Extraction of novel sulfated polysaccharides from Aphanothece sacrum (Sur.) Okada, and its spectroscopic characterization

We extracted polysaccharides (PS) from Aphanothece sacrum using a hot alkaline solution which degraded other biopolymers such as proteins and nucleotides. The spectroscopy and elemental analyses indicated the PS contain carboxyls and sulfate groups. The degree of sulfation was estimated as about 10 mol %. 1H NMR studies demonstrated that the PS of A. sacrum had a dimethylated fucose unit. The combination of sulfate group and fucose in the prokaryotic PS was first evidenced by the direct spectroscopic studies. The PS showed efficient gelation behavior, binding to metal ions abundant in soil, and the swelling volume of the gel was approximately 250 times the dry volume. These results imply that PS of A. sacrum, which has been mass cultivated in Japan for a long time, may have potential as an environmentally benign water absorbent.

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Chelated compounds and derivative of β-alkoxycarbonylalkyltin chlorides — 5-arylazo-8-quinolinolates, alizarinates, and thiocyanate: preparation and spectroscopic studies

Canadian Journal of Chemistry ◽

10.1139/v87-210 ◽

1987 ◽

Vol 65 (6) ◽

pp. 1241-1246 ◽

Cited By ~ 14

Author(s):

Barun Kanti Deb ◽

Amiya Kanti Ghosh

Keyword(s):

Complex Formation ◽

Structural Features ◽

Spectroscopic Studies ◽

Nucleophilic Attack ◽

Hydroxyl Groups ◽

Chelating Ligands ◽

Carbonyl Groups ◽

H Nmr ◽

Elemental Analyses ◽

Subsequent Elimination

Complex formation with chelating ligands like 5-phenylazo-8-quinolinol, 5-(2I-carboxyphenylazo)-8-quinolinol, 1,2-dihydroxyanthraquinone (i.e., alizarin), and 1-nitroso-2-naphthol is due to nucleophilic attack on tin of the β-alkoxycarbonylalkyltin chlorides (a unique class of PVC stabilizer intermediates) with the subsequent elimination of hydrogen chloride. A number of complexes of the types R2SnL2, RSnL2Cl, R2SnLCl, R2Sn(LIHI)2, R2SnLII, and RSnLIICl (where R = CH3OCOCH2CH2—, C4H9OCOCH2CH2—, and CH3OCOCH(CH3)CH2—; LH = 5-phenylazo-8-quinolinol, 1-nitroso-2-naphthol; LIHHI = 5-(21-carboxyphenylazo)-8-quinolinol; and LIIH2 = 1,2-dihydroxyanthraquinone) and a thiocyanate derivative viz. (CH3OCOCH2CH2)2Sn(SCN)2 have been prepared. 5-Arylazo-8-quinolinols exhibit azo–hydrazone tautomeric equilibria but their complexes exist only in the azo form. β-Alkoxycarbonylethyltin alizarinates are somewhat different from other complexes. In these complexes two hydroxyl groups of alizarin have been utilised in complex formation, moreover, one of the two carbonyl groups of alizarin also remains involved in coordination to tin. In (CH3OCOCH2CH2)2Sn(SCN)2, the thiocyanate group is possibly linked to tin atom through nitrogen. All the complexes and the thiocyanate derivative have been characterised by elemental analyses, electronic, ir, and 1H nmr spectra. Possible structural features of the compounds are discussed.

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1.2-Verzweigte Carbosiloxan-Dendrimere mit Hauptgruppenelementund Übergangsmetall-modifizierten Oberflächen / 1.2-Branched Carbosiloxane-Dendrimers with Main-Group Element and Transition-Metal Modified Surfaces

Zeitschrift für Naturforschung B ◽

10.1515/znb-1999-0608 ◽

1999 ◽

Vol 54 (6) ◽

pp. 751-756 ◽

Cited By ~ 5

Author(s):

Karin Brüning ◽

Bettina Lühmann ◽

Heinrich Lang

Keyword(s):

