Heterocyclic Fused Rings with Bridgehead Nitrogen Atoms: Single Step Synthesis of Several Polyfunctionally Substituted Fused Pyridines

Khalafallah, A. K.; Elal, R.M. Abd; Kanzi, N. A. A. El

doi:10.1515/hc.2002.8.4.397

Cited by 8 publications

(3 citation statements)

References 5 publications

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“…The treatment of a compound 1 , with alkylidenemalononitriles ( 31 – 34 ) , in ethanol containing few drops of piperidine (2–5 drops), afforded the corresponding pyrimidine derivatives ( 35 – 38 ) (Scheme ) in low yields (55–65%). Meanwhile, irradiation of the aforesaid reaction mixture by microwaves for 10–13 min afforded the corresponding pyrimidine derivatives ( 35 – 38 ) in excellent yields (90–95%) (Table ).…”

Section: Resultsmentioning

confidence: 99%

Green Design, Synthesis, and Molecular Docking Study of Novel Quinoxaline Derivatives with Insecticidal Potential against Aphis craccivora

et al. 2022

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An efficient and environmentally friendly method was established for designing novel 3-amino-1,4-dihydroquinoxaline-2-carbonitrile ( 1 ) via the reaction of bromomalononitrile and benzene-1,2-diamine under microwave irradiation in an excellent yield (93%). This targeted amino derivative was utilized for the construction of a series of Schiff bases ( 8 – 13 ). A new series of thiazolidinone derivatives ( 15 – 20 ) were synthesized in high yields (89–96%) via treatment of thioglycolic acid with Schiff bases ( 8 – 13 ) under microwave irradiation in high yields (89–96%). Moreover, new pyrimidine derivatives ( 26 – 30 and 35 – 38 ) were prepared by treatment of compound 1 with arylidenes ( 21 – 25 ) and/or alkylidenemalononitriles ( 31 – 34 ) using piperidine as a basic catalyst under microwave conditions. Based on elemental analyses and spectral data, the structures of the new assembled compounds were determined. The newly synthesized quinoxaline derivatives were screened and studied as an insecticidal agent against Aphis craccivora . The obtained results indicate that compound 16 is the most toxicological agent against nymphs of cowpea aphids ( Aphis craccivora ) compared to the other synthesized pyrimidine and thiazolidinone derivatives. The molecular docking study of the new quinoxaline derivatives registered that compound 16 had the highest binding score (−10.54 kcal/mol) and the thiazolidinone moiety formed hydrogen bonds with Trp143.

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Section: Resultsmentioning

confidence: 99%

Green Design, Synthesis, and Molecular Docking Study of Novel Quinoxaline Derivatives with Insecticidal Potential against Aphis craccivora

et al. 2022

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“…We initially tried to prepare ethyl cyanoacrylate by the Knoevenagel condensation of ethyl cyanoacetate with paraformaldehyde in pyridine according to the reported procedure. 10 However, it was found that the resulting acrylate was extremely unstable and polymerized easily upon usual work-up and purification. To circumvent this problem, we turned to a strategy of conducting the con- A B densation and the subsequent Diels-Alder reaction with isoprene in one-pot.…”

Section: Figure 1 Skeleton Of Chamigrenes and Structures Of Laurencenones A-dmentioning

confidence: 99%

“…10 However, it was found that the resulting acrylate was extremely unstable and polymerized easily upon usual work-up and purification. To circumvent this problem, we turned to a strategy of conducting the con- densation and the subsequent Diels-Alder reaction with isoprene in one-pot.…”

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confidence: 99%

A New and Efficient Total Synthesis of (±)-Laurencenone C

Chu¹,

Liu²,

Zhu³

2010

Synlett

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A novel total synthesis of laurencenone C, a chamigrene sesquitepenoid natural product, has been accomplished in 11 steps. In the synthetic sequence, the B-ring of the spirocyclic core was constructed by a one-pot operation involving a Knoevenagel condensation between ethyl cyanoacetate and paraformaldehyde combined with a Diels-Alder reaction of the resulting ethyl 2-cyanoacrylate with isoprene. Moreover, a lithium naphthalenide-induced reductive alkylation of the Diels-Alder adduct was employed to create the C-6 quaternary center and to set the stage for assembling the A-ring.Laurencenone C (1) belongs to an abundant family of sesquitepenoids known as the chamigrenes, which includes more than one hundred members 1 and is characterized by a spiro[5.5]undecane core bearing two vicinal quaternary carbon centers at C-5 and C-6 positions. It was first isolated from the alga of the genus Laurencia obtuse, 1 along with three other structurally related chamigrenes, namely laurencenones A, B, and D (Figure 1). 2 These natural products contain the same A-ring bearing an enone moiety, and differ from each other by the functionalities on the B-ring. Like many other chamigrenes, 3 laurencenone C has attracted attention from the synthetic community with five total syntheses so far having been documented in the literature. 4-8 The first total synthesis was reported by Takeshita and co-workers. 4 In their synthetic sequence, a photo-cycloaddition of terpinolene with methyl 2,4-dioxopentanoate followed by a base-promoted retro-benzilic acid rearrangement of the resulting hydroxy spiro-[3.5]nonene ester was employed to prepare the key precursor for assembling the spiro framework. Following this, Chen's group described the synthesis of 1 by utilizing a crucial intramolecular radical cyclization of an a-allenic ketone to access the spiro ring fusion. 5 However, both syntheses provided 1 in relatively low overall yields (2.9 and 6.4%, respectively) due to the formation of other regio-and stereoisomers as side products in the key synthetic steps. In similar approaches, Srikrishna and co-workers twice described the total synthesis of 1 through the use of an Ireland ester Claisen rearrangement combined with a RCM reaction 6 or an intramolecular type II carbonyl ene reaction 7 as the key operations. Besides these approaches, the RCM strategy was also employed in an enantioselective synthesis of 1 recently reported by Stoltz and Grubbs et al. 8 As can be seen, the syntheses of 1, as well as other chamigrenes, 3 are critically dependent on the efficient creation of the quaternary spirocenter with the necessary functionalities for building the spiro[5.5]undecane core.

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Nuclear magnetic resonance data of C15H10N3O2

Jain

2010

Chemical Shifts and Coupling Constants for Hydrogen-1, Heterocycles

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Heterocyclic Fused Rings with Bridgehead Nitrogen Atoms: Single Step Synthesis of Several Polyfunctionally Substituted Fused Pyridines

Cited by 8 publications

References 5 publications

Green Design, Synthesis, and Molecular Docking Study of Novel Quinoxaline Derivatives with Insecticidal Potential against Aphis craccivora

Green Design, Synthesis, and Molecular Docking Study of Novel Quinoxaline Derivatives with Insecticidal Potential against Aphis craccivora

A New and Efficient Total Synthesis of (±)-Laurencenone C

Nuclear magnetic resonance data of C15H10N3O2

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