Photolysis of Thiopurines in the Presence of Oxygen+

Abstract Irradiation (λ > 290 nm) of 6-thiopurine and some 9-substituted 6-thiopurines in oxygen saturated tert-butanol leads to hypoxanthine, purine and purine-6-sulfonic acid or their substituted derivatives. Purine and hypoxanthine formation can be sensitized with dyes. The reaction of 6-thiopurine with singlet oxygen has also been performed with purine and hypoxanthine among other products. It seems however that 1O2 is not an important intermediate in the photooxygenation. The photoreaction may have some synthetic value. Hypoxanthines (~50%) or purines (35-45%) were obtained depending on the solvent used.

Download Full-text

Catalytic etherification of glycerol to tert-butyl glycerol ethers using tert-butanol over sulfonic acid functionalized mesoporous polymer

RSC Advances ◽

10.1039/c6ra18609b ◽

2016 ◽

Vol 6 (86) ◽

pp. 82654-82660 ◽

Cited By ~ 19

Author(s):

Pandian Manjunathan ◽

Manish Kumar ◽

Sathyapal R. Churipard ◽

S. Sivasankaran ◽

Ganapati V. Shanbhag ◽

...

Keyword(s):

Free Radical ◽

Radical Polymerization ◽

Sulfonic Acid ◽

Solvothermal Method ◽

Free Radical Polymerization ◽

Tert Butyl ◽

Mesoporous Polymer ◽

Glycerol Ethers ◽

Tert Butanol

Mesoporous polymers (MP) were synthesized by free radical polymerization of divinylbenzene by a solvothermal method followed by sulfonic acid functionalization by a post synthetic modification with conc.

Download Full-text

Effects of different plasticizers on highly crosslinked NaAlg/PSSAMA membranes for pervaporative dehydration of tert-butanol

New Journal of Chemistry ◽

10.1039/c9nj05466a ◽

2020 ◽

Vol 44 (11) ◽

pp. 4452-4466 ◽

Cited By ~ 1

Author(s):

Divya D. Achari ◽

Satishkumar R. Naik ◽

Mahadevappa Y. Kariduraganavar

Keyword(s):

Sodium Alginate ◽

Maleic Acid ◽

Sulfonic Acid ◽

Dibutyl Phthalate ◽

Dioctyl Phthalate ◽

Diethyl Phthalate ◽

Tert Butanol ◽

Polystyrene Sulfonic Acid

Polystyrene sulfonic acid-co-maleic acid (PSSAMA) crosslinked sodium alginate (NaAlg) membranes were developed by incorporating diethyl phthalate (DEP), dibutyl phthalate (DBP) and dioctyl phthalate (DOP).

Download Full-text

Metal nanoparticle-enhanced radiative transitions: Giving singlet oxygen emission a boost

Pure and Applied Chemistry ◽

10.1351/pac-con-10-09-24 ◽

2011 ◽

Vol 83 (4) ◽

pp. 885-898 ◽

Cited By ~ 14

Author(s):

Rasmus Toftegaard ◽

Jacob Arnbjerg ◽

Huaiping Cong ◽

Hossein Agheli ◽

Duncan S. Sutherland ◽

...

Keyword(s):

Singlet Oxygen ◽

Incident Light ◽

Optical Probe ◽

Metal Nanoparticle ◽

Oxidation Reactions ◽

Process Data ◽

Singlet Molecular Oxygen ◽

Optical Signals ◽

Radiative Transitions ◽

Important Intermediate

The fabrication and use of metal nanoparticles to influence electronic transitions in a given molecule is of growing interest; there is much to be gained by developing and exploiting methods to enhance weak optical signals. Singlet molecular oxygen, O2(a1∆g), which is an important intermediate in many oxidation reactions, particularly in biological systems, is ideally monitored by the 1275-nm O2(a1∆g) → O2(X3Σg–) phosphorescent transition. Unfortunately, the latter is highly forbidden and, as such, often presents a severe limitation in the application of this optical probe. In this paper, we describe how this weak phosphorescent transition can be enhanced by using localized surface plasmons (LSPs) from specially engineered gold nanostructures. In an attempt to elucidate the mechanism of this process, data were recorded from samples in which we decoupled the component of the plasmon resonance that absorbs incident light from the component that scatters incident light. We find that the latter appears to be the feature of significance in the process through which singlet oxygen phosphorescence is enhanced. In this work, we also illustrate how the singlet oxygen system provides an ideal model for a general study of metal-enhanced radiative rate constants.

