Stereoselective synthesis of (S)-oxiracetam and (S)-GABOB from (R)-glyceraldehyde acetonide

Sanyal, Ishita; Shukla, Brajesh Kumar; Barman, Piyali Deb; Banerjee, Anindyajit

doi:10.1016/j.tetlet.2013.03.035

Cited by 13 publications

(14 citation statements)

References 43 publications

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“…We comment on the recent paper by Sanyal et al (2013) in Microbiology describing how the ppk1 gene of Mycobacterium tuberculosis plays a crucial role in stress responses by integrating a pair of two component signalling pathways encoded by senX3-regX3 (regulating phosphate import) and mprAB (ultimately controlling transcription of the stringent response regulator rel). Contrary to the widely held belief that bacteria express just one or two polyphosphate kinases (PPKs), namely PPK1 or PPK2, evidence is presented that PPK1 and 2 are present together in less than half of taxa and that a third of taxa have neither enzyme.…”

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

“…There is no PPK1 in about 40 % of taxa. Consequently, the important mechanism described by Sanyal et al (2013) could have profound significance for other bacterial diseases. It adds urgency to the need to identify those unknown enzymes responsible for synthesizing polyphosphate (poly P) in the sizeable minority of bacteria that lack both PPK1 and PPK2.…”

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

“…We propose that the actin-like Arp proteins with PPK activity first identified by Kornberg's group (Gó mez-García & Kornberg, 2004), and with distant homologues in bacteria, may be early PPKs with continued activity in modern bacteria, particularly those that lack PPK1 and PPK2. In view of the crucial role of PPK1 in determining pathogenic responses in M. tuberculosis shown by Sanyal et al (2013), the possible existence of other, unknown enzymes responsible for the synthesis of poly P in many bacterial species requires pressing investigation. Sanyal et al (2013) recently described in M. how the ppk1 gene of M. tuberculosis plays a crucial role in stress responses by integrating a pair of two component signalling pathways encoded by senX3-regX3 (regulating phosphate import) and mprAB (ultimately controlling transcription of the stringent response regulator rel).…”

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

“…In view of the crucial role of PPK1 in determining pathogenic responses in M. tuberculosis shown by Sanyal et al (2013), the possible existence of other, unknown enzymes responsible for the synthesis of poly P in many bacterial species requires pressing investigation. Sanyal et al (2013) recently described in M. how the ppk1 gene of M. tuberculosis plays a crucial role in stress responses by integrating a pair of two component signalling pathways encoded by senX3-regX3 (regulating phosphate import) and mprAB (ultimately controlling transcription of the stringent response regulator rel). Hence, PPK1 represents an essential determinant of pathogenicity by regulating the supply of phosphate groups for the activation of signalling pathways.…”

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

“…Consequently, the important mechanism described by Sanyal et al (2013) could have profound significance for other bacterial diseases. We have tested the widespread assumption of the universal distribution of PPK1 and/or PPK2 in bacteria.…”

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

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Most bacteria synthesize polyphosphate by unknown mechanisms

et al. 2014

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Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

Section: Most Bacteria Synthesize Polyphosphate By Unknown Mechanismsmentioning

confidence: 99%

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Most bacteria synthesize polyphosphate by unknown mechanisms

et al. 2014

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Effect of L‐oxiracetam and oxiracetam on memory and cognitive impairment in mild‐to‐moderate traumatic brain injury patients: Study protocol for a randomized controlled trial

Liu,

Nie

et al. 2024

Aging Medicine

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ObjectivesPatients with traumatic brain injury (TBI) often suffer memory and cognitive impairments, and oxiracetam‐like drugs are considered to have a positive impact on these symptoms potentially. However, the efficacy and safety of L‐oxiracetam and oxiracetam in TBI patients have not been sufficiently investigated.MethodsThe study adopts a multicenter, randomized, double‐blind, parallel‐group, phase 3 clinical trial design in 74 centers across 51 hospitals in China. A total of 590 TBI patients meeting criteria will be randomly allocated into three groups in a 2:2:1 ratio: L‐oxiracetam group, oxiracetam group, and placebo group. The treatment period is 14 days, with a follow‐up period of 90 days. The primary outcome measure is the change in the Loewenstein Occupational Therapy Cognitive Assessment score at 90 days after treatment. Secondary outcomes include changes in other cognitive assessments, neurological function, activities of daily living, and safety assessments.DiscussionThere is no robust evidence to suggest that L‐oxiracetam and oxiracetam can enhance memory and cognitive function in patients with mild to moderate TBI. This study has the potential to answer this crucial clinical question.Trial registrationchinadrugtrials.org.cn, identifier CTR20192539; ClinicalTrials.gov, identifier NCT04205565.

