Piazza San Marco (Venice, Italy)

Postcard depicting women dining in the Piazza San Marco (Saint Mark's Square) in Venice, Italy

Synthesis of lichesterol [ergosta-5,8(9),22-trien-3β-ol]

Ergosta-5,8(9),22-trien-3β-ol has been synthesized and its identity with lichesterol has been confirmed. Ergosteryl acetate was transformed into 7α-[NN′-bis(ethoxycarbonyl)hydrazino]ergosta-5,8(9), 22-trien-3β-yl acetate which was converted into lichesterol by reduction with lithium in ethylamine

A ready synthesis of 5\u3b1,14\u3b2-cholest-7-en-3\u3b2-ol

Reduction of 3\u3b2-acetoxy-8\u3b1,14\u3b1-epoxy-5\u3b1-cholestan-7- one or 3\u3b2-acetoxy-5\u3b1-cholest-8(14)-en-7-one with zinc dust in methanolic N-sulphuric acid yields 3\u3b2-acetoxy-5\u3b1,14\u3b2-cholest-7- ene with minor amounts of 3\u3b2-acetoxy-5\u3b1,14\u3b2-cholestan-7-one, and constitutes a novel, simple synthesis of 14\u3b2-steroids

Side-chain inversion of steroidal olefins promoted by hydrogen chloride

The reaction of hydrogen chloride on 7-, 8(14)-, and 14-ene steroids was investigated. A 14\u3b1-chloro compound is the product of kinetically controlled addition of the acid. A 14\u3b2-chloro compound with the side chain in the 17\u3b1 configuration originates in diethyl ether at temperatures lower than -30\ub0C in the presence of hydrogen chloride, via a carbocation at C14. There is evidence that the inversion occurs through two distinct rearrangements involving the intermediary formation of a 12,14\u3b1-cyclo-12,13-seco-5\u3b1-cholest-13(17)-ene

A novel synthesis of 3\u3b2-hydroxy-5\u3b1-cholest-8(14)-en-15-one

Jones oxidation of 5\u3b1-cholesta-8,14-dien-3\u3b2-yl acetate furnishes 9\u3b1-hydroxy-15-oxo-5\u3b1-cholest-8(14)-en-3\u3b2-yl acetate (4a). Treatment of (4a) with zinc dust and sulphuric acid followed by saponification gives 3\u3b2-hydroxy-5\u3b1-cholest-8(14)-en-15-one. On the basis of chemical and spectroscopic evidence, the product obtained by oxidation of 5\u3b1-cholest-8,14-dien-3\u3b2-ol is formulated as 9\u3b1-hydroxy- 5\u3b1-cholest-8(14)-ene-3,15-dione (4b) and not as 14\u3b1-hydroxy- 5\u3b1-cholest-8-ene-3,7-dione (3) as reported by others