ChemInform Abstract: Synthesis of 3‐(5‐Methylthiophen‐2‐yl)coumarins and Their Photochromic Dihetarylethene Derivatives.

Abstract

Synthesis of 3-(5-Methylthiophen-2-yl)coumarins and Their Photochromic Dihetarylethene Derivatives. -Unsymmetrical dithienylmaleic acid anhydride (III), incorporating a coumarin moiety, is synthesized in order to combine high photochromic performance and intense fluorescence of open form. Dithienylethene(III) exhibits long-wavelength absorption of cyclic form, good fatigue resistance, and thermal irreversibility. -(BOCHKOV, A. Y.; KRAYUSHKIN, M. M.; YAROVENKO, V. N.; BARACHEVSKY, V. A.; BELETSKAYA, I. P.; TRAVEN*, V. F.; J. Heterocycl. Chem. 50 (2013) 4, 891-898, http://dx.

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

“…), anhydrous dichloromethane, rt, 30 min, then 50 °C, 3 h, AlCl 3 , anhydrous dichloromethane, 0 °C, 15 min, rt, 15 min, 40 °C, 13 h, 71% [24,43]. Scheme 3: Synthesis of thiophene derivative 32: a) Magnesium, 2-ethylhexylbromide, spatula tip iodine, anhydrous diethyl ether, 45 °C, 2 h, 3-bromothiophene, [1,3-bis(diphenylphosphino)propane]dichloronickel(II), 45 °C, 14.5 h, 40% [47]; b) n-butyllithium, 2,2,6,6-tetramethylpiperidine, anhydrous tetrahydrofuran, −80 °C, iodomethane, then rt, overnight, 86% [48]; c) n-butyllithium, anhydrous tetrahydrofuran, −5 °C, 1 h, then −78°C, trimethyl borate, then rt, overnight, 25% [49,50].…”

“…In a manner similar to [49,50], 4-(2-ethylhexyl)-2-methylthiophene (31), which had been synthesised according to the published literature [47,48,51,52], was lithiated with n-butyl- lithium, and reacted with trimethyl borate [49,50]. Although a conversion could be detected with TLC, no boronic acid derivative of 31 could be isolated; it hydrolysed on the column back to the starting material.…”