Synthesis of novel 1‐phenyl‐1<i>H</i>‐indole‐2‐carboxylic acids. <b>II.</b> Preparation of 3‐dialkylamino, 3‐alkylthio, 3‐alkylsulfinyl, and 3‐alkylsulfonyl derivatives

Unangst, Paul C.; Connor, David T.; Stabler, S. Russell

doi:10.1002/jhet.5570240353

Cited by 16 publications

(12 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[13] On the other hand, the reaction of functionalised arylmagnesium reagents of type 7 [4] with 4-methoxybenzenesulfinyl chloride (9) [14] afforded the desired 4-methoxy-substituted sulfoxides 1 c-f in 70-91 % yield. [15] Having prepared the required diaryl sulfoxides 1 af, we performed the directed-metallation step (step 1 of Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

Difunctionalisation of Arenes and Heteroarenes by Directed Metallation and Sulfoxide–Magnesium Exchange

Melzig

Rauhut

Naredi‐Rainer

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

The aryl sulfoxide moiety allows an expedient two-step difunctionalisation of readily available diaryl sulfoxides. Highly functionalised 1,2,4-trisubstituted arenes and difunctionalised heteroarenes (furans, thiophenes, benzofurans and pyridines) were prepared in a two-step sequence, triggered by an aryl sulfoxide group. In the first step, the sulfoxide moiety acts as a metallation-directing group, allowing smooth ortho-magnesiation with TMPMgCl⋅LiCl (TMP=tetramethylpiperidine). After a quenching reaction with an electrophile, the resulting sulfoxide is converted into a second magnesium reagent with iPrMgCl⋅LiCl (sulfoxide-magnesium exchange), which can be trapped with various electrophiles. Highly chemoselective TMPMgCl⋅LiCl and iPrMgCl⋅LiCl are compatible with a broad range of functional groups (e.g., F, Cl, CF(3) , CN, CO(2) tBu, alkynyl, ethers, thioethers). Large-scale reactions (25-40 mmol) and the preparation of fully functionalised furans and thiophenes are also reported.

show abstract

Section: Resultsmentioning

confidence: 99%

Difunctionalisation of Arenes and Heteroarenes by Directed Metallation and Sulfoxide–Magnesium Exchange

Melzig

Rauhut

Naredi‐Rainer

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…Accordingly, moderate to low yields were observed in the case of enaminones 3i-j and 3m-n, and no conversion at all was detected with enaminones 3h and 3k-l (Table 4, entries [8][9][10][11][12][13][14]. In contrast, the cyclization of enaminones 3o-p resulted in good yields of the corresponding indoles 1o-p (Table 4, entries [15][16]. In spite of some moderate or low yields, 29 the methods summarized in Table 4 are in general more efficient and regioselective than those previously reported with the assistance of Lewis acids.…”

Section: Preparation Of Indoles 1a-pmentioning

confidence: 84%

“…However, even for the non-activated substrates 4k-l, the respective indoles 2k-l were obtained, albeit in low yields (Table 6, entries [11][12]. Likewise, α-anilinoacetophenones 4o-p satisfactorily reacted to give indoles 2n-o, respectively (Table 6, entries [14][15].…”

Section: Preparation Of Indoles 1a-pmentioning

confidence: 99%

“…28 Hereby, we have demonstrated that under these conditions compounds 4o-p can be obtained in high yields (Table 1, entries [15][16]. Therefore, with the purpose of enhancing the efficiency of the indole synthesis, we investigated the use of solvent-free manual grinding conditions for the conversion of enaminones 3 into indoles 1.…”

Section: Preparation Of Indoles 1a-pmentioning

confidence: 99%

“…[1][2][3] However, the protocols reported for the synthesis of 3-aminoindole derivatives are limited in scope, and usually require multistep preparation of the starting materials. 13,15 Therefore, the development of straightforward synthetic approaches to 3-dimethylaminoindoles from easily available starting materials is still a pressing task.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Iodine-mediated one-pot synthesis of indoles and 3-dimethylaminoindoles via annulation of enaminones

Jerezano¹,

Labarrios²,

Jiménez³

et al. 2013

Arkivoc

View full text Add to dashboard Cite

The synthesis of 2-carbonylindoles was achieved via a iodine-mediated cyclization of the corresponding enaminone precursors, which were formed by reaction of the -arylaminomethylene carbonyl derivatives with N,N′-dimethylformamide dimethyl acetal (DMFDMA). An alternative and more efficient procedure consisted of a similar cyclization of the enaminones, but under solvent-free and grinding reaction conditions. In another iodine-promoted procedure, 2-carbonyl-3-dimethylaminoindoles were synthesized via a one-pot cascade reaction between the -arylaminomethylene carbonyl derivative and DMFDMA.

show abstract

Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

2002

View full text Add to dashboard Cite

Reductive amination is an important tool for synthetic organic chemists in the construction of carbon‐nitrogen bonds. This reaction, also termed reductive alkylation, involves condensation of an aldehyde or ketone with an amine in the presence of a reducing agent. A wide variety of substrates can be used including aliphatic and aromatic aldehydes and ketones, and even benzophenones. A range of amines from ammonia to aromatic amines, including those with electron‐withdrawing substituents, can be employed. For particularly sluggish reactions, such as those involving weakly electrophilic carbonyl groups, poorly nucleophilic amines, or sterically congested reactive centers, additives such as molecular sieves or Lewis acids are often useful. This chapter focuses on those conditions in which the carbonyl component, amine, and reducing reagent react in the same vessel. This review is restricted to reductive aminations using borohydride and borane reducing agents. This chapter concentrates on reductive amination chemistry mediated by borohydride and other boron‐containing reducing agents from 1971, the year when sodium cyanoborohydride was introduced, through the middle of 1999. In addition to reductive aminations of aldehyde and ketone substrates, reactions of related structures including acetals, aminals, ketals, carboxylic acids, nitriles, and dicarbonyls that form a nitrogen‐containing ring are reviewed. Intramolecular processes in which the substrate contains both the carbonyl and amine moieties are described. The intramolecular variant is a useful method for preparing cyclic amines. All of the various boron‐containing hydride sources in reductive aminations, including labeled metal hydrides, are reviewed. Instances of reductive aminations that failed are described. Applications of this method to a solid support in parallel synthesis in combinatorial chemistry as well as reductive aminations that proceed in tandem with a second reaction such as reductive lactamizations are discussed.

show abstract

Synthesis of novel 1‐phenyl‐1H‐indole‐2‐carboxylic acids. II. Preparation of 3‐dialkylamino, 3‐alkylthio, 3‐alkylsulfinyl, and 3‐alkylsulfonyl derivatives

Cited by 16 publications

References 15 publications

Difunctionalisation of Arenes and Heteroarenes by Directed Metallation and Sulfoxide–Magnesium Exchange

Difunctionalisation of Arenes and Heteroarenes by Directed Metallation and Sulfoxide–Magnesium Exchange

Iodine-mediated one-pot synthesis of indoles and 3-dimethylaminoindoles via annulation of enaminones

Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

Contact Info

Product

Resources

About