Equilibrium constants for 1:1 -salt formation between tetracyanoethylene and [3.3]-, [3.4]-, [2.2]-, [1.9]-, [9]-, [4.4]-, and [6.6]paracyclophane were found to decrease in value in the order listed, the values being higher than that for the open-chain model compound, 1,3-bis(4-ethylphenyl)propane. A rough linear correlation between the equilibrium constants and the position of the \mix of the long-wavelength charge-transfer band in the visible spectrum of the -salts has been observed for these and four monosubstituted [2.2]paracyclophanes. An exception to the correlation was the -salt of [4.4]paracyclophane. The positions of max values of the long-wavelength chargetransfer band of the -salts of 13 substituted [3.3]paracyclophanes were determined. Possible correlations between A£t's (differences in electronic transition energies between the 5-substituted [3.3]paracyclophanes and [3.3]paracyclophane itself) and substituent constants were examined. A rough linear correlation was observed between AEt values and ," constants for the electron-withdrawing substituents. The nonsubstituted ring was the more basic of the two, and was probably the main site of salt formation. This correlation demonstrates the presence of transannular electronic effects in the [3.3]paracyclophane system. Comparison of the slope of the plot for the [3.3]paracyclophane derivatives with the formerly determined slope of the plot for the [2.2]paracyclophane derivatives demonstrated the transannular effects in the latter system to be greater. An even poorer linear correlation was observed between AEt of -salts of [3.3]paracyclophane substituted with electron-providing groups and + (r = 0.25) values. From its AEt value the acetamido substituent appeared to function as a moderately strong electron-withdrawing group when attached to [3.3]paracyclophane, whereas its " value indicates that the group should be a weak electron donor. This abnormal behavior was also observed for 5-acetamido[3.4]paracyclophane, but not for 4-acetamido[2.2]paracyclophane. The 1:1 tetracyanoethylene-[3.3]paracyclophane salt was prepared in a crystalline form and analyzed.The formation of stable --salts between tetra-cyanoethylene2 3(TCNE) and the [m.njparacyclo-phanes3a provided a simple means of investigating the change in the -base strength of the aromatic hydrocarbons with changes in values of m and n,3a and with changes in substituents on the aromatic nucleus of [2.2]paracyclophane.3b The relative basicities of the (CH2)" tetracyanoethylene [m. nlparacyclophane -acid base (1) The authors wish to thank the National Science Foundation for a grant used in support of this research. M. S. also wishes to thank the National Science Foundation for a National Science Foundation Predoctoral Fellowship, 1965Fellowship, -1969 (2) T.
A series of 13 aromatically monosubstituted [3.3]paracyclophanes have been prepared for study of their spectral and -base properties. Nitration, acetylation, and bromination of [3.3 Jparacyclophane (I) led to monosubstituted derivatives which, in turn, were converted to the other compounds. Reduction of 5-nitro[3.3]paracyclophane (II) gave 5-amino[3.3]paracyclophane (III) characterized as its acetyl derivative (IV). This same compound (IV) was prepared from 5-acetyl[3.3]paracyclophane (V) by a Schmidt rearrangement, and this cycle of reactions demonstrates that no rearrangements occurred during the original electrophilic substitutions of the [3.3]paracyclophane nucleus. Clemmenson reduction of acetyl derivative V gave 5-ethyl[3.3Iparacyclophane (VI), whereas oxidative cleavage by the bromoform reaction provided 5-carboxy[3.3]paracyclophane (VII), methylation of which gave 5-carbomethoxy[3.3]paracyclophane (VIII). Treatment of 5-bromo[3.3]paracyclophane (IX) with cuprous cyanide in quinoline at 225°g ave 5-cyano[3.3]paracyclophane (X). Metalation with butyllithium of bromo compound IX provided the lithio derivative, methylation of which with dimethyl sulfate gave 5-methyl[3.3Iparacyclophane (XI). Oxidation of this lithio derivative with nitrobenzene provided 5-hydroxy[3.3]paracyclophane (XII) characterized as its methyl ether, 5-methoxy[3.3]paracyclophane (XIII), and acetyl derivative, 5-acetoxy[3.3]paracyclophane (XIV). In the nitration and acetylation reactions the first substituent entered the ring under conditions milder than usual. The presence of an acetyl group deactivated both rings toward further electrophilic attack in either ring. The nmr and mass spectral properties of the above compounds are reported. The 5-substituted [3.3]paracyclophanes, unlike the 4-substituted [2.2]paracyclophanes, exhibited normal chemical shifts for protons ortho, para, and pseudo-gezn (proton closest to substituent in transannular ring) to the substituent. The protons pseudogem to the amino and bromo substituents were exceptions, and exhibited downfield shifts less than half as great as those found for the pseudo-gem protons in the corresponding 4-aminoand 4-bromo[2.2]paracyclophanes. These differences are interpreted in terms of the differences in geometry of the [3.3]-and [2.2]paracyclophanes. All of the substituted [3.3]paracyclophanes and the parent compounds gave strong parent peaks in their mass spectra. The parent hydrocarbon also gave peaks that correspond to a fragmentation to two entities, one equal to half the parent mass and the other to half the parent mass minus one. The substituted compounds fragmented similarly. The structures of these entities are discussed.(4) (a) H.
ester of the E unsaturated acid was reduced in the same way as the Z ester to the E alcohol and purified by glpc. Compound 21 had the following nmr spectrum: 0.95 (s, 6, geminal CHS), 1.4-1.7 (m, 4, two CH2), 1.96 (s, 2, CH2 trans to the carbinol group), 2.18 (s, 1, OH), 2.20 2, (t, 2,CH2 cis to the carbinol group), 4.13 (d, 2, CH2OH), 5.37 1, (t, 1, C=CH). The ir spectrum was similar to that of 2.
In a series of bifunctional benzyloxy ethers, the scope and limitations of the unexpected C-0 cleavage at the ether function with charge retention on the benzyloxy moiety (m/e 107) has been investigated. Deuteriumlabeling experiments indicated that simple C-0 ether cleavage alone could not account for the formation of this ion. Its generation was found to be independent of the distance between the two functional groups. From these and other data, it was concluded that the structure of this ion was best represented as protonated benzaldehyde.
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