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Saturated rings

Cyclic sulfur imides are molecules in which one (or more) of the sulfur atoms in a cyclic sulfur allotrope is replaced by an NR (R = H, alkyl) group (see 2.1-2.4 [Pg.68]

The 15-membered ring Se9(N Bu)6 (6.9) is a unique member of the series of cyclic chalcogen imides (see Section 12.8.1). It was first obtained as the major product of the reaction of LiN( Bu)SiMe3 with Se2Cl2 or SeOCl2. It is also formed, in addition to smaller cyclic selenium imides, in the cyclocondensation of SeCl2 with er -butylamine in THF or from the decomposition of the sele-nium(IV) diimide BuN=Se=N Bu.  [Pg.69]

Unfortunately, structures of monosubstituted cyclic hydrocarbons which would allow a systematic correlation between C—F bond distances and ring size have not been reported in the literature. Some polyfluorinated and the perfluorinated cyclopropanes were studied by MW and ED and the C—F bond lengths are listed in Table 14. If only one fluorine is bonded to a ring carbon atom, the C—F bonds are long ca 137 to 139 pm), very similar to that in fluoromethane [139.1(1) pm]. An unexpected result is that the cis standing bonds [Pg.42]

TABLE 14. C—F bond distances (in pm) in three-membered rings [Pg.43]

For larger saturated rings only perfluorinated derivatives have been studied in the gas phase. No data have been reported for perfluorocyclopentane, and five-membered rings containing S(II), S(IV) and S(VI) are considered instead (Table 15). Within their experimental error limits, the C—F bond distances in these perfluorinated cyclic compounds are [Pg.43]

Contrary to chemical intuition, the cis isomer of 1,2-difluoroethylene is more stable by 1.08(12)kcalmoT1 than the trans form. Furthermore, the C—F bond lengths are markedly shorter in the cis compound. These differences in cis and trans C—F bond distances have been reproduced correctly by ab initio calculation155 and an explanation for these un- [Pg.44]


Saturated ring systems lose side chains at the alpha carbon. Upon fragmentation, two ring atoms are usually lost. [Pg.815]

There are variations in representation of rings in different disciplines. The dye industry does not designate aromaticity or double bonds in rings. AH double bonds and aromaticity are shown in the Encyclopedia as a matter of course. For example, tetralin has an aromatic ring and a saturated ring and its stmcture appears in the Encyclopedia with its common name. Registry Number enclosed in brackets, and parenthetical CA index name, ie, tetralin [119-64-2] (1,2,3,4-tetrahydronaphthalene). With names and stmctural formulas, and especiaHy with CAS Registry Numbers, the aim is to help the reader have a concise means of substance identification. [Pg.563]

Aromatic rings in lignin may be converted to cyclohexanol derivatives by catalytic hydrogenation at high temperatures (250°C) and pressures (20—35 MPa (200—350 atm)) using copper—chromium oxide as the catalyst (11). Similar reduction of aromatic to saturated rings has been achieved using sodium in hquid ammonia as reductants (12). [Pg.139]

Meth5i-6-(p-methylphenyl)-2-heptene. Saturated rings (see stmcture 120). [Pg.319]

Alternative ( soft ) ionization techniques are not usually required for aromatic isothiazoles because of the stability of the molecular ions under electron impact. This is not the case for the fully saturated ring systems, which fragment readily. The sultam (25) has no significant molecular ion under electron impact conditions, but using field desorption techniques the M + lY ion. is the base peak (73X3861) and enables the molecular weight to be confirmed. [Pg.143]

These cover the following topics (a) theoretical methods, with emphasis on the utility of such methods b) molecular dimensions, as determined by X-ray, electron diffraction and microwave spectra (c) molecular spectra, covering NMR, IR, UV, mass and photoelectron spectra [d) thermodynamic aspects, such as stability, ring strain, aromaticity, shape and conformation of saturated and partially saturated rings (c) tautomerism, including prototopic and ring-chain (/) betaine and other unusual structures. [Pg.4]

Ring size UnsaturatetC Saturated Ring size Unsaturated Saturated... [Pg.12]

Indazole IH > 2H in the gas phase. position. 3. Alkyl group prefers 5-position. 4. Preferential annelation of saturated rings is at 3,4-positions. Substituents do not affect predominance of... [Pg.205]

