A route to 2,3-bis(phosphino)succinic anhydrides and related compounds is described. The compounds are formed by reaction of a secondary phosphine with maleic anhydrides which bear a leaving group at the alkenic carbon atom. The reaction of bromomaleic anhydride with diphenylphosphine proceeds via diphenylphosphinomaleic anhydride. An acid-catalysed Michael addition leads to cis-2,3-bis(diphenylphosphino)succinic anhydride, which in turn rearranges to the trans isomer by an acid-catalysed process. The trans isomer was isolated as a hydrobromide. The formation of diphosphines from the corresponding maleic acids and esters has also been observed. A primary phosphine does not lead to a phosphinosuccinic anhydride.Addition of a base to the bis(phosphino)succinic anhydride generally leads to the elimination of the phosphine moiety. However, the anhydride ring can be opened with sodium methoxide and a diphosphine, with both a carboxylic acid and a carboxylate ester moiety, is formed in moderate yield. Two conformers or isomers of this compound are obtained, both of which decarboxylate readily to give methyl 2,3-bis(diphenylphosphino)propanoate.Co-ordination of the diphosphine system to PtII prevents both the elimination of secondary phosphine and the decarboxylation of carboxylic groups.

Formation and reactions of bis(phosphino)succinic anhydrides

Es werden Synthese und Eigenschaften der Phosphor-d(+)-weinsaure beschrieben und im Zusammenhang damit eine Hypothese zur Biogenese der Weinsaure in Vorschlag gebracht.

Phosphor‐d(+)‐weinsäure

The green flame of the Beilstein test, a familiar sight to all chemists, has been used for the identification of chlorine, bromine, and iodine in organic compounds for over a century. The test was first reported in 1872 by F. Beilstein, from whom it takes its name, as a method of determining the presence of and approximate amounts of halogen in organic compounds. He attributed the flame test to Berzelius who had used it to detect the halogen in inorganic compounds, but this fact seems to have been over-looked with the passage of time, for Berzelius is never mentioned in the literature in connection with the test.

H. Bretschneider

Papers

Über die (+)-Dibenzolsulfonyl-weinsäure