A convergent synthesis of 1,3,4-oxadiazoles from acyl hydrazides under semiaqueous conditions

Tokumaru, Kazuyuki; Johnston, Jeffrey N.

doi:10.1039/c7sc00195a

Cited by 38 publications

(20 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…14 Aside from their attractive features for drug development, 17 innovative new uses for oxadiazoles continue to emerge, as do methods for their synthesis. 18 A complement of experiments in the oxadiazole synthesis revealed that the expected diacyl hydrazide was not an intermediate.…”

Section: Resultsmentioning

confidence: 99%

“…In this reaction, controlling the generation rate for the iodonium species by slow addition of UHP is crucial to achieve good yields, presumably to limit acyl hydrazide overoxidation, a process that would draw the electrophilic acyl diazene intermediate away from productive reaction with an α-bromo nitroalkane. 14,15 …”

Section: Resultsmentioning

confidence: 99%

“…14,15,16 Control experiments indicated that the mechanistic diversion point between amide and oxadiazole formation may be after the formation of the hypothesized tetrahedral intermediate (Scheme 1, 3a ). We also became interested in the synthesis of triazole heterocycles from heteroaryl hydrazines as an outgrowth of oxadiazole synthesis, based on the hypothesis that they might share a possible mechanistic intersection point in 3b (Scheme 1) and the analogous cyclization.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis Using Diverted Umpolung Amide Synthesis

2017

Self Cite

View full text Add to dashboard Cite

Umpolung Amide Synthesis (UmAS) has emerged as a superior alternative to conventional amide synthesis methods based on carbonyl electrophiles in a range of situations, particularly when epimerization-prone couplings are prescribed. In an unanticipated development during our most recent studies, it was discovered that diacyl hydrazide products from UmAS were not formed as intermediates when using an acyl hydrazide as the amine acceptor. This resulted in a new preparation of 1,3,4-oxadiazoles from α-bromonitroalkane donors. We hypothesized that a key tetrahedral intermediate in UmAS was diverted toward a more direct pathway to the heterocycle product rather than through formation of the diacyl hydrazide, a typical oxadiazole progenitor. In studies reported here, diversion to 1,2,4-triazole products is described, a behavior hypothesized to also result from an analogous tetrahedral intermediate, but one formed from heteroaromatic hydrazine acceptors.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis Using Diverted Umpolung Amide Synthesis

2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Tokumaru et al [55] in 2017 found new approach to prepare 1,3,4-oxadiazoles. They reported new method to deliver the 2,5-disubstituted oxadiazole directly, avoiding 1,2-diacyl hydrazide intermediate by coupling α-bromo nitroalkanes with acyl hydrazides.…”

Section: Synthesis Of 134-oxadiazoles From Acyl Hydrazidesmentioning

confidence: 99%

A Review on the Preparation of 1,3,4-Oxadiazoles From the Dehydration of Hydrazines and Study of Their Biological Roles

Nayak

Poojary

2019

Chemistry Africa

View full text Add to dashboard Cite

Heterocyclic chemistry is the interesting area for the effective approach and for the invention of biologically active 1,3,4-oxadiazole cores. 1,3,4-Oxadiazole is a five membered heterocyclic ring which plays key role in the development of new medicinal species for the treatment of numerous diseases. Hence, nowadays researchers have developed the innovative methods for the synthesis of 1,3,4-oxadiazole derivatives and their medicinal applications. Therefore, results of recent developments in the synthesis and biological applications of 1,3,4-oxadiazole candidates over the past 15 years (2005-2019) are reviewed in the present article. The information in the present article may be useful to many researchers which lead to exploration of new therapeutic species for the society.

show abstract

“…On the contrary, oxadiazoles are deployed as bioisostere for ester, ketone, carbamate and amide functionalities ,. While exploiting with their modulation at 2‐ and 5‐postions, they are valued for divergent physicochemical and pharmacokinetic profiles . Favorable ADME properties and metabolic stability against peptidase and hydrolytic esterase enzymes make oxadiazole as an essential pharmacophore .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Single‐Crystal X‐Ray, Hirshfeld and Antimicrobial Evaluation of some New Imidazopyridine Nucleus Incorporated with Oxadiazole Scaffold

2018

View full text Add to dashboard Cite

To avert the menace of pathogens in medical parlance, emerging attractive strategy is combining two different active fragments in a single molecule for scientific solutions. Trisubstituted imidazo[1,2-a]pyridine-carboxylate was engrossed as a hybrid with oxadiazole. The three dimensional and crystal structures of compounds 3-[5-(2-chlorophenyl)-1,3,4-oxadiazol-(4 e) were determined using single crystal X-ray diffraction studies and their crystal packing was analyzed using Hirshfeld surface computational analysis. The molecular conformation of 4 c (planar) and 4 e (twisted) and crystal packing is different and this may be due to substitution effect. In addition, both compounds have common intermolecular interactions of the type C-H…π and intercontacts H…H contributes more to the Hishfeld surfaces. Screening for microbial activity acknowledged, 2,8-dimethyl-3-[5-(3-nitrophenyl)-1,3,4-oxadiazol-2-yl] imidazo[1,2-a]pyridine (4 f) and 6-chloro-2-methyl-3-[5-(4-methylphenyl)-1,3,4-oxadiazol-2-yl]imidazo[1,2-a]pyridine (4 g) as most effective against Staphyllococus aureus, over all other derivatives. Meanwhile, 4 f also showed pronounced antifungal activity against Candida albicans. Further 4 f was endorsed by time kill assay as bactericidal in its action.[a] S.

show abstract

A convergent synthesis of 1,3,4-oxadiazoles from acyl hydrazides under semiaqueous conditions

Abstract: An innovative new synthesis approach to disubstituted 1,3,4-oxadiazoles is described, inspired by Umpolung Amide Synthesis (UmAS).

Cited by 38 publications

References 32 publications

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis Using Diverted Umpolung Amide Synthesis

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis Using Diverted Umpolung Amide Synthesis

A Review on the Preparation of 1,3,4-Oxadiazoles From the Dehydration of Hydrazines and Study of Their Biological Roles

Synthesis, Single‐Crystal X‐Ray, Hirshfeld and Antimicrobial Evaluation of some New Imidazopyridine Nucleus Incorporated with Oxadiazole Scaffold

Contact Info

Product

Resources

About

A convergent synthesis of 1,3,4-oxadiazoles from acyl hydrazides under semiaqueous conditions

Abstract: An innovative new synthesis approach to disubstituted 1,3,4-oxadiazoles is described, inspired by Umpolung Amide Synthesis (UmAS).

Cited by 38 publications

References 32 publications

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis­ Using Diverted Umpolung Amide Synthesis

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis­ Using Diverted Umpolung Amide Synthesis

A Review on the Preparation of 1,3,4-Oxadiazoles From the Dehydration of Hydrazines and Study of Their Biological Roles

Synthesis, Single‐Crystal X‐Ray, Hirshfeld and Antimicrobial Evaluation of some New Imidazopyridine Nucleus Incorporated with Oxadiazole Scaffold

Contact Info

Product

Resources

About

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis Using Diverted Umpolung Amide Synthesis

1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis Using Diverted Umpolung Amide Synthesis