146983-84-8Relevant academic research and scientific papers
Photochemistry of N-phthaloyl derivatives of methionine
Griesbeck, Axel G.,Mauder, Harald,Mueller, Ingrid,Peters, Eva-Maria,Peters, Karl,Von Schnering, Hans Georg
, p. 453 - 456 (1993)
Photocarboxylation of N-phthaloyl derivatives of methionine sulfoxide 1b and methionine sulfone 1c was observed in acetone as the major reaction. For 1a a fast electron transfer initiated cyclization which leads to the bicyclization product 3 (X-ray structure)was observed in the sensitized photolysis. Direct photolysis of 1a leads preferentially to the tricylic product 4 and the decarboxylation product 5. The methionine methyl ester 6a-c showed electon transfer initiated cyclization (for 6a) and disproportionation (for 6b), whereas 6c proved to be photostable.
Oxidations catalysed by rhenium(V) oxides 2. Clean sulfide oxidation by urea-hydrogen peroxide
Gunaratne, H. Q. Nimal,McKervey, M. Anthony,Feutren, Stephanie,Finlay, James,Boyd, John
, p. 5655 - 5658 (2007/10/03)
Three rhenium(V) oxo phosphine complexes and methyltrioxorhenium have been used as catalysts for oxidation of sulfides to sulfoxides with urea- hydrogen peroxide as oxidant in acetonitrile; partial enantioselective oxidation of methylphenyl sulfide was ob
Photochemical transformations of proteinogenic and non-proteinogenic amino acids
Griesbeck, Axel G.
, p. 272 - 283 (2007/10/03)
The photochemistry of N-activated enantiomerically pure α-amino acids is described with emphasis on chemo-, regio-, stereo-, and spin selectivity. An especially valuable chromophore is the phthalimido group. The first excited singlet states are short-lived and deactivated (chemically) via homolytic CH cleavage or (physically) via electron-transfer steps. The first excited triplet states are chemically deactivated via electron-transfer reactions and subsequent deprotonation/coupling steps. A wide variety of product types were synthesized, and potential target molecules were available by tuning the reaction conditions. Also remote groups can be activated by means of electron-transfer steps, which represents an attractive new synthetic protocol for macrocyclization.
A Photochemical Route to Vinylglycine and a Vinylglycine Dipeptide
Griesbeck, Axel G.,Hirt, Joachim
, p. 1957 - 1962 (2007/10/03)
Enantiomerically pure vinylglycine (4b) can be prepared from natural ("chiral pool") amino acids by photoelimination of γ-functionalized N-phthaloyl amino acid esters.Two routes have been developed: (a) a three-step synthesis of substrate 3b from (S)-methionine and subsequent photolysis, (b) the use of N-phthaloyl activated methyl 2-amino-4-chloro- or -4-bromo-butanoates 3d,e which are available from (S)-methionine (four-step synthesis) or from (S)-homoserine (two-step synthesis).The photoelimination (of HOSMe from 3b and of HX from 3d,e) proceeds quantitatively and leads to N,C-protected vinylglycine 4a in high yields.This strategy could also be applied to peptide-bound substrates as was shown for the protected Met-Gly (5b) which was transformed into the N-protected vinylglycineglycine dipeptide 6 in three steps. - Keywords: Vinylglycine; Photoelimination; Norrish-II photoreaction; Dipeptide; Peptide modification, photochemical
