A solid-phase synthetic approach to pH-independent rhodamine-type fluorophores

Abstract

An efficient methodology using the Fukuyama-Mitsunobu reaction was successfully applied to prepare various Rhodamine B-based amides with the locked possibility to form a lactam ring. The procedure was developed for solid-phase synthesis, which can be advantageously applied to the synthesis of chemical libraries in a combinatorial fashion. A series of derivatives including aliphatic as well as aromatic rhodamine amides alkylated via a reaction with various alcohols were synthesized, and their spectral properties were investigated. Blocking lactamization via N-alkylation enabled us to prepare rhodamine derivatives with an excellent fluorescence response. In comparison to their non-alkylated counterparts, these derivatives exhibited pH independence and higher quantum yields.

Bis-Rhodamine B System as a Tin Detector or Molecular Electronics Device

“…The synthesis is based on the knowledge reported earlier for similar systems with one rhodamine dye. 19,20 We extended the reported synthesis for further reaction sequences and bound another rhodamine moiety (Schemes 1 and 2). 1).…”

“…This alkylation should block the spirolactam cyclization of one rhodamine moiety, assuring to keep fluorescence regardless of the analyte pH. The synthesis is based on the knowledge reported earlier for similar systems with one rhodamine dye. , We extended the reported synthesis for further reaction sequences and bound another rhodamine moiety (Schemes and ).…”

Polymer-Supported Synthesis of Various Pteridinones and Pyrimidodiazepinones

“…The oily nitro derivatives 9, 12, and 16 were dissolved in acetic dered zinc (0.5 g) was added. The reaction mixture was stirred at ro h to obtain dihydropteridinones 1, at room temperature for 3 pyrrolopteridinones 2, and at 80 °C for 3-13 h to obtain pyrimidod lution was filtered, evaporated to dryness, and purified by column 25 (m, 6H), 0.87 (t, J = 6.9 Hz, 3H). 13…”

Rhodamine B Amide Derivatives with Anticancer Activity and Fluorescence Properties for Potential Theranostic Applications

“…[6,13] Solid-phase chemistry for efficient synthesis of Nalkylated rhodamine amide derivatives developed by Brulikova et al exhibited high photostability, pH-independent features, and practical utility as sensors in a biological application. [14] Csuk et al reported the cytotoxic effects of ester and amide derivatives of RHB on different human tumor cell lines which revealed lesser EC 50 values as low as 0.23 and 0.15 μM for ethyl and hexyl ester, against MCF-7 tumor cells, with lack of selectivity; alternatively morpholinyl derived RHB amide showed good selectivity, but not as cytotoxic as RHB ester, i. e., EC 50 is 0.44-3.76 μM for MCF-7 breast adenocarcinoma cells, furthermore could not explain the selectivity behavior of simple morpholinyl compounds in contrast to the complex triterpenoids. [15] Lately, B.…”

“…Solid‐phase chemistry for efficient synthesis of N ‐alkylated rhodamine amide derivatives developed by Brulikova et al. exhibited high photostability, pH‐independent features, and practical utility as sensors in a biological application [14] . Csuk et al.…”