The synthesis of dinaphthothiophenes

Abstract

The synthesis of dinaphtho[1,2‐b:2′,3′‐d]thiophene (6), dinaphtho[2,1‐b:2′,3′‐d]thiophene (15), dinaphtho‐[1,2‐b:1′,2′‐d]thiophene (20), dinaphtho[2,1‐b:1′,2′‐d]thiophene (26), dinaphtho[2,3‐b:2′,3′‐d]thiophene (37) and dinaphtho[1,2‐b:2′,1′‐d]thiophene (45) has been accomplished.

1,1-Dioxonaphtho[1,2-b]thiophene-2-methyloxycarbonyl (α-Nsmoc) and 3,3-Dioxonaphtho[2,1-b]thiophene-2-methyloxycarbonyl (β-Nsmoc) Amino-Protecting Groups

“…Treatment of these derivatives of p-chloroaniline (PCA) with 2 eqv. of piperidine in CDCl 3 -DMSO-d 6 showed that under the conditions and at the concentrations used, which were the same in all three cases, rough halftimes for release of p-chloroaniline were 2.0, 2.4 and 7.4 min. in the cases of the α-Nsmoc, Bsmoc and β-Nsmoc systems respectively.…”

Synthesis of Annulated Anthracenes, Carb­azoles, and Thiophenes Involving Bradsher‐Type Cyclodehydration or Cycli­zation–Reductive‐Dehydration Reactions

“…2‐(Dibenzo[ b , d ]thiophen‐2‐ylmethyl)benzoic Acid (5m): The reduction of keto acid 4m (3 g, 9.03 mmol), using zinc dust (3.88 g, 59.63 mmol) and mercuric chloride (0.38 g, 1.39 mmol) following a procedure similar to that described for 5a , gave benzyl acid 5m (2.04 g, 71 %) as a colourless solid, m.p. 118–120 °C (ref 23. 118–120 °C).…”

“…Anthra[1,2‐ d ]benzo[ b ]thiophene (7m): Cyclodehydration of 2‐(dibenzo[ b,d ]thiophen‐2‐ylmethyl)benzaldehyde ( 6m ; 0.3 g, 0.99 mmol) using BF 3 · OEt 2 (0.03 g, 0.20 mmol) following a procedure similar to that described for 7a gave 7m (0.25 g, 88 %) as a pale green solid, m.p. 168 °C (ref 23. 228–230 °C).…”

Synthesis of Unsymmetric Monosubstituted and Disubstituted Dinaphthothiophenes

“…Furthermore, Tedjamulia et al . prepared all three classes of DNTs from formyl‐benzonaphthothiophenes . A Horner–Wadsworth–Emmons reaction was used to add a styrene unit, followed by an iodine‐catalyzed photocyclization that gave yields of 45–76%.…”