Syntheses in the Direction of Morphine. II.¹ Some Intermediates and Model Compounds

The preparation of C-1 and C-2 methylated acenaphthenes

“…To make the ketone 2, ethyl a-naphthylacetate was alkylated with excess methyl iodide and sodium hydride (5). Such conditions gave only monomethylation, as had been shown previously for analogous alkylations with methyl iodide in the presence of potassium t-butoxide (6).…”

Two (+)-α,4-dimethyl-2-oxocyclohexaneacetic acids: hydrogen bonding in a terpenoid γ-keto acid and in a diastereomeric lactol

“…Many -and especially -carboxy ketones and carboxy aldehydes whose geometries permitting it exist at least partly as the lactols in liquid phases (Chadwick & Dunitz, 1979;Dobson & Gerkin, 1996;Valente et al, 1998). Although the factors affecting this tendency have been studied (Soffer et al, 1950;Jones, 1963), the open and closed forms often lie so close energetically that small changes in the structure or the medium can shift the equilibria appreciably (Valters & Flitsch, 1985), so that predictions regarding equilibrium values for speci®c cases remain hazardous. Some such keto acids crystallize exclusively as lactols (Thompson et al, 1985;Papadakis et al, 2003).…”

The epimeric 9-oxobicyclo[3.3.1]nonane-3-carboxylic acids: hydrogen-bonding patterns of theendoacid and the lactol of theexoacid

“…Such ring±chain tautomerism is relatively common in -and -carboxy ketones and carboxy aldehydes (Chadwick & Dunitz, 1979;Thompson et al, 1985;Dobson & Gerkin, 1996;Valente et al, 1998;Tsao et al, 2003). Although there appears to be some preference for -over -lactones (Soffer et al, 1950;Jones, 1963), examples of the latter are not lacking. In either case, the open and closed forms often lie so close energetically that small changes in structure or the medium can shift the equilibria appreciably (Valters & Flitsch, 1985), and for (II), the speci®c source of stability for the -lactol form is not obvious.…”