Propyl units

The aliphatic n-propyl unit in the siloxane oligomer has been considered to be a source of potential instability and accordingly there has been considerable interest in aromatic aminofunctional polydimethylsiloxane oligomers. Some of the early efforts [39] generated oligomers by reacting the chloropropyl group with aminophenol under nucleophilic displacement conditions to synthesize the aromatic amine functionality. However, this approach has the drawback that the... 

Simple cleavage with the loss of 43 mass units may be indicative of an acetyl or a propyl unit in the molecule. Isotope peak intensities may help to identify the correct composition, but of greater value in this respect is high-resolution mass measurement. From the accurate masses of the molecular and fragment ions, the elanental composition of a neutral fragment can be determined. More about this important technique is discussed in Chapter 3. 

Table 12 also indicates the manner in which propyl, butyl, and pentyl carbon units prefer to be added to the bridgehead of adamantane. Although the isopropyl unit is more highly branched than the n-propyl unit, l-(2-propyl)-adamantane possesses four skew interactions whereas the l-(l-pn yl)-adamantane derivative has a minimum energy conformation with only two skews, and is calculated to have a small energy advantage. A similar advantage is held for 1-propyl (A///. -49.20 kcal mole" (2Sb)) over 2-propyl AH. —48.87 kcal mole" (25A)) when t-butyl is substituted for 1-adamantyl that is, 2,2-dimethylpentane is more stable than 2,2,3-trimethylbutane. 

Using a ruthenium complex and tri-tert-butylphosphine as a ligand, a tandem isomerization reaction of allylic alcohols followed by a C-H bond activation directed by a carbonyl group formed in situ was reported. The transformation, which is performed in the presence of triethoxyvinylsUane, leads to the incorporation of a (triethoxysilyl)propyl unit at the C3 position of l-(furan-2-yl)prop-2-en-l-ol (eq 31). ... 

Small fractions of a similar type of merocyanine dye moieties (Me) were also covalently tagged onto poly(sodium 2-acrylamido-2-methylpropanesulfonate) (AMc-3, 4) and poly[(3-(methacrylamino)propyl)trimethylammonium chloride] (QMc-1, 5) [49], The observed pKobs value of 10.92 for AMc-3 was higher than that for the neutral reference (NMc-3, 6) by 2.24 pH units. By contrast, the... 

Experimental studies on models of the propagating radicals in S-AN copolymerization32,33 and a few other systems34 provide support for an explicit penultimate unit effect. Of particular interest is the data of Tirrcll and coworkers. They investigated the relative reactivity of S and AN towards various /-substituted propyl radicals (Scheme 7.3 and Table 7.2). They found that ... 

The most commonly used siloxane modifiers are those having phenyl, trifluoro-propyl and cyanopropyl substituents. Introduction of phenyl units into the polydimethylsiloxane backbone either in the form of methylphenylsiloxane or diphenyl-siloxane increases the thermal and oxidative stability, glass transition temperature and the organic solubility characteristics of the resulting copolymers. At low levels (5-10 percent by weight) of incorporation, bulky phenyl groups also break up the regularity of polydimethylsiloxane chains and inhibit the crystallization (Tc... 

Inhibitors for proteases plasmepsin I and II of the malaria parasite Plasmodium falciparum, with a good plasmepsin/human protease cathepsin D selectivity, have been identified via library construction involving rapid microwave-accelerated Suzuki reactions [57]. The phenyl ring of the biphenyl unit in the lead compound M-((lS)-l- [((lS,2S)-3- [(lS)-2-amino-l-(4-phenyl-benzyl)-2-oxoethyl]amino -2-hydroxy-l-phenoxypropyl)amino]carbonyl -2-methylpropyl)pyridine-2-carboxamide has been altered by performing Suzuki reactions on N-((lS)-l- [((lS,2S)-3- [(lS)-2-amino-l-(4-bromobenzyl)-2-oxoethyl]amino -2-hydroxy-l-phenoxypropyl)amino]carbonyl -2-methyl-propyl)pyridine-2-carboxamide (Scheme 37). In particular, a 2-benzofuryl moiety proved to be interesting since a Ki value of 13 nM for plasmepsin I and... 

