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Rana S, Shaw R, Pratap R. Influence of steric hindrance on the 1,4- versus 1,6-Michael addition: synthesis of furans and pentasubstituted benzenes. Org Biomol Chem 2024; 22:5361-5373. [PMID: 38869426 DOI: 10.1039/d4ob00686k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
We described the influence of steric hindrance on the 1,4- versus 1,6-Michael addition reaction on 2-(3,3-bis(methylthio)-1-arylallylidene)malononitriles. An efficient and direct synthesis of trisubstituted furans was achieved through the reaction of 2-(3,3-bis(methylthio)-1-arylallylidene)malononitriles and acetone under mild conditions in good to moderate yield by the 1,4-Michael addition. Further exploration of the reaction with a sterically hindered aryl group containing 2-(3,3-bis(methylthio)-1-arylallylidene)malononitriles afforded biaryls by an in situ generated nucleophile through the 1,6-Michael addition. The synthetic utility of furan is further explored. These precursors are easily accessible from aryl methyl ketones. Various functional groups like alkyl, aryl, nitrile, amine, aroyl, and thiomethyl can be directly installed in the benzene and furan rings. A one-pot approach for the construction of a benzene nucleus was also developed. The structure of two compounds was confirmed by X-ray crystallography.
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Affiliation(s)
- Shally Rana
- Department of Chemistry, University of Delhi, North Campus, Delhi-110007, India.
- Department of Chemistry, School of Science Indrashil University, Rajpur, Kadi, Ahmedabad-Mehsana Highway, Gujarat, 382740, India
| | - Ranjay Shaw
- Department of Chemistry, GLA University, Mathura, 281406, India
| | - Ramendra Pratap
- Department of Chemistry, University of Delhi, North Campus, Delhi-110007, India.
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2
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Ghatak T, Shah C, Althagafi I, Giri NG, Nath M, Pratap R. Iodine/DMSO-mediated one-pot access towards 1-aryl-2-(pyrazol-5-yl)ethane-1,2-diones via a domino reaction from functionalized pent-2-ene-1,5-diones. Org Biomol Chem 2024; 22:1859-1870. [PMID: 38348745 DOI: 10.1039/d3ob01997g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
A facile one-pot cascade synthesis involving simultaneous in situ pyrazole formation followed by iodine/DMSO-mediated oxidation has been established to afford 1-aryl-2-(3-aryl)-1H-pyrazol-5-yl-ethane-1,2-diones. Primarily, a two-pot approach has been established which includes the reaction of 3-methylthio-1,5-diaryl-2-pentene-1,5-diones with hydrazine in the first step to afford pyrazole, which was eventually oxidized in the next steps in the presence of iodine in DMSO. Furthermore, we performed both steps in the same pot to afford 1,2-dicarbonyl compounds in good yield. The structure of one of the compounds was confirmed by single crystal X-ray analysis. DMSO served as a solvent as well as an oxidant. Moreover, N-substituted hydrazines provided 1-(1-substituted-3-aryl-1H-pyrazol-5-yl)-2-arylethane-1,2-diones regioselectively. Furthermore, for synthetic application, 1-aryl-2-(3-aryl)-1H-pyrazol-5-yl-ethane-1,2-diones were treated with o-phenylenediamine to afford pyrazole-functionalized quinoxaline in good yield. A control reaction was carried out to understand the mechanism of product formation.
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Affiliation(s)
- Trisha Ghatak
- Department of Chemistry, University of Delhi, Delhi, 110007, India.
| | - Chandan Shah
- Department of Chemistry, University of Delhi, Delhi, 110007, India.
| | - Ismail Althagafi
- Department of Chemistry, Faculty of Science, Umm Al-Qura University, Makkah, 21955, Saudi Arabia
| | - Nand Gopal Giri
- Department of Chemistry, Shivaji College, University of Delhi, Raja Garden, New Delhi-110027, India
| | - Mahendra Nath
- Department of Chemistry, University of Delhi, Delhi, 110007, India.
| | - Ramendra Pratap
- Department of Chemistry, University of Delhi, Delhi, 110007, India.
