64201-03-2Relevant articles and documents
Optical activity of oxo amide crystals
Asahi, Toru,Nakamura, Makoto,Kobayashi, Jinzo,Toda, Fumio,Miyamoto, Hisakazu
, p. 3665 - 3669 (1997)
It has been known that oxo amide crystals made up of achiral molecules can be photochemically converted into optically active β-lactams by irradiation with a high pressure mercury lamp. Although the oxo amide crystal belongs to an enantiomorphic class D2, its optical activity could not be detected so far. We successfully measured the components of the gyration tensor of the oxo amide crystal by using the HAUP (high accuracy universal polarimeter) method: g11 = -3.5 x 10-4 (-79°/mm), g22 = -1.4 x 10-4 (-32°/mm), g33 = -3.0 x 10-4 (-68°/mm) at 305 K, where the optical rotatory powers are indicated in parentheses. It has been proved by direct experiments that the optical activity of the reactant and the product in this reaction system remains unchanged over the photocyclization process.
Medium effects on Zwitterionic-biradicaloid intermediates from two phenyl-α-oxoamides. Irradiations in fluid and solid protic media, neat solid phases, and the solid, smectic and isotropic phases of a completely saturated phosphonium salt at different tem
Chesta, Carlos A.,George, Mathew,Luo, Chuping,Weiss, Richard G.
, p. 570 - 583 (2008/09/17)
The photochemical processes of two N,N-dialkyl phenyl-α-oxoamides, N,N-diisopropyl phenyl-α-oxoamide (1) and N,N-dibenzyl phenyl-α-oxoamide (2), are investigated at different temperatures in methanol and ethylene glycol (to probe the influences of H-bondi
Asymmetric induction during photocyclization of chiral and achiral α-oxoamides within achiral zeolites
Natarajan, Arunkumar,Ramamurthy
, p. 4533 - 4542 (2008/09/19)
The photochemistry of 31 α-oxoamides capable of undergoing γ-hydrogen transfer has been examined within zeolites. These molecules, upon excitation, yield two products - a β-lactam and oxazolidinone - in solution, both resulting from γ-hydrogen transfer. W
Photocyclization of α-keto amides in homogeneous solution and aqueous cyclodextrin media. The role of zwitterions and diradicals in photoinduced electron transfer reactions
Chesta, Carlos A.,Whitten, David G.
, p. 2188 - 2197 (2007/10/02)
A mechanistic investigation of the photoreaction of the N,N-disubstituted benzoyl amides, PhCOCONR'R" 1-4 (1: R' = C2H5, R" = Ph; 2: R' = R" = C2H5; 3: R' = R" = CH2Ph; 4: R' = R" = i-C3Hs
X-ray structural studies of chiral β-lactam formation from an achiral oxo amide using the chiral-crystal environment
Sekine,Hori,Ohashi,Yagi,Toda
, p. 697 - 699 (2007/10/02)
Chiral crystals of the achiral oxo amide 1, prepared in large quantities, were irradiated in the solid state to give the optically active β-lactam 2 in high optical and chemical yields. The asymmetric induction mechanism has been elucidated by X-ray struc
PHOTOCHEMICAL REACTIONS OF alpha -OXO AMIDES. NORRISH TYPE II REACTIONS VIA ZWITTERIONIC INTERMEDIATES.
Aoyama,Sakamoto,Kuwabara,Yoshida,Omote
, p. 1958 - 1964 (2007/10/02)
The mechanism of the photochemical reactions of alpha -oxo amides was studied. Establishment of the intermediacy zwitterions was accomplished by the detection of iminium ions formed by protonation of the zwitterions and by the independent generation of the zwitterions by the reaction of hydroxyphenylketene with imines. The remarkable substituent and solvent effects in the photoreactions were rationalized on the basis of the mechanism.
