SYNTHESIS OF Α-Aminoaldehydes AND Α-Aminoketones. A REVIEW

Fisher, Lawrence E.; Muchowski, Joseph M.

doi:10.1080/00304949009356309

Cited by 65 publications

(24 citation statements)

References 172 publications

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“…23 In view of their remarkable impact on several areas of organic chemistry, a large number of synthetic studies have focused on the construction of these high-value synthons. Classically, these processes rely on the nucleophilic substitution of an α-halogenated ketone (1) with an amine (2) or azide (4) (Scheme 2, 1), 24 or the electrophilic amination of eno-Lewis A. T. Allen…”

Section: Introductionmentioning

confidence: 99%

Recent advances in the synthesis of α-amino ketones

et al. 2021

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Section: Introductionmentioning

confidence: 99%

Recent advances in the synthesis of α-amino ketones

et al. 2021

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“…a-Amino aldehydes are well-known to be autocatalytically transformed into more stable amino ketones [29] [30]. Since in the chemical reaction two aamino aldehydes react under exchange of their N-atoms, such a process seems unlikely under physiological conditions.…”

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confidence: 99%

The Biosynthesis of Branched Dialkylpyrazines in Myxobacteria

Nawrath

Dickschat

Kunze

et al. 2010

Chemistry & Biodiversity

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The biosynthesis of the volatiles 2,5- and 2,6-diisopropylpyrazine (2 and 3, resp.) released by the myxobacteria Nannocystis exedens subsp. cinnabarina (Na c29) and Chondromyces crocatus (strains Cm c2 and Cm c5) was studied. Isotopically labeled precursors and proposed pathway intermediates were fed to agar plate cultures of the myxobacteria. Subsequently, the volatiles were collected by use of a closed loop stripping apparatus (CLSA), and incorporation into the pyrazines was followed by GC/MS analysis. [(2)H(8)]Valine was smoothly incorporated into both pyrazines clearly establishing their origin from the amino acid pool. The cyclic dipeptide valine anhydride (16)--a potential intermediate on the biosynthetic pathway to branched dialkylpyrazines--was synthesized containing (2)H(1) labels in specific positions. Feeding of [(2)H(16)]-16 and [(2)H(12)]-16 in both valine subunits mainly resulted in the formation of pyrazines derived from only one labeled amino acid, whereas only traces of the expected pyrazines with two labeled subunits were found. To investigate the origin of nitrogen in the pyrazines, a feeding experiment with [(15)N]valine was performed, resulting in the incorporation of the (15)N label. The results contradict a biosynthetic pathway via cyclic dipeptides, but rather point to a pathway on which valine is reduced to valine aldehyde. Its dimerization to 2,5-diisopropyldihydropyrazine 36 and subsequent oxidation results in 2. The proposed biosynthetic pathway neatly fits the results of earlier labeling studies and also explains the formation of the regioisomer 2,6-diisopropylpyrazine 3 by isomerization during the first condensation step of two molecules valine aldehyde. A general biosynthetic pathway to different classes of pyrazines is presented.

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“…Monoalkylation of the a-tert-butoxycarbonylamino ketones 1 A solution of the a-tert-butoxycarbonylamino ketone (2.0 mmol) in anhydrous DMF (5 mL) was added to a stirred suspension of sodium hydride (prepared from 0.10 g (2.1 mmol) of a 50% dispersion in mineral oil by washing with dry hexane) in dry DMF (5 rnL) maintained in a nitrogen atmosphere at P C . After the addition was completed, stining at O°C was continued until hydrogen evolution was complete (0.25 h) and then the alkyl halide (2.4 mmol) was added.…”

Section: -N-tert-butoxycarbonylaminoacetophenone (2 R' = Ph)mentioning

confidence: 99%

“…Numerous syntheses of these important starting materials have been devised (1) and new developments in this field continue apace (2)(3)(4)(5)(6)(7)(8). We recently demonstrated (9) that the monoanions of N-formylated a-amino ketones, like those of benzamidoacetone (lo), are regioselectively alkylated on the a-carbon atom and that acidic hydrolysis of these products provided access to a-alkyl-aamino ketones with satisfactory efficiency.…”

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confidence: 99%

“…5For example, the alkylation of 2 (R1 = Ph) with methyl iodide gave material which had 'H nmr absorptions at 8 1 Removal of the t-Boc group from 4 was effected slowly with excess trifluoroacetic acid at ambient temperature or rapidly with excess methanolic hydrochloric acid at reflux temperature. The salts of the a-alkyl-a-amino ketones 5 were thus obtained in overall yields quite comparable to those reported for the a-formamido ketone process ( Table 2).…”

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confidence: 99%

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