The Constitution of Retene and Its Derivatives.

The aromatisation of terpenes and steroids by dehydrogenation

“…7 The relative disposition of the methyl and isopropyl groups in retene was eventually established by Bucher in 1910. 8 The application of dehydrogenation by sulfur as a structural tool, was first used by Vesterberg in 1903 9 who showed that the purified resin acid, abietic acid 12 gave retene 13.…”

“…This involved selectively cleaving and degrading the 8( 14)-double bond to give a keto-aldehyde. Insertion of nitrogen and dehydrogenation afforded 30 8-azaretene in which the nitrogen marked the position of the double bond. The azaretene was then synthesised.…”

The Chemistry of Retene.

“…Bucher's brilliant work (39) establishing the structure of retene appeared almost simultaneously with Lux's (105) studies on the Beckmann rearrangement of retenequinone monooxime. A few months later Lux published a more lengthy account of his work (106), together with the results of an extension of his experiments.…”

SEVEN-MEMBERED RING COMPOUNDS.* VI.1 BROMINATION OF 2,3,4-TRIMETHOXYBENZOSUBERONE

“…Oxidation of the monobromide III (1.0 g.) in aqueous pyridine with 6.0 g. of potassium permanganate (15) gave, after addition of 6 N sulfuric acid and solid sodium bisulfite followed by cooling in ice-water, 0.37 g. of crystalline material. Sublimation at 130-150°/ 0.2-0.3 mm.…”

“…Found: C, 64.09; H, 7.42. Oxidation of VIII with potassium permanganate (15) gave material which sublimed at 150--160°/0.08 mm. (bath temperature) and crystallized from ether m.p.…”