SUBJECTS compounds 678 contains carbon

The property possessed by certain colloids of forming a gel-like structure on standing but which revert to a liquid form when subjected to agitation. The term has also been applied to the stiffening effect shown by uncured rubber compounds containing fillers, particularly carbon black. 

The chemistry of compounds containing Si-Si bond(s) is an intriguing subject in the field of organosilicon chemistry because Si-Si bonds have unique physical and chemical properties. The reactivities of Si-Si bonds is often compared with those of carbon-carbon double bonds. The current interest in polysilanes in material science stems from the fact that they exhibit unusual properties implying considerable electron delocalization in the polymer chain [62]. This section concerns with the unique elecrochemical properties of compounds containing Si-Si bonds (Sect. 2.4). 

The scope of the present article comprises syntheses of sugar-type compounds containing four or more carbon atoms, an aldehyde or a ketone group, and a minimum of two hydroxyl groups (or their equivalents, such as amino or thiol groups) at least one of them being bound to a center of chirality. The subject of aldol-type reactions of formaldehyde and two- or three-carbon atom hydroxy aldehydes and hydroxy ketones has been omitted a comprehensive discussion of this topic, including a historical survey, has appeared in this Series.5... 

It seems obvious that electron-withdrawing groups enhance nucleophilic addition and inhibit electrophilic addition because they lower the electron density of the double bond. This is probably true, and yet similar reasoning does not always apply to a comparison between double and triple bonds.70 There is a higher concentration of electrons between the carbons of a triple bond than in a double bond, and yet triple bonds are less subject to electrophilic attack and more subject to nucleophilic attack than double bonds.71 This statement is not universally true, but it does hold in most cases. In compounds containing both double and triple bonds (nonconjugated), bromine, an electrophilic reagent, always adds... 

On a molar basis, most organic compounds contain similar amounts of hydrogen and carbon, and processes involving transfer of hydrogen between covalently bound sites rank in importance in organic chemistry second only to those involving the carbon-carbon bond itself. Most commonly, hydrogen is transferred as a proton between atoms with available electron pairs (l), i.e. Bronsted acid/base reactions. The alternative closed shell process, hydride transfer or shift, involves motion of a proton with a pair of electrons between electron deficient sites (2). These processes have four and two electrons respectively to distribute over the three atomic centres in their transition structures. It is the latter process, particularly when the heavy atoms are both first row elements, which is the subject of this review. The terms transfer and shift are used here only to differentiate intermolecu-lar and intramolecular reactions. 

C2ZD A compound that contains carbon, hydrogen, chlorine, and oxygen is subjected to carbon-hydrogen analysis. Can the mass percent of oxygen in the compound be determined using this method Explain... 

A by now classic retrosynthesis of prostaglandins PGFj and PGEj (Fig, 4) leads to the bicydic lactone [12), five-carbon phosphonium salt [13], and phosphonate [14] (19). These compounds contain all the carbon atoms of the prostaglandins and, in [12], aU but one of the chiral centers. Lactone [12] has come to be knovm genetically as the Corey lactone, and its synthesis in one enantiomeric form has been the subject of numerous complementary investigations. 

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