Concise Enantiospecific Synthesis of a Coccinellied Alkaloid, (−)-Adalinine

Honda, Toshio; Kimura, Mika

doi:10.1021/ol006712b

Cited by 64 publications

(18 citation statements)

References 8 publications

(11 reference statements)

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“…Ethyl Ester (10d) 28 A solution of 5d (400 mg, 1.27 mmol) in CH 2 Cl 2 (3 mL) and TFA (0.16 mL, 2.4 mmol) was stirred for 3 h at 25°C. After removal of the volatiles in vacuo, the resulting oil was dissolved in CH 2 Cl 2 (5 mL).…”

Section: (2s)-5-[(z)-2-oxopropylidene]pyrrolidine-2-carboxylic Acidmentioning

confidence: 99%

A Convenient Protocol for the Alkylidenation of Lactams

Elliott¹,

Wordingham²

2006

Synthesis

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A convenient two-step preparation of alkylidenepyrrolidines is reported.Alkylidenepyrrolidines have long been used as synthetic intermediates, particularly in the synthesis of pyrrolidines and porphyrins. 1 These compounds are generally prepared by reaction of a thioamide with a a-bromocarbonyl compound in a reaction commonly known as the Eschenmoser sulfide contraction. 2 The O-alkylation of lactams followed by treatment with a malonate-type nucleophile also gives the same compounds, 3 although we have found this method to be somewhat capricious. During the course of studies directed towards the batzelladine alkaloids, 4 we required a broad range of alkylidenepyrrolidines, and therefore sought a more convenient method for their preparation. It is well known that imides and carbamates derived from g-lactams can be selectively attacked at the lactam carbonyl by a range of nucleophiles, including Grignard reagents, 5,6 other organometallics, 7,8 heteronucleophiles 9 and stabilised anions 10-13 (Equation 1). The products of this reaction have been cyclised to the corresponding pyrrolines and pyrrolidines in a number of instances, 6,8,12 but we are aware of only a single example of the application of this general approach to alkylidenepyrrolidine synthesis, this being the preparation of sulfonyl alkylidenepyrrolidines. 14, 15 We have therefore undertaken a study of this approach, and now report an efficient and convenient two-step preparation of alkylidenepyrrolidines which can be carried out on a multi-gram scale. Equation 1Lactams 1, 16 2 17 and 3 18 were prepared according to literature procedures. Compounds 1 and 2 underwent ready reaction with ketone and ester enolates to provide a range of compounds 4 and 5 as shown in Equation 2 (Table 1). As expected, the b-keto esters existed solely in the keto form, while the 1,3-diketones showed significant (R 2 = CH 3 ) to total (R 2 = Ph) enolisation. In all cases with ketone and ester enolates, the reactions were clean and high-yielding, and in many instances the crude products were essentially pure.

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Section: (2s)-5-[(z)-2-oxopropylidene]pyrrolidine-2-carboxylic Acidmentioning

confidence: 99%

A Convenient Protocol for the Alkylidenation of Lactams

Elliott¹,

Wordingham²

2006

Synthesis

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“…The synthesis of target 3,4-dialkyl-2,6-diaryl-piperidin-4-ol derivatives (7-12) was accomplished by a Mannich reaction followed by reduction using Grignard reagent as shown in scheme 1. The parent compound, cis-2,6-diarylpiperidin-4-one derivatives (1)(2)(3)(4)(5)(6) were synthesized by double mannich reaction using ketone, arylaldehyde and ammonium acetate in a stoichiometry of 1:2:1 ratio [7,8]. The product obtained was subjected to column chromatography using benzene-chloroform (3:1) eluent.…”

Section: Resultsmentioning

confidence: 99%

“…2,6-disubstituted-piperidine derivatives are regarded as an important building block of many alkaloid natural products, therapeutic drugs and they serve a role as key intermediates for synthesis of various organic compounds including thiazolidones, oxirane, thiazine, etc [1][2][3][4]. The substituted piperidine derivatives are found to possess of various antimicrobial activities including anti-inflammatory, anti-tuberculosis, antipyretic, antibacterial, antifungal, etc [5,6].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Substituted 3,4‐Dialkyl‐2,6‐Diaryl‐Piperidin‐4‐ol Derivatives and Their Conformational Study

Maruthavanan¹,

Venkatesan

2012

Journal of Chemistry

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“…When precipitation of the Salkylated product 14 appeared to be complete, the solvent was removed and replaced by acetonitrile, in which the salt is moderately soluble. Treatment with triphenylphosphine as thiophile and N-methylpiperidine as base, in accordance with the procedure of Honda and Kimura, 17 effected the expected sulfide contraction to give enaminone 15 in 64% yield. 18 The hydrogen-bonded Z geometry of this product was apparent from the chemical shift of the CH 2 signal adjacent to the double bond (d H = 2.39 ppm); anisotropic deshielding by the carbonyl group in related E enaminones generally causes a downfield shift of about 0.5 ppm.…”

Section: Methodsmentioning

confidence: 99%

A Versatile Synthesis of (±)-Deoxyfebrifugine, an Antimalarial Alkaloid Analogue, and Related Compounds

Michael¹,

Koning²,

Pienaar³

2006

Synlett

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The title compound was prepared by a simple route involving Eschenmoser sulfide contraction between 3-(3-bromo-2-oxopropyl)quinazolin-4(3H)-one (11) and piperidine-2-thione (13) followed by chemoselective catalytic hydrogenation. This short but flexible procedure also permitted access to N-alkyl analogues, and to analogues in which the piperidine ring was replaced by other saturated nitrogen-containing heterocycles.

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Concise Enantiospecific Synthesis of a Coccinellied Alkaloid, (−)-Adalinine

Cited by 64 publications

References 8 publications

A Convenient Protocol for the Alkylidenation of Lactams

A Convenient Protocol for the Alkylidenation of Lactams

Synthesis of Substituted 3,4‐Dialkyl‐2,6‐Diaryl‐Piperidin‐4‐ol Derivatives and Their Conformational Study

A Versatile Synthesis of (±)-Deoxyfebrifugine, an Antimalarial Alkaloid Analogue, and Related Compounds

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