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3
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Goud SB, Guin S, Prakash M, Samanta S. Cu(OAc) 2/DABCO-mediated domino reaction of vinyl malononitriles with cyclic sulfamidate imines: access to 6-hydroxyaryl-2-aminonicotinonitriles. Org Biomol Chem 2022; 20:352-357. [PMID: 34931209 DOI: 10.1039/d1ob02095a] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A novel Cu(II)-salt/DABCO-mediated one-pot access to a myriad of highly substituted biologically relevant 2-aminonicotinonitriles possessing a resourceful phenolic moiety with satisfactory yields is reported. This method involves cyclic sulfamidate imines as 1C1N sources and different kinds of acyclic/cyclic vinyl malononitriles as 4C sources for pyridine synthesis via a vinylogous Mannich-cycloaromatization sequence process, creating two new C-N bonds under mild conditions. Importantly, this de novo strategy is applicable to gram-scale syntheses, underlining the method's practicability and allowing for a wide range of substrates with excellent functional group tolerance.
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Affiliation(s)
- S Banuprakash Goud
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, 453552 India.
| | - Soumitra Guin
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, 453552 India.
| | - Meher Prakash
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, 453552 India.
| | - Sampak Samanta
- Department of Chemistry, Indian Institute of Technology Indore, Simrol, 453552 India.
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Farajpour B, Alizadeh A. Recent advances in the synthesis of cyclic compounds using α,α-dicyanoolefins as versatile vinylogous nucleophiles. Org Biomol Chem 2022; 20:8366-8394. [DOI: 10.1039/d2ob01551j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This article provides a review of the applications of α,α-dicyanoolefins as versatile vinylogous nucleophiles in the synthesis of various cyclic compounds, covering the literature from the past 13 years.
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Affiliation(s)
- Behnaz Farajpour
- Department of Chemistry, Tarbiat Modares University, P. O. Box 14115-175, Tehran, Iran
| | - Abdolali Alizadeh
- Department of Chemistry, Tarbiat Modares University, P. O. Box 14115-175, Tehran, Iran
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5
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Elagamy A, Shaw R, Shah C, Pratap R. Iodine-Mediated Synthesis of 2-(Methylthio)-4 H-chromen-4-ones and Study of Their Halogenation Reactions. J Org Chem 2021; 86:9478-9489. [PMID: 34232643 DOI: 10.1021/acs.joc.1c00788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An efficient iodine-mediated method is developed for the synthesis of functionalized 2-(methylthio)-4H-chromen-4-ones by intramolecular cyclization of easily accessible 1-(2-benzyloxy-aryl)-3,3-bis-methylsulfanyl-propenones. The synthesized chromen-4-ones turn out to be a key precursor for various kinds of chemical reactions. Mechanistically, we observed that iodine-mediated intramolecular cyclization of ketene dithioacetal proceeded through a radical pathway. 3-Halo-2-(methylthio)-4H-chromen-4-ones were achieved via various two- or one-pot halogenation approaches.
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Affiliation(s)
- Amr Elagamy
- Department of Chemistry, University of Delhi, North Campus, Delhi, India, 110007
| | - Ranjay Shaw
- Department of Chemistry, University of Delhi, North Campus, Delhi, India, 110007
| | - Chandan Shah
- Department of Chemistry, University of Delhi, North Campus, Delhi, India, 110007
| | - Ramendra Pratap
- Department of Chemistry, University of Delhi, North Campus, Delhi, India, 110007
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Shally, Althagafi I, Shaw R, Elagamy A, Kumar A, Pratap R. A [5 + 1] annulation strategy for the synthesis of multifunctional biaryls and p-teraryls from 1,6-Michael acceptor ketene dithioacetals. Org Biomol Chem 2020; 18:6407-6417. [DOI: 10.1039/d0ob00998a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A [5 + 1] annulation approach was used to access multifunctional biaryls and p-teraryls from ketene dithioacetals.
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Affiliation(s)
- Shally
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | | | - Ranjay Shaw
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - Amr Elagamy
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - Abhinav Kumar
- Department of Chemistry
- University of Lucknow
- Lucknow
- India
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