Benzyl-ethyl-isopropyl

Trisubstituted carbon-centred radicals chemically appear planar as depicted in the TT-type structure 1. However, spectroscopic studies have shown that planarity holds only for methyl, which has a very shallow well for inversion with a planar energy minimum, and for delocalized radical centres like allyl or benzyl. Ethyl, isopropyl, tert-butyl and all the like have double minima for inversion but the barrier is only about 300-500 cal, so that inversion is very fast even at low temperatures. Moreover, carbon-centred radicals with electronegative substituents like alkoxyl or fluorine reinforce the non-planarity, the effect being accumulative for multi-substitutions. This is ascribed to no bonds between n electrons on the heteroatom and the bond to another substituent. The degree of bending is also increased by ring strain like in cyclopropyl and oxiranyl radicals, whereas the disubstituted carbon-centred species like vinyl or acyl are bent a radicals [21]. 

Benzyl-ethyl-isopropyl- IV/ld, 358 Bis-[3-methyl-2-methylen-3-butenyl]-E18, 1032 (Allen + Amin) Dipropyl-phenyl- XI/1, 216 Hexyl-phenyl- XI/1, 947 Anilln... 

The acetates of most alcohols are also commercially available and have diverse uses. Because of their high solvent power, ethyl, isopropyl, butyl, isobutyl, amyl, and isoamyl acetates are used in ceUulose nitrate and other lacquer-type coatings (see Cellulose, esters). Butyl and hexyl acetates are exceUent solvents for polyurethane coating systems (see Coatings Urethane polymers). Ethyl, isobutyl, amyl, and isoamyl acetates are frequentiy used as components in flavoring (see Flavors and spices), and isopropyl, benzyl, octyl, geranyl, linalyl, and methyl acetates are important additives in perfumes (qv). 

Tris-carbamato-iron(III) complexes [Fe(02CNR2)3] have been prepared for R = ethyl, isopropyl, cyclohexyl (cx), and benzyl, and binuclear //-oxo derivatives (for R = Et, cx) and various /U3-OXO, //4-0X0, and /i-carbamato polynuclear complexes also obtained. Iron(III) chloride reacts with potassium 2-prqpanenitronate, K(pn), to give [Fe(Me2C=N02)3] (mean Fe—0 = 2.019 A, mean bite angle 66.0 A), which in ethanol gives binuclear [(pn)2Fe(//-OEt)2Fe(pn)2]. ... 

Commercial polymers have been produced from methyl, ethyl, isopropyl, n-butyl, isotubtyl, t-butyl, stcaryl, benzyl and trimethylsilyl vinyl ethers. The polylmethyl vinyl ether) called PVM or Resyn is produced by the polymerization of the monomer by boron trifluoride in propane at —40°C in the presence of traces of an alkyl phenyl sulfide. The polymer may have isotactic, syndiotactic or stereoblock configurations depending on the solvent and catalyst used. 

The woik of Tuleen and Stevens on the regioselectivity of chlorination of a series of unsymmetrically substituted dialkyl sulfides with NCS provides clues to Ae directive effects implicit in the mechanisms encompassed by Scheme 3. These observations are collected in Scheme 6 where the preferred site of chlorination in each case is indicated with an arrow, the number over the arrow indicating the majortminor product ratio (minor = 1). In the first example, chlorination of benzyl methyl sulfide (2) produces chlorobenzyl methyl sulfide exclusively. Secondly, chlorination of benzyl ethyl sulfide (3) and benzyl isopropyl sulfide (4) also shows a marked, though not exclusive, preference for the benzylic position. In the latter case the extent of benzylic chlorination can be modulated by ring substitution. The directive effects in these internal competitions for p-methyl and p-chloro substituents are correlated by the Hammett relationship with a value of p = 1.0, which is consistent with a mechanism involving abstraction of the more acidic proton in the chlorosulfonium ion intermediate. Further indications of the im-... 

Benzyl-ethyl- E15/2, 2367 (R2CH — CO — Cl/Amin) Isopropyl-phenyl- E15/2, 2367 (R2CH — CO — Cl/Amin)... 

Isopropyl-benzyl)-ethyl]- E16a, 447 (Hydrazon-Red.) l-Isopropyl-2-(l-methyl-... 

