Optically-active bis(methyl-1-naphthylphenylsilyl)mercury

(+)-Bis(methyl-1-naphthylphenylsilyl)mercury has been prepared, though probably in an optically impure state. Racemization without decomposition takes place at about 150°, and stereospecific cleavages of the Si—Hg bonds are possible.     

A Formal Calculus for the Enumerative System of Sequences—III. Further Developments

We use the material of Parts I and II to obtain further results in sequence enumeration. These include the enumeration of sequences with respect to both maximal π₁ and π₂-paths, and the enumeration of sequences with distinguished substrings. We use the material to derive an enumerative proof of a generalization of a result of Foata and Schützenberger. Finally, we reconsider the enumeration of permutations with periodic pattern and show that the required generating function may be exhibited as the solution of a set of first-order nonlinear differential equations. Subsequent work has shown these to be matrix Riccati equations, although we refer to them here as Volterra equations.     

Landau parameters for nuclear matter using the Skyrme interaction

Landau parameters for nuclear matter are calculated for several Skyrme interactions. Resulting values of G_o and G′_o are in disgreement with empirical values and lead to instability against spin collapse in several cases. A suitable generalization of the interaction is suggested to overcome these difficulties.     

Polarisation parameters in neutral pion photoproduction

The polarisation parameters Σ, P and T have been measured for the process γp→π⁰p in the photon energy range 1300–2100 MeV and c.m. angles between 30° and 110°, in an experiment with a polarised beam and polarised target. The results are compared with a recent theoretical analysis which fits data from threshold to 16 GeV. The new data are in general agreement with the analysis, but with some significant discrepancies in detail.     

Peptides—XXXX: Synthesis of the 68–75 fragment of a lysozyme analogue

The 68–75 subfragment has been prepared by a 4+4 fragment condensation using DCCI/HOBt. The constituent 68–71 and 72–75 fragments being prepared stepwise by the pivalic mixed anhydride method. The octapeptide prepared by this approach was shown to be identical with that synthesised by a solid phase method using a phenolic polymer as the support.     

Peptides—XXXV: Synthesis of the 17–26 fragment of a lysozyme analogue

The fully protected 17–26 fragment of a lysozyme analogue has been synthesised. A fragment condensation approach has been employed using the protected subfragments 17–19, 20–22 and 23–26. In the synthesis of the subfragments the use of the diphenylphosphinyl mixed anhydride method has been demonstrated.