Protecting-group-free enantioselective tandem allylic substitution of o-phenylenediamines and o-aminophenols

A practical and concise total synthesis of tricyclic ketone 7 (CDE ring), a valuable intermediate for the synthesis of racemic camptothecin and analogs, was described (8 chemical steps and 29% overall yield). The synthesis starts with two inexpensive, readily available materials and is operationally simple to perform. It is worth mentioning that the reported protecting group-free synthesis, with advantages of a short route, would be helpful for the future development of industry-scale syntheses of camptothecin-family alkaloids.

Download Full-text

Fluoroquinolone-3-carboxamide Amino Acid Conjugates: Synthesis, Antibacterial Properties And Molecular Modeling Studies

Medicinal Chemistry ◽

10.2174/1573406415666190904143852 ◽

2020 ◽

Vol 17 (1) ◽

pp. 71-84

Author(s):

Riham M. Bokhtia ◽

Siva S. Panda ◽

Adel S. Girgis ◽

Hitesh H. Honkanadavar ◽

Tarek S. Ibrahim ◽

...

Keyword(s):

Experimental Data ◽

Antibacterial Activity ◽

Amino Acid ◽

Bacterial Infections ◽

Antibacterial Agents ◽

Antibacterial Properties ◽

Computational Studies ◽

Protecting Group ◽

Amino Acid Conjugates ◽

Molecular Modeling Studies

Background: Bacterial infections are considered as one of the major global health threats, so it is very essential to design and develop new antibacterial agents to overcome the drawbacks of existing antibacterial agents. Method: The aim of this work is to synthesize a series of new fluoroquinolone-3-carboxamide amino acid conjugates by molecular hybridization. We utilized benzotriazole chemistry to synthesize the desired hybrid conjugates. Result: All the conjugates were synthesized in good yields, characterized, evaluated for their antibacterial activity. The compounds were screened for their antibacterial activity using methods adapted from the Clinical and Laboratory Standards Institute. Synthesized conjugates were tested for activity against medically relevant pathogens; Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27856) Staphylococcus aureus (ATCC 25923) and Enterococcus faecalis (ATCC 19433). Conclusion: The observed antibacterial experimental data indicates the selectivity of our synthesized conjugates against E.Coli. The protecting group on amino acids decreases the antibacterial activity. The synthesized conjugates are non-toxic to the normal cell lines. The experimental data were supported by computational studies.

Download Full-text

Synthesis of (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(Carboxymethyl)]oxime, New Hapten for Dihydrotestosterone (17β-hydroxy-5α-androstan-3-one)

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19971642 ◽

1997 ◽

Vol 62 (10) ◽

pp. 1642-1649 ◽

Cited By ~ 2

Author(s):

Ivan Černý ◽

Tereza Slavíková ◽

Vladimír Pouzar

Keyword(s):

Hydroxy Group ◽

Carboxy Group ◽

Title Compound ◽

Oxidative Cleavage ◽

Hydroxy Derivative ◽

Borohydride Reduction ◽

Protecting Group ◽

Free Hydroxy Group

Addition of 4-methoxybenzyl alcohol to 3β-hydroxy-5α-androst-15-en-17-one gave the mixture of isomeric 15-(4-methoxyphenyl)methoxy derivatives from which, after acetylation and chromatography, the major 15β isomer was separated. Borohydride reduction gave 17β-hydroxy derivative which was protected as methoxymethyl ether. Oxidative cleavage of protecting group at position 15 and the subsequent Jones oxidation afforded corresponding 15-ketone. Its oximation with O-(carboxymethyl)hydroxylamine, deacetylation and methylation with diazomethane gave protected O-(carboxymethyl)oxime derivative with free hydroxy group at position 3. Its oxidation afforded dihydrotestosterone derivative and successive deprotection of position 17 and of carboxy group led to final (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(carboxymethyl)]oxime. The title compound was designed as dihydrotestosterone hapten for heterologous radioimmunoassays.

Download Full-text

Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20052075 ◽

2005 ◽

Vol 70 (12) ◽

pp. 2075-2085 ◽

Cited By ~ 5

Author(s):

Jiří Kroutil ◽

Klára Jeništová

Keyword(s):

Fluoride Anion ◽

Ring Cleavage ◽

Protecting Group ◽

Reaction Conditions ◽

Aziridine Ring ◽

Cleavage Reactions ◽

Derivatives Of ◽

Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

Download Full-text

A Convenient Protecting Group for Uridine Ureido Nitrogen: (4,4′-Bisfluorophenyl)methoxymethyl Group

Synthesis ◽

10.1055/a-1464-2473 ◽

2021 ◽

Author(s):

Michio Kurosu ◽

Katsuhiko Mitachi ◽

David Mingle

Keyword(s):

Chemical Transformation ◽

Relative Stability ◽

Protecting Group

Abstract(4,4′-Bisfluorophenyl)methoxymethyl (BFPM) group of uridine ureido nitrogen shows good relative stability in a variety of chemical transformation reactions for uridine. The BFPM group can be cleaved by 2% of TFA in CH2Cl2 without affecting the Boc group.

