Zur darstellbarkeit von spirobenzthiazolopyranen

Electrochromics by Intramolecular Redox Switching of Single Bonds

“…On cooling of the refluxed mixture (30 min), the product 3 a ± c was deposited as orange crystals, which were recrystallized from acetonitrile/diethylether. Monomethincyanine 4: Triethylamine (1.5 mL) was added to a solution of 2-ethyl-3-methylbenzothiazolium toluene-4-sulfonate [38] (1.61 g, 4.61 mmol) and 13 [36] (1.25 g, 4.61 mmol) in ethanol (20 mL Trimethincyanine 6: Compound 15 (300 mg, 0.93 mmol) was suspended in methanol (50 mL). After adding 17 (455 mg, 1.40 mmol), the mixture was heated to reflux for 1 h. On cooling 6 (256 mg, 62 %) was deposited as purple prisms; m.p.…”

“…Synthesis of bis-monomethincyanines 3 a ± c. peptide synthesis, appropriate dicarboxylic acids 11 a ± c were activated through their mixed carboanhydrides and transformed with o-methylaminothiophenol into the bis-benzothiazolium salts 12 a ± c. [35] Condensation of 12 a ± c with 2-chloro-3-methylbenzothiazolium salt 13 [36] afforded the expected bis-monomethincyanines 3 a ± c in good yield (51 ± 64 %). [37] Similarly, the model compound 4 was prepared from 2-ethyl-3-methylbenzothiazolium toluene-4-sulfonate [38] and 13 in 68 % yield.…”