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Robert Southgate - One of the best experts on this subject based on the ideXlab platform.
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Olivanic Acid analogues part 10 x ray crystallographic study of the stereochemistry of some 7 heteroatom substituted 7 acetyl 8 oxo 3 oxa 1 azabicyclo 4 2 0 octane 2 spirocyclohexanes functional group control of the stereoselectivity of their reducti
Journal of The Chemical Society-perkin Transactions 1, 1992Co-Authors: John H Bateson, Robert Southgate, Stephen Christopher Martin Fell, Drake S Eggleston, Paul W BauresAbstract:(6RS, 7SR)-7-Acetyl-7-azido-8-oxo-3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane 3 was obtained by reaction of mesyl azide with the trans-ketone 2 in the presence of aqueous base, and the stereochemistry of its major sodium borohydride reduction product, (6RS,7SR,9SR)-7-azido-7-(1-hydroxyethyl)-8-oxo-3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane 4, was determined by X-ray crystallography. X-Ray studies of the keto sulfide 17 and the chloro ketone 20 confirmed their (6RS,7SR) relative stereochemistry. Reduction of 17 gave the alcohol 18 also with (6RS,7SR,9SR) stereochemistry. In contrast, reduction of 20 with trialkylborohydride reagents gave the (6RS,7SR,9RS)-chloro alcohol 21, and a mechanism is proposed to account for this reversal of C-9 stereoselectivity.
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Olivanic Acid analogues part 11 ozonolysis of α ethylideneazetidinones ozonide fragmentation to α amino Acid n carboxyanhydrides
Journal of The Chemical Society-perkin Transactions 1, 1992Co-Authors: John H Bateson, Stephen Christopher Martin Fell, Arun C Kaura, Robert SouthgateAbstract:Ozonolysis of (E)-7-ethylidene[3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexan]-8-one failed to provide the α-oxoazetidinone 2, but afforded an α-amino Acid-N-carboxyanhydride [3,8-dioxa-1-azabicyclo[4.3.0]nonane-2-spirocyclohexane]-7,9-dione 5. [3-Oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane]-7,8-dione 2 was instead obtained from the trans-ketone 9 by a sequence involving Baeyer–Villiger oxidation of the azido ketone 10.
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Olivanic Acid analogues part 9 allylic oxidative functionalisation of substituted azetidinones synthesis of some 4 acyloxy 7 oxo 1 azabicyclo 3 2 0 hept 2 ene 2 carboxylates
Journal of The Chemical Society-perkin Transactions 1, 1991Co-Authors: John H Bateson, Alison M Robins, Robert SouthgateAbstract:Sharpless oxidation (ButO2H, SeO2) of the protected allyl azetidinone 7 gave the allylic alcohol 8 which was transformed to the 5,6-trans-4α-acetoxyOlivanic Acid derivative 16. Kharasch–Sosnovsky benzoyloxylation (PhCO3But, CuCl, PhH, heat) of the silylated 7-azabicyclo[4.2.0]oct-3-enes 17b,c provided inter alia allylic benzoates 18b,c and 21b,c. These were synthetic precursors of the 5,6-cis-Olivanic Acid analogues 23 and 26, which contain 8- and 4α-benzoyloxy groups, respectively.
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Olivanic Acid analogues part 8 halogenation and sulphenylation reactions leading selectively to cis carbapenem precursors stereospecific synthesis of 6 epithienamycin
Journal of The Chemical Society-perkin Transactions 1, 1991Co-Authors: John H Bateson, Alison M Robins, Robert SouthgateAbstract:Introduction of halogen or sulphenyl substituents at C-7 of ketone 1, followed by stereospecific reduction steps, provides a selective route either to the (6RS,7RS,9RS) isomer 11 or to the (6RS, 7RS, 9SR) isomer 14 of 7-(1-hydroxyethyl)-8-oxo-3-oxa-1-azabicylo[4.2.0]octane-2-spirocyclohexane. The synthetic utility of chloride 6 is illustrated by its transformation to (±)-6-epithienamycin 25, and to the C-6 epimers of a (±)-6-chloroOlivanic Acid analogue 39.
