We investigated the thermoresponsive behavior of poly­(acrylamide-co-acrylonitrile) (poly­(AAm-co-AN)) with an upper critical solution temperature (UCST) in water to apply this polymer in cosmetic products that can be easily removed by washing with hot water. Six kinds of poly­(AAm-co-AN) polymers were synthesized, and those containing higher contents of AN units showed higher UCSTs in water. The amount of AN units in the resulting copolymer was controlled only by adding AN immediately prior to the polymerization to prevent its loss due to volatilization. We also analyzed the UCST behavior of poly­(AAm-co-AN) by fluorometry by labeling the polymer with an environment-sensitive fluorophore. The fluorescence spectra, fluorescence quenching titration results, and time-resolved fluorescence anisotropy measurements revealed that poly­(AAm-co-AN) loosely aggregated below the UCST, and the dipole–dipole interaction between the cyano groups in AN units and the hydrogen bonds between the amide groups in the AAm units were responsible for the cross-linking of the aggregates.

The structure of a C-symmetric epidithiodiketopiperazine alkaloid, SCH 64874, was determined by semisynthesis. The relative stereochemistry of the β-hydroxy carboxylic acid chain having three chiral centers was determined by comparison of the NMR data of the four possible diastereomeric β-hydroxy carboxylic acid fragments with those of SCH 64874. Condensation of the (-)-deacetylaranotin core with two enantiomeric β-hydroxy carboxylic acids revealed the relative stereochemistry of SCH 64874. The relative stereochemistry of the β-keto carboxylic acid chain of the analogous alkaloid hirsutellomycin was determined in a stepwise manner. The C4'-C6' syn relationships were predicted by comparing the NMR data of the corresponding ester fragments with that of hirsutellomycin. The relative stereochemistry of the whole molecule, including the epimerizable C2' stereocenter, was determined by introduction of four possible side chains into the bisdethiodi(methylthio)deacetylaranotin core. We found that the stereochemistry of C2' converged with that of the thermodynamically stable form influenced by the core structure.

Divergent total syntheses of isobatzellines A/B and batzelline A were accomplished. A fully substituted common indole intermediate bearing C-2 methylthio and C-5 chloro groups was constructed via ring expansion of benzocyclobutenone oxime sulfonate with NaSMe and a benzyne-mediated cyclization/functionalization sequence as the key steps. The total synthesis of isobatzelline B was achieved via formation of the iminoquinone structure by the redox-neutral acid-promoted C-5 proto-dechlorination of the common indole intermediate. The total syntheses of isobatzelline A and batzelline A were completed in a divergent manner by oxidation of the common indole intermediate using MnO2 or Mn­(OAc)3, respectively.

An indole synthesis via ring expansion of benzocyclobutenone oxime sulfonate was developed. Utility of the indole synthesis was demonstrated by the total synthesis of (+)-CC-1065. The middle and right segments were constructed by a sequential ring expansion of the symmetrical benzo-bis-cyclobutenone. The left segment was also constructed via ring expansion of the methyl-substituted benzocyclobutenone oxime sulfonates. After condensation of these three segments, the dienone cyclopropane structure was formed to complete the total synthesis.

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