Cyclopropanones and related compounds. Part II. Adducts from reduction of di-(α-bromobenzyl) ketone in the presence of dienes. Photolysis of α-phenyl ketones

Photochemistry of dispiro-1,3-cyclobutanediones in methylene chloride and methanol solutions

“…A duplicate run was performed as above and methanol was added to the solution on termination of the irradiation. Glpc analysis of the photolysate indicated the presence of cyclohexanone (18%), methyl cyclohexanecarboxylate (10%), 3 (re = 6) (60%), and three unidentified components in 1, 3, and 3% yields, respectively. Treatment of the crude product with methanol followed by cooling led to a 45% isolated yield of 3 (re = 6).…”

Optical rotation of ribonuclease

“…Curve C, for example, has a trough at 233 µ even though it represents only 6-7% helix as estimated by the trough amplitude method. 2 The absorption band responsible for this trough has been located at 222 µ by studies of circular dichroism3 and has been assigned to the , •* transition of the peptide group. This is an unusual position for this transition.…”

Cicloadições [3+4] via cátions oxialílicos: aplicações em sínteses orgânicas

“…Mais tarde, Cookson et alii 6,7 desenvolveram outro procedimento mais eficiente para o preparo dos oxabiciclos 2a e 2b através da redução da α,α'-dibromocetona 6 com NaI, na presença de furano (Esquema 3). Neste caso foi observada a formação de grande quantidade da furilcetona 2c, resultante da reação de substituição eletrofílica entre o furano e o cátion oxialílico gerado in situ.…”

“…Para avaliar a generalidade desta cicloadição Cookson et alii 7 realizaram experimentos com ciclopentadieno e Nmetilpirrol cujos resultados (compostos 7a-b e 8) são mostrados no esquema 3. No caso do N-metilpirrol apenas o produto da substituição eletrofílica 8 foi isolado.…”