Reductive electrochemical formation of 6H-dibenzo[b,d]pyran-6-one and 2-benzopyran-1(1H)-one

In the present Letter several carbolactones (oxidative products) are obtained under aprotic cathodic conditions in the preparative scaled electrolysis of 1,2-quinones in a divided electrochemical cell and in the presence of oxygen. When 9,10-phenanthrenequinone is reduced 6H-dibenzo[b,d]pyran-6-one and [1,1′-biphenyl]-2,2′-dicarboxylic acid are obtained as major products. In the reduction of 1,2-naphthoquinone, 2-benzopyran-1(1H)-one, and 2-(2-carboxyethenyl)-benzoic acid were formed as main products. The proposed mechanism to explain the formation of these and other products, that involves an electron-transfer reaction to the oxygen in air, is now discussed.

Kitāb Risālat al-murīd al-makhṣūṣ min rabbihi al-ḥamīd / lil-Sayyid al-ʻārif al-kabīr wa-al-quṭb al-shahīr ʻAbd Allāh ibn ʻAlawī al-Ḥaddād : manuscript, 1865 or 6

Written in one column, 9 lines per page, in black and red.

Nomination of Robert B. Pirie, Jr. : hearing before the Subcommittee on Manpower and Personnel of the Committee on Armed Services, United States Senate, Ninety-sixth Congress, first session, on the nomination of Robert B. Pirie, Jr., to be Assistant Secretary of Defense for Manpower, Reserve Affairs, and Logistics, April 6, 1979.

Mode of access: Internet.

Concerto no. 6, in B flat, for violin and piano /

Acc. arr. for piano.

Quartet no. 6 B♭ major : for 2 violins, viola and violoncello /

Publisher's no.: Edition Eulenburg, no. 21.

Trio VII [i. e. 6] in B♭, op. 97 /

Mode of access: Internet.

Concerto grosso for string orchestra, no. 12, B minor, op. 6, no. 12.

Mode of access: Internet.

Sextett, B dur. Op. 6. [Für] Pianoforte, Flöte, Oboe, Klarinette, Horn, Fagott

Mode of access: Internet.