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Zhang J, Litke A, Keller K, Rai R, Chang CWT. Synthesis of novel aminoglycosides via allylic azide rearrangement for investigating the significance of 2′-amino group. Bioorg Med Chem 2010; 18:1396-405. [DOI: 10.1016/j.bmc.2010.01.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 01/11/2010] [Accepted: 01/12/2010] [Indexed: 10/19/2022]
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Zhang J, Keller K, Takemoto JY, Bensaci M, Litke A, Czyryca PG, Chang CWT. Synthesis and combinational antibacterial study of 5''-modified neomycin. J Antibiot (Tokyo) 2009; 62:539-44. [PMID: 19629142 PMCID: PMC2783947 DOI: 10.1038/ja.2009.66] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A library of 5″-modified neomycin derivatives were synthesized for an antibacterial structure-activity optimization strategy. Two leads exhibited prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Antibacterial activities were measured when combined with other clinically used antibiotics. Significant synergistic activities were observed which may lead to the development of novel therapeutic practices in the battle against infectious bacteria.
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Abstract
An innovative approach for manipulating glycosyltransferase-catalyzed glycosylation has now been developed (Truman et al.). Created using a domain-swapping strategy, these chimeric glycotransferases have predictable substrate specificity and may lead to the breakthrough developments in the preparation of carbohydrate-containing molecules of biological interest.
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Zhang J, Chang CWT. One-Pot Synthesis of 1- and 2-Substituted Naphtho[2,3-d][1,2,3]triazole-4,9-diones. J Org Chem 2009; 74:4414-7. [DOI: 10.1021/jo9004926] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zhang J, Chiang FI, Wu L, Czyryca PG, Li D, Chang CWT. Surprising alteration of antibacterial activity of 5"-modified neomycin against resistant bacteria. J Med Chem 2009; 51:7563-73. [PMID: 19012394 DOI: 10.1021/jm800997s] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A facile synthetic protocol for the production of neomycin B derivatives with various modifications at the 5'' position has been developed. The structural activity relationship (SAR) against aminoglycoside resistant bacteria equipped with various aminoglycoside-modifying enzymes (AMEs) was investigated. Enzymatic and molecular modeling studies reveal that the superb substrate promiscuity of AMEs allows the resistant bacteria to cope with diverse structural modifications despite the observation that several derivatives show enhanced antibacterial activity compared to the parent neomycin. Surprisingly, when testing synthetic neomycin derivatives against other human pathogens, two leads exhibit prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) that are known to exert a high level of resistance against clinically used aminoglycosides. These findings can be extremely useful in developing new aminoglycoside antibiotics against resistant bacteria. Our result also suggests that new biological and antimicrobial activities can be obtained by chemical modifications of old drugs.
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Zhang J, Chang CWT. Divergent Synthesis of Three Classes of Aryl N-Glycosides by Solvent Control. J Org Chem 2008; 74:685-95. [DOI: 10.1021/jo8020133] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lee ST, Gardner DR, Chang CWT, Panter KE, Molyneux RJ. Separation and measurement of plant alkaloid enantiomers by RP-HPLC analysis of their Fmoc-Alanine analogs. PHYTOCHEMICAL ANALYSIS : PCA 2008; 19:395-402. [PMID: 18438757 DOI: 10.1002/pca.1064] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
INTRODUCTION Ammodendrine (1), anabasine (2) and coniine (3) can cause congenital malformations in livestock. They appear naturally in both enantiomeric forms, and can cause variable physiological responses. A method to measure the enantiomeric ratio of these natural toxins is needed. OBJECTIVE To develop a simple and economical method in order to determine the enantiomeric ratios of piperidine and pyrrolidine alkaloids in small samples of plant material. METHODOLOGY Mixtures of isolated or purified plant alkaloids were converted to their Fmoc-L-Ala-alkaloid analogues forming diastereomeric mixtures, which were then analysed by high pressure liquid chromatography (HPLC) with mass spectrometry (MS) and ultraviolet (UV) detection to determine enantiomeric ratios. RESULTS The diastereomeric analogs for ammodendrine, anabasine and nornicotine could be separated and the enantiomeric ratios determined. The Fmoc-L-Ala-coniine analogue was not resolved under the HPLC conditions studied. The enantiomeric ratios of the selected plant alkaloids were measured and found to differ between both location within a species and location between species. CONCLUSION A low-cost HPLC method to analyse the enantiomeric ratio of plant alkaloids containing primary or secondary amine nitrogens via conversion to their respective diastereomeric analogues has been developed.