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The Total Synthesis of Inostamycin A

Jung

Lee

et al. 2016

Angewandte Chemie

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The first total synthesis of inostamycin Ai s described. With efficient and stereoselective synthetic routes to aldehyde 3 and ketone 4 developed through asymmetric aldol reactions,a ddition reactions and reduction, and with chiral building blocks,t he two large fragments were coupled with remarkable anti stereoselectivity and efficiency by aldol condensation. The coupling reaction provided the complete carbon skeleton with all the requisite functional groups and stereogenic centers for inostamycin A. The two quaternary carbons at C20 and C16 of ketone 4 were elaborated in ahighly stereocontrolled manner by addition reactions of the transmetallated 5 to ethyl ketone 6 and the transmetallated 7 to methyl ketone 8,r espectively,i nw hicht he use of LaCl 3 for transmetallation was critical for high coupling efficiency.Inostamycin Awas isolated from the fermentation broth of Streptomyces sp.M H816-AF15 in 1990.[1] Its structure was first assigned by NMR spectroscopy and later confirmed by X-ray analysis of its sodium salt to manifest the relative stereochemistry.T he crystal structure of the sodium salt showed an ionophoric pseudo cyclic molecular shape,i n which the sodium cation coordinates to the two carboxylate oxygens,t he two hydroxyl oxygens at C9 and C17, the carbonyl oxygen, and the inner tetrahydrofuranyl oxygen.[1]Scrutiny of the reported crystal structure allowed us to identify am istakenly translated stereochemistry of the ethyl group at the C2 position. Accordingly,t he relative stereochemistry of inostamycin As hould be revised from 1 to 2 (Figure 1). Ther elated compounds,i nostamycins Ba nd C, were separated from the same microorganism af ew years later, and the structures were differentiated by aC 2m ethyl substituent and am issing carboxylic acid group,r espectively.[2] It is likely that the C2 stereochemistry of inostamycin Bs hould also be corrected. Inostamycins are known to display antimicrobial and cytocidal activities,w ith inostamycin As howing the highest potency.[2] Only inostamycin A exhibits inhibitory activity against cytidine-5'-d iphosphate 1,2-diacyl-sn-glycerol (CDP-DG):inositol transferase to reduce phosphatidylinositol turnover, and restrain cell proliferation and transformation.[3a] Other prospective physiological properties of inostamycin Ai nclude restoration of paclitaxel cytotoxicity to augment apoptosis, [5] and cytostatic suppression of tumor recurrence.[3b] Thes tructural complexity,anticancer agents from multidrug resistance, [4] and potentiation of and pharmacological potential of inostamycin A attracted us to attempt its synthesis.H erein, we describe the first total synthesis of inostamycin A 2.[6]Our retrosynthetic blueprint was framed by severing the C9 À C10 bond of 2 to engender the aldehyde part 3 and the ethyl ketone part 4 (Scheme 1). Forsynthesis of 3,weplanned to cleave the C2 À C3 and C5 À C6 bonds,w hich would be restored with the four stereogenic centers by aldol condensations.T he remaining asymmetric centers were to be supplied by two enantiome...

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Stereoselective synthesis of (S)-oxiracetam and (S)-GABOB from (R)-glyceraldehyde acetonide

Cited by 13 publications

References 43 publications

Most bacteria synthesize polyphosphate by unknown mechanisms

Most bacteria synthesize polyphosphate by unknown mechanisms

Effect of L‐oxiracetam and oxiracetam on memory and cognitive impairment in mild‐to‐moderate traumatic brain injury patients: Study protocol for a randomized controlled trial

The Total Synthesis of Inostamycin A

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