Synthesis of mixed acyclic imides using pentafluorophenyl esters

Andrus, Merritt B.; Li, Wenki; Keyes, Robert F.

doi:10.1016/s0040-4039(98)01112-5

Cited by 42 publications

(27 citation statements)

References 17 publications

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“…In these cases, we applied a method nowadays frequently used in peptide synthesis. [14][15][16] For our purposes, we synthesised a series of highly reactive pentafluorophenyl esters and 1-benzoyl imidazole. These may be regarded as 'mixed' anhydrides of two Brönsted acids, a carboxylic acid and a phenol or imidazole, respectively.…”

Section: Resultsmentioning

confidence: 99%

Convenient syntheses of 1,1,1,3,3,3-hexafluoro-2-organyl-propan-2-ols and the corresponding trimethylsilyl ethers

et al. 2005

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Section: Resultsmentioning

confidence: 99%

Convenient syntheses of 1,1,1,3,3,3-hexafluoro-2-organyl-propan-2-ols and the corresponding trimethylsilyl ethers

et al. 2005

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“…Firstly, (S)-BocPhe was methylated with MeI in the presence of NaH (90 %) and the resulting Boc-N-Me-Phe-OH (23) was converted to the pentafluorophenyl ester [30] (24) (93 %). The activated ester 24 was then reacted with the anion generated by treating methyl (S)-5-benzyltetramate (S)-2 g ((S)-dolapyrrolidone) with n-butyllithium at À78 8C, giving compound 25 in 81 % yield.…”

Section: Resultsmentioning

confidence: 99%

A Flexible Asymmetric Approach to Methyl 5‐Alkyltetramates and Its Application in the Synthesis of Cytotoxic Marine Natural Product Belamide A

Lan

Wang

et al. 2010

Chemistry A European J

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By using a methyl tetramate derivative (R)- or (S)-9 as a novel chiral building block, a direct, flexible, and highly enantioselective approach to methyl (R)- or (S)-5-alkyltetramates (2) is disclosed. Among the synthesized methyl 5-alkyltetramates 2, methyl 5-methyltetramate (2 a) is found in cytotoxic mirabimide E (4) and dysideapyrrolidone (5), and methyl 5-benzyltetramate (2 g) is a substructure in the potent antineoplastic dolastatin 15 (3). On the basis of this method, the first asymmetric synthesis of the antimitotic tetrapeptide belamide A (7) has been achieved in seven steps from (S)-9, with an overall yield of 23.8 %. Not only have the structure and absolute configuration of (+)-belamide A (7) been confirmed, but also the solvent used for recording the (13) C NMR spectrum, the (13) C NMR spectrum data correlation, and optical rotation data of natural belamide A (7) have been revised.

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“…As shown, excellent yields were obtained in the reactions of aliphatic nitriles (entries 1-9). In the case of aryl nitriles, the corresponding amides were also produced as side products, therefore the yields decreased in these cases (entries [10][11][12][13][14][15][16]. We decided to conduct the same reaction with other typical Lewis acids such as AlCl 3 , FeCl 3 , ZnCl 2 , NaHSO 4 , etc.…”

Section: Methodsmentioning

confidence: 99%

“…6a Other procedures for the synthesis of acyclic imides involve aminocarbonylation of aryl bromides, 8 reaction of azalactone with oxygen and palladium, 9 ruthenium tetroxide oxidation of N-acylated alkyl amines, 10 and reaction of pentafluorophenyl (PFP) esters with deprotonated amides. 11 The more sophisticated methods involve the treatment of amides with reagents such as dimethyl acetals of amides, 12 N,N-bis(trimethylsilyl)formamide, 13 a,a,a-trichloromethyl carbonyl compounds, 14 diketene, 15 or vinyl esters. 16 Silica sulfuric acid is a versatile and stable acidic catalyst which has been used successfully for several organic transformations.…”

mentioning

confidence: 99%