No abstract

South Parks Road, Oxford OX1 3QYStructural investigation of the products obtained by microbiological hydroxylation of substrates in the androstane, pregnane, and mstrane series has involved examining the l H n.m.r. spectra of 344 steroids, 243 of them being new compounds. Mild oxidation of the products gives polyketones in which the positions of the oxo-groups are characterised by the chemical and solvent shifts of the 18-H and 19-H signals. This information is supplemented by the chemical shifts of the products' 18-H and 19-H signals, and by the positions and form of their )CH-OH resonances : the latter are especially useful in establishing the configurations of the hydroxy-groups.FOR the past five years we have been studying the hydroxylation of mono-and di-oxygenated steroids with a range of micro-0rganisrns.l The intention was to vary the positions of the oxygen substituents around the steroid nucleus in a systematic manner: it was -gate, ibid., 1969, 463. hoped that the use of relatively simple substrates would facilitate interpret at ion of the microbiological behaviour. A considerable body of results has accrued from examining monoketones, keto-alcohols, and diketones derived from handrostane, 5a-pregnane, and 5a-cestrane ; a series of papers describing the work will be submitted shortly to this Journal. The preparation of substrates and related chemical studies are being recorded in a separate series2

No abstract

Protection of a primary amine group is achieved by incorporating it into an N-substituted 2,5dimethylpyrrole system. The method affords protection against strong bases and nucleophiles, heating with concentrated alkali, standard mineral acid work-up conditions, and various other reagents.Phenyl-, pyridyl-, thiazolyl-, and alkyl-amines have been studied. All give trisubstituted pyrroles in high yield ( > 80%) by reaction with hexane-2,5-dione. The pyrroles from the first three types are stable to storage; even the N-alkyl compounds can be used without difficulty. Regeneration of the amine group, by treatment with hydroxylamine hydrochloride, is efficient (ca. 80% yield) with the phenyl, pyridyl, and alkyl compounds but lesssatisfactory (6&65%generally but down to 25% in twocases) with the thiazolyl derivatives.

No abstract