Noncyclic compounds

In order to avoid ambiguity, it was previously recommended that these prefixes be modified when names already preempted for noncyclic compounds would otherwise be generated. The recommendation was that when immediately followed by -in or -ine, phospha- be changed to phosphora , arsa- to arsen- and stiba- to antimon-. This recommendation has been superseded by a suitable change in the stem suffix (see ahead), but is mentioned here because it is still substantially used in modern literature, including other chapters of this present work. 

Structure Influence on the Rate of Hydrogenation of Unsaturated Noncyclic Compounds... 

An alternative, low-yielding route to the tetrahydro-l/7-3-benzazepines 223 from the amides 222 via an intramolecular Barbier reaction has been reported (Equation 29) <2005H(65)2925>. The other significant products from this reaction were the deiodinated noncyclized compounds. 

In such representations the convention is to assume a carbon atom at each apex of the ring and that the carbon valency of 4 is made up by the appropriate number of hydrogen atoms, which are not shown explicitly A similar convention is used to simplify the writing of the structure of noncyclic compounds as well, as illustrated in some of the examples below. 

The IR spectra of, for example, oxepanes (GOG, GH stretching, and GH2 deformation) are similar to analogous noncyclic compounds. 

A 1 1 mixture of the hydridosilylamides Me2(H)SiNLiCMe3 and Me2(H)SiNLiSiMe3 gives MesSiH, the expected 1,3-cyclodisilazanes 5-7 [6, 7] and surprisingly the noncyclic compounds 8 and 9 in the presence of MesSiCl in -hexane under mild conditions (Scheme 2) The amides are stable in boiling -hexane. 

Noncyclic compounds are sometimes referred to as acyclic compounds. 

In Chapter 2, you learned that the general molecular formula for a noncyclic alkane is C H2n+2- You also learned that the general molecular formula for a cyclic alkane is C H2 because the cyclic stmcture reduces the number of hydrogens by two. Noncyclic compounds are also called acyclic compounds ( a is Greek for non or not ). 

In the noncyclic compounds for which structural data are available, a dihedral angle of about 90° occurs between the planes of the valencies of adjacent sulfur atoms. Reported values lie between 74° in cesium hexa-sulfide (3) and 108° in barium pentathionates (119). In six- and particularly in five-membered cyclic disulfides, the angle is smaller, and may for steric reasons also become larger, but planar, tram groups with 180° dihedral angle have not been observed. 

Structures corresponding to C3H5O are possible in noncyclic compounds if they contain a carbon-carbon or carbon-oxygen double bond. 

Cyclic compounds undergo the same reactions as noncyclic compounds. For example, cyclic alkanes and cyclic alkenes undergo radical substitution reactions with chlorine or bromine (Scheme 4.24). 

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