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Olivanic Acid analogues vi biomimetic synthesis of ps 5 6 epi ps 5 and benzyl mm22381
Journal of The Chemical Society-perkin Transactions 1, 1990Co-Authors: John H Bateson, R I Hickling, Terence C Smale, Robert SouthgateAbstract:Michael addition of thiols to 6-substituted azabicyclo[3.2.0]hept-2-ene-2-carboxylates, followed by reintroduction of the double bond with iodobenzene dichloride-pyridine under anhydrous conditions, provides a biomimetic strategy for the synthesis of 3-alkylthio-substituted Olivanic Acids (carbapenems) and their derivatives. This is illustrated by syntheses of representatives of the PS-5 and MM22381 series of antibacterial natural products
John H Bateson - One of the best experts on this subject based on the ideXlab platform.
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Olivanic Acid analogues part 10 x ray crystallographic study of the stereochemistry of some 7 heteroatom substituted 7 acetyl 8 oxo 3 oxa 1 azabicyclo 4 2 0 octane 2 spirocyclohexanes functional group control of the stereoselectivity of their reducti
Journal of The Chemical Society-perkin Transactions 1, 1992Co-Authors: John H Bateson, Robert Southgate, Stephen Christopher Martin Fell, Drake S Eggleston, Paul W BauresAbstract:(6RS, 7SR)-7-Acetyl-7-azido-8-oxo-3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane 3 was obtained by reaction of mesyl azide with the trans-ketone 2 in the presence of aqueous base, and the stereochemistry of its major sodium borohydride reduction product, (6RS,7SR,9SR)-7-azido-7-(1-hydroxyethyl)-8-oxo-3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane 4, was determined by X-ray crystallography. X-Ray studies of the keto sulfide 17 and the chloro ketone 20 confirmed their (6RS,7SR) relative stereochemistry. Reduction of 17 gave the alcohol 18 also with (6RS,7SR,9SR) stereochemistry. In contrast, reduction of 20 with trialkylborohydride reagents gave the (6RS,7SR,9RS)-chloro alcohol 21, and a mechanism is proposed to account for this reversal of C-9 stereoselectivity.
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Olivanic Acid analogues part 11 ozonolysis of α ethylideneazetidinones ozonide fragmentation to α amino Acid n carboxyanhydrides
Journal of The Chemical Society-perkin Transactions 1, 1992Co-Authors: John H Bateson, Stephen Christopher Martin Fell, Arun C Kaura, Robert SouthgateAbstract:Ozonolysis of (E)-7-ethylidene[3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexan]-8-one failed to provide the α-oxoazetidinone 2, but afforded an α-amino Acid-N-carboxyanhydride [3,8-dioxa-1-azabicyclo[4.3.0]nonane-2-spirocyclohexane]-7,9-dione 5. [3-Oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane]-7,8-dione 2 was instead obtained from the trans-ketone 9 by a sequence involving Baeyer–Villiger oxidation of the azido ketone 10.
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Olivanic Acid analogues part 9 allylic oxidative functionalisation of substituted azetidinones synthesis of some 4 acyloxy 7 oxo 1 azabicyclo 3 2 0 hept 2 ene 2 carboxylates
Journal of The Chemical Society-perkin Transactions 1, 1991Co-Authors: John H Bateson, Alison M Robins, Robert SouthgateAbstract:Sharpless oxidation (ButO2H, SeO2) of the protected allyl azetidinone 7 gave the allylic alcohol 8 which was transformed to the 5,6-trans-4α-acetoxyOlivanic Acid derivative 16. Kharasch–Sosnovsky benzoyloxylation (PhCO3But, CuCl, PhH, heat) of the silylated 7-azabicyclo[4.2.0]oct-3-enes 17b,c provided inter alia allylic benzoates 18b,c and 21b,c. These were synthetic precursors of the 5,6-cis-Olivanic Acid analogues 23 and 26, which contain 8- and 4α-benzoyloxy groups, respectively.
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Olivanic Acid analogues part 8 halogenation and sulphenylation reactions leading selectively to cis carbapenem precursors stereospecific synthesis of 6 epithienamycin
Journal of The Chemical Society-perkin Transactions 1, 1991Co-Authors: John H Bateson, Alison M Robins, Robert SouthgateAbstract:Introduction of halogen or sulphenyl substituents at C-7 of ketone 1, followed by stereospecific reduction steps, provides a selective route either to the (6RS,7RS,9RS) isomer 11 or to the (6RS, 7RS, 9SR) isomer 14 of 7-(1-hydroxyethyl)-8-oxo-3-oxa-1-azabicylo[4.2.0]octane-2-spirocyclohexane. The synthetic utility of chloride 6 is illustrated by its transformation to (±)-6-epithienamycin 25, and to the C-6 epimers of a (±)-6-chloroOlivanic Acid analogue 39.
