New insight into experimental and theoretical properties of some para-like substituted 2-azidothiophenes

Valenti, Francesco; Zanirato, Paolo

doi:10.1039/a807350c

Cited by 4 publications

(4 citation statements)

References 28 publications

(17 reference statements)

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“…In contrast, 2-azidothiophene could not be obtained by this protocol, because it is inherently instable. This finding corresponds to the observations of Zanirato et al that, depending on the nature of the substituents, 5-substituted 2-azidothiophenes are more or less instable at elevated temperatures [ 33 ].…”

Section: Resultssupporting

confidence: 91%

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

Potratz¹,

Mishra²,

Bäuerle³

2012

Beilstein J. Org. Chem.

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SummaryHerein we present a three-component one-pot procedure to synthesize co-oligomers of a donor–acceptor–donor type, in which thiophene moieties work as donor and 1,2,3-triazoles as acceptor units. In this respect, terminally ethynylated (oligo)thiophenes were coupled to halogenated (oligo)thiophenes in the presence of sodium azide and a copper catalyst. Optoelectronic properties of various thiophene-1,2,3-triazole co-oligomers were investigated by UV–vis spectroscopy and cyclic voltammetry. Several co-oligomers were electropolymerized to the corresponding conjugated polymers.

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Section: Resultssupporting

confidence: 91%

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

Potratz¹,

Mishra²,

Bäuerle³

2012

Beilstein J. Org. Chem.

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“…As in previous reports on 2-azido heteroaryls, 1b,8 azides 6, 4 and 7 were found to be more unstable with respect to azides 1, 2 and 3, which are probably stabilized by the sp 2 nitrogen at the 3-position, and 5, whose stability is assisted by the plike trimethylsilyl group. 5 All the azidoazoles are potential key intermediates for the synthesis of novel heterocyclic systems by ring transformation or intermolecular cycloaddition. In the present study, we examined the chemistry of the 1,3-dipolar cycloaddition (1,3-DC) of azidoazoles 1-7 with (trimethysilyl)acetylene (TMSAc) as a route to silylated bisheteroaryls such as triazole-azoles 1b-7b (Scheme 4).…”

Section: Resultsmentioning

confidence: 99%

“…In some instances, the dissociation and ring cleavage occur via a concerted mechanism without intervention of a 'free' nitrene. 5 Furthermore, the ring cleavage is not general; in some cases it competes with either an intramolecular cyclization (with the participation of an ortho-neighboring group 1b, 6 ) or with an intermolecular 1,3-cycloaddition 2,4-7 (in the presence of activated dipolarophiles), affording fused-or bisheteroaryls, respectively. These chemical behaviors are similar to those reported in the literature for analogous systems.…”

Section: Methodsmentioning

confidence: 99%

On the utility of the azido transfer protocol: synthesis of 2- and 5-azido N-methylimidazoles, 1,3-thiazoles and N-methylpyrazole and their conversion to triazole–azole bisheteroaryls

Zanirato

Cerini

2005

Org. Biomol. Chem.

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The azido transfer procedure of heteroaryllithium and tosyl azide was used to synthesize selected 2- and 5-azidoazoles. This procedure, which is based on the fragmentation of the appropriate lithium triazene salts 1a-7a, successfully afforded 2-azido-N-methylimidazole 1, 2-azido-1,3-thiazole 2, 2-azidobenzo-1,3-thiazole 3, 5-azido-N-methylpyrazole 4, 5-azido-N-methylimidazole 6[via 2-(trimethylsilyl)-5-azido-N-methylimidazole 5], and 5-azido-1,3-thiazole 7 (via 5-lithio-1,3-thiazole), but attempts to prepare 5-azido-2-(trimethylsilyl)-1,3-thiazole 8 from the corresponding triazene 7a failed, affording only the desilylated azide in poor yield. Azides - underwent 1,3-dipolar cycloaddition when mixed with neat (trimethylsilyl)acetylene, giving 1-heteroaryl-4-trimethylsilyl-1,2,3-triazoles 1b-7b generally in very high yields.

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“…Very recently, we have identified 3-furylnitrene (Scheme ) in the triplet ground state among the photolysis products of 3-furoyl azide via the intermediacy of furoyl nitrene . However, 2-furylnitrene and the heavier sulfur analogous 2-thienylnitrene (Scheme ) remain hitherto unobserved, although their stability and electronic properties have been computationally explored. − Calculations at the SF-CCSD(T)/cc-pVTZ level on aromatic nitrenes suggest that their stability correlates with the singlet–triplet splitting, and increased delocalization of the radical electron onto the radical stabilizing substituents can decrease electron pair repulsion, thus preferentially stabilizing the singlet state . Similar to the studies on 2-furylnitrene and 2-furylcarbene, previous ab initio molecular orbital theory at the MP2/6-31G(d,p) level predicted that 2-thienylnitrene in the closed-shell singlet state is in fact a transition state which forms a ring-opening product without a barrier .…”

Section: Introductionmentioning

confidence: 99%

Photodecomposition of Thienylsulfonyl Azides: Generation and Spectroscopic Characterization of Triplet Thienylsulfonyl Nitrenes and 3-Thienylnitrene

Yang

Deng

et al. 2019

J. Phys. Chem. A

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The photochemistry of 2-thienylsulfonyl azide (1) and 3thienylsulfonyl azide (6) has been disclosed by combining matrixisolation spectroscopy with quantum chemical calculations. Two novel heteroaryl sulfonyl nitrenes, 2-thienylsulfonyl nitrene (2) and 3thienylsulfonyl nitrene (7), have been generated during the 266 nm laser photolysis of 1 and 6, respectively. Both nitrenes in the triplet ground state have been characterized with matrix-isolation IR ( 15 Nlabeling) in solid Ar (10.0 K), N 2 (10.0 K), and Ne (2.8 K) matrixes and EPR spectroscopy (2, |D/hc| = 1.452 cm −1 and |E/hc| = 0.0058 cm −1 ; 7, | D/hc| = 1.492 cm −1 and |E/hc| = 0.0060 cm −1 ) in solid toluene at 5.0 K. Upon subsequent UV-light irradiation (365 nm), no Curtius rearrangement but decomposition of 2 occurs by SO 2 -elimination and the concurrent formation of ring-opening product (s-Z)-4-thioxo-2-butenenitrile (3) via the intermediacy of the putative 2-thienylnitrene (4). In contrast, violet-light irradiation (400 ± 20 nm) of 7 causes SO 2 -elimination to yield triplet 3-thienylnitrene (8), for which the IR spectroscopic identification is supported by quantum chemical calculations at the B3LYP/6-311++G(3df,3pd) level. 3-Thienylnitrene is highly reactive, since it not only combines with SO 2 to furnish 3-thienyl-N-sulfonylamine (9) but also undergoes ring-opening to (s-E)-4-thioxo-2-butenenitrile (10) under the UV-light irradiation (365 nm).

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New insight into experimental and theoretical properties of some para-like substituted 2-azidothiophenes

Cited by 4 publications

References 28 publications

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

On the utility of the azido transfer protocol: synthesis of 2- and 5-azido N-methylimidazoles, 1,3-thiazoles and N-methylpyrazole and their conversion to triazole–azole bisheteroaryls

Photodecomposition of Thienylsulfonyl Azides: Generation and Spectroscopic Characterization of Triplet Thienylsulfonyl Nitrenes and 3-Thienylnitrene

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