2‐(4‐alkylamido‐2‐hydroxyphenyl)benz‐X‐azoles as intermediates for the synthesis of dyes

Abstract

Nineteen substituted 2‐phenylbenz‐X‐azoles, which are intermediates for the synthesis of dyes, were prepared from p‐aminosalicylic acid (PAS). Substituents in the phenyl ring are 2′‐hydroxy and/or 4′‐amino and 4′‐alkylamido with alkyl chains ranging from C1 to C15. The preferred route of the synthesis is discussed. The melting points and the Rf values are correlated with the structure. An extensive discussion of the electronic absorption spectra, involving other compounds with the same general structure, is reported.

Dramatic Substituent Effects on the Photoluminescence of Boron Complexes of 2‐(Benzothiazol‐2‐yl)phenols

“…The para derivative 2 a (R' = Me) was synthesized according to the literature procedure. [6,7] Then, we prepared the difluoroboron complexes 3 and 4 from the BTP m and BTP p , respectively ( Figure 2), by treatment with boron trifluoride etherate in the presence of triethylamine. We also prepared diphenylboron analogues such as 5 a, [8] but it was rather unstable in acetonitrile.…”

An amino-substituted 2-(2′-hydroxyphenyl)benzimidazole for the fluorescent detection of phosgene based on an ESIPT mechanism

“…As shown in Scheme 2 , P1 was synthesized by one-pot condensation reaction of o -phenylenediamine with 5-aminosalicylic acid in PPA at 160 °C for 3 h. 37 The related proposed sensing product P1-CO was synthesized through fast twice carbamylation reaction between P1 and triphosgene in the presence of TEA with good isolated yield. HPLC-MS analysis of the reaction mixture showed a complete conversion of P1 and the 5′-amino group did not react with phosgene under this condition (Fig.…”

“…5-Aminosalicylic acid (0.153 g, 1.0 mmol) and o -phenylenediamine (0.108 g, 1.0 mmol) were mixed and stirred in polyphosphoric acid (85% phosphorus pentoxide, 10 mL) at 160 °C over a period of 3 h. 37 Then the reaction mixture was poured into distilled water (20 mL), and the precipitate were collected and washed by saturated NaHCO 3 aqueous solution to pH 8–9. The obtained crude product was further purified by column chromatography (ethyl acetate: petroleum ether = 3 : 1) to give P1 (0.108 g, yield 48%) as a purple solid.…”

Luminescent properties of benzothiazole derivatives and their application in white light emission

“…benzothiazole (AHBA) was synthesized according to the literature. 27 To a solution of n-caprylic acid (2.16 g, 15 mmol) in 50 mL toluene was added 1,1 0 -carbonyldiimidazole (CDI, 2.43 g, 15 mmol) under dry argon. The mixture was stirred at reux temperature for 6 hours and then cooled down to room temperature.…”