Rapid and efficient protocol for Willgerodt–Kindler’s thioacetamides catalyzed by sulfated polyborate

Rekunge, Deelip S.; Khatri, Chetan K.; Chaturbhuj, Ganesh U.

doi:10.1007/s00706-017-2013-x

Cited by 23 publications

(2 citation statements)

References 34 publications

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“…[ 19 ] This limitation gave insights for development of polymeric boric acid catalyst such as sulfated and aluminized polyborate with enhanced catalytic activity. [ 20 ] The presence of aluminum and boron in aluminized polyborate generates mild Lewis acidic character and makes it suitable for catalytic applications. [ 21 ]…”

Section: Introductionmentioning

confidence: 99%

An expedient and straightforward solvent‐free synthesis of 1,8‐dioxo‐octahydroxanthenes using eco‐friendly aluminized polyborate catalyst

Aute

Kshirsagar

Uphade

et al. 2020

Journal of Heterocyclic Chem

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The present work deals with a catalytic application of aluminized polyborate as a mild solid acid catalyst for multicomponent synthesis of 1,8-dioxooctahydroxanthenes under solvent-free condition at 100 C-110 C. It involves selective domino Knoevenagel-Michael reaction of 1 mole of aromatic aldehyde with 2 moles dimedone. The aluminized polyborate is simply synthesized by using boric acid and aluminum trichloride and characterized by FT-IR, XRD, SEM and EDAX techniques. The mild Lewis acidity, crystalline solid nature, stability and recyclability are significant features of the catalyst. The solvent-free condition, clean reaction profile, inexpensive and non-toxic catalyst, operational simplicity, good to excellent product yields, reduced reaction time and applicability to wide range of substrate are crucial features of this protocol.

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Section: Introductionmentioning

confidence: 99%

An expedient and straightforward solvent‐free synthesis of 1,8‐dioxo‐octahydroxanthenes using eco‐friendly aluminized polyborate catalyst

Aute

Kshirsagar

Uphade

et al. 2020

Journal of Heterocyclic Chem

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“…Although various methods and variants (e.g., using sulfated polyborate 153 or ferrous chloride 154 as a catalyst) have been developed to allow for lower reaction temperatures, most of those conditions proceed well for aromatic ketone substrates but are highly problematic for the preparation of aliphatic thioamides. The second strategy employs thiohydrolysis of the corresponding nitriles to give primary thioamides (Figure 2.1b).…”

Section: Introductionmentioning

confidence: 99%

Towards Synthesis of Simplified Analogues of Pateamine A

Xu¹

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<p>Pateamine A (22) is a natural product that was isolated from a marine sponge inhabiting the coast of New Zealand. It exhibits potent inhibition of protein synthesis and nonsense-mediated mRNA decay through binding with eIF4A isoforms. Due to the scarcity of pateamine A (22) in the natural source and the low yield of total synthesis of pateamine A, it is necessary to prepare structurally simplified analogues which would allow further research on structure-activity relationships (SAR) of pateamine A (22). Based on the structure-activity relationship studies reported by Romo and co-workers, a simplified triazole analogue 182 lacking methyl groups was synthesized by Hemi Cumming, a previous Ph.D. student who studied at Victoria University of Wellington. The antiproliferative activity of this analogue was found to be significantly lower than that of pateamine A, suggesting that the thiazole embedded within the molecule or the excised methyl groups are crucial for its potency. Therefore, to further explore the necessary features for its selective activity for eIF4A isoforms, new thiazole analogues 183 – 186 and triazole analogues (10S)-and (10R)-analogue 187 were targeted in this project. The preparation of the thiazole-containing macrocyclic core of analogues 183 and 184 was achieved. It features: (1) gold-catalysed thiazole formation through coupling between an alkyne fragment and a thioamide fragment; (2) preparation of the Z,E-dienoate moiety by base-induced ring-opening of a δ-substituted-α, β-unsaturated lactone; and (3) a modified Mukaiyama macrolactonisation. The synthesis of the triazole-containing macrocyclic core of (10S)-analogue 187 was completed. It features: (1) a copper-catalysed triazole formation through 1,3-dipolar cycloaddition between an alkyne fragment and an azide fragment; (2) preparation of the Z,E-dienoate moiety by base-induced ring-opening of δ-substituted-α, β-unsaturated lactone; and (3) a modified Mukaiyama macrolactonisation. Studies on the preparation of a side-chain fragment with suitable functionalities to allow coupling with the various macrocycles through olefination reactions were also conducted. The attachment of the side-chain fragment onto the macrocyclic cores for the synthesis of the targeted analogues 183 and 184 and (10S)-analogue 187 will be investigated in future work. These experimental results will inform the synthesis of new generation analogues to further study the key structures required for effective binding to the protein target eIF4A and selectivity between isoforms.</p>

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Environmentally Benign, Highly Efficient and Expeditious Solvent‐Free Synthesis of Trisubstituted Methanes Catalyzed by Sulfated Polyborate

et al. 2017

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Highly efficient and environmental friendly one‐pot synthesis of trisubstituted methanes form aldehydes and heteroaryls with sulfated polyborate catalyst was conveniently performed under solvent‐free grinding condition at room temperature. The catalyst is recyclable up to five consecutive runs and column chromatography‐free isolation of the trisubstituted methanes in excellent yields was achieved.

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Rapid and efficient protocol for Willgerodt–Kindler’s thioacetamides catalyzed by sulfated polyborate

Cited by 23 publications

References 34 publications

An expedient and straightforward solvent‐free synthesis of 1,8‐dioxo‐octahydroxanthenes using eco‐friendly aluminized polyborate catalyst

An expedient and straightforward solvent‐free synthesis of 1,8‐dioxo‐octahydroxanthenes using eco‐friendly aluminized polyborate catalyst

Towards Synthesis of Simplified Analogues of Pateamine A

Environmentally Benign, Highly Efficient and Expeditious Solvent‐Free Synthesis of Trisubstituted Methanes Catalyzed by Sulfated Polyborate

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