High molecuiar-weight poly(dimethylsilmethy1enes) have been prepared by the catalytic polymerisation of 1 ,I ,3,3-tetramethyl-I ,3-drsilacyclobutane ; di-p-chloro-dichlorobis(alkene)diplatinum( I I ) compounds proved to be the most reactive of several catalyst systems studied. The molecular weight of the polymer could be controlled by the addition of small amoumts of alkyl silicon hydrides or carbon tetrabromide, and ihe polysilmethylenes then contained Si-H or Si-Br groups. Poly(dimethylsilme.thylene) gums were converted into a new type of rubber.THE unusual reactivity of silacyclobutaiies and 1,3-disilacyzhbutanes, attributed to the strain energy of the compressed ring systems, has been the subject of several recent Communications.l Disilacyclobutanes polynierise on htating at above 200" or on prolonged reaction with potassium hydroxide,2 but generally the polymers so obtained are of relatively low molecular weight, e.g., 15,00@ after heating at 304)" for 14 hours under pressure., We yenberg and Nelson have recently reported that platinum on charcoal or chloroplatinic acid bring about polymerisation of these monomers at 1100".Independently we have found that many materials function as catalysts for the polymerisation of compounds of type (I), the most effective being alkene platinum chlorides such as di-p-chloro-dichlorobis(cyc1ohexerae)diplatinum(iI), (C,H,,),Pt,Cl,, which causes vigorous polvnierisations at temperatures between 20 and 60". However, the range of catalysts (Table 1) TABLE 1 Relative efficiencies of catalysts in polymerisation of 1,1,3,3-tetraniethyl-l,3-disilacyclobutane Poly,iiet.isa?io>l complete within 5 mi%.

Macassar 11, the principal aromatic extractive from the heartwood of Macassar I11 is its methyl Betnlin is also present in the heartwood and betulinic acid in the Diospyros celebica Bakh, is the naphthol (IV). cther. sapwood.MANY Ebenaceae heartwoods are dark brown or black, especially Ilios$yros spy., sonic of which are of commercial value. Although several investigations of Diosp3?ros have been reported little attention has been paid to the heartwoods (ebony) and the nature of the pigments is unknown.Macassar ebony, the heartwood of D. celebica Bakh, was briefly examined by Sandermann and Dietrichs during a study of the termite resistance of various timbers. Paper chromatography of a light petroleum extract revealed the presence of several compounds, three of which showed a blue fluorescence in ultraviolet light in the presence of ammonia; they were named macassar I, IT, and 111, in order of increasing RF value. Only macassar 11 was isolated. We now report on the structure of macassar I1 and 111. Me0OMc M e 0 OR McOMc 0 3 0 (11)The isolation procedure of Sanderniann and Dietrichs was modified by dividing the light petroleum extract into acidic and neutral fractions. The former yielded macassar IT, and the latter macassar I11 and betulin. None of the inacassar group could be detected in the sapwood but betulinic acid was isolated.Macassar I1 has the molecular formula C13H,,0, containing one C-Me and two O-Megroups. It gives a blue fluorescent solution in aqueous sodium hydroxide, and form a picrate? a monoacetate, a monobenzoate, and a monomethyl ether by treatment with dimethyl sulphate and potassium carbonate. The methyl ether is identical with macassar 111. From these data, and the ultraviolet absorption (Table 1) , macassar I1 appears to be a dimethoxymethylnaphthol. Oxidation of macassar I1 with alkaline hydrogen peroxide yielded 3-methoxy-5-methylphthalic anhydride which established the substitution pattern in one ring, whilst treatment with sodium metaperiodate (and several other oxidising agents) afforded a monomethoxymethyl-p-naphthaquinone whose light absorption was nearly identical with that of 8-methoxy-l,2-naphthaquiiione. The oxidation product is evidentljy the quinone (I) and was found to be different from the alternative (11), obtained by synthesis. The formation of the o-quinone (I) indicates2 the presence of a methosyl group ortho to the phenolic group in macassar 11, and therefore macassar 111, its methyl ether, must be (111; R = Me). This is supported by its nuclear magnetic resonance (n.m.r.) spectrum and was confirmed by synthesis (see below).Its failure to react with diazomethane in ether parallels the known behaviour of 8-methoxy-1 -naphthol although 1-met hox y-2-napht hol and 2-inethoxy-1-napht hol react sluggishly under these conditions. However both the two latter compounds, aid macassar IT, can It follows that macassar I1 is either the naphthol (11; R = H) or the isomer (IV).