ChemInform Abstract: NMR SPECTRA OF PYRAZOLE DERIVATIVES OF BORON

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

Download Full-text

Preparation of 2,3-Dideoxy-2,3-epimino and 3,4-Dideoxy-3,4-epimino Derivatives of 1,6-Anhydro-β-D-hexopyranoses by Mitsunobu Reaction

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19980813 ◽

1998 ◽

Vol 63 (6) ◽

pp. 813-825 ◽

Cited By ~ 8

Author(s):

Jiří Kroutil ◽

Tomáš Trnka ◽

Miloš Buděšínský ◽

Miloslav Černý

Keyword(s):

Nmr Spectra ◽

Mitsunobu Reaction ◽

Derivatives Of ◽

C Nmr

A series of new 2-, 3- and 4-benzylamino-2-, 3- and 4-deoxy derivatives of 1,6-anhydro-β-D-hexopyranoses were prepared from 1,6:2,3- and 1,6:3,4-dianhydro-β-D-hexopyranoses by treatment with benzylamine and converted into 2,3-(N-benzylepimino)-2,3-dideoxy- and 3,4-(N-benzylepimino)-3,4-dideoxy-β-D-hexopyranoses of the D-allo, D-galacto and D-talo configuration by Mitsunobu reaction. The structures of benzylamino and benzylimino derivatives were confirmed by 1H and 13C NMR spectra.

Download Full-text

ChemInform Abstract: HETEROCYCLIC STEROIDAL, (16,15-C)PYRAZOLE DERIVATIVES OF ESTRADIOL AND ESTRONE

Chemischer Informationsdienst ◽

10.1002/chin.197546444 ◽

1975 ◽

Vol 6 (46) ◽

pp. no-no

Author(s):

P. DE RUGGIERI ◽

M. FAZIO ◽

G. MONOTORO ◽

O. SIGHINOLFI

Keyword(s):

Pyrazole Derivatives ◽

Derivatives Of

Download Full-text

Semisynthesis and acaricidal activities of isoxazole and pyrazole derivatives of a natural product bisdemethoxycurcumin

Journal of Pesticide Science ◽

10.1584/jpestics.d13-027 ◽

2013 ◽

Vol 38 (4) ◽

pp. 214-219 ◽

Cited By ~ 6

Author(s):

Jinxiang Luo ◽

Wei Ding ◽

Yongqiang Zhang ◽

Zhenguo Yang ◽

Yang Li ◽

...

Keyword(s):

Natural Product ◽

Pyrazole Derivatives ◽

Derivatives Of

Download Full-text

Carbon-13 NMR spectra of 1,6-bis derivatives of hexa-2,4-diynes

Magnetic Resonance in Chemistry ◽

10.1002/mrc.1260260720 ◽

1988 ◽

Vol 26 (7) ◽

pp. 626-628 ◽

Cited By ~ 1

Author(s):

K. C. Majumdar ◽

R. N. De ◽

B. K. Sen ◽

A. Banerji ◽

A. K. Mitra

Keyword(s):

Nmr Spectra ◽

Derivatives Of

Download Full-text

13C NMR spectra of hydrogenated polymers ofexo-5-methyl-,endo-5-methyl-, and 5,5-dimethyl-derivatives of bicyclo[2.2.1]hept-2-ene prepared by ring-opening metathesis polymerization

Macromolecular Chemistry and Physics ◽

10.1002/(sici)1521-3935(19980401)199:4<687::aid-macp687>3.0.co;2-a ◽

1998 ◽

Vol 199 (4) ◽

pp. 687-693 ◽

Cited By ~ 1

Author(s):

Andrew G. Carvill ◽

Ruth M. E. Greene ◽

James G. Hamilton ◽

Kenneth J. Ivin ◽

Alan M. Kenwrigth ◽

...

Keyword(s):

13C Nmr ◽

Ring Opening ◽

Nmr Spectra ◽

13C Nmr Spectra ◽

Ring Opening Metathesis Polymerization ◽

Metathesis Polymerization ◽

Derivatives Of

Download Full-text

Carbonylniobium Chemistry, IV Derivatives of η5 -C5H5Nb(CO)4 with Tridentate Phosphines

Zeitschrift für Naturforschung B ◽

10.1515/znb-1983-0409 ◽

1983 ◽

Vol 38 (4) ◽

pp. 446-448 ◽

Cited By ~ 4

Author(s):

Martin Hoch ◽

Dieter Rehder

Keyword(s):

Nmr Spectra ◽

Membered Ring ◽

Vanadium Complexes ◽

Ring Complexes ◽

Derivatives Of ◽

Induced Reaction

Abstract The photo-induced reaction between CpNb(CO)4 and Ph2P(CH2)2PR(CH2)2PPh2 (L; R = Ph, Cy) yields the chelated five-membered ring complexes cis-[CpNb(CO)2L] (two isomers in the case of R = Cy). The uncordinated PPh2 group reacts with CpNb(CO)3THF to form CpNb(CO)2(μ-L)CpNb(CO)3. IR, 31P and 93Nb NMR spectra are discussed and compared with corresponding data of the analogous vanadium complexes.

Download Full-text