Oxidation of phosphazine by singlet oxygen. High-field phosphorus-31 NMR spectroscopic studies of 3-phospha-1,2-dioxa-4,5-diazine and phospha-1,2-dioxetane

1985 ◽  
Vol 107 (19) ◽  
pp. 5539-5540 ◽  
Author(s):  
Takeshi Akasaka ◽  
Rikiya Sato ◽  
Wataru Ando
Keyword(s):  
Singlet Oxygen ◽  
High Field ◽  
Spectroscopic Studies

High field NMR spectroscopic studies of arteannuin B and a reappraisal of the structure of arteannuin C

1991 ◽  
Vol 30 (10) ◽  
pp. 3469-3471 ◽  
Author(s):  
P.K. Agrawal ◽  
R.A. Vishwakarma ◽  
D.C. Jain ◽  
R. Roy
Keyword(s):  
High Field ◽  
Spectroscopic Studies

scholarly journals Phytochemical and Biological Investigations of Eurya acuminata (Theaceae)

2017 ◽  
Vol 15 (2) ◽  
pp. 151-154 ◽  
Author(s):  
Tahmid Faisal ◽  
Monira Ahsan ◽  
Jakir Ahmed Choudhury ◽  
ATM Zafrul Azam
Keyword(s):  
Brine Shrimp ◽  
High Field ◽  
Methanol Extract ◽  
Methanolic Extract ◽  
Antimicrobial Properties ◽  
Spectroscopic Studies ◽  
Vincristine Sulfate ◽  
Thrombolytic Activity ◽  
Aqueous Fraction ◽  
Lc50 Value

The methanol extract of the powdered leaf of Eurya acuminata was investigated for isolation of secondary metabolites and two compounds were obtained by using VLC, column chromatography and TLC. The compounds were identified as phytol (1) and ?-sitosterol by extensive spectroscopic studies, including high field NMR analyses as well as co-TLC with authentic samples. The methanol extract of leaf of E. acuminata and its organic and aqueous soluble partitioning materials were evaluated for cytotoxic, thrombolytic and antimicrobial properties. In the cytotoxicity study the aqueous fraction of crude methanolic extract showed significant lethality towards brine shrimp having LC50 value 8.821 ?g/ml as compared to standard vincristine sulfate (0.404 ?g/ml). In the study for thrombolytic property, different extract of E. acuminata exhibited various thrombolytic activity ranging from 13.66 to 31.89 % as compared to standard streptokinase (46.51 %). No antimicrobial activity was observed from leaf extracts.Dhaka Univ. J. Pharm. Sci. 15(2): 151-154, 2016 (December)

scholarly journals There are two major types of skeletal keratan sulphates

1990 ◽  
Vol 271 (1) ◽  
pp. 243-245 ◽  
Author(s):  
I A Nieduszynski ◽  
T N Huckerby ◽  
J M Dickenson ◽  
G M Brown ◽  
G H Tai ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Nasal Septum ◽  
High Field ◽  
Structural Features ◽  
Spectroscopic Studies ◽  
Neuraminic Acid ◽  
Keratan Sulphate

High-field 1H-n.m.r.-spectroscopic studies supported by chemical carbohydrate analyses show that skeletal keratan sulphates (KS-II) of bovine origin may be sub-classified into two groups. Keratan sulphate chains from articular and intervertebral-disc cartilage (KS-II-A) contain two structural features, namely alpha(1----3)-fucose and alpha(2----6)-linked N-acetyl-neuraminic acid residues, that are absent from keratan sulphates from tracheal or nasal-septum cartilage (KS-II-B).

Oleanane Glycosides from Eclipta prostrata

1970 ◽  
Vol 4 (2) ◽  
Author(s):  
Mohammad S Rahman ◽  
Rasheduzzaman Chowdhury ◽  
Chodhury M Hasan ◽  
Mohammad A Rashid
Keyword(s):  
Key Words ◽  
13C Nmr ◽  
Full Text ◽  
High Field ◽  
Stem Bark ◽  
Spectroscopic Studies ◽  
Hexane Extract ◽  
Nmr Data ◽  
Eclipta Prostrata ◽  
First Time

Two oleanane-type glycosides eclalbasaponin II (1) and eclalbasaponin I (2) along with the ubiquitous steroid, stigmasterol were isolated from an n-hexane extract of the stem bark of Eclipta prostrata. The structures of the isolated compounds were confirmed by extensive spectroscopic studies, notably high field NMR and MS. The 13C NMR data of the parent saponins 1 and 2 are reported here for the first time. Key words: Eclipta prostrata, Compositae, Oleanane glycoside, Eclalbasaponin I, Eclalbasaponin II. Dhaka Univ. J. Pharm. Sci. Vol.4(2) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

Controlled oxidations of benzo[a]pyrene

1986 ◽  
Vol 64 (7) ◽  
pp. 1247-1253 ◽  
Author(s):  
E. Lee-Ruff ◽  
H. Kazarians-Moghaddam ◽  
M. Katz
Keyword(s):  
Singlet Oxygen ◽  
High Field ◽  
Chemical Shifts ◽  
Product Distribution ◽  
Major Product ◽  
Nuclear Overhauser Enhancement ◽  
Nuclear Overhauser ◽  
Singlet Oxygen Reaction ◽  
Proton Chemical Shifts ◽  
Oxygen Reaction

The four diones derived from benzo[a]pyrene oxidation have been characterized by high-field nuclear magnetic resonance techniques including 2-D COSY and selective nuclear Overhauser enhancement. All the proton chemical shifts for these four quinones have been uneqivocally assigned. The direct photoxidation of benzo[a]pyrene gives a product distribution very similar to the TPP photosensitized oxygenation, suggesting singlet oxygen is involved in the former. A major product, which was characterized as the 6-seco derivative 6 and not previously reported, was detected in the singlet oxygen reaction. The presence of this product suggests a possible mechanism for quinone formation in the singlet oxygen reaction. One-electron oxidations of benzo[a]pyrene were carried out using tris(p-bromophenyl)aminium hexachloroantimonate and quenching of the radical cation with superoxide or water. The product distribution in this case was quite different from that obtained in the direct photooxidation.

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