scholarly journals ISOLASI SENYAWA SESQUITERPEN DARI FRAKSI AKTIF ANTIBAKTERI ALGA LAUT MERAH Laurencia tronoi

2021 ◽  
Vol 9 (1) ◽  
pp. 35
Author(s):  
Verly Dotulong
Keyword(s):  
H Nmr ◽  
C Nmr

Tujuan penelitian ini adalah mendapatkan  “senyawa baru yang diisolasi dari fraksi aktif  antibakteri yaitu fraksi heksana alga laut merah laurencia tronoi,  sehingga alga laut ini dapat dikembangkan sebagai pangan fungsional”. Metode ekstraksi yang digunakan adalah maserasi dengan metanol-air 50%, pada ekstrak metanol air dilakukan fraksinasi berkesinambungan dengan menggunakan pelarut n-heksana, etilasetat dan air. Fraksi n-heksana yang mempunyai aktivitas antibakteri tertinggi selanjutnya dimurnikan untuk mendapatkan isolat murni dengan menggunakan kromatografi kolom sebanyak 3 tahap.  Pendeteksian hasil pemisahan pada tiap tahap dilakukan dengan menggunakan kromatografi Lapis tipis. Pemisahan tahap 1 dan 2 menggunakan fasa diam silika gel 60F254 dan fasa  gerak heksana-etilasetat, sedangkan pemisahan tahap ke-3 menggunakan fasa diam silika gel 60F254 RP-18  dan fasa gerak air-metanol hingga didapatkan isolat murni. Karakterisasi struktur isolat murni  menggunakan metode spektrokopi NMR. Isolat murni yang dihasilkan berupa padatan amorf  berwarna putih dengan hasil interpretasi terhadap spectrum H-NMR, C-NMR, DEPT, HMQC, HMBC dan COSY adalah termasuk golongan senyawa sesquiterpen mempunyai rumus molekul C15H26O4  mempunyai nama IUPAC 3,3,9a-trimetil-6-metilen-dekahidro-1H-benzo[7] annulen-1,2,4a,8-tetraol. Isolat murni ini diduga adalah senyawa baru karena berdasarkan penelusuran literatu belum ditemukan struktur yang sama dengan struktur isolat murni yang dihasilkan dalam penelitian ini.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

Synthesis of 2-amino-5,7-dimethyl-4-oxopyrido[3,4-e]-1,3-thiazines

1983 ◽  
Vol 48 (12) ◽  
pp. 3426-3432 ◽  
Author(s):  
Dušan Koščík ◽  
Pavol Kristian ◽  
Ondrej Forgáč
Keyword(s):  
Spectral Data ◽  
Chlorine Atom ◽  
Mass Spectra ◽  
High Reactivity ◽  
Secondary Amines ◽  
Dimroth Rearrangement ◽  
H Nmr ◽  
New Synthesis ◽  
C Nmr

New synthesis of pyrido[3,4-e]-1,3-thiazines consisting in reaction of 2,6-dimethyl-4-chloronicotinoyl isothiocyanate with primary or secondary amines, or with benzaldehyde phenylhydrazone, is described. High reactivity of the chlorine atom does not allow isolation of the corresponding thioureas, arising as intermediates, except in the case of the benzylamino derivative. Structure of the products was unequivocally confirmed by their spectral data (IR, UV, 1H NMR, 13C NMR and mass spectra). The synthesized derivatives do not undergo the Dimroth rearrangement.

Oxynemorensine, an alkaloid from Senecio nemorensis L., var. subdecurrens GRISEB

1980 ◽  
Vol 45 (2) ◽  
pp. 548-558 ◽  
Author(s):  
Antonín Klásek ◽  
Petr Sedmera ◽  
Jindřich Vokoun ◽  
Anna Boeva ◽  
Svatava Dvoráčková ◽  
...  
Keyword(s):  
Unsaturated Acid ◽  
Mass Spectra ◽  
H Nmr ◽  
C Nmr

From S. nemorensis L., var. subdecurrens GRISEB. there were isolated the previously obtained alkaloids nemorensine (I), retroisosenine (II), bulgarsenine (III) and, in addition, the alkaloid oxynemorensine which was assigned the structure VIII on the basis of the interpretation of the 1H-NMR, 13C-NMR, mass spectra, and on that of the identification of the products of hydrolysis and reduction. Furthermore, the isolation of the cis-nemorensic acid (V) as well as that of the unsaturated acid IV, and the transformation of bulgarsenine (III) to nemorensine (I) were described.

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

2006 ◽  
Vol 71 (10) ◽  
pp. 1470-1483 ◽  
Author(s):  
David Šaman ◽  
Pavel Kratina ◽  
Jitka Moravcová ◽  
Martina Wimmerová ◽  
Zdeněk Wimmer
Keyword(s):  
Analytical Data ◽  
Chiral Hplc ◽  
Nmr Analysis ◽  
Target Structure ◽  
Enantiomerically Pure ◽  
Whole Cells ◽  
H Nmr ◽  
Structure Assignment ◽  
Related Compounds ◽  
C Nmr

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

Synthesis, characterization and computational studies of 1,3-bis[(E)-furan-2-yl)methylene]urea and 1,3-bis[(E)-furan-2-yl)methylene]thiourea

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Kazeem Adelani Alabi ◽  
Ibrahim Olasegun Abdulsalami ◽  
Moriam Dasola Adeoye ◽  
Shukurat Modupe Aderinto ◽  
Rasheed Adewale Adigun
Keyword(s):  
Energy Surface ◽  
Salmonella Typhi ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Thiourea Derivatives ◽  
H Nmr ◽  
Complete Relaxation ◽  
Cercospora Zeae Maydis ◽  
Global Parameters ◽  
C Nmr