They can be further classified according to the degree of saturation and the position of double bonds. The fully saturated ring is tetrahy dro-1,3-oxazine ... [Pg.312]

Two closely related indoles fused to an additional saturated ring have been described as CNS agents. The first of these is obtained in straightforward manner by Fischer indole condensation of functionalized cyclohexanone 0 with phenyl hydrazine (19). The product, cyclindole (21) shows antidepressant activity. The fluorinated analogue flucindole (26) can be prepared by the same scheme. An alternate route starting from a somewhat more readily available intermediate involves as the first step Fischer condensation of substituted phenyl hydrazine with 4-hydroxycyclohexanone (23). The resulting alcohol (24) is then converted to its tosylate (25). Displacement by means of dimethyl amine leads to the antipsychotic agent flucindole (26). ... [Pg.168]

A saturated ring with an aliphatic side chain favors cleavage at the bond connecting the ring to the rest of the molecule. Compounds containing cyclohexyl rings fragment at m/z 83, 82, and 81, corre-... [Pg.85]

A mechanism for its formation was also proposed. Essentially, this involved protonation of 2-methylfuran followed by dimerization and trimerization to a 2,4-difuryl tetrahydrofuran derivative which suffered an acid catalysed cleavage of the saturated ring to produce a carbenium ion possessing an alcoholic function at the other end of... [Pg.60]

Dittmer and Christy64 studied the reactions of thiete sulphone. Included in these was an attempt to synthesize thiete itself, a highly strained olefin of theoretical interest, by the LAH reduction of thiete sulphone. The reduction was expected to be feasible since Bordwell and McKellin63 had found that thietane sulphone was readily reduced, but the only product that Dittmer and Christy isolated was 1-propanethiol (equation 23). Reduction of the thiete sulphone with sodium borohydride in basic aqueous methanol gave a 61% yield of the saturated ring, thietane sulphone. [Pg.935]

Three-membered saturated rings are usually planar, but other three-membered rings can have some flexibility. Cyclobutane is not planar but exists as in 96, with an angle between the planes of The deviation from planarity is presumably... [Pg.177]

In summary, we can divide saturated rings into four groups, of which the first and... [Pg.185]

K Relaxation mechanism was also proposed [130-133], The % relaxation originates from cyclic delocalization of % electrons in the double bond through the hyperconjugation with a bonds on the saturated ring atoms under control of the orbital phase property [134, 135],... [Pg.122]


See other pages where Saturated rings is mentioned: [Pg.11]    [Pg.127]    [Pg.254]    [Pg.158]    [Pg.172]    [Pg.116]    [Pg.81]    [Pg.82]    [Pg.8]    [Pg.37]    [Pg.8]    [Pg.126]    [Pg.231]    [Pg.131]    [Pg.164]    [Pg.33]    [Pg.776]    [Pg.111]    [Pg.244]    [Pg.266]    [Pg.287]    [Pg.290]    [Pg.292]    [Pg.320]    [Pg.1]    [Pg.13]    [Pg.293]    [Pg.241]    [Pg.123]    [Pg.327]    [Pg.393]    [Pg.184]    [Pg.265]   
See also in sourсe #XX -- [ Pg.227 ]




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Bridgehead nitrogen saturated bicyclic 6/5 ring-fused systems

Bridgehead nitrogen saturated bicyclic 615 ring-fused systems with

Conformational equilibria in nitrogen-containing saturated six-membered rings

Conformational equilibria in nitrogencontaining saturated six-membered rings

Conformational equilibria in saturated six-membered rings

Fused saturated rings

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Original ring analysis of saturated mineral oil fractions

Partially and fully saturated ring systems

Polymers, saturated, ring analysis

Ring Saturation of Phenolic Ethers

Ring Saturation without Hydrogenolysis

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Ring saturation

Ring saturation

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Ring-saturated thymine derivatives

Saturate concentrates, ring distributions

Saturate concentrates, ring-number

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Saturated Carbocyclic Ring Synthesis

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Saturated bicyclic 6/5 ring-fused systems

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Saturated bicyclic 6/5 ring-fused systems with bridgehead nitrogen and a single additional

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Saturated five-membered ring

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Saturated heterocyclic ring systems, proton

Saturated nitrogen-containing rings

Saturated ring compounds

Saturated ring structure

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