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Li J, Chiang FI, Chen HN, Chang CWT. Synthesis and antibacterial activity of pyranmycin derivatives with N-1 and O-6 modifications. Bioorg Med Chem 2007; 15:7711-9. [PMID: 17870543 PMCID: PMC2692305 DOI: 10.1016/j.bmc.2007.08.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 08/24/2007] [Accepted: 08/28/2007] [Indexed: 10/22/2022]
Abstract
Continuing from our ongoing effort in modifying aminoglycoside antibiotics with the goal of counteracting drug resistant bacteria, we have further derivatized pyranmycin, a neomycin class aminoglycoside antibiotic, with modifications at O-6 and N-1 positions. The revealed SAR results demonstrated that the antibacterial activity of pyranmycin can be modulated by different acylic substituents at O-6. Among these results, the 6-O-aminoethyl derivative, JT050, showed effective activity against resistant strain Escherichia coli (pTZ19U-3) and E. coli (pSF815), which provides insight into further structural modifications.
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Deng S, Gangadharmath U, Chang CWT. Sonochemistry: a powerful way of enhancing the efficiency of carbohydrate synthesis. J Org Chem 2007; 71:5179-85. [PMID: 16808504 DOI: 10.1021/jo060374w] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using sonication as a means of facilitating organic reactions in carbohydrate chemistry was explored under the conditions used for traditional organic synthesis. An array of representative reactions, including hydroxy group manipulation (acylation, protection/deprotection, acyl group migration), thioglycoside synthesis, azidoglycoside synthesis, 1,3-dipolar cycloaddition and reductive cleavage of benzylidene, commonly used in the synthesis of carbohydrate derivatives was examined. A series of glycosylation reactions that employ thioglycosides, glycosyl trichloroacetimidate, glycosyl bromide and glycosyl acetate as the glycosyl donors was also examined. Our results demonstrate that sonication can significantly shorten the reaction time, enhance the reactivity of reactant and lead to superior yield and excellent stereoselectivity. More importantly, a general protocol of glycosylation may finally be developed. Sonication is compatible to the conditions used for traditional organic synthesis. We believe that sonication can also be applied to other areas of synthetic processes.
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Li J, Chiang FI, Chen HN, Chang CWT. Investigation of the regioselectivity for the staudinger reaction and its application for the synthesis of aminoglycosides with N-1 modification. J Org Chem 2007; 72:4055-66. [PMID: 17465564 PMCID: PMC2553255 DOI: 10.1021/jo062588j] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The criteria for controlling the regioselectivity of Staudinger reduction of azides have been investigated. These findings enable a convenient direct N-1 modification of the perazidoneamine and perazidoribostamycin resulting in the synthesis of aminoglycoside antibiotics with activity against drug-resistant bacteria.
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Zhang J, Chen HN, Chiang FI, Takemoto JY, Bensaci M, Chang CWT. Sonication-Assisted Library Synthesis of Oxazolidinone−Carbohydrate Conjugates. ACTA ACUST UNITED AC 2006; 9:17-9. [PMID: 17206828 DOI: 10.1021/cc060146f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Li J, Tom Chang CW. Recent Developments in the Synthesis of Novel Aminoglycoside Antibiotics. ACTA ACUST UNITED AC 2006. [DOI: 10.2174/187152106777697844] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Lee ST, Wildeboer K, Panter KE, Kem WR, Gardner DR, Molyneux RJ, Chang CWT, Soti F, Pfister JA. Relative toxicities and neuromuscular nicotinic receptor agonistic potencies of anabasine enantiomers and anabaseine. Neurotoxicol Teratol 2006; 28:220-8. [PMID: 16488116 DOI: 10.1016/j.ntt.2005.12.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 12/14/2005] [Accepted: 12/15/2005] [Indexed: 11/16/2022]
Abstract
Anabasine occurring in wild tree tobacco (Nicotiana glauca) and anabaseine occurring in certain animal venoms are nicotinic receptor agonist toxins. Anabasine lacks the imine double bond of anabaseine; the two possible enantiomers of anabasine occur in N. glauca. A comparision of the relative potencies of S- and R-anabasine has not been previously reported. We separated the enantiomers of anabasine by reaction of the racemic N. glauca natural product with 9-fluorenylmethoxycarbonyl-L-alanine (Fmoc-L-Ala-OH) to give diastereomers, which were separated by preparative reversed phase HPLC. The S- and R-anabasine enantiomer fractions were then obtained by Edman degradation. A mouse bioassay was used to determine the relative lethalities of S- and R-enriched anabasine enantiomers. The intravenous LD50 of the (+)-R-anabasine rich fraction was 11 +/- 1.0 mg/kg and that of the (-)-S-anabasine-rich fraction was 16 +/- 1.0 mg/kg. The LD50 of anabaseine was 0.58 +/- 0.05 mg/kg. Anabaseine was significantly more toxic in the mouse bioassay than S-anabasine (27-fold) and R-anabasine (18-fold). The relative agonistic potencies of these three alkaloids on human fetal nicotinic neuromuscular receptors were of the same rank order: anabaseine>>R-anabasine>S-anabasine.
