Joining direction

Many aromatic aldehydes (having the -CHO group joined directly to the benzene ring) undergo polymerisation when heated with a solution of potassium cyanide in aqueous ethanol. Thus benzaldehyde gives benzoin, a compound of double function, since it contains both a secondary alcoholic and a ketonic... 

The elements of stereoisomerism considered thus far consist of a point occupied by an atom and a line wholly occupied by one or more bonds. The ligands are joined directly to these elements. This emphasis on bonding relationships appears to be proper, as the distinction between constitutional and steric isomerism similarly depends on established patterns of connectedness. From this point of view it seems less than satisfactory if direct connectedness between specific atoms is assumed, when chemical theory envisions no such localized bond. This situation prevails in the description of ir complexes such as the metallocenes. Initially (44a), the 1,2- (22) or 1,3-heteroligated ferrocenes were considered to... 

To introduce new atoms, as already stated, you do not need to select any atom or bond simply follow the technique explained above when discussing the CHAOS program (press the button of the mouse near the atom at which you want to start drawing and, without releasing the button, drag the mouse to where you want the new atom. Once there, release the button). This technique can also be used to create bonds between atoms already on screen, but not joined directly. 

A triblock copolymer consisting of a sequence of three blocks joined directly or through unspecified junction units ... 

The effective pumping speed required to evacuate a vessel or to carry out a process inside a vacuum system will correspond to the inlet speed of a particular pump (or the pump system) only if the pump is joined directly to the vessel or system. Practically speaking, this is possible only in rare situations. It is almost always necessary to include an intermediate piping system comprising valves, separators, cold traps and the like. All this... 

Center The specimen with volume of V is joined directly with the leak detector LD (effective pumping speed of S). 

It is therefore quite easy to see why such a very large number of silicates is possible. In fact, the chemistry of these substances is now so developed that it can be classed next in importance to the chemistry of carbon compounds. It must not be assumed, however, that there is any direct relationship between the chemistry of silicates and that of carbon compounds. It is true that in both groups chains, rings and layers of atoms occur, but the structural features of the two groups are totally different. The silicon ions in silicates are always coupled to each other by oxygen ions, while in the carbon compounds the carbon atoms are joined directly to each other. Again, the bonds between carbon atoms are purely homo-polar, while the silicates must be regarded as partly ionic compounds. 

Benzoxazin-4-ones (39) react with amines to give quinazolinones (40) (77JOC656), but this typical reaction is replaced in 1,3-benzoxazine-2-thiones (41) by the formation of imino derivatives (42) since now the oxygen ring atom is joined directly to the aryl nucleus (76MI22700). 

Of the sixteen isomeric aldohexoses, only D-glucose has been found as a carbohydrate component of cardenolides. It generally occurs in combination with other sugars, and rarely are cardenolides found in which a d-glucose residue is joined directly to the aglycon moiety.6 Prior to the work... 

In streptocyanine dyes both ends of the methine chain are joined directly to nitrogen atoms, and a double enamine structure is thus present. The dyes are extremely susceptible to hydrolysis, particularly if they contain secondary nitrogen atoms. Stable dyes are obtained if the nitrogen is part of a heterocyclic ring system. Streptocyanine dyes are brilliant yellow dyes that dye polyacrylonitrile and acid-modified polyamide fibers with outstanding lightfastness [1],... 

This chapter summarizes the sparse data on 1,5-naphthyridines with substituents that are joined directly or indirectly to the nucleus through a sulfur atom. Included are any tautomeric or nontautomeric 1,5-naphthyridinethiones, extranuclear mercapto-1, 5-naphthyridines, alkylthio-1,5-naphthyridines, bis(l,5-naphthyridinyl) sulfides or disulfides, 1,5-naphthyridine sulfoxides or sulfones, and 1,5-naphthyridinesulfonic acids or their derivatives. However, several categories have no known representatives. 

This chapter should summarize data on 1,6-naphthyridines that bear substituents joined directly or indirectly to the nucleus through a sulfur atom for a list of such derivatives, see Chapter 5. In fact, very few thio-1,6-naphthyridines have been reported. Accordingly, available information is simply listed here. 

This chapter covers 1,8-naphthyridines bearing nitrogenous substituents that are joined directly or indirectly to the nucleus through their nitrogen atoms. 

The second of XAS method (XAFNS or XANES) is more useful and allows from the adsorption investigation to learn whether formed compound is the outer-sphere complex or inner-sphere complex. When the adsorbed ion was hydrated, then, it forms outer-sphere complex, if it loses water from the hydratation sphere it joins directly to the solid. XAS investigations showed that Co2+ ions adsorbing on TiC>2 or AI2O3 form inner-sphere complexes. Selenates on FeOOH may form both kinds of the complexes. Further investigations with this method allow us state if single or polynuclear connections are formed on the surface [103,106]. 

An enol ether type of vinyl group is present in ethyl vinyl ether, a reagent used for the protection of alcohols. This time all the coupling constants are smaller because of the electronegativity of the oxygen atom, which is now joined directly to the double bond. 

An enol is exactly what the name implies an ene-ol. It has a C=C double bond and an OH group joined directly to it. Simple carbonyl compounds have enols too—in the margin is the enol of cyclohexanone (just dimedone without the extras). 

This chapter covers pyrazines bearing nitrogenous substituents that are joined directly or indirectly to the nucleus through their nitrogen atom exceptionally, any isocyanato- or isothiocyanatopyrazines are relegated to Chapter 8 in order to be close to pyrazinecarbonitriles and the like. 

UC-OX, VC-OX, and WC-OX. The sum of all such contributions from asymmetric atoms constitutes the optical rotation of the molecule. Atoms not joined directly to asymmetric carbon atoms are assumed to have negligible, second-order effects. The contribution made to the optical rotation by one of the constituent structures, for example, UC-CX, is assumed to depend on the projected angle between the UC and CX bonds (see Fig. 3). In the carbohydrate series, this angle is readily determined from the con-... 

The first polymer, with the Ph2P group joined directly to the polymer, does a straightforward Wittig reaction without mishap. After the reaction, the P=0 groups in the polymer must be reduced back to Ph2P groups before the next appMcation. 

Hydrogen atoms attached to carbon joined directly to an aromatic ring are called benzylic hydrogens. 

We have seen (Sec. 14.24) that an alkyl halide is conveniently detected by the precipitation of insoluble silver halide when it is warmed with alcoholic silver nitrate. The reaction occurs nearly instantaneously with tertiary, allyl, and benzyl bromides, and within five minutes or so with primary and secondary bromides. Compounds containing halogen joined directly to an aromatic ring or to a doubly-bonded carbon, however, do not yield silver halide under these conditions. Bromo-benzene or vinyl bromide can be heated with alcoholic AgN03 for days without the slightest trace of AgBr being detected. In a similar way, attempts to convert aryl... 

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