Transition Metal ◽

Second Generation ◽

Spectroscopic Studies ◽

Main Group ◽

Group Element ◽

H Nmr ◽

Main Group Element ◽

Elemental Analyses ◽

Modified Surfaces ◽

First And Second Generation

The preparation of the first and second generation carbosiloxane dendrimers Si[OCH2- CH2CH2 SiMe(OCH2C=CH)2]4 (3) and Si{OCH2H2CH2SiMe[OCH2CH2CH2SiMe(OCH2 - C=CH)2]2}4 (5) by the reaction o f Si(OCH2CH2CH2SiMeCl2)4 (1) or Si[OCH2CH2CH2SiMe- (OCH2CH2CH2SiMeCl2)2]4 (4) with HOCH2C =CH (2) in the presence o f NEt3 is described. Dendrimers 3 and 5 contain propargyloxy units as terminal groups, which can be transferred to Co2((CO)8 (6) to give the hexacarbonyldicobalt functionalized dendritic molecules Si{OCH2CH2CH2[(η-OCH2C=CH)CO2(CO)6]2}4 (7) and Si{OCH2CH2CH2SiMe-(OCH2CH2CH2SiMe[(η-OCH2C=CH)CO2(CO)6]2)2}4 (8). All compounds were characterized by elemental analyses, spectroscopic studies (IR,1H-, 13C{1H }-, 29Si{1H} NMR) as well as GPC investigations

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Preparation and spectroscopic studies of Fe(II), Ru(II), Pd(II) and Zn(II) complexes of Schiff base containing terephthalaldehyde and their transfer hydrogenation and Suzuki-Miyaura coupling reaction

Open Chemistry ◽

10.1515/chem-2019-0074 ◽

2019 ◽

Vol 17 (1) ◽

pp. 571-580 ◽

Cited By ~ 2

Author(s):

Nevin Turan ◽

Kenan Buldurun ◽

Naki Çolak ◽

İsmail Özdemir

Keyword(s):

Schiff Base ◽

Coupling Reaction ◽

Spectroscopic Characterization ◽

Spectroscopic Studies ◽

Transfer Hydrogenation ◽

Spectroscopic Techniques ◽

Catalytic Activities ◽

H Nmr ◽

Optimized Conditions ◽

C Nmr

AbstractThis study describes synthesis, spectroscopic characterization and catalytic activities of Fe(II), Ru(II), Pd(II) and Zn(II) complexes with a novel Schiff base ligand (L) derived from methyl 2-amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate and terephthalaldehyde. We used spectroscopic techniques including IR, UV-Vis, 1H-NMR, 13C-NMR, elemental analysis and also mass analysis and magnetic susceptibility measurements to identify the products. The Pd(II) complex was used as a potential catalyst for Suzuki-Miyaura coupling reaction of some aryl halides under optimized conditions. The effect of various bases such as NaOH, KOH, and KOBut was investigated in transfer hydrogenation (TH) of ketones by isopropyl alcohol as the hydrogen source. Ru(II) and Pd(II) complexes showed catalytic activity while Zn(II) and Fe(II) metal complexes failed to do that.

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Synthesis and Spectroscopic Characterization of Lead(II)bis{O,O'-ditolyldithiophosphates} and their Adducts with 2,2'-Bipyridyl and 1,10-Phenanthroline

E-Journal of Chemistry ◽

10.1155/2011/165895 ◽

2011 ◽

Vol 8 (s1) ◽

pp. S113-S118

Author(s):

Disha Jain Alok Chaturvedi ◽

R.K. Upadhayay

Keyword(s):

Spectroscopic Characterization ◽

Spectroscopic Studies ◽

Ammonium Salts ◽

Molar Ratio ◽

Spectroscopic Techniques ◽

Lead Atom ◽

H Nmr

The reaction of lead(II) dichloride with ammonium salts ofO,O'-ditolyldithiophosphoric acid have been carried out in 1:2 molar ratio by refluxing in benzene. These compounds have been further used to synthesize the adduct of the type lead(II)bis{O,O'-ditolyldithiophosphates}.2,2'-bipyridyl and lead(II)bis {O,O'-ditolyldithiophosphates}.1,10-phenanthroline by the reaction of lead(II)bis{O,O'-ditolyldithiophosphates} and 2,2'-bipyridyl and 1,10-phenanthro-line in the presence of unimolar dichloromethane and ethanol. All these complexes have been characterized by spectroscopic techniques such as IR,1H NMR and31P NMR. On the basis of spectroscopic studies tetracoordinated nature of lead atom in ditolyldithiophosphates complexes and hexacoordinated nature in their adducts have been established.

