Über 1.2.4‐ Triazole, XIV. Die Bromierung von 1.2.4‐Triazolen

Kröger, Carl‐Friedrich; Miethchen, Ralf

doi:10.1002/cber.19671000720

Cited by 34 publications

(9 citation statements)

References 16 publications

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“…3,5-Dibromo-lH-I,2,4-triazole (10.0 g, 44.1 mntoles), prepared by the method of Kroger and Mietchen [23], was suspended in 200 ml of benz-vol. 23 ene, and 1.0 g (5 meq) of dihydropyran was added.…”

Section: Mar-apr 1986mentioning

confidence: 99%

Proton‐ionizable crown compounds. 4. New macrocyclic polyether ligands containing a triazole subcyclic unit

Bradshaw

Tse

Arena

et al. 1986

Journal of Heterocyclic Chem

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A series of macrocyclic polyether (crown) ligands containing the proton‐ionizable s‐triazole subcyclic unit were prepared by reacting the 1‐THP blocked 3,5‐bis(chloromethyl)‐1H‐1,2,4‐triazole with various oligoethylene glycols. The starting bis(chloromethyl)triazole is a vessicant and must be used with caution. Triazolo‐18‐crown‐6 (5) formed stable complexes with barium, strontium, copper and benzylammonium cations but not with potassium or lithium. The crystal structure of 5 showed the triazole proton to be on nitrogen 3 which is outside the macroring cavity.

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Section: Mar-apr 1986mentioning

confidence: 99%

Proton‐ionizable crown compounds. 4. New macrocyclic polyether ligands containing a triazole subcyclic unit

Bradshaw

Tse

Arena

et al. 1986

Journal of Heterocyclic Chem

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“…were obtained adapting conditions previously reported for the bromination of triazoles [7], while the coupling reaction involving complexes 3a and 3b was carried out using standard conditions similar to those reported for the coupling of heteroaromatic compounds. [8] NMR and HPLC analysis of 3a and 3b clearly indicate that only one isomer, N2 bound, is obtained in both cases.…”

Section: Resultsmentioning

confidence: 99%

Ni(0) catalysed homo-coupling reactions: a novel route towards the synthesis of multinuclear ruthenium polypyridine complexes featuring made-to-order properties

Fanni

Pietro

Serroni

et al. 2000

Inorganic Chemistry Communications

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“…The crude product was purified by column chromatography (toluene-EtOAc-EtOH, 15:1:1) to give 71 mg (60%) of 28 as a colorless syrup. 1 Deoxy-a-D-glucopyranosyl)-5-methoxy-1H-1,2,4-triazole (29) A mixture of diastereomers 19 and 26 (870 mg, 1.29 mmol) in EtOAc-MeOH (1:1, 30 mL) was treated with Pd/C in a hydrogen atmosphere as described for compound 28. Column chromatography (toluene-EtOAc-EtOH, 3:1:1; R f 0.19) gave 198 mg (59%) of 29 along with two incompletely deprotected by-products [R f 0.25 (20 mg) and R f 0.32 (70 mg)].…”

Section: -(2-deoxy-a-d-glucopyranosyl)-1h-124-triazole (28)mentioning

confidence: 99%

“…Column chromatography (toluene-EtOAc-EtOH, 3:1:1; R f 0.19) gave 198 mg (59%) of 29 along with two incompletely deprotected by-products [R f 0.25 (20 mg) and R f 0.32 (70 mg)]. 1 H NMR (250 MHz, CD 3 OD): d = 7.56 (s, 1 H, triazole-H), 5.91 (d, 1 H, 3 J 1,2 = 6.1 Hz, H-1), 4.56 (ddd, 1 H, 3 J 2a,3 = 5.5, 3 J 3,4 = 8.5, 3 J 2b,3 = 11.1 Hz, H-3), 4.09 (s, 3 H, OCH 3 ), 3.74 (dd, 1 H, 3 J 5,6a = 2.5, 2 J 6a,6b = 11.9 Hz, H-6a), 3.64 (dd, 1 H, 3 J 5,6b = 4.8, 2 J 6a,6b = 11.9 Hz, H-6b), 3.46 (ddd, 1 H, 3 J 5,6a = 2.5, 3 J 5,6b = 4.6, 3 J 4,5 = 9.6 Hz, H-5), 3.41-3.33 (m, 1 H, H-4), 2.40 (ddd, 1 H, 3 J 1,2a = 1.0, 3 J 2a,3 = 5.6, 2 J 2a,2b = 13.7 Hz, H-2a), 2.02 (ddd, 1 H, 3 J 1,2b = 6.2, 3 J 2b,3 = 11.1, 2 J 2a,2b = 13.7 Hz, H-2b). 13 C NMR (63 MHz, CD 3 OD): d = 161.1 (C-5 triazole), 148.1 (C-3 triazole), 80.0 (C-1), 76.6, 72.9, 70.0 (C-3, C-4, C-5), 62.6 (C-6), 59.1 (OCH 3 ), 36.4 (C-2).…”

