Catalysis: transition-state molecular recognition?

• Ian H. Williams

Beilstein J. Org. Chem. 2010, 6, 1026–1034, doi:10.3762/bjoc.6.117

• an archetypal reaction in organic chemistry and an important process in biochemistry. Catechol-O-methyl transferase (COMT) catalyses methyl transfer from S-adenosylmethionine (SAM) to a catechol (Scheme 1), and this reaction manifests an unusually large inverse secondary kinetic isotope effect as

• compared with a model, uncatalysed reaction in solution: the isotope effect VCH3 /VCD3 = 0.83 ± 0.05 for methylation of 3,4-dihydroxyacetophenone with SAM at 37 °C catalysed by COMT was found [11] to be more inverse than the value of kCH3 /kCD3 = 0.97 ± 0.02 for methylation of methoxide ion by S

• 3,4-dihydroxyacetophenone with SAM at 37 °C catalysed by COMT. In contrast, we calculated kCH3 /kCD3 = 0.99 ± 0.16 for methylation of methoxide ion by S-methyldibenzothiophenium ion at 25 °C in methanol, as compared with the experimental value [12] of 0.97 ± 0.02. The computational results reproduce

Chiral gels derived from secondary ammonium salts of (1R,3S)-(+)-camphoric acid

• Tapas Kumar Adalder,
• N. N. Adarsh,
• Ravish Sankolli and
• Parthasarathi Dastidar

Beilstein J. Org. Chem. 2010, 6, 848–858, doi:10.3762/bjoc.6.100

• monocarboxylate (SAM) [36][37], secondary ammonium dicarboxylate (SAD) [38][39], primary ammonium monocarboxylate (PAM) [40][41] and primary ammonium dicarboxylate (PAD) [42][43] appear to play a crucial role in gel formation (Scheme 1). In the present work we intend to exploit SAD synthons to make chiral gels

Synthesis, electronic properties and self-assembly on Au{111} of thiolated (oligo)phenothiazines

• Adam W. Franz,
• Svetlana Stoycheva,
• Michael Himmelhaus and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2010, 6, No. 72, doi:10.3762/bjoc.6.72

• presence of a gold-coated silicon wafer. Monolayer formation is confirmed by ellipsometry and the results compared to those obtained by force field and DFT calculations. Keywords: cyclic voltammetry; ellipsometry; phenothiazines; SAM; thiols; Introduction Functional organic π-systems [1] are of great

• ] qualifies them as excellent models for switchable conductive or semiconductive molecular wires. Encouraged by successful electrode modifications with conjugated thiolated anilines [38] and SAM formation of thiolated phenylethynyl phenothiazines [39], and in continuation of our investigations directed

• “alligator-clips” and their electronic properties as studied by cyclic voltammetry (CV), spectroscopic and spectrometric methods. Furthermore, their chemisorption and SAM formation on Au{111} were studied by ellipsometry. Results and Discussion Synthesis The facile bromine–lithium exchange of bromo

Synthesis of phosphonate and phostone analogues of ribose-1-phosphates

• Pitak Nasomjai,
• David O'Hagan and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2009, 5, No. 37, doi:10.3762/bjoc.5.37

• step in the biosynthesis involves the fluorinase, an enzyme that catalyses nucleophilic attack of fluoride ion on SAM (3) to generate 5′-FDA (4). The initial fluorinated product 5′-FDA (4) is then depurinated by a purine nucleotide phosphorylase (PNP) to give 5-fluoro-5-deoxyribose-1-phosphate (5