Two efficient routes have been established for the preparation of both enantiomers of cis‐(2‐aminocyclobutyl)acetic acid, a conformationally restricted analogue of GABA. Both procedures converged on the racemic N‐tert‐butoxycarbonyl derivative of the target compound, which was resolved through chiral derivatization with an oxazolidinone auxiliary, which also allowed determination of the absolute configuration of the new compounds. The first route involved the homologation of cis‐2‐aminocyclobutanecarboxylic acid, whereas the second route employed an intramolecular photocyclization protocol, which provided an expedient, cis‐selective access to the lactam form of the target structure.

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A series of three short oligomers (di-, tri-, and tetramers) of cis-2-(aminomethyl)cyclobutane carboxylic acid, a γ-amino acid featuring a cyclobutane ring constraint, were prepared, and their conformational behavior was examined spectroscopically and by molecular modeling. In dilute solutions, these peptides showed a number of low-energy conformers, including ribbonlike structures pleated around a rarely observed series of intramolecular seven-membered hydrogen bonds. In more concentrated solutions, these interactions defer to an organized supramolecular assembly, leading to thermoreversible organogel formation notably for the tripeptide, which produced fibrillar xerogels. In the solid state, the dipeptide adopted a fully extended conformation featuring a one-dimensional network of intermolecularly H-bonded molecules stacked in an antiparallel sheet alignment. This work provides unique insight into the interplay between inter- and intramolecular H-bonded conformer topologies for the same peptide template.

The photochemical electrocyclization reaction of the title compound in the presence of β-cyclodextrin was examined in different conditions. No enantioselectivity was observed in solution, but solid-state reactions of a 1:1 complex as a suspension or a thin film, followed by reduction, provided (1R,5R)-2-azabicyclo[3.2.0]heptan-3-one in isolated yields up to 79% and with ee values up to 45%.

The discoloration of the food colorant E131 (Patent Blue V) by K2S2O8 and KIO3 was investigated by spectrophotometric method. The discoloration is first order with respect to the food colorant and the oxidants. The discoloration rate constant increases with the increase in initial concentration of the oxidant and temperature; whereas discoloration decreases with the increase in concentration of E131 and chloride ion. In the presence of persulfate, Cu(II) and Fe(II) have a catalytic effect on discoloration but Ni(II) has not. The thermodynamic parameters (Ea, ∆H # , ∆S # , ∆G # ) of the discoloration in the presence and absence of Cu(II) and Fe(II) are calculated.