The intramolecular reaction of dialkyl peroxides with carbanions, generated via chemoselective metal-heteroatom exchange or deprotonation, provides a new approach to cyclic ethers. Applied in tandem with C-C bond formation, the strategy enables a one-step annelation to form oxaospirocycles.

On deprotonation, 1-arylindazolium salts form 1-arylindazol-3-ylidenes which rearrange spontaneously via ring cleavage, ring closure and subsequent proton transfer to substituted 9-aminoacridines. By contrast, the N-heterocyclic carbene of 2-phenylindazolium cannot rearrange similarly and was trapped by sulfur.

Although lowering the pK2 of neutral amino acids only weakens their concentrative uptake by Ehrlich cells, the same change greatly enhances uptake of diamino acids. This effect does not arise merely from putting the distal amino group in its uncharged form, but depends on an enhanced deprotonation of the alpha-amino group. Parallel effects are seen for the transport system for basic amino acids...

Triosephosphate isomerase (TIM) is a proficient catalyst of the reversible isomerization of dihydroxyacetone phosphate (DHAP) to d-glyceraldehyde phosphate (GAP), via general base catalysis by E165. Historically, this enzyme has been an extremely important model system for understanding the fundamentals of biological catalysis. TIM is activated through an energetically demanding conformational ...

1,5-Diarylbiguanides, where the aryl groups are phenyl (HL1), 3,5-dimethylphenyl (HL2), 3,5-dimethoxyphenyl (HL3), 4-t-butylphenyl (HL4) or 4-bromophenyl (HL5), have been prepared and characterised. HL3 and HL5 have been structurally characterised by X-ray crystallography, which shows them to adopt the expected tautomeric form for biguanides. They have extensive hydrogen-bonding interactions in...

Diphenyl-(4-{2-[4-(2-pyridin-4-yl-vinyl)-phenyl]-vinyl}-phenyl)-amine (DPVPA) constitutes a novel acido-triggered reversible luminescent and nonlinear optical switch. Remarkably, for the first time the Electric-Field Induced Second Harmonic generation (EFISH) technique is used to reveal a protonation-deprotonation NLO contrast.

A synthesis of the core ring structure of the fargenin/fargenone family of natural products is presented. The general strategy is based upon biosynthetic speculation and exploits a cascade reaction, which transforms a spirocyclic dienone into the core ring system via a deprotonation-oxy-Michael-Wittig olefination sequence. This study represents the first synthesis work towards this family of na...

Reaction of o-mesitylsulfonylhydroxylamine (MSH) with Ph(2)Se results in the [Ph(2)SeNH(2)](+) cation; low temperature deprotonation (LDA), bromination (NBS) and then treatment with Ph(2)Se-Na[BPh(4)] generates [Ph(2)SeNSePh(2)][BPh(4)], via the selenimides Ph(2)Se=NH and Ph(2)Se=NBr.

The fluorescence of a designed water-soluble 4-sulfonato-1,8-naphthalimide dye can be switched on by the synchronous host-guest complexation with cucurbit[7]uril and decrease in pH (from 9 to 7). This affords a dual resettable (by addition of cadaverine as competitor or by deprotonation) logic gate based on modulation of photoinduced electron transfer.

The tris(thiourea) receptor, L, in the presence of excess H(2)PO(4)(-) has been found to encapsulate a trivalent phosphate ion within a π-stacked dimeric capsular assembly of the receptor with twelve strong H-bonds via deprotonation, as evident from the origin of a new set of signals in the (1)H NMR titration experiments.