PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 17127657

Oxidation studies on Andrographolide.

Vijayavitthal T Mathad·Satish Kumar·Kanwal Raj
View original source ↗Export metadata ↓

Abstract

Jones oxidation of Andrographolide (1), gave mixture of three products (3-dehydroandrographolide (5), 3,19-bis dehydroandrographolide (6) and 19-dehydroandrographolide (7). Tritylation of andrographolide at C19-OH resulted to products 8 and diene 9, which can be converted to its acetate 10 and oxidation product 11.

Explore related subjects

Acetic AnhydridesAndrographisDiterpenesMolecular StructureOxidation-ReductionTriphenylmethyl CompoundsComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Vijayavitthal T Mathad, Satish Kumar, Kanwal Raj. 2006. Oxidation studies on Andrographolide.. https://doi.org/10.1080/14786410500441466

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Gas chromatographic methods for monitoring of wastewater chlorophenol degradation in anaerobic reactors.

Wastewater samples from an anaerobic reactor were extracted with hexane and derivatized with diazomethane (method 1) and with acetic anidride (method 2). Gas chromatography with electron-capture detection (ECD) was employed for separating the parent compound and intermediates trichlorophenols (TCP) and dichlorophenols (DCP) which originated from the penta chlorophenol (PCP) degradation process. The relations between concentrations of PCP, TCP and DCP areas were linear in the range of concentrations of 0.2 to 8 mg/L and 0.025 mg/L to 5 mg/L for methods 1 and 2, respectively. The repeatability of the extraction methods was satisfactory, with variation coefficients lower than 11%. For method 1, at the fortification level of 0.2 mg/L, recovery of PCP, TCP, and DCP was 112%, 74% and 45%, respectively. For method 2, the corresponding recovery values at the fortification level of 0.1 mg/L were 91%, 93% and 103%, respectively. Storage of the frozen samples did not alter their PCP determination properties. The chromatographic methods adapted for chlorophenol determination in wastewater were suitable with relatively simple manipulation techniques. The obtained results were reproducible and allowed identification of intermediates formed during the PCP degradation process.

Acetic Anhydrides↗
PubMed2006

Three distinct reactions of 3,4-dihydroisoquinolines with azlactones: novel synthesis of imidazoloisoquinolin-3-ones, benzo[a]quinolizin-4-ones, and benzo[d]azocin-4-ones.

A facile and direct synthetic entry to tricyclic imidazoloisoquinolin-3-ones and benzo[a]quinolizin-4-ones is reported based on the ring annulation of 1-unsubstituted and 1-substituted dihydroisoquinolines with azlactones under neutral conditions in a one-step procedure. Bicyclic 2,3-dihydrobenzo[d]azocin-4-ones were also prepared using simple azlactone and 1-substituted dihydroisoquinolines in a one-pot reaction. [reaction: see text]

Acetic Anhydrides↗
PubMed2006

Enhancement of MALDI-MS spectra of C-terminal peptides by the modification of proteins via an active ester generated in situ from an oxazolone.

For selective C-terminal derivatization of peptides and proteins, we have devised a method for activating the C-terminal carboxyl group by extending the oxazolone chemistry. A mixture of formic acid and acetic anhydride was found to be effective for the formation of an oxazolone, which was converted to an active ester in situ in the presence of a phenol or an N-hydroxide. In particular, the resulting active ester with pentafluorophenol facilitated the subsequent reaction with an amine and the hydrazine derivative to yield the C-terminal amide and hydrazide, respectively. The peptides thus coupled with arginine methyl ester or 2-hydrazino-2-imidazoline containing the guanidino moiety exhibited the positive-ion peaks in matrix-assisted laser desorption/ionization (MALDI) mass spectra with appreciably enhanced intensities. As expected from the reaction mechanism, the carboxyl groups of aspartic and glutamic acid residues were not modified, while the amino groups that could react with the activated peptides were concomitantly protected by formylation. The MALDI peaks corresponding to the C-terminal peptide fragments of proteins were specifically enhanced, discriminating against those from internal peptides that were not tagged with a positive charge. In favorable cases, the C-terminal peptide fragments were clearly discerned by MALDI-MS after chymotryptic digestion and were identified by their MALDI postsource decay analysis. Based on these results, we suggest a method for C-terminal sequencing of a protein.

Acetic Anhydrides↗