Download Full-text

Synthesis and Antiproliferative Evaluation of 2-Deoxy-N-glycosylbenzotriazoles/imidazoles

Molecules ◽

10.3390/molecules26123742 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3742

Author(s):

Caleigh S. Garton ◽

Noelle K. DeRose ◽

Dylan Dominguez ◽

Maria L. Turbi-Henderson ◽

Ashley L. Lehr ◽

...

Keyword(s):

Cell Lines ◽

Cancer Cell ◽

Addition Reaction ◽

Protecting Group ◽

Human Breast ◽

Lung Cancer Cell ◽

Subsequent Removal ◽

Anticancer Properties ◽

Tributyltin Hydride ◽

High Yields

A series of 2-deoxy-2-iodo-α-d-mannopyranosylbenzotriazoles was synthesized using the benzyl, 4,6-benzylidene and acetyl protected D-glucal in the presence of N-iodosuccinimide (NIS). Subsequent removal of the iodine at the C-2 position using tributyltin hydride under free radical conditions afforded the 2-deoxy-α-d-glucopyranosylbenzotriazoles in moderate to high yields. This method was extended to the preparation of substituted 2-deoxy-β-d-glucopyranosylimidazoles as well. The stereoselectivity of the addition reaction and the effect of the protecting group and temperature on anomer distribution of the benzotriazole series were also investigated. The anticancer properties of the newly synthesized compounds were evaluated in a series of viability studies using HeLa (human cervical adenocarcinoma), human breast and lung cancer cell lines. The N-[3,4,6-tri-O-benzyl-2-deoxy-α-d-glucopyranosyl]-1H-benzotriazole and the N-[3,4,6-tri-O-acetyl-2-deoxy-α-d-glucopyranosyl]-2H-benzotriazole were found to be the most potent cancer cell inhibitors at 20 µM concentrations across all four cell lines.

Download Full-text

Continued exploration of trifunctional alkyl 4-chloro-2-diazo-3-oxobutanoates: streamlined entry into [1,2,3]triazolo[5,1-c][1,4]benzoxazines and [1,2,3]triazolo[5,1-c][1,4]benzoxazepines

Synthesis ◽

10.1055/a-1348-9031 ◽

2021 ◽

Author(s):

Anton V. Budeev ◽

Grigory Kantin ◽

Dmitrii Viktorovich Dar'in ◽

Mikhail Krasavin

Keyword(s):

Medicinal Chemistry ◽

Phenol Removal ◽

Protecting Group

Further exploration of the trifunctional character of previously introduced alkyl 4-chloro-2-diazo-3-oxobutanoates in reactions with N-protected substituted o-aminophenols followed by deprotection provided a convenient entry into [1,2,3]triazolo[5,1-c][1,4]benzoxazines which are of high medicinal importance as documented in the literature. The same approach applied to N-protected substituted o-(aminomethyl)phenols afforded [1,2,3]triazolo[5,1-c][1,4]benzoxazepines which are practically unexplored from medicinal chemistry perspective. The syntheses start with SN2-type alkylation of the phenol. Removal of the protecting group triggered an imine formation followed by the Wolff 1,2,3-triazole synthesis.

Download Full-text

Synthese neuer Pyridin-C-nukleoside der 2 ,3 -Didesoxyribose durch „inverse“ [4+2]-Cycloaddition Synthesis of Novel Pyridine-C-nucleosides of 2,3-Dideoxyribose by „Inverse“ [4+2]-Cycloaddition

Zeitschrift für Naturforschung B ◽

10.1515/znb-1997-0715 ◽

1997 ◽

Vol 52 (7) ◽

pp. 851-858 ◽

Cited By ~ 6

Author(s):

Gunther Seitz ◽

Johanna Siegl

Keyword(s):

Cycloaddition Reaction ◽

Alder Reaction ◽

Diels Alder ◽

The Novel ◽

Protecting Group ◽

Enol Ethers ◽

Inverse Electron Demand ◽

Diels Alder Reaction ◽

Cyclic Ketene Acetals

The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could be deprotected by treatment with 70% trifluoroacetic acid to furnish the free C-nucleosides 10 and 11. The triazine „aglycon“ of 8 contains an electron deficient diazadiene system, highly activated to react with various electron rich dienophiles such as enamines, enol ethers and several cyclic ketene acetals in an „inverse“ [4+2]-cycloaddition reaction. The Diels-Alder adducts spontaneously eliminate N2 and after follow-up reactions the O-TBDPS protected pyridine-C-nucleosides 13, 15, 17,19, 21 and 23 are formed. Removal of the protecting group by treatment with CF3CO2H /H2O leads to the corresponding 2’,3’-dideoxy-β-D-ribofuranosyl- pyridines.

Download Full-text