Palladium(0)-Catalyzed Intramolecular Heck Reaction: A Resourceful Route for the Synthesis of Naphthoxepine and Naphthoxocine Derivatives

Majumdar, K. C.; Ansary, Inul; Sinha, Biswajit; Chattopadhyay, Buddhadeb

doi:10.1055/s-0029-1216984

Cited by 19 publications

(12 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The precursors for this study 4b-k and 7 were prepared according to our earlier published procedure. 30 We initiated our investigation with the substrate 4a. When the substrate 4a was treated with diethyl acetylenedicarboxylate (1.5 equiv) in CHCl 3 in the presence of triphenylphos-…”

Section: Figurementioning

confidence: 99%

Aromatic Electrophilic Substitution vs. Intramolecular Wittig Reaction: Vinyltriphenylphosphonium Salt Mediated Synthesis of 4-Carboxyalkyl-8-formyl Coumarins

Majumdar¹,

Ansary²,

Samanta³

et al. 2011

Synlett

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Figurementioning

confidence: 99%

Aromatic Electrophilic Substitution vs. Intramolecular Wittig Reaction: Vinyltriphenylphosphonium Salt Mediated Synthesis of 4-Carboxyalkyl-8-formyl Coumarins

Majumdar¹,

Ansary²,

Samanta³

et al. 2011

Synlett

Self Cite

View full text Add to dashboard Cite

show abstract

“…literature. 13 The ligand H 2 L was synthesised (scheme 1) by refluxing 2-hydroxy-1-naphthaldehyde(1.0 g, 5.8 mmol) with 1,3-diaminopropane (0.215 g, 2.9 mmol) in 30 mL dehydrated ethanol. After 3 h, the reaction solution was evaporated under reduced pressure to yield a yellow coloured solid, which was dried under vacuum and stored over CaCl 2 for subsequent use.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, crystal structure and catecholase activity of a Ni(II) complex derived from a tetradentate Schiff base ligand

Basu¹,

Mitra

Ghosh³

et al. 2014

J Chem Sci

View full text Add to dashboard Cite

A new nickel(II) complex [Ni(L)] (1) [H 2 L = 1,1-(1E,1 E)-(propane-1,3-diylbis(azan-1-yl-1ylidene))bis(methan-1-yl-1-ylidene)dinaphthalen-2-ol] was synthesized and X-ray crystallographically characterized. 1 crystallizes in orthorhombic crystal system with Cmc21 space group. The unit cell dimensions of the crystal are a = 30.6345(4) Å, b = 8.45340(10) Å, c = 7.75180(10) Å. Structural analysis reveals a tetradentate chelation behaviour of the dianionic ligand H 2 L having a distorted square planar geometry around Ni(II) with NiN 2 O 2 chromophore in 1. The title complex 1 behaves as an effective catalyst towards oxidation of 3,5-ditertiarybutyl catechol (3,5-DTBC) in acetonitrile to its corresponding quinone derivative in air. The reaction follows first-order reaction kinetics with rate constant 4.28 × 10 −5 min −1. The reaction follows Michaelis-Menten enzymatic kinetics with a turnover number of (K cat) 140.72 h −1 in acetonitrile.

show abstract

“…The hydroxy aldehydes 1a-d were prepared according to our earlier published procedure. 17 A 3:1 mixture of 7-exo cyclized diiodo product 4a 18 and uncyclized iodo derivative 5 were formed when a mixture of compound 3a, molecular iodine (1 equiv) and NaHCO 3 (1 equiv) were stirred at room temperature in anhydrous acetonitrile for six hours. The 8-endo cyclized product 6 was not obtained (Scheme 2).…”

Section: Figurementioning

confidence: 99%

Molecular Iodine Mediated Intramolecular Cyclization: An Efficient Method for the Synthesis of Benzoxepine Derivatives

Majumdar¹,

Sinha²,

Ansary³

et al. 2010

Synlett

Self Cite

View full text Add to dashboard Cite

A simple, efficient and cost effective method for a divergent synthesis of benzoxepine derivatives using a hitherto unreported, highly regioselective, tandem iodocyclization procedure is described.A wide range of natural products possess a seven-membered oxacycle in their molecular architecture. 1 Moreover, these units serve as target molecules in numerous synthetic studies. 2 The benz[b]oxepine ring system occurs in a small number of biologically active natural products isolated mainly from plant sources. 3 Some of these compounds exhibit oral hypotensive and antiulcer properties. 4 The fungal metabolites pterulone and its analogue 5 inhibits the eukaryotic respiratory chain at the NADH site of the ubiquinone oxidoreductase, possesses potent antifungal activity and are only weakly cytotoxic ( Figure 1). On the other hand, Pterulinic acid also exhibits significant antifungal and either weak or no cytotoxic activity, and is an effective inhibitor of eukaryotic respiration. 6 Figure 1Many synthetic methods, including palladium-mediated intramolecular Heck reaction, 7 RCM 8 and transition-metal-mediated cyclizations, 9 have been utilized for the construction of medium-sized heterocycles, especially oxepines and oxocine derivatives. Recently we have successfully synthesized medium-ring heterocycles based on a sulfanyl radical addition and cyclization procedure, 10 but sometimes these methods suffer from complex reaction conditions, difficulty in separation of products and from the toxicity of thiophenol. Recent activity in the study of biologically active oxepines and oxepanes has required the search for versatile, cost effective reagents and simple reaction conditions for the synthesis of these heterocycles. During the last few years iodine has found wide utility because it is an inexpensive, non-toxic and readily available electrophilic reagent that enables iodocyclization reactions to generate compounds with synthetic and biological applications. 11 Iodocyclization of heteroatoms with tethered alkynes has been found to be an effective and high-yielding method of preparing a large number of heterocyclic compounds, e.g., furans, 12 pyrroles, 13 indoles, 14 benzo[b]furans 15 and benzo[b]thiophenes. 16 Iodonium-promoted heteroannulations are quite attractive because they offer an alternative protocol for the synthesis of complex molecules that are not always accessible using common organometallic reagents. Although many examples are available for the construction of five-and sixmembered heterocycles utilizing iodine-mediated cyclization, to our knowledge, the synthesis of medium-ring heterocycles has not been reported so far. These findings prompted us to undertake a study on iodine-mediated cyclizations for the synthesis of benzoxepine derivatives. These would provide an alternative and easy procedure for the construction of some benzoxepine skeletons, which are present as a basic structural moiety in a number of naturally occurring compounds. Herein we report the results.The required precursors 3a-d for our prese...

show abstract

Palladium(0)-Catalyzed Intramolecular Heck Reaction: A Resourceful Route for the Synthesis of Naphthoxepine and Naphthoxocine Derivatives

Abstract: The synthesis of oxocines and oxepines is difficult. Two efficient protocols have been developed for the construction of naphthoxepine and naphthoxocine derivatives by sequential Wittig olefination and intramolecular Heck reaction.

Cited by 19 publications

References 5 publications

Aromatic Electrophilic Substitution vs. Intramolecular Wittig Reaction: Vinyltriphenylphosphonium Salt Mediated Synthesis of 4-Carboxyalkyl-8-formyl Coumarins

Aromatic Electrophilic Substitution vs. Intramolecular Wittig Reaction: Vinyltriphenylphosphonium Salt Mediated Synthesis of 4-Carboxyalkyl-8-formyl Coumarins

Synthesis, crystal structure and catecholase activity of a Ni(II) complex derived from a tetradentate Schiff base ligand

Molecular Iodine Mediated Intramolecular Cyclization: An Efficient Method for the Synthesis of Benzoxepine Derivatives

Contact Info

Product

Resources

About