Design and Synthesis of Long‐Wavelength Fluorescent Boronic Acid Reporter Compounds

Abstract

Three new fluorescent probes based on the 4-amino-1,8-naphthalimide structure were synthesized, and their sugar binding properties were studied by using D-fructose, D-glucose and D-sorbitol in 0.1 M phosphate buffer at pH 7.4. All three compounds showed fluorescence intensity changes upon addition of sugars. In this series, compound 1c gave

Synthesis, Evaluation, and Computational Studies of Naphthalimide‐Based Long‐Wavelength Fluorescent Boronic Acid Reporters

“…The apparent pK a values of 1 a in 1 % methanol/buffer were slightly different from those of previous studies in 0.1 % methanol/buffer. [13] The trend of the apparent pK a values with the other three boronic acids (Table 2), as expected. [1,4,13] These apparent pK a values showed a general Hammett correlation, as expected from our earlier publication (data not shown).…”

“…[12,[37][38][39] In our recent work, 4-amino-1,8-naphthalimide was used as a template for a series of long-wavelength fluorescent boronic acid reporters that showed fluorescence intensity increases upon sugar binding. [13] Somewhat related work was also reported by Trupp and co-workers. However, in their work, an added aliphatic linker with an appended amino group was used to modulate the fluorescence properties of a naphthalimide fluorophore.…”

“…For example, the binding constant of 1 a with fructose was 57 m À1 in 0.1 % methanol/buffer solution and changed to 25 m À1 in 1 % methanol/buffer. [13] However, the binding constants with other sugars showed little change with this minor change in methanol concentration.…”

“…In our previous work, we also studied other protecting groups and found that use of the methoxymethyl (MOM) protecting group resulted in chelation of the palladium catalyst in the borylation step and subsequently diminished borylation efficiency. [13] Therefore, in the first step of protection, 4-amino-1,8-naphthalimide (2) was treated with sodium methoxide/methanol in DMF at room temperature and was then treated with benzyl bromide to afford 4-amino-N-benzyl-naphthalimide 3 (Scheme 2). Among the alkylating agents 5 a-e, three were not commercially available and were prepared through benzylic bromination of the corresponding bromotoluene analogues 4 c-e by treatment with AIBN and NBS in CCl 4 at 70 8C (reflux conditions).…”

Computer‐Based De Novo Design, Synthesis, and Evaluation of Boronic Acid‐Based Artificial Receptors for Selective Recognition of Dopamine

“…After standing for 1 min, each mixture (0.7 mL) was transferred into a 1 cm quartz cuvette, and the fluorescence intensity was recorded. [31,48] When a diol was added to the ARS-boronic acid mixture, a concentrationdependent fluorescent intensity decrease was observed (Figure 4 A, for the case of dopamine), which allowed for binding constant determination (Figure 4 B). [31,32,47] By using this method, the binding constants of 1 a-d with dopamine were determined ( Table 1).…”