51149-28-1Relevant academic research and scientific papers
Easy synthesis of β-O-4 type lignin related polymers
Kishimoto, Takao,Uraki, Yasumitsu,Ubukata, Makoto
, p. 1067 - 1073 (2007/10/03)
The β-O-4 structure is the most abundant substructure in lignin. Lignin related polymers composed of only the β-O-4 structure were prepared using simple aromatic compounds as starting materials. Acetophenone derivatives were brominated, polymerized in the presence of K2CO3 and reduced with NaBH4 to give the lignin related polymers. These are linear polymers which resemble natural lignins in their structures, although they do not have a γ-hydroxymethyl group. The number average degree of polymerization (DPn) was determined with peracetate of the polymers by gel permeation chromatography. The DPn of guaiacyl type polymers ranged from 15.2-21.4, where the value for the syringyl type was 11.3 and for the p-hydroxyphenyl type 16.9. The Guaiacyl type polymer was very soluble in usual lignin solvents such as 1,4-dioxane-water (96:4, v/v) and DMSO, but only slightly soluble in acetone-water (9:1, v/v). The Royal Society of Chemistry 2005.
New Phototriggers: Extending the p-Hydroxyphenacyl π-π* Absorption Range
Conrad II, Peter G.,Givens, Richard S.,Weber, J?rg F. W.,Kandler, Karl
, p. 1545 - 1547 (2007/10/03)
(Matrix Presented) Introducing 3-methoxy or 3,5-dimethoxy substituents on the 4-hydroxyphenacyl (pHP) photoremovable protecting group has been explored with two excitatory γ-amino acids, L-glutamic acid and γ-amino butyric acid (GABA). These substituents significantly extend the absorption range of the pHP chromophore, e.g., the tail of absorption bands of 2a,b extend above 400 nm, well beyond the absorptions of aromatic amino acids and nucleotides. Irradiation releases the amino acids with rate constants of ~107 s-1 and appearance efficiencies (Φapp) of 0.03-0.04. The photoproducts are formed through the pHP excited triplet and are primarily products of photoreduction and photohydrolysis. 1a,b also rearranged to the phenylacetic acid 3.