Section: -(2-deoxy-a-d-glucopyranosyl)-1h-124-triazole (28)mentioning

confidence: 99%

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Synthesis and Reactivity of Halogenated 1,2,4-Triazole Nucleoside Analogues with High Potential for Chemical Modifications

Libnow¹,

Wille²,

Christiansen³

et al. 2006

Synthesis

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1,2,4-Triazole nucleoside analogues bonded at N-1 of the base were synthesized by addition of N-halo-3,5-dibromo-1,2,4-triazoles to 1,2-unsaturated carbohydrate derivatives (glycals). Examples are given for 1,5-anhydro-3,4,6-tri-O-acetyl-2-deoxy-D-arabino-hex-1-enitol (tri-O-acetyl-D-glucal), and 1,5-anhydro-3,4,6-tri-O-benzyl-2-deoxy-D-arabino-hex-1-enitol (tri-O-benzyl-D-glucal), respectively. The graduated reactivity of the three halogens [C-5 (triazole) > C-2 (sugar) > C-3 (triazole)] in the addition products allows subsequent regioselective replacement and deprotection reactions like hydrodehalogenations, nucleophilic substitutions (by methoxide, hydrazine, benzylamine, thiophenolate), deacetylations, and debenzylations, respectively. Thus, the paper opens a new synthetic approach to triazole nucleoside analogues of 2-deoxy-sugars. X-ray analyses support the structures of nine products. 1,3,5-Tribromo-1,2,4-triazole (1), synthesized by a very simple procedure in 1967, 1 attracted interest as a bromination reagent shortly after publication. 2 Addition products of 1 to suitable unsaturated compounds offer valuable synthetic potential due to the graduated reactivities of the halogens in nucleophilic addition-elimination reactions. Thus, investigations on 3,5-dibromo-1-methyl-1,2,4-triazole have shown that the halogen atom located on C-5 is significantly more reactive than that on C-3. 3,4 This observation was convincingly confirmed by recent studies on various 1-alkyl-3,5-dibromo-1,2,4-triazoles 5 and on 1-(2,3,5-tri-O-acetyl-b-D-ribofuranosyl)-3(5)-bromo-5(3)-carbamido-1,2,4-triazole 6 as well as reactions with 1-phenyl-5-bromo-1,2,4-triazole. 7,8 It is assumed that the mesomeric discrimination of intermediate A relative to B is the reason for the difference in reactivity of the halogens (Scheme 1).Various methods for regiospecific and stereoselective electrophilic addition reactions of azole and azine derivatives to pyranoid and furanoid glycals were reported in the literature as key steps in nucleoside syntheses. 9-12 Herdewijn et al. 13,14 and Eschenmoser et al. 15 synthesized pyranose nucleosides and investigated their incorporation into oligonucleotides, respectively. The biological activity of 1,2,4-triazole nucleoside analogues has been widely demonstrated, 16-19 thus our efforts were focused on providing a new synthetic strategy towards 2-deoxy-sugar derivatives. The strategy presented in this paper allows the design of triazole nucleoside analogues with a variable pattern of groups on the C-5 of the triazole ring. This was achieved by regioselective additions of 1,3,5-trihalogeno-1,2,4-triazoles to 1,2-unsaturated sugars (glycals) combined with subsequent regioselective replacement of the halogens by nucleophiles or by hydrogen. Indeed, the enol ether unit of a glycal ensures, above all, the addition step is highly regioselective but rarely diastereoselective. [20][21][22] However, the loss of stereochemistry becomes less important because the halogen atom, introduced into C-2 of the sugar moiety, is...

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Über 1.2.4‐ Triazole, XIV. Die Bromierung von 1.2.4‐Triazolen

Cited by 34 publications

References 16 publications

Proton‐ionizable crown compounds. 4. New macrocyclic polyether ligands containing a triazole subcyclic unit

Proton‐ionizable crown compounds. 4. New macrocyclic polyether ligands containing a triazole subcyclic unit

Ni(0) catalysed homo-coupling reactions: a novel route towards the synthesis of multinuclear ruthenium polypyridine complexes featuring made-to-order properties

Synthesis and Reactivity of Halogenated 1,2,4-Triazole Nucleoside Analogues with High Potential for Chemical Modifications

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