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Santhoshkumar AC, Durugappa B, Doddamani SV, Siby A, Valmiki PK, Somappa SB. Diastereoselective Synthesis of Fused Tricyclic Pyridopyrimidines via Tandem Cyclization of Allenoates and Cyclic Amidines. Org Lett 2023; 25:7711-7715. [PMID: 37843814 DOI: 10.1021/acs.orglett.3c03053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
The tandem cyclization of easily accessible allenoates and cyclic amidines for the synthesis of functionalized tricyclic pyridopyrimidines is reported herein. The annulation featured a broad substrate scope with good functional group tolerance under very mild conditions (35 examples, 32-85% yields). The pyridopyrimidines were obtained in a very short reaction time (1 min), at room temperature, under neat conditions, which offers an alternative way to the sustainable synthesis of functionalized pyridopyrimidines. The scalability of the developed protocol is further demonstrated by a gram-scale synthesis.
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Affiliation(s)
- Athira C Santhoshkumar
- Chemical Sciences & Technology Division, Council of Scientific and Industrial Research (CSIR)-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvananthapuram, Kerala 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Basavaraja Durugappa
- Chemical Sciences & Technology Division, Council of Scientific and Industrial Research (CSIR)-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvananthapuram, Kerala 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Siddalingeshwar V Doddamani
- Chemical Sciences & Technology Division, Council of Scientific and Industrial Research (CSIR)-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvananthapuram, Kerala 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Aiswarya Siby
- Chemical Sciences & Technology Division, Council of Scientific and Industrial Research (CSIR)-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvananthapuram, Kerala 695019, India
| | - Praveen K Valmiki
- Chemical Sciences & Technology Division, Council of Scientific and Industrial Research (CSIR)-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvananthapuram, Kerala 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Sasidhar B Somappa
- Chemical Sciences & Technology Division, Council of Scientific and Industrial Research (CSIR)-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvananthapuram, Kerala 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
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Jamwal P, Sharma A, Gurubrahamam R. Decomposition of Alkynyl Hydrazones: Synthesis of Allenoates, Dihaloallenoates, and Angularly Fused Tricyclic Azepines. Org Lett 2023; 25:6607-6612. [PMID: 37669229 DOI: 10.1021/acs.orglett.3c01994] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
An unprecedented decomposition of unprotected alkynyl hydrazones is attempted that has provided allenoates, tetrasubstituted α,γ-dihaloallenoates, and functionalized tricyclic azepines. A reaction of alkynyl hydrazones with N-halosuccinimides captures the electrophile in 2-fold that delivers fully substituted dibromo- and diiodoallenoates in good yields. In addition, a DABCO-promoted Wolff-Kishner reduction of hydrazones, followed by isomerization, provides versatile allenoates under mild conditions. In contrast, a similar decomposition with ambiphilic DBU furnishes a completely different tricyclic azepine scaffold in excellent yield and diastereoselectivity.
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Affiliation(s)
- Paru Jamwal
- Department of Chemistry, Indian Institute of Technology Jammu, NH-44, PO Nagrota, Jagti, Jammu, Jammu and Kashmir 181221, India
| | - Akashdeep Sharma
- Department of Chemistry, Indian Institute of Technology Jammu, NH-44, PO Nagrota, Jagti, Jammu, Jammu and Kashmir 181221, India
| | - Ramani Gurubrahamam
- Department of Chemistry, Indian Institute of Technology Jammu, NH-44, PO Nagrota, Jagti, Jammu, Jammu and Kashmir 181221, India
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Durugappa B, C S A, Doddamani SV, Somappa SB. DBU-Catalyzed Diastereo/Regioselective Access to Highly Substituted Spiro-oxetane Oxindoles via Ring Annulation of Isatins and Allenoates. J Org Chem 2023. [PMID: 37363866 DOI: 10.1021/acs.joc.3c00664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
A facile and efficient method for the diastereo/regioselective synthesis of highly functionalized spiro-oxetane oxindoles has been described. The 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-catalyzed reaction proceeds via spiro-annulation of isatins and allenoates. The reaction is compatible with a wide range of isatins containing electron-donating groups (EDGs) and electron-withdrawing groups (EWGs) with various allenoates affording the corresponding products in acceptable yields. It is noteworthy that this is the first protocol for constructing structurally diverse motifs of highly functionalized spiro-oxetane oxindoles of pharmaceutical relevance.
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Affiliation(s)
- Basavaraja Durugappa
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Athira C S
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Siddalingeshwar V Doddamani
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sasidhar B Somappa
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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D B, C S A, D SV, T AK, Somappa SB. Multicomponent Synthesis of Spiro-dihydropyridine Oxindoles via Cascade Spiro-cyclization of Knoevenagel/Aza-Michael Adducts. J Org Chem 2022; 87:13556-13563. [PMID: 36194438 DOI: 10.1021/acs.joc.2c01063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An efficient, straightforward, and one-pot synthesis of biologically relevant spiro-dihydropyridine oxindoles was described via readily available isatin, malononitrile, allenoate, and amines. The metal/organocatalyst-free, Et3N-mediated reaction proceeds via cascade spiro-cyclization of in situ generated Knoevenagel/aza-Michael adducts. The reaction has great flexibility over electron-rich and electron-poor substituents affording desired products in good to excellent yields. We have also demonstrated the selected spiro-dihydropyridines for late-stage diversification into new spiro-dihydropyridine hybrids of pharmaceutical relevance.
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Affiliation(s)
- Basavaraja D
- Chemical Sciences & Technology Division, CSIR-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvanthapuram 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR, Ghaziabad 201002, India
| | - Athira C S
- Chemical Sciences & Technology Division, CSIR-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvanthapuram 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR, Ghaziabad 201002, India
| | - Siddalingeshwar V D
- Chemical Sciences & Technology Division, CSIR-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvanthapuram 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR, Ghaziabad 201002, India
| | - Ashitha K T
- Chemical Sciences & Technology Division, CSIR-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvanthapuram 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR, Ghaziabad 201002, India
| | - Sasidhar B Somappa
- Chemical Sciences & Technology Division, CSIR-National Institute for Interdisciplinary Science & Technology (NIIST), Thiruvanthapuram 695019, Kerala, India.,Academy of Scientific and Innovative Research (AcSIR, Ghaziabad 201002, India
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Hajinasiri R. Allenoates in organic synthesis. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.133053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ethylbenzene Hydroperoxide: An efficient oxidizing agent for diastereoselective synthesis of Spiroepoxy oxindoles. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.154126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ashitha KT, Krishna A, Basavaraja D, Sasidhar BS. Recent Advances in the Transition Metal-Free Synthesis of Heterocycles from α, β-Unsaturated Ketones. Org Chem Front 2022. [DOI: 10.1039/d2qo00278g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Heterocyclic compounds are an inevitable part of our life. These important classes of molecules have a wide range of applications starting from life-sustaining drugs to agrochemicals. Numerous methods, including metal...
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