Synthesis of (3S,4S)-3,4-Dihydroxyprolines from L-Tartaric Acid.

Arakawa, Yoji; Yoshifuji, Shigeyuki

doi:10.1248/cpb.39.2219

Cited by 29 publications

(14 citation statements)

References 1 publication

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“…Temperature effects were also briefly investigated; addition of PhMgBr to a solution of imine cooled to À 78 8C followed by warming to room temperature yielded the adduct 29 d in only 16 % (entry 12). Purification of the imine by an aqueous work-up procedure to remove excess DBU, [31] followed by addition of Grignard led only to a much lower yield of adducts 29 d, b (5 % for phenylmagnesium bromide, 10 % for ethylmagnesium bromide, entries 16 and 17, respectively). It is possible that this may be attributed to the intermediate formation of a hydrated, hemiaminal form of imine 2 on exposure to water, which might be unreactive to subsequent Grignard addition.…”

Section: Optimisation Of Organometallic Additionsmentioning

confidence: 99%

Highly Diastereoselective Additions to Polyhydroxylated Pyrrolidine Cyclic Imines: Ready Elaboration of Aza‐Sugar Scaffolds To Create Diverse Carbohydrate‐Processing Enzyme Probes

Chapman

Courtney

Hay

et al. 2003

Chemistry A European J

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Representative diastereomeric, erythritol and threitol polyhydroxylated pyrrolidine imine scaffolds have been rapidly elaborated to diversely functionalized aza-sugars through highly diastereoselective organometallic (RM) additions (R=Me, Et, allyl, hexenyl, Ph, Bn, pMeO-Bn). The yields for these additions have all been substantially enhanced from previously optimised levels (<58 %) for normal additions using a reverse addition procedure (e.g. R=Ph; 44 % normal mode --> 78 % reverse mode). The high diastereoselectivities (>98 % de for all except R=Me) are consistent with additions that are controlled by the configuration of the C-2 centre adjacent to the azomethine imine carbon and the conformation of the pyrrolidine imine. The high potential of this method was demonstrated by concise syntheses of 1-epi- and 2-epi-desacetylanisomycins. In addition, the late stage addition of hydrophobic substituents, which this imine addition methodology allows, enabled the preparation of novel aza-sugars with enhanced inhibitory potential. This was highlighted by the screening of a representative selection of these "hydrophobically-modified" aza-sugars against a diverse panel of 12 non-mammalian and human carbohydrate-processing enzymes. This identified a novel nanomolar alpha-galactosidase inhibitor (IC(50)=250 nM) and a novel highly selective glucosylceramide synthase inhibitor (IC(50)=52 microM, no alpha-glucosidase inhibition at 1 mM). Furthermore, analysis of the structure-activity relationships of racemic series of inhibitors allowed some validation of Fleet's mirror-image enzyme active site postulate.

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Section: Optimisation Of Organometallic Additionsmentioning

confidence: 99%

Highly Diastereoselective Additions to Polyhydroxylated Pyrrolidine Cyclic Imines: Ready Elaboration of Aza‐Sugar Scaffolds To Create Diverse Carbohydrate‐Processing Enzyme Probes

Chapman

Courtney

Hay

et al. 2003

Chemistry A European J

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“…(3S,4S)-3,4-Bis[(tert-butyl)dimethylsilyloxy]pyrrolidine (3h) was prepared by a literature method. [30] Analysis: Melting points are uncorrected and were determined with a Reichert Austria apparatus (1°C precision).…”

Section: Methodsmentioning

confidence: 99%

“…1 H NMR analysis of the mixed Ti IV complexes proved particularly diagnostic for determining the ratio of the different trialkanolamines, due to the downfield shift of the benzylic proton upon coordination to the metal centre. [30] The Ti IV complex mixture 2c-mix was used in the oxidation of dibenzylamine (3a) by CHP, under the standard reaction conditions for the oxidation protocol (Table 1, Entry 13). The resulting kinetic profile is shown in Figure 4 (curve symbol: black diamond).…”