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Preparation and Properties of Rhodium(III) Complexes with the Tetradentate Ligand N,N'-Bis(2'-pyridinecarboxamide)-1,8-naphthalene

Zeitschrift für Naturforschung B ◽

10.1515/znb-1994-0118 ◽

1994 ◽

Vol 49 (1) ◽

pp. 111-118 ◽

Cited By ~ 2

Author(s):

Evy Manessi-Zoupa ◽

Theodoros F. Zafiropoulos ◽

Spyros P. Perlepes

Keyword(s):

Solid State ◽

Chelating Agent ◽

Bidentate Ligand ◽

Octahedral Complex ◽

Tetradentate Ligand ◽

Conductivity Measurements ◽

Nmr Studies ◽

X Ray ◽

H Nmr ◽

Elemental Analyses

AbstractSynthetic procedures are described that allow access to a number of new Rh(III) complexes with the tetradentate bis-amide ligand N,N'-bis(2'-pyridinecarboxamide)-1,8-naphthalene (LH2). These complexes have the formulae Rh(LH2)Cl3, Na[RhLX2] • H2O (X = Cl, CN) and [RhLA2]ClO4 (A = pyridine, 1-methylbenzotriazole). The compounds have been characterized by elemental analyses, conductivity measurements, X-ray powder patterns, spectroscopic (IR, UV/VIS, 1H NMR) studies and electrochemical methods. The neutral amide behaves as a bis-bidentate ligand in the oligomeric or polymeric, octahedral complex Rh(LH2,)Cl3. Monomeric, trans octahedral structures are assigned for the complexes of L2− in the solid state; the doubly deprotonated ligand acts as a tetradentate chelating agent with the four nitrogens as ligating atoms.

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Microwave-Assisted Solution Phase Synthesis of Novel 2-{4-[2-(N-Methyl-2-pyridylamino)ethoxy]phenyl}-5-Substituted 1,3,4-Oxadiazole Library

Organic Chemistry International ◽

10.1155/2011/751894 ◽

2011 ◽

Vol 2011 ◽

pp. 1-5 ◽

Cited By ~ 5

Author(s):

Santosh L. Gaonkar ◽

Izuru Nagashima ◽

Hiroki Shimizu

Keyword(s):

Oxidative Cyclization ◽

Biologically Active ◽

Environmentally Benign ◽

Efficient Catalyst ◽

Phase Synthesis ◽

H Nmr ◽

Solution Phase Synthesis ◽

Elemental Analyses ◽

Chloramine T ◽

C Nmr

A new series of 2-{4-[2-(N-methyl-2-pyridylamino)ethoxy]phenyl}-5-substituted 1,3,4-oxadiazoles were synthesized by the oxidative cyclization of hydrazones derived from 4-[2-(methylpyridin-2-ylamino)ethoxy]benzaldehyde and aryl hydrazines using chloramine-T as an efficient catalyst. All steps were assisted by microwave irradiation. Microwave enables all these reactions to be simple, rapid, high yielding, and avoid chromatograph purification and led environmentally benign total synthesis of focused oxadiazole library. All the synthesized compounds were isolated in good yield and characterized by 1H NMR, 13C NMR, and elemental analyses. The title compounds represent a novel class of biologically active heterocycles.

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Meso-mesityl dithia- and diselenarubyrins: existence of planar and inverted forms in solution

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424602000506 ◽

2002 ◽

Vol 06 (06) ◽

pp. 403-409

Author(s):

Seenichamy Jeyaprakash Narayanan ◽

Sundararaman Venkatraman ◽

Venkatara-manarao G. Anand ◽

Tavarekere K. Chandrashekar

Keyword(s):

Spectroscopic Studies ◽

Nmr Studies ◽

H Nmr ◽

Protonated Forms

Syntheses, characterization and spectroscopic studies of meso-mesityl substituted rubyrins are reported. Specifically, it has been shown that these rubyrins behave differently from the meso-phenyl containing rubyrins in their structure. 1 H NMR studies reveal the existence of both planar and inverted isomers in solution in different ratios both in the freebase and protonated forms.

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Azaoxa Macrocyclic and Acyclic Complexesof Lanthanides

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19980363 ◽

1998 ◽

Vol 63 (3) ◽

pp. 363-370 ◽

Cited By ~ 13

Author(s):

Violetta Patroniak-Krzyminiewska ◽

Wanda Radecka-Paryzek

Keyword(s):

Schiff Base ◽

Spectral Data ◽

Macrocyclic Ligand ◽

Lanthanide Ions ◽

H Nmr ◽

Elemental Analyses ◽

Acyclic Complexes ◽

Schiff Base Cyclocondensation

The template reactions of 2,6-diacetylpyridine with 3,6-dioxaoctane-1,8-diamine in the presence of dysprosium(III), thulium(III) and lutetium(III) chlorides and erbium(III) perchlorate produce the complexes of 15-membered macrocyclic ligand with an N3O2 set of donor atoms as a result of the [1+1] Schiff base cyclocondensation. In contrast, analogous reactions involving the lighter lanthanide ions (lanthanum(III), samarium(III) and europium(III)) yield the acyclic complexes with terminal acetylpyridyl groupings as products of the partial [2+1] condensation. The complexes were characterized by spectral data (IR, UV-VIS, 1H NMR, MS), and thermogravimetric and elemental analyses.