The mesogenic units with methylenic spacers were prepared by reacting the sodium salt of either 4-methoxy-4 -hydroxybiphenyl or 4-phenylphenol with a bromoester in DMF at 82° C for at least 4 hours in the presence of tetrabutylammonium hydrogen sulfate (TBAH) as phase transfer catalyst. In this way, ethyl 4-(4-oxybi-phenyl)butyrate, ethyl 4-(4-methoxy-4 -oxybiphenyl)butyrate, ethyl 4-(4-oxybiphenyl)valerate, ethyl 4-(4-methoxy-4 -oxybiphenyl)-valerate, n-propyl 4-(4-oxybiphenyl)undecanoate and n-propyl 4-(4-methoxy-4 -oxybiphenyl)undecanoate were obtained. These esters were hydrolyzed with base and acidified to obtain the carboxylic acids. The corresponding potassium carboxylates were obtained by reaction with approximately stoichiometric amounts of potassium hydroxide. Experimental details of these syntheses were described elsewhere (27). 

The IR-spectra of a mixture of propyl chloride/tributylstannyl 2-methylpro-panoate (the saturated analogs of vinyl chloride/TBSM) analogous to vinyl chloride and TBSM units in their copolymer revealed the formation of coordination bonds... 

As seen from Table 10, both the methyl resonance in dimethyl cyclopropenone (7.75 r) and the separation of CH2 units a and 0 to the three-ring in di-n-propyl cyclopropenone (0.85 ppm) compare well to corresponding values for the covalent cyclopropene derivatives, but differ strongly from those of the positively charged cyclopropenium species. 

Single crystal x-ray diffraction studies showed that the crystals of halcinonide recrystallized from tz-propyl alcohol-water azeotrope (79 22) are orthorhombic and belong to the gpace group P2 2 2, with unit ell constants of a = 10.007 A, = 11.875 A ana Q = 19.460 A. Density is 1.330 gm/cm2 3, as measured by flotation in a hexane-carbon tetrachloride gradient. The molecular weight calculated from the unit cell volume and density is 461 daltons (theoretical is 455 daltons). 

Most of the LC polymer systems discussed so far contain the LC moiety incorporated in the polymer main chain. One of the few examples of polarized emission of light using a side-chain LC system was reported by Chang et al. [107]. A polyacrylate was used as the polymer backbone. The nematic LC side-chains consisted of ethyl- and propyl-substituted bis-tolan units. When deposited on a rubbed PEDOT film, polarized EL dichroic ratios were reported to be around 6. 

Another complex involving the formation of a cyclopentadienyl unit is obtained from the interaction of ethyl or propyl acetylene with Fe3(CO)i2 117). The products contain the complexes Fe3(CO)7(HC2R)4 (R = Et, re-Pr), and the crystal structure of the ethyl derivative indicates the presence of the substituted 1,2,3-triethylcyclopentadienyl group bonded to one iron center with an ethylallyl group cr- and n-bonded to the three metal centers. The formation of adducts of this type must involve the fission of the C=C bond of the acetylene. 

Abbreviations DOPE, l,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine DOTAP, iV-[l-(2, 3-dioleoyloxy)propyl]-A,iV,JV-trrmethylanimoniumchloride TE, transfection efficiency DC, dendritic cells RLU, relative light units chol, cholesterol. 

According to Cameron et al. [11], mercury is redistributed into all of the hydrocarbon cuts after stream cracking. They found that the most highly contaminated fractions were butyl or propyl cuts, accounting for approximately 90 to 95% of the total mercury in the distillation column. About 75% of the mercury that entered a steam cracked unit was not found in the hydrocarbon products, but, rather, contaminated the internals of the unit. Of course, this mercury, when contacted with a clean, mercury-free feedstock wiU render the product mercury-rich. On the other hand, should the raw mercury-containing feedstock or one of its contaminated cuts be transported to another site, then the transport vessel will be polluted. 

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