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The rate of solvolysis of 1-phenylethyl chloride has been followed both polarimetrically and titrimetrically in 60% and in 70% dioxan. The polarimetric rate exceeds the titrimetric rate, and the extent of racemisation decreases slightly with increasing water-content of the medium. The effects of added salts (LiCIO4, NEt4CIO4, LiCl, and in less detail NaOH, and LiBr) have been examined; these results confirm the conclusion to be drawn from the discrepancy between the polarimetric and titrimetric rate coefficients, namely that ion-pair intermediates are involved in this reaction. They suggest also that the first stage of solvolysis is slightly reversed by added chloride ions. The exchange of radiochloride into the organic chloride has also been examined, and is consistent with the above conclusion. The possibility that styrene is an intermediate significant in these solvolyses has been excluded.

Four tetrabenzo[b,d,h,j][1,6]diazacyclododecines and their tetrahydro-derivatives have been prepared. 1H N.m.r. and u.v. spectroscopy are used to determine the geometry of the tetrabenzodiazadodecines. It is concluded that they have the EE configuration, with dihedral angles in the biphenyl moieties of 55–60° and with angles of twist about the ArC–CHN and ArN–NCH single bonds of 10–20 and 80–70° respectively. N.m.r. spectra in the presence of chiral lanthanide shift reagents show that at least two of the compounds are chiral.

Mass spectra of four tetrahydrotetrabenzo[b,d,h,j] [1,6]diazacyclododecines are reported. Loss of phenan-threne gives 2,2′-diaminobiphenyl or the appropriate substituted diamine as the base peak in three cases. Substituents ortho to the biphenyl link substantially modify the fragmentation pattern. Mass spectra of the four 2,2′-diaminobiphenyls have been determined for comparison.

Reaction of 2,2′-diaminobiphenyl with o-phthalaldehyde yielded a number of products including two bi-(14H-dibenzo[4,5:6,7][1,3]diazepino[2,1-a]isoindol-14-ylidene)s, (A) and (B); each was converted on heating into a third isomer (D). The crystal structure of (A), and that of (D), as the solvated trifluoroacetate salt, were determined; (A), previously thought to be the trans-isomer, is in fact the cis-(R,R)/(S,S)-isomer (1a), a racemic compound, and (D) is the meso trans-(R,S)isomer (2b). Compound (B) is considered to be the racemic trans-(R,R)/(S,S)-isomer (2a). The crystal structures of (A) and (D) and the 13C n.m.r. and u.v. spectra of all three isomers are discussed.

X-Ray crystal structure analysis confirms that two of the four tetrabenzo [b,d,h,j][1,6]diazacyclododecines previously investigated have 12-membered rings; there is a strong presumption that the other two have a similar structure. Three of the four compounds undergo (dimethylamino)borane reduction to the tetrahydro derivatives in a process shown by X-Ray analysis and/or n.m.r. spectroscopy to involve C–N bond breaking and ring contraction from 12- to seven-membered rings. The fourth compound is shown by X-ray analysis to retain its (presumed) 12-membered ring structure when the tetrahydro derivative is produced by catalytic hydrogenation.

Racemisation parameters have been determined for 1,11-dichloro-5,7-dihydrodibenz[c,e]oxepin (1) and 1,11-di-chloro-6,7-dihydro-6,6-dimethyl-5H-dibenz[c,e]azepinium bromide (2). Their u.v. and c.d. spectra are discussed. Rotations of sodium 6,6′-dichlorodiphenate and 6,6′-dichloro-2,2′-bishydroxymethylbiphenyl are strongly temperature-dependent.

Quaternary azepinium salts have been prepared from 4- and 6-nitro-2,2′-bisbromomethylbiphenyl. No optical activity was observed among the compounds with the p-nitro group, but suitable salts derived from the o-nitro-compound showed mutarotation in solution at room temperature. Racemisation data for the azepinium picrate from a 6-nitrobiphenyl, in acetone, show that it has an unusually high Arrhenius parameter A. The energy barrier to racemisation is discussed in relation to that in similar bridged compounds, and some apparent discrepancies between polarimetric results and those obtained by n.m.r. spectroscopy are pointed out. A related unbridged bisquaternary salt has been prepared and obtained optically active. It is optically stable up to ca. 90°, but the very low specific rotation has so far prevented quantitative study of its racemisation.

The preparation of (–)-6,7-dihydro-1,11-dimethoxy-5H-dibenz[c,e]azepine-6-spiro-1′-piperidinium iodide starting from (+)-6,6′-dimethoxydiphenic acid is described. Its optical stability has been determined approximately. Methyl 6-methoxydiphenate has been prepared and used for the synthesis of monomethoxydibenzazepinium salts.

Methoxycarbonyl groups in racemic biphenyls show separation of the methyl proton magnetic resonance signals in the presence of large amounts of chiral shift reagents.

Mass spectra of four tetrabenzo[b, d, h, j][1, 6]diazacyclododecines are reported. The common pattern of fragmentation is altered by the presence of ortho methoxycarbonyl groups.

13 Azomethines have been prepared from 2-amino-9,10-dihydrophenanthrene by reaction with aromatic aldehydes. Those with p-alkoxy, p-cyano or p-phenyl substituents in the aldehydic ring have a nematic mesophase. U.v. spectra, 1 H and 13C n.m.r. spectra, and mass spectra of the series are discussed. Mass spectra show that ortho-substituents in the aldehydic ring substantially modify the fragmentation pattern.

N.m.r. spectra of 28 azomethines of the type Ar1CHNAr2 have been measured in deuteriochloroform. Susbtituent and steric effects on the chemical shift of the aldimine proton are discussed. ortho-Substitution in the aldehyde ring has a deshielding effect on this proton whereas ortho-substitution in the amine ring is shielding. The CHN group causes a downfield shift of ca. 0.60 p.p.m. for aromatic protons ortho to the carbon.

Optically active 3,4-dimethoxy-2-(5-methoxy-2-vinylphenyl)stilbene (III) and 2′-ethyl-5,6,5′-trimethoxy-2-(β-phenethyl)biphenyl (IV) have been prepared from thebaine and their racemisation has been studied. Compound (IV) and the closely related compound (V) are highly optically stable (Erac∼ 34 kcal mol–1). The stilbene (III) racemises more readily (Erac 27·8 kcal mol–1). Their u.v. spectra and optical stabilities are discussed.

1-Bromo-1-chloro-1-fluoroacetone has been prepared by the dibromination of monochloroacetone followed by replacement of one bromine atom by fluorine in an exchange reaction with mercuric fluoride under rigorously controlled conditions.