Synthesis of 1-alkoxy-1,2,3,4-tetra-hydrocarbazoles by mercury(II) mediated heterocyclization of 2-cyclohex-2′-enyl-N-alkylanilines

1996 ◽  
Vol 74 (8) ◽  
pp. 1592-1596 ◽  
Author(s):  
K. C. Majumdar ◽  
U. Das
Keyword(s):  
Key Words ◽  
Claisen Rearrangement ◽  
Supporting Evidence ◽  
Chemical Transformations ◽  
Key Words 1 ◽  
Acid Catalyzed ◽  
High Yields

The title compounds 3(a–i) were synthesized in high yields by the mercury(II) mediated heterocyclization of 2-cyclohex-2′-enyl-N-alkylanilines 2(a–g), which in turn were obtained by the acid-catalyzed amino Claisen rearrangement of 3-N-alkylanilinocyclohexenes 1(a–g). Additional supporting evidence for the structure of product 3 was obtained from chemical transformations. Key words: 1-alkoxy tetrahydrocarbazole, mercury(II) mediated heterocyclization, amino Claisen rearrangement, 3-N-methylanilinocyclohexene.

Nucleic acid related compounds. 63. Synthesis of 5′-deoxy-5′-methyleneadenosine and related Wittig-extended nucleosides

1991 ◽  
Vol 69 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Stanislaw F. Wnuk ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Key Words ◽  
Organic Bases ◽  
Key Words Adenosine ◽  
Tosyl Group ◽  
High Yields ◽  
Related Compounds

Treatment of the purified 5′-aldehyde (2a) (derived from 6-N-benzoyl-2′,3′-O-isopropylideneadenosine (1a)) with methylenetriphenylphosphorane and successive deprotection with ammonia and acid gave 9-(5,6-dideoxy-β-D-ribo-hex-5-enofuranosyl)adenine (5′-deoxy-5′-methyleneadenosine) (4). Oxidation of 1a or 2′,3′-O-isopropylideneadenosine (1b) and treatment of the crude 5′-aldehydes (2a or 2b) with (p-toluenesulfonylmethylene)triphenylphosphorane gave high yields of the 5′-deoxy-5′-tosylmethylene derivatives (5a or 5b). Removal of the tosyl group from 5b to give 3b was effected with tributylstannyllithium, but sulfone cleavage by the usual reductive methods failed. Reduction and deprotection of 5a or 5b gave 9-[5,6-dideoxy-6-(p-toluenesulfonyl)-β-D-ribo-hexofuranosyl]adenine (6b). Isomerization of the vinyl tosyl (5b) to a 4′,5′-unsaturated allylic tosyl derivative (7) occurred under cleavage conditions and in solutions of aqueous or organic bases. Key words: adenosine, 5′-deoxyadenosine, 5′-methylene-5′-deoxyadenosine, nucleosides.

Efficient Synthesis of Diarylmethylamines via Lewis Acid Catalyzed Friedel–Crafts Reactions of Donor–Acceptor Aziridines with N,N-Dialkylanilines

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 281-289
Author(s):  
Yerin Kim ◽  
Yong Il Kwon ◽  
Sung-Gon Kim
Keyword(s):  
Lewis Acid ◽  
Efficient Synthesis ◽  
Broad Scope ◽  
Donor Acceptor ◽  
Acid Catalyzed ◽  
High Yields

A method for efficient and mild synthesis of diarylmethylamine scaffold, via Lewis acid catalyzed Friedel–Crafts reaction of donor­–acceptor aziridines with N,N-dialkylanilines to afford a biologically important diarylmethylamine derivatives in high yields (up to 88%), is presented. This reaction is suitable for the synthesis of various diarylmethylamine derivatives and has a broad scope for electron-rich arenes, including dimethoxybenzene.

