Syntheses with pyrimidine-lithium compounds

Abstracts of some accepted Tetrahedroa papers

34 Titanchloroxyd

gilt als ebenso aktiver katalysator

beim Olefin-Hydrochlorieren.

Abstract-The action of TiCI, on alcohols gives compounds of the type Ti(OR)Cl, where R = Compounds where R is a secon&ry or ferriary isoCIH,-, sec.C,H,-, terr.C,H,and cy~loC,H~, group as distinct from a primary group are unstable, decomposing on keeping at room temperature and slowly at 0” yielding HCI, an olefne and alkyl halide and a residue of titanium oxychloride. The latter is a very active catalyst for the polymerisation of propylene isobutylene and styrene forming polymers of low molecular weight. Titanium oxychloride is also an active catalyst in the addition of HCl to olefines.

SYNTHESES

WITH PYRIMIDINE-LITHIUM

COMPOUNDS

T. i. V. ULBRICHT of Pharmacology, Yale University school of Madicino, New Haven, Connecticut

Department

(Received 27 October 1958) Ab&aet-The principles of the preparation, reactivity and use of organolithium compounds is briefly discussed in relation to recent work with N-heterocyclic derivatives. The synthesis of thymilreC”H, and Sethyluracil from a pyrimidine-lithium intermediate, and the separation of uracil and thymine by ion-exchange chromatography, are described. It is shown that such syntheses can be carried out with compounds containing active hydrogens by taking advantage of the higher reactivity of lithium-carbon bonds, and this is illustrated in a synthesis of thymidine from 5-bromode-oxyuridincl

SYNTHESIS OF D- AND L-kS0IRIDOMYRMECIN AND RELATED COMPOUNDS K. J. CLARK, G. I. FRAY, R. H. JAEGER and Sir ROBERT ROBINSON Research Laboratory, Shell Chemical Company Ltd., Egham (Received 12 December 1958) Abatmet-Starting from bcitronelial of natural origin, D-iridodial and D-isoiridomyrmecin were synthesised. * The latter furnished, on oxidation, a nepetulinic acid, which was the enantiomorph of A mixture of the two specimens afforded a rocemate of a degradation product of nepetalactone. higher melting point. L-Citronellal, obtained (Boake, Roberts & Co.) by a series of chemical transformations from pinene was similarly converted into L-iridodial and L-isoiridomyrmecin, The latter was identical with the natural product from Irtimyrmex nitidus.

ASYMMETRIC

ANNELLATION

EFFECTS-PART

II

E. CLAR Chemistry Department, The University of Glasgow (Receiced 29 December 1958) Abatrac-The

comparison

of the U.V. absorption

spectra of scenes, 1:2-3:edibenzacenes

and tetra-