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Nisar B, Rubab SL, Raza AR, Tariq S, Sultan A, Tahir MN. An efficient protocol for the synthesis of highly sensitive indole imines utilizing green chemistry: optimization of reaction conditions. Mol Divers 2018; 22:709-722. [PMID: 29644489 DOI: 10.1007/s11030-018-9826-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 03/26/2018] [Indexed: 11/30/2022]
Abstract
Novel and highly sensitive indole-based imines have been synthesized. Their synthesis has been compared employing a variety of protocols. Ultimately, a convenient, economical and high yielding set of conditions employing green chemistry have been designed for their synthesis.
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Affiliation(s)
- Bushra Nisar
- Department of Chemistry, The University of Lahore, Sargodha Campus, Lahore Road, Sargodha, 40100, Pakistan
| | - Syeda Laila Rubab
- Department of Chemistry, University of Education, Jauharabad Campus, Jauharabad, 41200, Pakistan
| | - Abdul Rauf Raza
- Ibn e Sina Block, Department of Chemistry, University of Sargodha, Sargodha, 40100, Pakistan.
| | - Sobia Tariq
- Ibn e Sina Block, Department of Chemistry, University of Sargodha, Sargodha, 40100, Pakistan
| | - Ayesha Sultan
- Department of Chemistry, University of Education, Faisalabad Campus, Faisalabad, 38000, Pakistan
| | - Muhammad Nawaz Tahir
- Ibn ul Haithum Block, Department of Physics, University of Sargodha, Sargodha, 40100, Pakistan
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2
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Jones RC, Herasymchuk K, Mahdi T, Petrov A, Resanović S, Vaughan DG, Lough AJ, Quail JW, Koivisto BD, Wylie RS, Gossage RA. Tautomerism and metal complexation of 2-acylmethyl-2-oxazolines: a combined synthetic, spectroscopic, crystallographic and theoretical treatment. Org Biomol Chem 2013; 11:3484-93. [PMID: 23591452 DOI: 10.1039/c3ob25867j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A synthetic, structural and theoretical investigation into the solid-state, solution and gas phase structure(s) of six 2-acylmethyl-4,4-dimethyl-2-oxazolines is reported. Four of these materials, viz.α-[(4,5-dihydro-4,4-dimethyl-2-oxazolyl)methylene]benzenemethanol (3a), α-[(4,5-dihydro-4,4-dimethyl-2-oxazolyl)methylene]-(4-nitrobenzene)methanol (3b), 1-(4,5-dihydro-4,4-dimethyl-2-oxazolyl)-3,3-dimethyl-1-buten-2-ol (3d) and (E)-1-phenyl-2-((3aR)-3,3a,8,8a-tetrahydro-2H-indeno[1,2-d]oxazol-2-ylidene)ethanone (3f) have been characterised in the solid-state by single crystal X-ray diffraction studies. These data represent the first solid-state structural studies of this class of compounds and details the first synthesis and full characterisation of chiral derivative 3f. All four of these materials are shown to exist in the solid phase in the enamine tautomeric form (e.g., 3a is best described as 2-[4,4-dimethyl-2-oxazolidinylidene]-1-phenylethanone) and it is suggested (NMR, IR) that this isomeric form is likely also retained in solution (e.g., CDCl3) as the more stable isomer. An investigation of the relative gas phase stabilities of the three possible (i.e., the (Z)-enol, keto and enamine) isomers of all five compounds by DFT at the B3LYP/6-311G(d) level of theory confirms the latter as the most stable form. The energy differences between the enamine and keto tautomers have been calculated to be the lowest for derivative 3d. These results are compared and contrasted with the previously reported NMR studies of such compounds which have identified the keto form as being a minor (albeit solution) tautomer. Equilibrium solution tautomer distributions for 3d are found to be solvent dependent. The protonated form of 3a, isolated as the HSO4(-) salt (i.e.4a), has been further characterised in the solid state by single crystal X-ray diffraction. These data represent the first example of a protonated oxazoline to be structurally elucidated and confirms that upon protonation, the keto (oxazoline) tautomer is the energetically favoured form in the solid-state. This observation is further supported by DFT studies for the gas phase protonated forms of such materials. Further DFT (B3LYP/6-311G(d)) calculations employing the SM8 or SMD solvation models were then applied to address the observed solution isomeric distribution for 3d; these results corroborate the gas phase theoretical treatment and also yield values that predict the higher solution stability of the enamine form as observed, although they fail to account for the existence of the keto form as a minor solution state tautomer. To access the availability of an enol-form, via hypothetical de-protonation to the enolate, compound 3a was treated with hydrated Cu(NO3)2 in EtOH solution. The resulting isolated green-coloured product (5), the first metal derivative of this entire class of ligands, is best described (IR, X-ray diffraction) as a coordinated enolate complex, i.e., Cu(3a-H)2. Complex 5 crystallizes in the P21/c space group with four molecules in the unit cell. The coordination geometry around the formal Cu(2+) metal centre is determined to be highly distorted square planar in nature (τ4 = 0.442). TD-DFT is used to give a reasonable explanation for the intensity of the absorbance band observed in the visible region for solutions of 5. These latter experiments strongly suggest that the title class of compounds may have considerable potential as ligands in coordination chemistry and/or metal-mediated catalysis.
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Affiliation(s)
- Roderick C Jones
- School of Chemistry, University of Tasmania, Hobart, TAS 7001, Australia
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Pichette S, Aubert-Nicol S, Lessard J, Spino C. Photochemical and thermal ring-contraction of cyclic hydroxamic acid derivatives. J Org Chem 2012. [PMID: 23198744 DOI: 10.1021/jo3023507] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cyclic hydroxamic acids can undergo a thermal ring contraction after an in situ triflation. High yields of ring-contraction products are obtained with DBU when the migrating carbon is a methylene, while best results are obtained with Et(3)N for the migration of quaternary carbons. In some cases, the regiochemical outcome of the reaction can be controlled by changing the base. This novel thermal rearrangement complements a similar but photochemical rearrangement of N-mesyloxylactams.