The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small β-stannyl effect

1996 ◽  
Vol 74 (7) ◽  
pp. 1366-1368 ◽  
Author(s):  
I. Egle ◽  
V. Gabelica ◽  
A.J. Kresge ◽  
T.T. Tidwell
Keyword(s):  
Key Words ◽  
Isotope Effect ◽  
Acid Concentration ◽  
Rate Constant ◽  
Perchloric Acid ◽  
Hydronium Ion ◽  
Stabilizing Effect ◽  
Aromatic Product ◽  
Acid Catalyzed ◽  
The Difference

Rates of conversion of 1-(tri-n-butylstannyl)-2-phenylethyne to phenylethyne in H2O and D2O solutions of perchloric acid were found to be proportional to acid concentration, giving the hydronium ion rate constant [Formula: see text] and the isotope effect [Formula: see text]. The magnitude of this isotope effect suggests that the reaction occurs by rate-determining hydron transfer to the substrate, producing a vinyl carbocation; this carbocation then loses its tributylstannyl group, giving phenylacetylene as the only detectable aromatic product. The hydronium ion rate constant, when compared to the rates of protonation of phenylethyne and 1-(trimethylsilyl)-2-phenylethyne, gives a β-stannyl stabilizing effect of δΔG≠ = 6.6 kcal mol−1 and a differential β-stannyl/β-silyl effect of δΔG≠ = 3.2 kcal mol−1. These stabilizations are very much smaller than previously reported β-stannyl effects. Possible reasons for the difference are suggested. Key words: β-stannyl effect, β-silyl effect, carbocation stabilization, protodemetalation.

SiO2·12WO3·24H2O: a Highly Efficient Catalyst for the Synthesis of 5-Arylidene Barbituric Acid in the Presence of Water

2009 ◽  
Vol 62 (4) ◽  
pp. 353 ◽  
Author(s):  
Ji-Tai Li ◽  
Ming-Xuan Sun
Keyword(s):  
Room Temperature ◽  
Barbituric Acid ◽  
Aqueous Media ◽  
Aromatic Aldehydes ◽  
Efficient Catalyst ◽  
Highly Efficient ◽  
Efficient Route ◽  
Acid Catalyzed ◽  
High Yields

The condensation of aromatic aldehydes and barbituric acid catalyzed by SiO2·12WO3·24H2O in aqueous media at room temperature gave 5-arylidene barbituric acid in high yields with or without the use of ultrasound, providing a simple and efficient route to synthesis of these compounds.

Nucleophilic Cyclization/Electrophilic Substitution of (2,2-Dialkoxyethyl)ureas: Highly Regioselective Access to Novel 4-(Het)arylimidazolidinones and Benzo[d][1,3]diazepinones

Synthesis ◽  
2020 ◽  
Vol 52 (21) ◽  
pp. 3263-3271
Author(s):  
Andrey V. Smolobochkin ◽  
Almir S. Gazizov ◽  
Nazerke K. Otegen ◽  
Julia K. Voronina ◽  
Anna G. Strelnik ◽  
...  
Keyword(s):  
Substitution Reaction ◽  
Electrophilic Substitution ◽  
Biologically Active ◽  
Electrophilic Substitution Reaction ◽  
Reaction Sequence ◽  
Active Compounds ◽  
Acid Catalyzed ◽  
High Yields ◽  
Nucleophilic Cyclization ◽  
Mechanism Of The Reaction

Imidazolidin-2-one and 1,3-benzodiazepin-2-one scaffolds are structural motifs of many biologically active compounds. Herein, we report a highly regioselective acid-catalyzed intramolecular nucleophilic cyclization/intermolecular electrophilic substitution reaction sequence of (2,2-dialkoxyethyl)ureas. The reaction benefits from readily available starting materials, a simple workup procedure, moderate to high yields of target compounds, and provides a convenient entry to previously unknown 4-(het)arylimidazolidinones and 5-(het)arylbenzodiazepinones. The proposed mechanism of the reaction is also discussed.

