Total synthesis of ent-calystegine B4 via nitro-Michael/aldol reaction

Kamimura, Akio; Miyazaki, Koichiro; Suzuki, Shuzo; Ishikawa, Shingo; Uno, Hidemitsu

doi:10.1039/c2ob25386k

Cited by 5 publications

(4 citation statements)

References 33 publications

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“…To synthesize the reported structure of phomolide H ( 2 ), l ‐dimethyl tartrate ( 11 ) was first protected as the 2,3‐acetonide (Scheme ), both esters were reduced by using LiAlH 4 , and the resulting 1,4‐diol was monosilylated to form its TBS‐ether, which was followed by Swern oxidation to give aldehyde 12 . The protected threose 12 was then subjected to a Wittig reaction employing the pinacol–acetaldehyde phosphonium salt 13 , known as DualPhos, which enabled stereoselective olefination ( E/Z > 5:1) to give the latent alkenal 10 .…”

Section: Resultsmentioning

confidence: 99%

Total Enantioselective Synthesis of the Endophytic Fungal Polyketide Phomolide H and Its Structural Revision

McNulty

McLeod

2016

Eur J Org Chem

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A total synthesis of the proposed structure of the natural polyketide‐macrolactone phomolide H 2 has been achieved following a bidirectional strategy from l‐tartaric acid. The originally assigned structure of phomolide H displayed discordant NMR spectroscopic data in comparison with synthetic 2. The synthetic strategy was extended to prepare diastereomers and epimeric methyl‐ethers of the natural product, structural analysis of which revealed a match of the natural product with diastereomer 27. The structural revision of phomolide H from 2 to the methanol solvate of compound 27 is presented.

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Section: Resultsmentioning

confidence: 99%

Total Enantioselective Synthesis of the Endophytic Fungal Polyketide Phomolide H and Its Structural Revision

McNulty

McLeod

2016

Eur J Org Chem

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“…The three-step route proceeded in an overall 37% yield and was reproducible on a multigram scale. Alternatively, compound 9 was accessible starting from l -diethyl tartrate 10 , which was converted into aldehyde 11 following a reported method. − Simultaneous removal of the tert -butyldimethylsilyl (TBS) and isopropylidene-protecting groups by treatment with 1.25 M HCl/MeOH led to the formation of methyl threoside 9 in 35% yield over five steps. Such a synthetic sequence can also be easily performed on a large scale.…”

Section: Resultsmentioning

confidence: 99%

“…A solution of compound 11 − (1.0 g, 3.64 mmol) in 1.25 M methanolic HCl (100 mL) was stirred at room temperature for 12 h. The reaction mixture was quenched with solid NaHCO 3 and filtered. The filtrate was evaporated to give a crude residue, which was purified by silica gel chromatography (gradient DCM/MeOH, 25:1, v/v; 20:1, v/v; 15:1, v/v) to afford compound 9 (244 mg, 50%), as a mixture of anomers 9α and 9β .…”

Section: Methodsmentioning

confidence: 99%

Scalable Synthesis, In Vitro cccDNA Reduction, and In Vivo Antihepatitis B Virus Activity of a Phosphonomethoxydeoxythreosyl Adenine Prodrug

Luo

Kalkeri

et al. 2020

J. Med. Chem.

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Standard literature procedures for the chemical synthesis of L-threose nucleosides generally employ L-ascorbic acid as starting material. Herein, we have explored two alternative routes that start from either L-arabitol or L-diethyl tartrate, both affording 2-O-methyl-L-threofuranose as a key building block for nucleobase incorporation. The access to multigram quantities of this glycosyl donor in a reproducible fashion allows for the preparation of 2′-deoxy-α-L-threofuranosyl phosphonate nucleosides on a large scale. This methodology was applied to the gram scale synthesis of an aryloxy amidate prodrug of phosphonomethoxydeoxythreosyl adenine. This prodrug exerted potent activity against an entecavir-resistant hepatitis B virus (HBV) strain, while leading to a significant reduction in the levels of HBV covalently closed circular DNA in a cellular assay. Furthermore, its remarkable anti-HBV efficacy was also confirmed in vivo using a hydrodynamic injection-based HBV mouse model, without relevant toxicity and systemic exposure occurring.

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“…Isosorbide (Is, 98+%) was purchased from Alfa Aesar Chemical Co. (Tianjin, China). Dimethyl succinate (DMS, 99%) was purchased from Sinopharm Chemical Reagent Co., Ltd. 2,3- O -Isopropylidene- l -threitol (ITh) was synthesized according to the literature. , The synthetic procedures of ITh and its FT-IR, 1 H NMR, and HR-MS data are provided in SI (Figures S1 and S2). Other solvents (AR grade) were obtained from Kelong Chemical Corporation, and used without further purification.…”

Section: Methodsmentioning

confidence: 99%

Renewable Sugar-Based Diols with Different Rigid Structure: Comparable Investigation on Improving Poly(butylene succinate) Performance

Duan

Dong

et al. 2015

ACS Sustainable Chem. Eng.

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In order to improve the mechanical and oxygen barrier properties of poly(butylene succinate) (PBS), two series of sugar-containing PBS copolyesters with different molecular stiffness were synthesized and comparatively investigated, in which a cyclic alditol, isosorbide (Is) or 2,3-O-isopropylidene-l-threitol (ITh) was, respectively, used as a comonomer. Both cyclic alditols were easily available from biomass feedstock, such that Is is a bicyclic compound derived from d-glucose, and ITh is a monocyclic acetalized compound coming from naturally occurring l-tartaric acid. All these copolyesters containing up to 30 mol % of sugar-based units had satisfactory number-average molecular weights in the 16 000–83 000 g mol–1 range, and presented a random microstructure together with excellent thermal stability. The sugar-containing copolyesters were all semicrystalline and still possessed the monoclinic crystal structure of PBS. The incorporation of either Is or ITh units with rigid cyclic structure into PBS chain decreased the crystallinity and crystallization rate of PBS, while it enhanced its glass transition temperature. In addition, the partial replacement of 1,4-butanediol by sugar-based units endowed PBS with steadily enhanced hydrophilicity. Depending on the type and content of sugar units, the copolyesters show different oxygen barriers and mechanical properties. It was found that copolyester with bicyclic Is sugar units exhibited a better oxygen barrier and mechanical property than that with monocyclic ITh units.

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Total synthesis of ent-calystegine B4 via nitro-Michael/aldol reaction

Cited by 5 publications

References 33 publications

Total Enantioselective Synthesis of the Endophytic Fungal Polyketide Phomolide H and Its Structural Revision

Total Enantioselective Synthesis of the Endophytic Fungal Polyketide Phomolide H and Its Structural Revision

Scalable Synthesis, In Vitro cccDNA Reduction, and In Vivo Antihepatitis B Virus Activity of a Phosphonomethoxydeoxythreosyl Adenine Prodrug

Renewable Sugar-Based Diols with Different Rigid Structure: Comparable Investigation on Improving Poly(butylene succinate) Performance

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