A simple explanation for the symmetry and degeneracy of the genetic code has been suggested. An alternative to the wobble hypothesis has been proposed. This hypothesis offers explanations for: i) the difference between thymine and uracil, ii) encoding of tryptophan by only one codon, iii) why E. coli have no inosine in isoleucine tRNA, but isoleucine is encoded by three codons. The facts reveal...

The yellow-green luminescence from firefly luciferase has long been understood to be the emission from enol-oxyluciferin. However, a recent experiment showed that an oxyluciferin constrained to the keto form produced a yellow-green emission in luciferase (Branchini, B. R.; Murtiashaw, M. H.; Magyar, R. A.; Portier, N. C.; Ruggiero, M. C.; Stroh, J. G. J. Am. Chem. Soc. 2002, 124, 2112-2113). Th...

Tautomerism in organic chemistry has been extensively studied in condensed phase by spectrometric methods, mainly by IR and NMR techniques. Mass spectrometry studies start 40 years ago but just recently it has been recognized the importance of the mass spectral data for the study of tautomerism in the gas phase. Mass spectrometry can provide valuable information in regard to tautomeric equilibr...

Aldehydes, ketones, carboxylic esters, carboxylic amides, imines and N,N-disubstituted hydrazones react as electrophiles at their sp2-hybridized carbon atoms. These compounds also become nucleophiles, if they contain an H atom in the a-position relative to their C O or C N bonds. This is because they can undergo tautomerization to the corresponding enol as seen in Chapter 12. They are also C,H-...

Molecules bearing β-keto-enol functionality are potential candidates for coordination chemistry. Reported herein is the first synthesis and use of a novel designed ligand based on β-keto-enol group embedded with pyridine and thiophene moieties. The product was prepared in a one-step procedure by mixed Claisen condensation and was characterized by EA, m/z, FT-IR, (¹H, (13)C) NMR and single-cryst...