V, racemic rro/i5-methyl-l,2-cyclohexanediol, inversion W, racemic and meso-HOCH2CHOHCHOHCHTOH X, racemic 2,3-butanediol Y, me50-2,3-butanediol. 16. m-Methylanisole. 17. K, anisyl alcohol. 18. (a) / r/-Butyl ethyl ether (b) w-propyl ether (c) isopropyl ether. 19. L, / methylphenetole M, benzyl ethyl ether N, 3-phenyl-1-propanol... 

A solid-phase oxidative method for the conversion of 1,4-dihydropyridines to pyridines in good yields (76 90%) was carried out by employing phenyliodine(III) Z)w(trifluoroacetate) (FIFA) at room temperature. The dealkylation at the 4-position in the case of ethyl-, isopropyl-, and benzyl-substituted dihydropyridine derivatives with FIFA was circumvented by using elemental sulfur in solvent-free conditions under MWI for 5-7 min, compared to 3 5 min for the traditional heating to yield products 155 and 156 in 68% and 85% yields, respectively (Scheme 34) (99JCS(F1)1755). 

In this reaction, too, the stability of the alkyl radical being eliminated influences the ease of fragmentation. The order of ease of elimination based on results from the two studies cited above is t-butyl> isopropyl > benzyl > ethyl >chloromethyl> methyl l-bicyclo[2.2.1]heptyl. Radicals derived from ethers and acetate are also subject to fragmentation, with elimination of a ketone or ester ... 

A more complicated behavior was observed for complexes of the types [Ru (R)(CO)2(a-diimine)] and [Re(R)(CO)3(a-diimine)] with R = ethyl, isopropyl, or benzyl [48]. In this case, the CIDEP patterns varied strongly with R, the metal ion, and the solvent. Again, metal-carbon bond homolysis was demonstrated by assigning the spectra to radicals R-. However, the CIDEP patterns exhibited varying contributions due to the radical-pair mechanism and the triplet mechanism. Possible involvement of a third mechanism allowing for... 

Methyl vinyl ether yields a crystalline polymer only when methylene chloride is present as a solvent. However, ethyl, isopropyl, and /7-butyl vinyl ethers do not yield crystalline polymers. Branched alkyl vinyl ethers, other than isobutyl vinyl ether, and benzyl ether also yield crystalline polymers [20]. The crystallinity of the polymers (isotactic) is similar in soluble and insoluble catalyst systems [21]. 

Figure 11.20 Stabilization quotient Q of nicotinic acid esters (ethyl, isopropyl, butyl, benzyl and hexyl) as a function of percentage binding of ester, (a) to three non-ionic surfactants based on PEG lOCX) O PEG l(X)0-lauryl ether, X PEG l(XX)-myristyl ether, PEG 1000 palmityl ether, and (b) to three stearyl surfactant derivatives, O PEG 900 stearyl ether, X PEG 1400 stearyl ether and PEG 2000 stearyl ether. In both (a) and (b) ionic strength is 0.083, temperature 20.0 0.1° C and borate buffer pH 10.(X) 0.02 used. Redrawn from Lippold et al [137], by permission.

Compounds 275-278 are yellow oils, while 279 (Fig. 112) is crystalline (melting point 36°C). These oxidized components are the methyl, ethyl, isopropyl, t.butyl and benzyl esters of 2,5,5-tris-(3-methyl-2-butenyl)-3-carboxy-2-cyclopentene-1,4-dione respectively. The nature of the incorporated ester group corresponds to the alcoholic co-solvent. 

Varma and Kumar (1999) reported the use of phenyliodine (III) bis(trifluoroacetate) (FIFA) or elemental sulfur for oxidation of 1,4-dihydropyri-dines to pyridines under microwave irradiations. Dealkylation at the 4-position in the cases of ethyl, isopropyl and benzyl substituted dihydropyridine derivatives with FIFA is circumvented by an alternative general procedure using elemental sulfur, which provides pyridines in good yield (68-90%). 

Methyl, ethyl, n-propyl, isopropyl, n-hutyl, benzyl, cyclohexyl esters of formic, acetic, oxalic, succinic, tartaric, citric, benzoic, salicylic (and other substituted benzoic acids), phthalic and cinnamic acids phenyl esters of acetic, benzoic and salicylic acids. 

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. 

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