Download Full-text

Photochemistry and Spectroscopy of Singlet Oxygen in Solvents. Recent Advances which Support the Old Theory

Chemistry & Chemical Technology ◽

10.23939/chcht10.04si.519 ◽

2016 ◽

Vol 10 (4s) ◽

pp. 519-530 ◽

Cited By ~ 5

Author(s):

Boris Minaev ◽

Keyword(s):

Singlet Oxygen ◽

Chemical Reactivity ◽

Dye Sensitization ◽

Medical Treatments ◽

New Synthesis ◽

Semiempirical Theory ◽

Wide Range ◽

Direct Laser ◽

Important Intermediate ◽

Specific Reactions

Molecular oxygen is a paramagnetic gas with the triplet O2( ) ground state which exhibits just sluggish chemical reactivity in the absence of radical sources. In contrast, the excited metastable singlet oxygen O2( ) is highly reactive; it can oxygenate organic molecules in a wide range of specific reactions which differ from those of the usual triplet oxygen of the air. This makes the singlet oxygen an attractive reagent for new synthesis and even for medical treatments in photodynamic therapy. As an important intermediate O2( ) has attracted great attention of chemists during half-century studies of its reactivity and spectroscopy, but unusual properties of singlet oxygen makes it difficult to unravel all mysterious features. The semiempirical theory of spin-orbit coupling in dioxygen and in collision complexes of O2 with diamagnetic molecules proposed in 1982 year has explained and predicted many photochemical and spectral properties of dioxygen produced by the dye sensitization in solvents. Recent experiments with direct laser excitation of O2 in solvents provide a complete support of the old theory. The present review scrutinizes the whole story of development and experimental verification of this theory.

Download Full-text

Electron Microscopy of Mycoplasma Pneumoniae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065341 ◽

1971 ◽

Vol 29 ◽

pp. 258-259 ◽

Cited By ~ 1

Author(s):

E. S. Boatman ◽

G. E. Kenny

Keyword(s):

Electron Microscopy ◽

Light Microscopy ◽

Growth Phase ◽

Hela Cells ◽

Sulfonic Acid ◽

Gamma Globulin ◽

Horse Serum ◽

Morphological Aspects ◽

The Family

Information concerning the morphology and replication of organism of the family Mycoplasmataceae remains, despite over 70 years of study, highly controversial. Due to their small size observations by light microscopy have not been rewarding. Furthermore, not only are these organisms extremely pleomorphic but their morphology also changes according to growth phase. This study deals with the morphological aspects of M. pneumoniae strain 3546 in relation to growth, interaction with HeLa cells and possible mechanisms of replication.The organisms were grown aerobically at 37°C in a soy peptone yeast dialysate medium supplemented with 12% gamma-globulin free horse serum. The medium was buffered at pH 7.3 with TES [N-tris (hyroxymethyl) methyl-2-aminoethane sulfonic acid] at 10mM concentration. The inoculum, an actively growing culture, was filtered through a 0.5 μm polycarbonate “nuclepore” filter to prevent transfer of all but the smallest aggregates. Growth was assessed at specific periods by colony counts and 800 ml samples of organisms were fixed in situ with 2.5% glutaraldehyde for 3 hrs. at 4°C. Washed cells for sectioning were post-fixed in 0.8% OSO4 in veronal-acetate buffer pH 6.1 for 1 hr. at 21°C. HeLa cells were infected with a filtered inoculum of M. pneumoniae and incubated for 9 days in Leighton tubes with coverslips. The cells were then removed and processed for electron microscopy.

Download Full-text