TERPENOIDS: V. SENEGENIN: FUNCTIONAL GROUPS AND PART STRUCTURE

1964 ◽  
Vol 42 (3) ◽  
pp. 491-501 ◽  
Author(s):  
J. J. Dugan ◽  
P. De Mayo ◽  
A. N. Starratt
Keyword(s):  
Functional Groups ◽  
Empirical Formula ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Carboxyl Group ◽  
Secondary Hydroxyl ◽  
Part Structure ◽  
Oxygen Atoms

Senegenin, the sapogenin from Polygalasenega has been shown to contain chlorine; it has the empirical formula C30OH45O6Cl. The oxygen atoms, contrary to earlier work, are contained in two carboxyl groups and two secondary hydroxyl groups. There is one isolated ethylenic linkage. The environment of the hydroxylic functions and one carboxyl group has been shown to be as in (XI).

One step introduction of the activated carboxyl groups with long aliphatic arm onto hydroxyl groups containing polymers

1990 ◽  
Vol 55 (5) ◽  
pp. 1321-1325
Author(s):  
Luboš Arnold ◽  
Jiří Smrt
Keyword(s):  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Carboxyl Group ◽  
One Step ◽  
Nitrophenyl Ester

Bis-N-hydroxysuccinimide ester of 1,10-decanediol bis-succinate (Ia) reacts with hydroxyl groups bearing polymers (Spheron, cellulose, Sephacryl) affording activated carboxyl group containing derivatives IIa. Analogous 4-nitrophenyl group bearing Spheron derivative IIb was prepared starting from bis-4-nitrophenyl ester of 1,10-decanediol bis-succinate (Ib). 3'-O-(4,4'-Dimethoxytriphenylmethyl)-2'-deoxythymidine 5'-(6-amino-1-hexyl)-phosphate (V) was developed as reagent to determine the extent of activated carboxyl groups. Attachment ranging from 3.1-7.3 μmol/g was achieved.

Comparative Studies of Brown Coal and Lignin. II. The Action of Concentrated Alkali at Elevated Temperatures

1960 ◽  
Vol 13 (4) ◽  
pp. 567 ◽  
Author(s):  
BM Lynch ◽  
RA Durie
Keyword(s):  
Functional Groups ◽  
Brown Coal ◽  
Comparative Studies ◽  
Elevated Temperatures ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Brown Coals ◽  
Simple Chemical ◽  
Phenolic Hydroxyl Groups ◽  
Dihydric Phenol

A study was made of the products formed by treating brown coal or lignin with concentrated aqueous or ethanolic alkali at 200 �C. With brown coals a major redistribution of the oxygen-containing functional groups appeared to occur, because the products contained aliphatically linked carboxyl groups and aliphatic hydroxyl, as well as phenolic hydroxyl groups. The behaviour of lignin under the same conditions was less clear but sufficiently similar to that of brown coal to suggest that reactions of the same type were occurring in both cases. Reactions involving decarboxylation, ring scission of dihydric phenol structures, and subsequent hydrogenation are suggested tentatively as the main steps in the formation of the products. The results provide some additional evidence for the view that there is a simple chemical relation between Victorian brown coal and lignin.

scholarly journals Obtaining humic materials by mechanochemical reduction

2021 ◽  
Vol 340 ◽  
pp. 01001
Author(s):  
Natalya Yudina ◽  
Elizaveta Linkevich ◽  
Anna Saveleva ◽  
Oleg Lomovsky
Keyword(s):  
Mechanical Activation ◽  
Functional Groups ◽  
Fulvic Acids ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Humic And Fulvic Acids ◽  
Humic Materials ◽  
Spectral Coefficients ◽  
Mechanochemical Modification

In the study, a mechanochemical modification of peat was carried out, leading to an increase in the number of functional groups and an increase in the solubility of humic complexes with metals. It was shown that the mechanical activation of peat in the presence of Zn significantly increased the yield of extractable fulvic acids. An analysis of the spectral coefficients showed that humic and fulvic acids extracted from peat were characterized by an increased content of alcohol hydroxyl groups, C–O carbohydrate moieties, and carboxyl groups.

