“…An excellent starting material proved to be the readily prepared and commercially available 2,5-dimethylpyrrole ( 11 ). Reaction of 11 with freshly generated thiocyanogen in methanol smoothly (82%) afforded the known 2,5-dimethyl-3,4-dithiocyanopyrrole ( 12 ), which reacted with BOC anhydride to give (90%) the corresponding N -BOC derivative 13 , as shown in Scheme . 1 …”
Section: Resultsmentioning
confidence: 99%
“…After the ice melted, the resulting precipitate was collected by filtration, washed with water, and air-dried. The crude material was purified by recrystallization in dichloromethane/hexane (1:4) to give the pure product (90.1 g, 82%) as a white solid: mp 134−136 °C (lit. , mp 132 °C); 1 H NMR (360 MHz, CDCl 3 ) δ 9.00 (s, 1H), 2.39 (s, 6H).…”
The synthesis of the first derivatives of bis(pyrrolo[3,4-d])tetrathiafulvalene has been studied in detail. Starting from the readily available 2,5-dimethylpyrrole (11) and N-phenyl-2,5-dimethylpyrrole, bis(2,5-dimethylpyrrolo[3,4-d])tetrathiafulvalene (8) and the N,N'-disubstituted derivatives 6, 7, 9, and 10 were prepared in good yields by practical procedures. In contrast to the other types of aromatic annelated tetrathiafulvalenes (TTFs), which have appreciably higher oxidation potentials than TTF, the redox behavior of the pyrrolo tetrathiafulvalenes (TTFs) is very close to that of TTF itself. The potential of pyrrolotetrathiafulvalenes as a new series of organic metal building blocks is shown by the two-probe conductivities of the tetracyanoquinodimethane (TCNQ) complexes of the N-phenyl compound 7 and the N-methyl compound 9, which give higher values than TTF-TCNQ under similar conditions.
“…An excellent starting material proved to be the readily prepared and commercially available 2,5-dimethylpyrrole ( 11 ). Reaction of 11 with freshly generated thiocyanogen in methanol smoothly (82%) afforded the known 2,5-dimethyl-3,4-dithiocyanopyrrole ( 12 ), which reacted with BOC anhydride to give (90%) the corresponding N -BOC derivative 13 , as shown in Scheme . 1 …”
Section: Resultsmentioning
confidence: 99%
“…After the ice melted, the resulting precipitate was collected by filtration, washed with water, and air-dried. The crude material was purified by recrystallization in dichloromethane/hexane (1:4) to give the pure product (90.1 g, 82%) as a white solid: mp 134−136 °C (lit. , mp 132 °C); 1 H NMR (360 MHz, CDCl 3 ) δ 9.00 (s, 1H), 2.39 (s, 6H).…”
The synthesis of the first derivatives of bis(pyrrolo[3,4-d])tetrathiafulvalene has been studied in detail. Starting from the readily available 2,5-dimethylpyrrole (11) and N-phenyl-2,5-dimethylpyrrole, bis(2,5-dimethylpyrrolo[3,4-d])tetrathiafulvalene (8) and the N,N'-disubstituted derivatives 6, 7, 9, and 10 were prepared in good yields by practical procedures. In contrast to the other types of aromatic annelated tetrathiafulvalenes (TTFs), which have appreciably higher oxidation potentials than TTF, the redox behavior of the pyrrolo tetrathiafulvalenes (TTFs) is very close to that of TTF itself. The potential of pyrrolotetrathiafulvalenes as a new series of organic metal building blocks is shown by the two-probe conductivities of the tetracyanoquinodimethane (TCNQ) complexes of the N-phenyl compound 7 and the N-methyl compound 9, which give higher values than TTF-TCNQ under similar conditions.
“…Based on that work, we have developed a preparation of 7 ( Scheme 2 ) [ 36 ]. Functionalised pyrrole 16 was prepared according to the literature [ 35 , 37 ] then tosylated in high yield to afford 17 . The reduction of the thiocyanate moieties with LiAlH 4 afforded the air-sensitive intermediate 18 (not characterised), which was treated with 1,1’-carbonyldiimidazole to afford 7 , in 83% yield over the two steps.…”
SummaryThe electron-donor and unique redox properties of the tetrathiafulvalene (TTF, 1) moiety have led to diverse applications in many areas of chemistry. Monopyrrolotetrathiafulvalenes (MPTTFs, 4) and bispyrrolotetrathiafulvalenes (BPTTFs, 5) are useful structural motifs and have found widespread use in fields such as supramolecular chemistry and molecular electronics. Protocols enabling the synthesis of functionalised MPTTFs and BPTTFs are therefore of broad interest. Herein, we present the synthesis of a range of functionalised MPTTF and BPTTF species. Firstly, the large-scale preparation of the precursor species N-tosyl-(1,3)-dithiolo[4,5-c]pyrrole-2-one (6) is described, as well as the synthesis of the analogue N-tosyl-4,6-dimethyl-(1,3)-dithiolo[4,5-c]pyrrole-2-one (7). Thereafter, we show how 6 and 7 can be used to prepare BPTTFs using homocoupling reactions and functionalised MPTTFs using cross-coupling reactions with a variety of 1,3-dithiole-2-thiones (19). Subsequently, the incorporation of more complex functionality is discussed. We show how the 2-cyanoethyl protecting group can be used to afford MPTTFs functionalised with thioethers, exemplified by a series of ethylene glycol derivatives. Additionally, the merits of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an alternative to the most common deprotecting agent, CsOH·H2O are discussed. Finally, we show how a copper-mediated Ullman-type reaction can be applied to the N-arylation of MPTTFs and BPTTFs using a variety of aryl halides.
“…The synthesis of the tetramethylated bis‐pyrrolo‐TTF 6 was carried out as outlined in Scheme and was inspired by the synthetic route ( vide supra ) developed by Cava and co‐workers. Initially, 2,5‐dimethyl‐3,4‐dithiocyanopyrrole 9 was reacted with tosyl chloride (TsCl) in acetonitrile (MeCN) in the presence of triethylamine (Et 3 N) and 4‐dimethylamino‐pyridine (DMAP) to afford the tosyl protected pyrrole 10 in 83% yield. The two thiocyanate groups of 10 were reduced in tetrahydrofuran (THF) with lithium aluminum hydride (LiAlH 4 ).…”
Section: Resultsmentioning
confidence: 99%
“…All of the reagents were obtained from commercial suppliers and used without further purification unless otherwise indicated. The compounds 2,5‐dimethyl‐3,4‐dithiocyanopyrrole 9 (Scheme ) and 4,5‐bismethylthio‐1,3‐dithiole‐2‐thione 13 were prepared according to the literature procedures. Anhydrous solvents were obtained from a Solvent Purification System, Innovative Technology, Inc (Sigma Aldrich, Steinheim, Germany).…”
An alternative and efficient protocol for the synthesis of methylated pyrrolo‐tetrathiafulvalenes have been developed. The key intermediate in this new synthetic protocol is 4,6‐dimethyl‐N‐tosyl‐(1,3)‐dithiolo[4,5‐c]pyrrole‐2‐one, which can be obtained in high yield in a three‐step synthetic procedure from 5‐dimethyl‐3,4‐dithiocyanopyrrole.
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