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1H NMR Conformational Studies in Water of Angiotensin II Analogues Modified at the N- and C-Termini: Interactions of the Aromatic Side Chains and Folding of the N-Terminal Domain

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19942523 ◽

1994 ◽

Vol 59 (11) ◽

pp. 2523-2532 ◽

Cited By ~ 4

Author(s):

John Hondrelis ◽

John Matsoukas ◽

George Agelis ◽

Paul Cordopatis ◽

Ning Zhou ◽

...

Keyword(s):

Shielding Effect ◽

Resonance Spectroscopy ◽

Nmr Studies ◽

Previous Suggestion ◽

Aminoisobutyric Acid ◽

H Nmr ◽

Neutral Ph ◽

Angiotensin Ii Analogues ◽

Proton Resonances ◽

Cosy Nmr

The conformation of [Sar1]angiotensin II in water at neutral pH has been examined by proton magnetic resonance spectroscopy at 400 MHz and in particular by comparing its 1H NMR spectral data with those of analogues modified at positions 1,4 and 6, namely [Sar1,Cha8]ANGII, [Des Asp1,Cha8]ANGII, [Aib1,Tyr(Me)4]ANGII, [Aib1,Tyr(Me)4,Ile8]ANGII, [N-MeAib1,Tyr(Me)4]ANGII, [N-MeAib1,Tyr(Me)4,Ile8]ANGII, ANGIII and [Sar1,Ile8]ANGII. Assignment of all proton resonances in these analogues was made possible by 2D COSY NMR experiments. The H-2 and H-4 protons for the histidine ring in [Sar1]ANGII, ANGII and ANGIII were shielded compared with the same protons in [Sar1,Ile8]ANGII, [Sar1,Cha8]ANGII and [Des Asp1,Cha8]ANGII; this shielding effect was not disturbed upon methylation of the tyrosine hydroxyl and/or replacement of residue 1 (sarcosine or aspartic acid) with aminoisobutyric acid (Aib) or N-methyl aminoisobutyric acid (N-MeAib). These data are consistent with our previous suggestion based on NMR studies in neutral DMSO that a characteristic folded conformation for ANGII previously observed in non-polar solvents can also be detected in water at neutral pH, but to a lesser degree.

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Ultrasound-assisted aqua-mediated synthesis of multi-substituted tetrahydropyridine-3-carboxylates using N-carboxymethyl-3-pyridinium hydrogensulfate ([N-CH2CO2H-3-pic]+HSO4−) as a new efficient ionic liquid catalyst

SN Applied Sciences ◽

10.1007/s42452-021-04671-9 ◽

2021 ◽

Vol 3 (6) ◽

Author(s):

Kobra Nikoofar ◽

Fatemeh Shahriyari

Keyword(s):

Ionic Liquid ◽

Reaction Times ◽

Aromatic Aldehydes ◽

Environmentally Benign ◽

H Nmr ◽

Sonic Waves ◽

Ft Ir ◽

High Yields ◽

Work Up ◽

C Nmr

AbstractA simple, straightforward, and ultrasound-promoted method for the preparation of some highly functionalized tetrahydropyridines reported via pseudo five-component reaction of (hetero)aromatic aldehydes, different anilines, and alkyl acetoacetates in the presence of [N-CH2CO2H-3-pic]+HSO4−, as a novel ionic liquid, in green aqueous medium. The IL was synthesized utilizing simple and easily-handled substrates and characterized by FT-IR, 1H NMR, 13C NMR, GC-MASS, FESEM, EDX, and TGA/DTG techniques. The procedure contains some highlighted aspects which are: (a) performing the MCR in the presence of aqua and sonic waves, as two main important and environmentally benign indexes in green and economic chemistry, (b) high yields of products within short reaction times, (c) convenient work-up procedure, (d) preparing the new IL via simple substrates and procedure.

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