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Olivanic Acid analogues vi biomimetic synthesis of ps 5 6 epi ps 5 and benzyl mm22381
Journal of The Chemical Society-perkin Transactions 1, 1990Co-Authors: John H Bateson, R I Hickling, Terence C Smale, Robert SouthgateAbstract:Michael addition of thiols to 6-substituted azabicyclo[3.2.0]hept-2-ene-2-carboxylates, followed by reintroduction of the double bond with iodobenzene dichloride-pyridine under anhydrous conditions, provides a biomimetic strategy for the synthesis of 3-alkylthio-substituted Olivanic Acids (carbapenems) and their derivatives. This is illustrated by syntheses of representatives of the PS-5 and MM22381 series of antibacterial natural products
Stephen Christopher Martin Fell - One of the best experts on this subject based on the ideXlab platform.
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Olivanic Acid analogues part 11 ozonolysis of α ethylideneazetidinones ozonide fragmentation to α amino Acid n carboxyanhydrides
Journal of The Chemical Society-perkin Transactions 1, 1992Co-Authors: John H Bateson, Stephen Christopher Martin Fell, Arun C Kaura, Robert SouthgateAbstract:Ozonolysis of (E)-7-ethylidene[3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexan]-8-one failed to provide the α-oxoazetidinone 2, but afforded an α-amino Acid-N-carboxyanhydride [3,8-dioxa-1-azabicyclo[4.3.0]nonane-2-spirocyclohexane]-7,9-dione 5. [3-Oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane]-7,8-dione 2 was instead obtained from the trans-ketone 9 by a sequence involving Baeyer–Villiger oxidation of the azido ketone 10.
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Olivanic Acid analogues part 10 x ray crystallographic study of the stereochemistry of some 7 heteroatom substituted 7 acetyl 8 oxo 3 oxa 1 azabicyclo 4 2 0 octane 2 spirocyclohexanes functional group control of the stereoselectivity of their reducti
Journal of The Chemical Society-perkin Transactions 1, 1992Co-Authors: John H Bateson, Robert Southgate, Stephen Christopher Martin Fell, Drake S Eggleston, Paul W BauresAbstract:(6RS, 7SR)-7-Acetyl-7-azido-8-oxo-3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane 3 was obtained by reaction of mesyl azide with the trans-ketone 2 in the presence of aqueous base, and the stereochemistry of its major sodium borohydride reduction product, (6RS,7SR,9SR)-7-azido-7-(1-hydroxyethyl)-8-oxo-3-oxa-1-azabicyclo[4.2.0]octane-2-spirocyclohexane 4, was determined by X-ray crystallography. X-Ray studies of the keto sulfide 17 and the chloro ketone 20 confirmed their (6RS,7SR) relative stereochemistry. Reduction of 17 gave the alcohol 18 also with (6RS,7SR,9SR) stereochemistry. In contrast, reduction of 20 with trialkylborohydride reagents gave the (6RS,7SR,9RS)-chloro alcohol 21, and a mechanism is proposed to account for this reversal of C-9 stereoselectivity.
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Olivanic Acid analogues part 7 lead tetra acetate oxidation of 3 alkylthio 7 oxo 1 azabicyclo 3 2 0 heptane 2 carboxylates
Journal of The Chemical Society-perkin Transactions 1, 1990Co-Authors: John H Bateson, Robert Southgate, Stephen Christopher Martin Fell, John W TylerAbstract:Lead tetra-acetate oxidation of alkylthiocarbapenams (2)–(4) gave α-acetoxy sulphides (5)–(7) with inversion of stereochemistry, Iodosobenzene diacetate was also an effective oxidant. Oxidation to sulphone and elimination of alkanesulphinic Acid provided the 3-acetoxy-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate system (13). Alternatively, elimination of acetic Acid from compounds (5) or (6) with DBU furnished a new route to alkylthiocarbapenems.
C K M Tripathi - One of the best experts on this subject based on the ideXlab platform.