Preparation of prednisolone‐appended α‐, β‐ and γ‐cyclodextrins: Substitution at secondary hydroxyl groups and in vitro hydrolysis behavior

2001 ◽  
Vol 90 (4) ◽  
pp. 493-503
Author(s):  
Hideki Yano ◽  
Fumitoshi Hirayama ◽  
Hidetoshi Arima ◽  
Kaneto Uekama
Keyword(s):  
Hydroxyl Groups ◽  
Secondary Hydroxyl ◽  
In Vitro Hydrolysis

17O, 13C, and 29Si NMR spectra of some acyloxy- and diacetoxysilanes and acetoxygermanes

1986 ◽  
Vol 51 (11) ◽  
pp. 2582-2589 ◽  
Author(s):  
Antonín Lyčka ◽  
Jaroslav Holeček ◽  
Karel Handlíř ◽  
Josef Pola ◽  
Václav Chvalovský
Keyword(s):  
Periodic System ◽  
Time Scale ◽  
Nmr Spectra ◽  
Group Element ◽  
29Si Nmr ◽  
Carboxyl Group ◽  
29Si Nmr Spectra ◽  
Oxygen Atoms

The 17O, 13C, and 29Si NMR spectra of (CH3)3SiOC(O)R, CH3(XCH2)Si(OC(O)CH3)2, and R3GeOC(O)CH3 compounds are reported. In the 17O NMR spectra at 350 K the only signal is observed with the two latter series, but two well-resolved signals are displayed with the (CH3)3SiOC(O)R compounds. The equivalence of both oxygen atoms in carboxyl group on the NMR time scale is discussed from the viewpoint of a possible coordination of the oxygen atoms to the IVB group element of the periodic system.

119Sn, 13C and 1H NMR Spectra of Tris(1-butyl)stannyl D-Glucuronate

1997 ◽  
Vol 62 (8) ◽  
pp. 1169-1176 ◽  
Author(s):  
Antonín Lyčka ◽  
Jaroslav Holeček ◽  
David Micák
Keyword(s):  
Chemical Shift ◽  
Carbonyl Group ◽  
1H Nmr ◽  
Equatorial Plane ◽  
Title Compound ◽  
Nmr Spectra ◽  
Hydroxyl Groups ◽  
Carboxylic Group ◽  
H Nmr ◽  
Oxygen Atoms

The 119Sn, 13C and 1H NMR spectra of tris(1-butyl)stannyl D-glucuronate have been measured in hexadeuteriodimethyl sulfoxide, tetradeuteriomethanol and deuteriochloroform. The chemical shift values have been assigned unambiguously with the help of H,H-COSY, TOCSY, H,C-COSY and 1H-13C HMQC-RELAY. From the analysis of parameters of 119Sn, 13C and 1H NMR spectra of the title compound and their comparison with the corresponding spectra of tris(1-butyl)stannyl acetate and other carboxylates it follows that in solutions of non-coordinating solvents (deuteriochloroform) the title compound is present in the form of more or less isolated individual molecules with pseudotetrahedral environment around the central tin atom and with monodentately bound carboxylic group. The interaction of tin atom with oxygen atoms of carbonyl group and hydroxyl groups of the saccharide residue - if they are present at all - are very weak. In solutions in coordinating solvents (hexadeuteriodimethyl sulfoxide or tetradeuteriomethanol), the title compound forms complexes with one molecule of the solvent. Particles of these complexes have a shape of trigonal bipyramid with the 1-butyl substituents in equatorial plane and the oxygen atoms of monodentate carboxylic group and coordinating solvent in axial positions.