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Affiliation(s)
- Simon Pichette
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1
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Spino C. Menthone and p-menthyl-3-carboxaldehyde as chiral auxiliaries. Chem Commun (Camb) 2011; 47:4872-83. [DOI: 10.1039/c0cc05543c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Drouin A, Winter DK, Pichette S, Aubert-Nicol S, Lessard J, Spino C. Photochemical Rearrangement of N-Mesyloxylactams: Stereospecific Formation of N-Heterocycles. J Org Chem 2010; 76:164-9. [DOI: 10.1021/jo101805q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexandre Drouin
- Département de Chimie, Université de Sherbrooke, 2500 boul. Université, Sherbrooke, Québec, Canada, J1K 2R1
| | - Dana K. Winter
- Département de Chimie, Université de Sherbrooke, 2500 boul. Université, Sherbrooke, Québec, Canada, J1K 2R1
| | - Simon Pichette
- Département de Chimie, Université de Sherbrooke, 2500 boul. Université, Sherbrooke, Québec, Canada, J1K 2R1
| | - Samuel Aubert-Nicol
- Département de Chimie, Université de Sherbrooke, 2500 boul. Université, Sherbrooke, Québec, Canada, J1K 2R1
| | - Jean Lessard
- Département de Chimie, Université de Sherbrooke, 2500 boul. Université, Sherbrooke, Québec, Canada, J1K 2R1
| | - Claude Spino
- Département de Chimie, Université de Sherbrooke, 2500 boul. Université, Sherbrooke, Québec, Canada, J1K 2R1
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Winter DK, Drouin A, Lessard J, Spino C. Photochemical Rearrangement of N-Chlorolactams: A Route to N-Heterocycles through Concerted Ring Contraction. J Org Chem 2010; 75:2610-8. [DOI: 10.1021/jo100181h] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dana K. Winter
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Alexandre Drouin
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Jean Lessard
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Claude Spino
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, Québec, Canada J1K 2R1
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Minville J, Girardin M, Spino C. Efficient preparation of chiral non-racemic sulfur compounds. CAN J CHEM 2007. [DOI: 10.1139/v07-091] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
p-Menthane-3-carboxaldehyde serves as an efficient chiral auxiliary in the preparation of chiral non-racemic S-alkylthiocarbamates or S-dithiocarbonates via the 3,3-sigmatropic rearrangement of the corresponding alkylthionocarbamates or xanthates. The transfer of chirality during rearrangement is complete, and the final products possess a chiral tertiary or quaternary carbon bearing sulfur. The rearranged products are then transformed into enantiopure cyclic or acyclic sulfur-containing products, depending on the means of clivage of the auxiliary. The synthesis of a potent MMP-13 inhibitor is presented.Key words: 3,3-sigmatropic rearrangement, p-menthane-3-carboxaldehyde, S-alkylthiocarbamate, S-dithiocarbonate, alkylthionocarbamate, xanthate, ring-closing metathesis.
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Belen’kii L, Gramenitskaya V, Evdokimenkova Y. The Literature of Heterocyclic Chemistry, Part IX, 2002–2004. ADVANCES IN HETEROCYCLIC CHEMISTRY 2006. [DOI: 10.1016/s0065-2725(06)92004-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Spino C, Godbout C, Beaulieu C, Harter M, Mwene-Mbeja TM, Boisvert L. p-Menthane-3-carboxaldehyde: a useful chiral auxiliary for the synthesis of chiral quaternary carbons of high enantiomeric purity. J Am Chem Soc 2005; 126:13312-9. [PMID: 15479086 DOI: 10.1021/ja046084j] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
(+)- or (-)-p-Menthane-3-carboxaldehyde is made in two easy steps from (+)- or (-)-menthone, respectively. This auxiliary allows for the synthesis of carbonyl compounds bearing a alpha-chiral quaternary carbon. The flexibility, efficiency, and ease of use of the method are demonstrated in a series of examples, which include the total synthesis of (+)-cuparenone as well as a partial synthesis of (-)-cassiol.
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Affiliation(s)
- Claude Spino
- Université de Sherbrooke, Département de Chimie, 2500 Boul. Université, Sherbrooke, Qc, Canada, J1K 2R1.
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Spino C, Gund VG, Nadeau C. A Chiral Cyclohexanone Linked to Polystyrene for Solid-Phase Synthesis of Chiral α-Carbonyls. ACTA ACUST UNITED AC 2005; 7:345-52. [PMID: 15762765 DOI: 10.1021/cc049859t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two chiral cyclohexanones were linked to polystyrene resin. The polymer-bound auxiliaries were subjected to a sequence of four reactions, the last of which cleaves the desired alpha-chiral carbonyl compound off the resin, concurrently regenerating the resin-bound auxiliary in its original form. The resin can then be reused.
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Affiliation(s)
- Claude Spino
- Département of Chimie, Université of Sherbrooke, 2500 Boulevard Université, Sherbrooke, Qc, Canada, J1K 2R1.
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Abstract
The SN2′ displacement of menthone-derived allylic carbonates with cuprate reagents occurs with high diastereoselectivity. This method can be used in an iterative fashion to construct stereocenters bearing a 1,3-relationship in a carbon chain. Each iteration provides the adduct in greater than 99% de. The synthesis of three fragments of the polyether ionophore ionomycin is disclosed.Key words: menthone, chiral auxiliary, SN2′ displacement, cuprate, iteration, ionomycin.
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