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Rai R, Chen HN, Czyryca PG, Li J, Chang CWT. Design and Synthesis of Pyrankacin: A Pyranmycin Class of Broad-Spectrum Aminoglycoside Antibiotic. Org Lett 2006; 8:887-9. [PMID: 16494466 DOI: 10.1021/ol0529750] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel broad-spectrum aminoglycoside antibiotic, pyrankacin, has been prepared. In addition to the synthetic innovation in dideoxygenation and regioselective Staudinger reduction, we have obtained prominent antibacterial activity against several clinically important pathogens in the course of this work.
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Chang CWT, Deng S. Cesium Trifluoroacetate or Silver Oxide Mediated Acyl Migration for the Construction of Disaccharide Building Blocks. Synlett 2006. [DOI: 10.1055/s-2006-933105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Wang J, Li J, Chen HN, Chang H, Tanifum CT, Liu HH, Czyryca PG, Chang CWT. Glycodiversification for the Optimization of the Kanamycin Class Aminoglycosides. J Med Chem 2005; 48:6271-85. [PMID: 16190754 DOI: 10.1021/jm050368c] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In an effort to optimize the antibacterial activity of kanamycin class aminoglycoside antibiotics, we have accomplished the synthesis and antibacterial assay of new kanamycin B analogues. A rationale-based glycodiversification strategy was employed. The activity of the lead is comparable to that of commercially available kanamycin. These new members, however, were found to be inactive against aminoglycoside resistant bacteria. Molecular modeling was used to provide the explanation. Thus, a new strategy for structural modifications of kanamycin class aminoglycosides is suggested.
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Rai R, McAlexander I, Chang CWT. SYNTHETIC GLYCODIVERSIFICATION. FROM AMINOSUGARS TO AMINOGLYCOSIDE ANTIBIOTICS. A REVIEW. ORG PREP PROCED INT 2005. [DOI: 10.1080/00304940509354969] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Li J, Chen HN, Chang H, Wang J, Chang CWT. Tuning the Regioselectivity of the Staudinger Reaction for the Facile Synthesis of Kanamycin and Neomycin Class Antibiotics with N-1 Modification. Org Lett 2005; 7:3061-4. [PMID: 15987205 DOI: 10.1021/ol051045d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] A novel method for achieving the desired regioselective reduction of the N-1 azido group on a tetraazidoneamine has been developed that leads to the synthesis of both kanamycin and neomycin class antibiotics bearing N-1 modification. Both classes of aminoglycosides are active against aminoglycoside-resistant bacteria carrying APH(3')-I and AAC(6')/APH(2'').
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Wang J, Elchert B, Hui Y, Takemoto JY, Bensaci M, Wennergren J, Chang H, Rai R, Chang CWT. Synthesis of trehalose-based compounds and their inhibitory activities against Mycobacterium smegmatis. Bioorg Med Chem 2005; 12:6397-413. [PMID: 15556758 DOI: 10.1016/j.bmc.2004.09.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 09/17/2004] [Accepted: 09/17/2004] [Indexed: 11/18/2022]
Abstract
The synthesis of a library of trehalose-based compounds has been accomplished, and their activities against Mycobacterium smegmatis have been determined. A preliminary structure-activity relationship (SAR) is reported. Despite not having a potent lead, one of the trehalose derivatives displays strong activity when applied with isoniazid (INH), which is known to have low sterilizing activity. The bacteriocidal nature of our compounds against Mycobacterium may be significant for the development of new therapies against tuberculosis.
