iaclude 2,6-dichloro-5-fiuoronicotiQonitrile (429), ethyl 2,6-dichloro-5-fiuoronicotiQate (430), 2-chloro-3-fiuoropyridine (393), 6-acetyl-2-(4-acetyl-l-piperaziQyl)-3-fiuoropyridine (431), and 5-fiuoro-2,6-dihydroxynicotiQamide (394). 

A significant development ia trifluoromethylpyridine synthesis strategy is the use of fluoriaated aUphatic feedstocks for the ring-constmction sequence. Examples iaclude the manufacture of the herbicide dithiopyr, utilising ethyl 4,4,4-trifluoroacetoacetate [372-31-6] CF2COCH2COOC2H (436,437). 2,3-Dichloro-5-trifluoromethylpyridine [69045-84-7], a precursor to several crop-protection chemicals (see Table 15), can be prepared by conversion of l,l,l-trichloro-2,2,2-trifluoroethane [354-58-5], CF CCl, to 2,2-dichloro-3,3,3-trifluoropropionaldehyde [82107-24-2], CF2CCI2CHO, followed by cycUzation with acrylonitrile [107-13-1] (415). 

Physical properties of glycerol are shown in Table 1. Glycerol is completely soluble in water and alcohol, slightly soluble in diethyl ether, ethyl acetate, and dioxane, and insoluble in hydrocarbons (1). Glycerol is seldom seen in the crystallised state because of its tendency to supercool and its pronounced freesing point depression when mixed with water. A mixture of 66.7% glycerol, 33.3% water forms a eutectic mixture with a freesing point of —46.5°C. 

Typically, soHd stabilizers utilize natural saturated fatty acid ligands with chain lengths of Cg—C g. Ziac stearate [557-05-1/, ziac neodecanoate [27253-29-8] calcium stearate [1592-23-0] barium stearate [6865-35-6] and cadmium laurate [2605-44-9] are some examples. To complete the package, the soHd products also contain other soHd additives such as polyols, antioxidants, and lubricants. Liquid stabilizers can make use of metal soaps of oleic acid, tall oil acids, 2-ethyl-hexanoic acid, octylphenol, and nonylphenol. Barium bis(nonylphenate) [41157-58-8] ziac 2-ethyIhexanoate [136-53-8], cadmium 2-ethyIhexanoate [2420-98-6], and overbased barium tallate [68855-79-8] are normally used ia the Hquid formulations along with solubilizers such as plasticizers, phosphites, and/or epoxidized oils. The majority of the Hquid barium—cadmium formulations rely on barium nonylphenate as the source of that metal. There are even some mixed metal stabilizers suppHed as pastes. The U.S. FDA approved calcium—zinc stabilizers are good examples because they contain a mixture of calcium stearate and ziac stearate suspended ia epoxidized soya oil. Table 4 shows examples of typical mixed metal stabilizers. 

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