Straightforward Synthesis of 2‐ and 2,8‐Substituted Tetracenes

Abstract

A simple regiospecific route to otherwise problematic substituted tetracenes is described. The diverse cores (E)-1,2-Ar CH (HOCH )C=C(CH OH)I (Ar =Ph, 4-MePh, 4-MeOPh, 4-FPh) and (E)-1,2-I(HOCH )C=C(CH OH)I, accessed from ultra-low cost HOCH C≡CCH OH at multi-gram scales, allow the synthesis of diol libraries (E)-1,2-Ar CH (HOCH )C=C(CH OH)CH Ar (Ar =Ph, 4-MePh, 4-iPrPh, 4-MeOPh, 4-FPh, 4-BrPh, 4-biphenyl, 4-styryl; 14 examples) by efficient Negishi coupling. Copper-catalysed aerobic oxidation cleanly provides dialdehydes (E)-1,2-Ar CH (CHO)C=C(CHO)CH Ar , which in many cases undergo titanium(IV) chloride-induced double Bradsher closure, providing a convenient method for the synthesis of regiochemically and analytically pure tetracenes (12 examples). The sequence is typically chromatography-free, scalable, efficient and technically simple to carry out.

(E)-Di-iodination of Alkynes Using Dried Dowex H+/NaI Approach

“…Surprisingly, compounds 19 and 21 were totally unknown and we could find only one reference for each of the compounds 14 , 36 15 , 5 20 , 3 and 22 (37) in the literature. In addition, in the preparation of compounds 18 and 23 , only two 38,39 or three 31,40,41 methods have been described, respectively. This was rather unexpected because of the importance of ( E )-di-iodinated compounds as discussed in the introduction.…”

“…NMR data were comparable with those reported elsewhere. 31 1 H NMR (CD 3 OD): δ 4.20 (s, 4H). 13 C{ 1 H} NMR (CD 3 OD): δ 104.5 (2C), 76.2 (2C).…”

Synthesis and thermoelectric properties of 2- and 2,8-substituted tetrathiotetracenes

“…Tetrathiotetracene synthesis. Direct reaction of readily available tetracenes (2a-h) 6 with elemental sulfur in DMF at reflux, in the manner of Perez-Alberne, 7 afforded the tetrathiotetracenes (1a-h) ( Table 1). All are readily isolated in good yields (74-99%) as very dark green powders by simple filtration of the hot reaction mixtures giving products with purities of ca.…”

Conjugate Addition Routes to 2‐Alkyl‐2,3‐dihydroquinolin‐4(1H)‐ones and 2‐Alkyl‐4‐hydroxy‐1,2‐dihydroquinoline‐3‐carboxylates

“…General: Details of our general laboratory set‐up and instrumentation have been already published . In brief, 2‐Me‐THF and Et 2 O were distilled from sodium‐benzophenone.…”