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Antimicrobial activities of microbial strains isolated from soil of stressed ecological niches of Eastern Uttar Pradesh, India
Indian Journal of Experimental Biology, 2009Co-Authors: Vineeta Singh, Vandana Praveen, Jaspreet Banga, C K M TripathiAbstract:Antimicrobial activities of twenty bacterial strains isolated from ten different stressed agro-ecological niches of Eastern Uttar Pradesh, India were evaluated against bacteria, yeasts and molds. Eleven isolates showing strong antimicrobial activities were characterized. Eight antifungal compounds were purified and partially characterized by Ultra-Violet (UV) absorption spectra and grouped into polyenes and non-polyenes. Antibacterial metabolites produced by four isolates were purified and chemically characterized, of which one isolate (AB) produced a new form of Olivanic Acid, and other three isolates (C5, Py and M4) produced antibacterial compounds having phenoxazone nucleus.
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production and statistical optimization of a novel Olivanic Acid by streptomyces olivaceus mtcc 6820
Process Biochemistry, 2008Co-Authors: Vineeta Singh, C K M TripathiAbstract:Abstract A microbial strain, isolated from soil samples, characterized as Streptomyces olivaceus MTCC 6820 showed broad-spectrum antibacterial activity. The compound produced was chemically characterized as a new form of Olivanic Acid. Olivanic Acid production was optimized statistically by Plackett-Burman design (PBD) and response surface methodology (RSM). Effects of soybean meal, glycerol, CaCO3 and dl -alanine were investigated with the help of PBD. The individual and interaction effects of the studied variables were evaluated by RSM using central composite design (CCD). By applying statistical design, antibiotic production was enhanced nearly 8 times (415 mg/l) as compared with the normal production medium (50 mg/l).
Vineeta Singh - One of the best experts on this subject based on the ideXlab platform.
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Olivanic Acid production in fed batch cultivation by streptomyces olivaceus mtcc 6820
2011Co-Authors: Vineeta SinghAbstract:Olivanic Acids, a compound of β lactum class have been studied due to their β-lactamases inhibiting nature. Effect of different medium components on Olivanic Acid (OA) production was evaluated by a soil isolated strain, Streptomyc es olivaceus MTCC 6820 in batch cultivations with glycerol (1.5%) and soybean meal (2%) as a carbon and nitrogen source. Production of Olivanic Acid was found to be maximum (50 mg/L) at the third day of batch fermentation. However the Olivanic Acid production was increased nearly eleven ti mes (565 mg/L) with sustained production up to ten days in fed batch cultivations under glycerol limiting conditions . Present work investigate the best experimental conditions for the Olivanic Acid production in terms of selection of feeding material and feeding time in fed batch fermentations. Results suggest that low supplementation of glycerol (2%) provides significantly higher Olivanic Acid production in comparison to other examined conditions.
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Antimicrobial activities of microbial strains isolated from soil of stressed ecological niches of Eastern Uttar Pradesh, India
Indian Journal of Experimental Biology, 2009Co-Authors: Vineeta Singh, Vandana Praveen, Jaspreet Banga, C K M TripathiAbstract:Antimicrobial activities of twenty bacterial strains isolated from ten different stressed agro-ecological niches of Eastern Uttar Pradesh, India were evaluated against bacteria, yeasts and molds. Eleven isolates showing strong antimicrobial activities were characterized. Eight antifungal compounds were purified and partially characterized by Ultra-Violet (UV) absorption spectra and grouped into polyenes and non-polyenes. Antibacterial metabolites produced by four isolates were purified and chemically characterized, of which one isolate (AB) produced a new form of Olivanic Acid, and other three isolates (C5, Py and M4) produced antibacterial compounds having phenoxazone nucleus.
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production and statistical optimization of a novel Olivanic Acid by streptomyces olivaceus mtcc 6820
Process Biochemistry, 2008Co-Authors: Vineeta Singh, C K M TripathiAbstract:Abstract A microbial strain, isolated from soil samples, characterized as Streptomyces olivaceus MTCC 6820 showed broad-spectrum antibacterial activity. The compound produced was chemically characterized as a new form of Olivanic Acid. Olivanic Acid production was optimized statistically by Plackett-Burman design (PBD) and response surface methodology (RSM). Effects of soybean meal, glycerol, CaCO3 and dl -alanine were investigated with the help of PBD. The individual and interaction effects of the studied variables were evaluated by RSM using central composite design (CCD). By applying statistical design, antibiotic production was enhanced nearly 8 times (415 mg/l) as compared with the normal production medium (50 mg/l).