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Lee ST, Molyneux RJ, Panter KE, Chang CWT, Gardner DR, Pfister JA, Garrossian M. Ammodendrine and N-methylammodendrine enantiomers: isolation, optical rotation, and toxicity. JOURNAL OF NATURAL PRODUCTS 2005; 68:681-5. [PMID: 15921409 DOI: 10.1021/np0580199] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Ammodendrine (1) was found to occur as a mixture of enantiomers in two different collections of plants identified as Lupinus formosus. The ammodendrine fraction was reacted in a peptide coupling reaction with 9-fluorenylmethoxycarbonyl-L-alanine (Fmoc-L-Ala-OH) to give diastereomers, which were separated by preparative HPLC. The pure D- and L-ammodendrine enantiomers were then obtained by Edman degradation. Optical rotation measurements revealed that the D- and L-enantiomers had optical rotations of [alpha]24D +5.4 and -5.7, respectively. D- and L-N-methylammodendrine enantiomers were synthesized from the corresponding ammodendrine enantiomers, and their optical rotations established as [alpha]23D +62.4 and -59.0, respectively. A mouse bioassay was used to determine the difference in toxicity between these two pairs of naturally occurring enantiomers. The LD50 of (+)-D-ammodendrine in mice was determined to be 94.1 +/- 7 mg/kg and that of (-)-L-ammodendrine as 115.0 +/- 7 mg/kg. The LD50 of (+)-D-N-methylammodendrine in mice was estimated to be 56.3 mg/kg, while that of (-)-L-N-methylammodendrine was determined to be 63.4 +/- 5 mg/kg. These results establish the rotation values for pure ammodendrine and N-methylammodendrine and indicate that there is little difference in acute murine toxicity between the respective enantiomers.
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Li J, Wang J, Czyryca PG, Chang H, Orsak TW, Evanson R, Chang CWT. Application of glycodiversification: expedient synthesis and antibacterial evaluation of a library of kanamycin B analogues. Org Lett 2004; 6:1381-4. [PMID: 15101747 DOI: 10.1021/ol0497685] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The expedient synthesis of a library of kanamycin B analogues is reported. The revealed SAR will guide future designs in developing kanamycin-type aminoglycoside antibiotics against drug-resistant bacteria.
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Wang J, Li J, Czyryca PG, Chang H, Kao J, Chang CWT. Synthesis of an unusual branched-chain sugar, 5-C-methyl-l-idopyranose for SAR studies of pyranmycins: implication for the future design of aminoglycoside antibiotics. Bioorg Med Chem Lett 2004; 14:4389-93. [PMID: 15357959 DOI: 10.1016/j.bmcl.2004.06.064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Revised: 06/19/2004] [Accepted: 06/21/2004] [Indexed: 10/26/2022]
Abstract
The syntheses of a challenging branched-chain sugar and several L-sugars have been accomplished. Their application in studies of the antibacterial activity of pyranmycins is reported, which could provide new strategies for the future design of aminoglycoside antibiotics.
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Elchert B, Li J, Wang J, Hui Y, Rai R, Ptak R, Ward P, Takemoto JY, Bensaci M, Chang CWT. Application of the synthetic aminosugars for glycodiversification: synthesis and antimicrobial studies of pyranmycin. J Org Chem 2004; 69:1513-23. [PMID: 14987005 DOI: 10.1021/jo035290r] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A divergent approach was employed for the synthesis of aminosugars, from which a novel library of aminoglycoside antibiotics (pyranmycins) was synthesized. Pyranmycins have comparable antibacterial activity as neomycin, a clinically used aminoglycoside antibiotic, against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Mycobacterium smegmatis. In addition, pyranmycins, like streptomycin, are bacteriocidal while isoniazid (INH) is bacteriostatic. Therefore, pyranmycins may provide new therapeutic options in the treatment against tuberculosis. Several members of pyranmycins also manifest modest anti-Tat and anti-Rev activities, which may aid in the development of new anti-HIV agents. Although the antibacterial activity of pyranmycins against aminoglycoside resistant bacteria is less than expected, the synthetic methodologies of utilizing a library of aminosugars can be a model for future studies of glycodiversification or glycorandomization.
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Li J, Wang J, Hui Y, Chang CWT. Exploring the optimal site for modifications of pyranmycins with the extended arm approach. Org Lett 2003; 5:431-4. [PMID: 12583736 DOI: 10.1021/ol027288c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] Continuing from the syntheses and the antibacterial studies of a library of pyranmycins, we further probed the proximity around ring III of pyranmycin by introducing an "extended arm" that has hydroxyethyl or aminoethyl groups at the O-2' ', O-3' ', or O-4' ' positions. The results from the antibacterial studies reveal the optimal structural motif is the attachment of an extended arm with a terminal hydroxyl group at the O-3' ' position.
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Chang CWT, Hui Y, Elchert B, Wang J, Li J, Rai R. Pyranmycins, a novel class of aminoglycosides with improved acid stability: the SAR of D-pyranoses on ring III of pyranmycin. Org Lett 2002; 4:4603-6. [PMID: 12489940 DOI: 10.1021/ol0269042] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The synthesis of a novel class of aminoglycosides, pyranmycins, is reported along with the structure activity relationship (SAR) of their antibacterial activity against Escherichia coli. Two pyranmycins show prominent activity (9 microM). Pyranmycins also manifest superior stability in acidic media. The SAR information will lead to the future designs of pyranmycin against drug resistant bacteria.
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