scholarly journals Hydrogenation of benzoic acid derivatives over Pt/TiO2 under mild conditions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Miao Guo ◽  
Xiangtao Kong ◽  
Chunzhi Li ◽  
Qihua Yang
Keyword(s):  
Electron Transfer ◽  
Benzoic Acid ◽  
High Efficiency ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
Benzoic Acids ◽  
Catalyst Poisoning ◽  
Benzoic Acid Derivatives ◽  
Mild Conditions ◽  
Transfer Direction

AbstractHydrogenation of benzoic acid (BA) to cyclohexanecarboxylic acid (CCA) has important industrial and academic significance, however, the electron deficient aromatic ring and catalyst poisoning by carboxyl groups make BA hydrogenation a challenging transformation. Herein, we report that Pt/TiO2 is very effective for BA hydrogenation with, to our knowledge, a record TOF of 4490 h−1 at 80 °C and 50 bar H2, one order higher than previously reported results. Pt/TiO2 catalysts with electron-deficient and electron-enriched Pt sites are obtained by modifying the electron transfer direction between Pt and TiO2. Electron-deficient Pt sites interact with BA more strongly than electron-rich Pt sites, helping the dissociated H of the carboxyl group to participate in BA hydrogenation, thus enhancing its activity. The wide substrate scope, including bi- and tri-benzoic acids, further demonstrates the high efficiency of Pt/TiO2 for hydrogenation of BA derivatives.

scholarly journals Mechanical Properties of Graphene Oxide Coupled by Multi-Physical Field: Grain Boundaries and Functional Groups

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Xu Xu ◽  
Zeping Zhang ◽  
Wenjuan Yao
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Grain Boundaries ◽  
Functional Groups ◽  
Oxygen Content ◽  
Tensile Fracture ◽  
Hydroxyl Groups ◽  
Molecular Configuration ◽  
Spatial Design ◽  
Out Of Plane

Graphene and graphene oxide (GO) usually have grain boundaries (GBs) in the process of synthesis and preparation. Here, we “attach” GBs into GO, a new molecular configuration i.e., polycrystalline graphene oxide (PGO) is proposed. This paper aims to provide an insight into the stability and mechanical properties of PGO by using the molecular dynamics method. For this purpose, the “bottom-up” multi-structure-spatial design performance of PGO and the physical mechanism associated with the spatial structure in mixed dimensions (combination of sp2 and sp3) were studied. Also, the effect of defect coupling (GBs and functional groups) on the mechanical properties was revealed. Our results demonstrate that the existence of the GBs reduces the mechanical properties of PGO and show an “induction” role during the tensile fracture process. The presence of functional groups converts in-plane sp2 carbon atoms into out-of-plane sp3 hybrid carbons, causing uneven stress distribution. Moreover, the mechanical characteristics of PGO are very sensitive to the oxygen content of functional groups, which decrease with the increase of oxygen content. The weakening degree of epoxy groups is slightly greater than that of hydroxyl groups. Finally, we find that the mechanical properties of PGO will fall to the lowest values due to the defect coupling amplification mechanism when the functional groups are distributed at GBs.

Halosugar nucleosides. II. Iodination of secondary hydroxyl groups of nucleosides with methyltriphenoxyphosphonium iodide

1970 ◽  
Vol 35 (9) ◽  
pp. 2868-2877 ◽  
Author(s):  
Julien P. H. Verheyden ◽  
John G. Moffatt
Keyword(s):  
Hydroxyl Groups ◽  
Secondary Hydroxyl

Relative basicities of the oxygen atoms of the Linquist polyoxometalate [Mo6O19]2− and their recognition by hydroxyl groups in radical cation salts based on functionalized tetrathiafulvalene π donors

1999 ◽  
pp. 1241-1248 ◽  
Author(s):  
Anne Dolbecq ◽  
Aude Guirauden ◽  
Marc Fourmigué ◽  
Kamal Boubekeur ◽  
Patrick Batail ◽  
...  
Keyword(s):  
Radical Cation ◽  
Hydroxyl Groups ◽  
Radical Cation Salts ◽  
Oxygen Atoms
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