AbstractUrea and thiourea derivatives: 1,3-bis[(E)-furan-2-yl)methylene]urea (BFMU) and 1,3-bis[(E)-furan-2-yl)methylene]thiourea (BFMT) were synthesized and characterized by spectrometry analyses (UV, IR, 1H NMR and 13C NMR). They were screened for antibacterial (Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa, Xanthomonas axonopodis and Streptococcus bovis) and antifungal (Fusarium oxysporum, Colletotrichum gloeosporioides and Cercospora zeae-maydis) activities. Quantum chemical calculations of frontier molecular orbital energies (EHOMO and ELUMO), and their associated global parameters were carried out by DFT levels of theory, with complete relaxation in the potential energy surface using 6-31G* basis set (DFT/B3LYP/6-31G*). Azomethine functional groups (C=N) appeared at δ 7.6 ppm and δ 7.0 ppm in the proton spectra, the peaks between δ 105 and δ 160 ppm of 13C spectra represent the methylene carbons (C=C). BFMU is a better inhibitor of P. aeruginosa and S. bovis, while BFMT is a better inhibitor of S. typhi, S. aureus and X. axonopodis and the fungi isolates (F. oxysporum, C. gloeosporioides and C. zeae-maydis) used. The global parameters agreed favorably with the experimental results, indicating the higher activity of BFMT.

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

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.

Triazolopyridine nucleosides. II. Glycosylations of 3-oxo-s-triazolo[4,3-a]pyridines with accompanying conversions into 2-oxo-s-triazolo[1,5-a]pyridine nucleosides

1977 ◽  
Vol 55 (5) ◽  
pp. 831-840 ◽  
Author(s):  
Brian Maurice Lynch ◽  
Suresh Chandra Sharma
Keyword(s):  
General Structure ◽  
Spectroscopic Properties ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
H Nmr ◽  
Pyridine Nitrogen ◽  
Methyl Derivatives ◽  
Fragmentation Patterns ◽  
Ribose Moiety ◽  
C Nmr

3-Oxo-s-triazolo[4,3-a]pyridine and various C-methyl derivatives (general structure 1) have been converted into the 2-β-D-ribofuranosyl species 2 and thence 4 via Friedel–Crafts catalyzed reaction with tetra-O-acetyl-β-D-ribofuranose, followed by deblocking. During the course of these reactions, rearrangements into the isomeric 3-β-D-ribofuranosyl-2-oxo-s-triazolo[1,5-a]-pyridines occur through ring-opening of the pyridine rings yielding species 3 and 5. The proportion of rearrangement products is dependent upon the position and number of the C-methyl substituents.Structural assignments for these compounds are based upon comparisons of spectroscopic properties (1H nmr, 13C nmr, uv) with model compounds from each isomeric series; structural assignments for these models are based on unequivocal mass-spectral fragmentation patterns. Unlike related triazolopyridine nucleosides with the ribose moiety attached to a pyridine nitrogen (Lynch and Sharma (1976)), there are no unusual aspects in the conformations of the nueleosides of types 4 and 5.

scholarly journals Design and synthesis of a novel 5-(aminomethylene)thiazolidine-2,4-dione derivatives as potent hepatitis-B virus polymerase inhibitors

2015 ◽  
Vol 10 (2) ◽  
pp. 271
Author(s):  
Wei-Guo Li ◽  
He-Qun Wang
Keyword(s):  
Hbv Dna ◽  
Biologically Active ◽  
Secondary Amines ◽  
Design And Synthesis ◽  
H Nmr ◽  
Viral Antigens ◽  
Polymerase Inhibitors ◽  
Potent Inhibition ◽  
B Virus ◽  
C Nmr

<p>A series of novel thiazolidinedione analogues (TZD) were designed and synthesized potent inhibitors of HBV capsid assembly. The synthesis of thiazolidine-2,4-dione derivatives (4a–4o), starting from the condensation of 5-(ethoxymethylene)thiazolidine-2,4-dione (1) with various secondary amines (3) derived from biologically active compounds. The newly synthesized TZD analogues 4a-4o were characterized by <sup>1</sup>H NMR, <sup>13</sup>C NMR, and MS and evaluated for their anti-HBV activity. Most of the compounds inhibited the expression of viral antigens at low concentration. Six compounds, 4g, 4h, 4l, 4m, 4n, and 4o, demonstrated potent inhibition of HBV DNA replication at submicromolar range. Of these five initial hits, compound 4o was the most active when compared with lamivudine.</p><p> </p><p> </p>

E-Homolupane Derivatives Substituted in Position 17 and 22a. 1H NMR, 13C NMR and IR Spectra

1995 ◽  
Vol 60 (4) ◽  
pp. 619-635 ◽  
Author(s):  
Václav Křeček ◽  
Stanislav Hilgard ◽  
Miloš Buděšínský ◽  
Alois Vystrčil
Keyword(s):  
Nmr Spectra ◽  
2D Nmr ◽  
Coupling Constants ◽  
Side Chain ◽  
Oxidation Reactions ◽  
H Nmr ◽  
Complete Assignment ◽  
Nmr Techniques ◽  
Intramolecular Association ◽  
C Nmr

A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1H NMR, 13C NMR and IR spectroscopy. The kind of intramolecular association of the 17α-hydroxy group was studied in connection with modification of the side chain and substitution in position 22a. Complete assignment of the hydrogen signals and most of the coupling constants was accomplished using a combination of 1D and 2D NMR techniques. The 1H and 13C NMR spectra are discussed.

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