Corresponding conjugates

This coordinate transformation gives rise to a corresponding transformation of the momenta via the canonical lift transformation [10]. Thus the corresponding conjugate momenta are p R, defined by... 

Jones and Civcir prepared a variety of alternating oligomeric furanipyridine compounds and studied their NMR chemical shifts as well as the pKa values for the corresponding conjugate acids. All of these compounds were synthesized by Paal-Knorr reactions of 1,4-diketones with hot polyphosphoric acid. A representative example is the conversion of 24 into 25 in 82% yield. ... 

The Gabriel-Cromwell reaction is a convenient strategy for the synthesis of vinylaziridines. Treatment of 4,5-dibromopent-2-enoate 50 with primary amines 51 in the presence of DBU afforded the corresponding conjugated aziridines 52 in 63-80% yields (Scheme 2.16) [28]. The use of DBU has proven to be essential for the successful conversion. 

Although carbohydrates and their corresponding conjugated glycoforms have long been regarded as only space-filling matrices or post-transcriptional accessory... 

It appeared that triethylamine is the base of choice for generating nitrosals (343). However, sterically less hindered amines deprotonate the C-4 atom to give, after retro-[4 + 2]-cycloaddition of the intermediate enamines (346), the corresponding conjugated enoximes (347). 

In other words, the liberated base A shall unite with a proton to give the corresponding conjugate acid HA of the base A because every base has its conjugate acid and vice versa. 

The energy released when a proton (or, hydron) reacts with a molecular entity (in a gas-phase reaction, either real or hypothetical) to produce the corresponding conjugate acid i.e., the negative of the enthalpy change. 

The presence of /3-unsaturation normally leads to the formation of the corresponding conjugated system. The usual order of reactivity of a /3 proton is thus benzylic, allylic > CH3 > CH2 > CH. However, this preference can be offset by additional substitution at the more activated position competition between the /3-elimination modes leads to a mixture of regio-isomers as shown in Scheme 20. 

In 1998, the rhodium-catalyzed conjugate addition of organostannanes to a,/9-unsatu-rated ketones and esters was reported by Oi [29]. In the reaction, which was carried out in the presence of [Rh(COD)(MeCN)2]BF4 in THF at 60°C, a variety of a,/9-unsatu-rated ketones and esters were transformed into the corresponding conjugate addition products. It is noted that the yield was highly dependent on the substitution pattern of the substrates. For example, /9-substituted enone 40 afforded an 86% yield of 41, whereas methyl vinyl ketone 42 gave only an 18% yield of 43 (Scheme 3.14). The addition of water to the reaction mixture improved the reactivity for the formation of 41 (98%) and 43 (80%) [30]. 

Oi and Inoue recently described the asymmetric rhodium-catalyzed addition of organosilanes [35]. The addition of aryl- and alkenyltriaUcoxysilanes to u,y9-unsaturated ketones takes place, in the presence of 4 mol% of a cationic rhodium catalyst generated from [Rh(COD)(MeCN)2]BF4 and (S)-B1NAP in dioxane/H20 (10 1) at 90°C, to give the corresponding conjugate addition products (Eq. 3). The enantioselectivity is comparable to that observed with the boronic acids, as the same stereochemical pathway is applicable to these reactions (compare Scheme 3.7). 

Curiously, the reaction rate becomes zero order with respect to buffer anion at higher buffer concentrations. If the zero-order rate constants for a variety of buffers are plotted versus pH, an apparent pJC is observed at pH 7.9 to 8.0 (Fig. 29). In contrast, the apparent pK observed in phosphate buffer is at 6.8. As described below, we propose that the difference in pK values is due to a slight difference in the Gibbs energies of the cis and trans peroxynitrite anions relative to the corresponding conjugate acid and has important consequences concerning the reactivity of peroxynitrite. 

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