836. Studies in the synthesis of cortisone. Part XVI. A new method of preparing 11-oxotigogenin

Abstract

See footnote t on p. 4830.The behaviour of 38 : 12a-dihydroxy-5a : 25D-spirostan-11-one and its di-1 [1956] Studies i n the Synthesis of Cortisone. Part X V I .

Tin-free Alternatives to the Barton-McCombie Deoxygenation of Alcohols to Alkanes Involving Reductive Electron Transfer

“…Over the years, some other unexpected reactivities have been observed. In the nineteen-sixties, two different groups reported independently the uncanny ability of allylic- [17] and β-keto acetates [18] to be reduced to alkanes by dissolving metals (Li or Ca) in liquid ammonia). Later, Stetter and Lehmann examined the behavior of allyl and benzyl benzoates upon reductive treatment with sodium.…”

Hormones

“…However, all variations share the following basic concepts: Miscellaneous Methods. Other commercial methods of cortisone production start with ergosterol (101) and stigmasterol [222], phytosterols of yeast and soybean oil, or with the sapogenin hecogenin (102), obtained as a waste product in the recovery of sisal [223,224] (see left figure below). However, these methods no longer have any importance.…”

Total synthesis of dl-oplopanone

“…After filtration through celite, all solvents were removed in vacuo to leave 0.090 g of a yellow oil whose nmr (CCl^) displayed two three-proton absorptions at 6 2.09 and 2.16 ppm, characteristic of acetyl groups, and a one proton absorption at 6 3.28 ppm, for the OH proton, which is con sistent with the expected a-acetoxy methyl ketone LVIII. Following a procedure derived from that reported by Chapman (37) for removal of an acetoxyl group Oi to a carbonyl group, in a 25 ml three-neck flask equipped with a Dewar condenser and mechanical stirrer was collected 10 ml of liquid ammonia (freshly distilled from dissolved sodium) and a solution of 0.090 g of the yellow oil in 5 ml anhydrous dioxane was added, followed by about 0.065 g (5 fold excess) of calcium. After stirring at reflux for 1 hr, the blue solution was filtered into a flask containing about 0.1 g solid ammonium chloride and swirled until the blue color disappeared.…”

“…A mechanism for this conversion has been proposed by Fieser (56), but probably the rearrangement involves much simpler intermediates. The tf-acetoxyl group was removed by reduction with calcium in ammonia and £-dioxane according to the procedure of Chapman (37), which also led to He is a member of the American Chemical Society and The Chemical Society (London) and an associate member of the American Institute of Chemical Engineers and the Society of the Sigma Xi.…”