1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• with amino acids to be used as colorimetric indicators, Folin [45] developed a method based on naphthoquinone since there were records in the literature that indicated that naphthoquinones reacted with amines and proteins to form colored products. Among the tested o-naphthoquinones, he found that 1,2

Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

• Yagang Zhang and
• Steven C. Zimmerman

Beilstein J. Org. Chem. 2012, 8, 486–495, doi:10.3762/bjoc.8.55

• orange–yellow in color. Azobenzene coupled DAN and DeUG modules were successfully used as colorimetric indicators for specific DAN–DeUG and DAN–UPy (2-ureido-4(1H)-pyrimidone) quadruply hydrogen-bonding interactions. Keywords: azobenzene dye; colorimetric indicators; 7-deazaguanine urea (DeUG); 2,7

• ) by their coupling to azobenzene dyes allowing them to serve as colorimetric indicators for supramolecular interactions. Beyond reporting the straightforward coupling of DAN and DeUG to azobenzene dyes, we show that the dye-recognition-unit conjugates act as selective polymer colorants (Figure 2). The

• the possibility of using these compounds as colorimetric indicators, two types of polymers bearing DAN and UPy were used (Figure 4). The DAN modified polystyrene (PS-DAN) was a gift from Dr. Cyrus Anderson and its synthesis will be published elsewhere. Commercially available polystyrene (PS) was used