Photochemistry of oximes. II. On the photo-induced formation of cycloalkanones and alkanoic acid amides from cycloalkanone oximes

Abstract

Cycloalkanone oximes were shown to give the corresponding alkanoic acid arnides when irradiated in iso-propanol. a-Alkylated cyclohexanone oxirnes gave products corresponding to preferential cleavage on the side of the more substituted carbonatom. iso-Propanol was shown to transfer two hydrogenatoms specifically to the excited oxime molecule, acetone being formed in the process. I n 1 % aqueous solution, irradiation of oximes gave the corresponding ketones, ammonia, and oxygen.

Quinone-sensitized Steady-state Photolysis of Acetophenone Oximes Under Aerobic Conditions: Kinetics and Product Studies†

“…Irradiation of p ‐methoxyacetophenone oxime in the presence of CA ( E s = 266 kJ/mol; E T = 206 kJ/mol) or BA resulted in the formation of the corresponding amide via a Beckmann rearrangement. The direct photolysis of oximes is known to produce amides (58–60); however, this was shown to occur from the lowest excited singlet state. Syn – anti isomerization was proposed to occur from the lowest excited triplet state (61).…”

Photo-induced molecular transformations. Part 87. Regiospecific photo-Beckmann rearrangement of steroidal α,β-unsaturated ketone oximes: synthesis of some steroidal enamino lactams

“…These investigations ' 7-24 indicate that the alkyl group is generally apt to migrate over the vinyl group in 5-or 6-membered cyclic ketone oximes although syn-anti isomerization under the conditions of the rearrangement makes the argument on the direction of the migration rather complex or sometimes unambiguous. The exclusive or competitive vinyl migrations have been found in mono-or fused cyclic ketone oximes ' 9 * 2 ' 7 2 3 in only a few cases. * A lower rate of the vinyl migration in cyclic ketone oximes is probably attributed to geometrical constraints which prohibit overlap of the orbitals of the vinyl group and the empty orbital generated on the nitrogen atom.…”

Solvent isotope effects on equilibriums of mono- and dihydration of neutral pteridine

“…3 Addition of D20 to carbonyl compounds is known to proceed with an equilibrium constant substantially more favorable than that for addition of water,4 and it seemed possible that fractionation factors might be useful in investigating interactions of pteridine with enzymes. In a thorough kinetic study of the nonenzymatic hydration of pteridine, Pocker et al 5 reported results in which no substantial solvent isotope effect on the equilibrium of monohydration of pteridine was evident at pH values at and above neutrality. Reinvestigating this reaction, we have confirmed that the solvent isotope effect on the monohydration of pteridine is close to unity.…”