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Excess viscosities and excess Gibbs energies of activation for viscous flow at five temperatures have been calculated for binary liquid mixtures of pyrrolidin-2-one with (C6–C10) alkan-1-ols from the experimental densities and viscosities of the mixed fluids. The excess viscosities and excess Gibbs energies of activation were negative, and increased with increasing temperature. The fitting of viscosities to the one-parameter (d) Nissan–Grunberg equation, and the two-parameter (ν12 and ν21) McAllister equation was extended to the C1–C5 alkanols using earlier results, and examined in terms of interactions between unlike molecules. The ν12 and ν21 parameters were positive and increased with increasing temperature. A minimum in the excess Gibbs energies and d values at equimolar concentrations of the two components has been observed for the pyrrolidin-2-one–pentan-1-ol system.

(S)-5-(Trityloxymethyl)pyrrolidin-2-one (1) is an efficient and recyclable chiral auxiliary in the asymmetric Diels–Alder reaction of the imide (2) with dienes, affording cycloadducts (3) with excellent diastereofacial selectivity.

Treatment of PdCl2(MeCN)2 and CuCl2 with pyrrolidin-2-one L gives a novel Pd–Cu heterometallic complex having a polymeric structure of [ClCu(L)4(µ-Cl)PdCl2·PdCl2]n which catalyses the oxidation of cyclohexene in ClCH2CH2Cl–MeOH.

As background to a proposed dendrobatid toxin 251 D synthesis, the stereoselectivity of epoxide formation from 5-acetylpyrrolidin-2-one (4) and dimethyloxosulphonium methylide was investigated. In THF under ‘salt-free’ conditions, the major epoxide product, selectivity 78 : 22, was (5SR)-5-[(1SR)-1-methyl-2-oxacyclopropyl] pyrrolidin-2-one (5), whereas addition of anhydrous ZnCl2 to the reaction mixture reversed the stereoselectivity to give epoxides (5) and (6) in the ratio 23 : 77. Configurations were assigned to these epoxides by comparison of n.m.r. spectra of the derived carbamates (15) and (16), and by an X-ray structure determination for epoxide (6). Related reactions are discussed.

U.v. data suggest that 1-(2-bromophenyl)pyrrolidin-2-one (2a) is substantially non-planar in solution while the related 1-(2-bromophenyl)azetidin-2-one (1a) is planar. Crystal structure studies of these two compounds show this effect exists in the solid also and that there is a 72° dihedral angle between normals to the phenyl and fivemembered rings in the γ-lactam (2a), while the rings in the β-lactam (1a) are coplanar. Compound (1a) crystallizes in space group C2/c with cell dimensions a= 15.91 (1), b= 7.70(1), c= 14.48(1)A, β= 103.84(1)° while compound (2a) crystallizes in space group P21/c with a=10.55(1), b= 6.83(1), c= 15.41(1)A, β= 112.02°(2). Both structures were solved by heavy atom methods.