Lewis Acid-Catalyzed Rearrangement of Fluoroalkylated Propargylic Alcohols: An Alternative Approach to β-Fluoroalkyl-α,β-enones

Synlett ◽  
2019 ◽  
Vol 30 (03) ◽  
pp. 356-360 ◽  
Author(s):  
Manickavasakam Ramasamy ◽  
Hui-Chang Lin ◽  
Sheng-Chu Kuo ◽  
Min-Tsang Hsieh
Keyword(s):  
Lewis Acid ◽  
Propargylic Alcohols ◽  
Alternative Approach ◽  
Acid Catalyzed ◽  
High Yields ◽  
High Stereoselectivity

A practical Lewis acid-catalyzed Meyer–Schuster rearrangement of fluoroalkylated propargylic alcohols, leading to a series of β-fluoroalkyl-α,β-enones, is developed. The methodology reported herein features moderate to high yields and high stereoselectivity in the synthesis of β-alkyl-β-fluoroalkyl-α,β-enones.

scholarly journals Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

2012 ◽  
Vol 8 ◽  
pp. 650-657 ◽  
Author(s):  
Xiufang Ji ◽  
Zhiming Li ◽  
Quanrui Wang ◽  
Andreas Goeke
Keyword(s):  
Carboxylic Acid ◽  
Ring Opening ◽  
Claisen Rearrangement ◽  
Ring Cleavage ◽  
Unsaturated Ester ◽  
Supplementary Method ◽  
Convenient Synthesis ◽  
High Yields ◽  
Acid Esters

The fused 2-vinyl or 2-phenyl substituted cyclobutanones 4 undergo stereoselective ring openings by the action of alkoxide ions (t-BuO− or MeO−) to produce novel vicinally disubstituted cycloalkene derivatives 5 and 6 in moderate to high yields. The ring cleavage usually occurs with complete regioselectivity. The accessibility of γ,δ-unsaturated ester or acid derivatives makes this transformation a good supplementary method for the well-established Johnson–Claisen rearrangement.

Friedel–Crafts alkylation of heteroarenes and arenes with indolyl alcohols for construction of 3,3-disubstituted oxindoles

RSC Advances ◽  
2015 ◽  
Vol 5 (123) ◽  
pp. 101713-101717 ◽  
Author(s):  
Xiaoxiao Wang ◽  
Jian Liu ◽  
Lubin Xu ◽  
Zhihui Hao ◽  
Liang Wang ◽  
...  
Keyword(s):  
Reaction Conditions ◽  
Camphorsulfonic Acid ◽  
Acid Catalyzed ◽  
High Yields

An intriguing camphorsulfonic acid catalyzed Friedel–Crafts alkylation of arenes with indolyl alcohols has been developed featuring mild reaction conditions, wide substrate scope and high yields.

scholarly journals Enantioselective 1,4-addition of cyclopropylboronic acid catalyzed by rhodium/chiral diene complexes

2015 ◽  
Vol 51 (40) ◽  
pp. 8528-8531 ◽  
Author(s):  
Ryosuke Takechi ◽  
Takahiro Nishimura
Keyword(s):  
Asymmetric Addition ◽  
Acid Catalyzed ◽  
High Yields

Rhodium-catalyzed asymmetric addition of cyclopropylboronic acids to electron-deficient alkenes proceeded to give high yields of the corresponding 1,4-addition products with high enantioselectivity.

scholarly journals Organocatalytic asymmetric selenofunctionalization of tryptamine for the synthesis of hexahydropyrrolo[2,3-b]indole derivatives

2013 ◽  
Vol 9 ◽  
pp. 1559-1564 ◽  
Author(s):  
Qiang Wei ◽  
Ya-Yi Wang ◽  
Yu-Liu Du ◽  
Liu-Zhu Gong
Keyword(s):  
Phosphoric Acid ◽  
Indole Derivatives ◽  
Chiral Phosphoric Acid ◽  
Acid Catalyzed ◽  
High Yields

A chiral phosphoric acid-catalyzed selenofunctionalization of tryptamine derivatives provides access to 3a-(phenylselenyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole derivatives in high yields and with synthetically useful levels of enantioselectivity (up to 89% ee).

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