Section: Ligand Preparation From Racemic Styrene Oxidementioning

confidence: 99%

Effective Oxidation of Secondary Amines to Nitrones with Alkyl Hydroperoxides Catalysed by (Trialkanolaminato)titanium(IV) Complexes

et al. 2010

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The effective catalytic oxidation of secondary amines to nitrones with alkyl hydroperoxides as the primary oxidants is described. The titanium alkoxide catalysts are protected from the water co-product by the combined use of a tightly binding trialkanolamine ligand and molecular sieves. Nitrones can be obtained in high yields (up to 98%) under homogeneous, anhydrous conditions and even in the absence of solvent. The reactions are fast (2-7 h) and good selectivity and complete conversion can be achieved with as little as 1% catalys

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“…The 20 % aqueous NaOH solution was replaced by a 10 % aqueous NaHCO 3 solution. N ‐Tosylsarcosine (2.8 g, 12 mmol), thionyl chloride (1.4 mL, 15 mmol), ( S , S )‐3,4‐bis(phenylacetoxy)pyrrolidine10f (830 mg, 3 mmol) and 10 % aqueous NaHCO 3 (13 mL) afforded 1 d (970 mg, 65 %). [ α ]$\rm{_{D}^{20}}$ =+24.4 ( c =0.7 in CHCl 3 ); 1 H NMR (200 MHz, CDCl 3 ): δ =7.70 (d, J =8.1 Hz, 2 H), 7.40–7.10 (m, 12 H), 5.20 (br dd, 2 H), 3.90–3.50 (m, 10 H), 2.70 (s, 3 H), 2.40 (s, 3 H); 13 C NMR (50 MHz, CDCl 3 ): δ =169.9, 169.8, 165.7, 143.7, 133.5, 132.9 (×2), 129.6, 128.9, 128.5, 127.4, 127.2, 75.0, 73.0, 52.6, 49.9 (×2), 40.8 (×2), 35.3, 21.3; IR (neat): $\tilde \nu$ =1745, 1655 cm −1 .…”

Section: Methodsmentioning

confidence: 99%

Enantioselective Vicinal Bis-Acylation of Olefins

et al. 2002

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A two‐step sequence for the asymmetric vicinal acylation of olefins by a [2+2+1] strategy is reported. The key reaction is a [2+2] cycloaddition of an olefin to a chiral keteniminium salt derived from N‐tosylsarcosinamide. This is followed by a regioselective Baeyer–Villiger oxidation of the resulting cyclobutanone to yield a lactol derivative that is equivalent to the product of addition of a carboxyl and a carbonyl group to the olefin. N‐Tosylsarcosinamides derived from prolinol methyl ether and 2,5‐dimethylpyrrolidine gave the best yields and diastereoselectivities. Five‐ and six‐membered cycloolefins only gave cis products as expected. With seven‐ and eight‐membered rings and cis 1,2‐disubstituted acyclic olefins, partial or complete epimerisation of the cis to the trans adducts was observed. Facial selectivities were generally good except for terminal olefins. The oxidation step proceeded in high yields to give crystalline compounds which could usually be obtained in enantiopure form by simple recrystallisation.

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Synthesis of (3S,4S)-3,4-Dihydroxyprolines from L-Tartaric Acid.

Cited by 29 publications

References 1 publication

Highly Diastereoselective Additions to Polyhydroxylated Pyrrolidine Cyclic Imines: Ready Elaboration of Aza‐Sugar Scaffolds To Create Diverse Carbohydrate‐Processing Enzyme Probes

Highly Diastereoselective Additions to Polyhydroxylated Pyrrolidine Cyclic Imines: Ready Elaboration of Aza‐Sugar Scaffolds To Create Diverse Carbohydrate‐Processing Enzyme Probes

Effective Oxidation of Secondary Amines to Nitrones with Alkyl Hydroperoxides Catalysed by (Trialkanolaminato)titanium(IV) Complexes

Enantioselective Vicinal Bis-Acylation of Olefins

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