Creation of new potent antifouling active compounds is important for the development of environmentally friendly antifouling agents. Fifteen isocyanide congeners derived from proteinogenic amino acids were synthesized, and the antifouling activity and toxicity of these compounds against cypris larvae of the barnacle Balanus amphitrite were investigated. All synthesized amino acid-isocyanides exhibited potent anti-barnacle activity with EC values of 0.07 - 10.34 μg/ml after 120 h exposure without significant toxicity. In addition, seven compounds showed more than 95% settlement inhibition of the cypris larvae at 10 μg/ml after 120 h exposure without any mortality observed. Considering their structure, these amino acid-isocyanides would eventually be biodegraded to their original nontoxic amino acids. These should be useful for further research focused on the development of environmentally friendly antifoulants.

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A direct method for preparing bis(alkylamino)maleonitriles from alcohols was developed. Treatment of tertiary alcohols with trimethylsilyl cyanide (TMSCN) and trimethylsilyl triflate (TMSOTf) in the presence of bismuth(III) triflate [Bi(OTf) 3 ] afforded the corresponding bis(alkylamino)maleonitriles in moderate-to-high yields. Tertiary alcohols with various functional groups such as halo, ether, ester, and imide functional groups were tolerated under these conditions. This is the first report of a synthetic method for the preparation of bis(alkylamino)maleonitriles in a single step from tertiary alcohols.

Bis(alkylamino)maleonitriles are starting materials for the synthesis of a number of important intermediates, including porphyrazines that serve as dyes, pigments, and models of biologically active substances; hence, the development of improved methods for their preparation is important. Herein, we report a facile new method for the preparation of bis(alkylamino)maleonitriles from isocyanides. Treatment of tert-alkyl isocyanides with trimethylsilyl cyanide (TMSCN) and trimethylsilyl triflate (TMSOTf) in the presence of bismuth(III) triflate [Bi(OTf)3] afforded the corresponding bis(alkylamino)maleonitriles in moderate yields. tert-Alkyl isocyanides bearing a variety of functional groups, including halide, ether, ester, imide, amide, and carbamate, are tolerated under the developed reaction conditions. To the best of our knowledge, this is the first report of a synthetic method for the preparation of bis(alkylamino)maleonitriles in a single step from tertiary alkyl isocyanides.