The molecular structure of 3(5)-methyl-4,5(3)-trimethylenepyrazole hydrochloride and its13C and15N NMR spectroscopy

1993 ◽  
Vol 23 (12) ◽  
pp. 961-965 ◽  
Author(s):  
Monique Perrin ◽  
Alain Thozet ◽  
Sylvain Lecocq ◽  
Jose Elguero ◽  
Ana Martinez ◽  
...  
Planta Medica ◽  
2014 ◽  
Vol 80 (10) ◽  
Author(s):  
S Groscurth ◽  
T Kühn ◽  
P Kessler ◽  
V Rukachaisirikul

2021 ◽  
Vol 83 (6) ◽  
pp. 49-54
Author(s):  
B.P. Matselyukh ◽  

The aim of this work was the isolation, purification and some properties investigation of two regulators of antibiotic biosynthesis of streptomycetes. Methods includes extraction of regulators from agar cultures and their concentration by vacuum rotary evaporator, thin layer chromatography and spectrophotometry. Results. Two strains of streptomycetes AN26 and B35 isolated from soils of different regions of Ukraine produce the regulators restoring the landomycin E biosynthesis and sporulation in mutant strain Streptomyces globispoprus 1912-B2. Both regulators were purified by thin layer chromatography and have the same Rf 0.69. Absorption curves of regulators were established by means of spectrophotometry. Maxima of absorption of regulators were 232.5 nm. The next study of the isolated regulators by means of NMR will give the possibility to elucidate their molecular structures. Conclusions. It is shown that two strains of streptomycetes isolated from the soils of Askania Nova and Brovary produce transcriptional regulators such as signaling molecules, which, like A-factor, restore the biosynthesis of antibiotics landomycin E and streptomycin in test strains S. globisporus 1912-B2 and S. griseis 1439, respectively. In terms of absorption maxima, they are similar and differ from similar indicators of known regulators of streptomycetes. It is possible that these compounds belong to new, not yet described signaling molecules, and the answer to this question will give future studies of their molecular structure by NMR spectroscopy.


Author(s):  
Rosa María Claramunt ◽  
María Dolores Santa María ◽  
Isabelle Forfar ◽  
Francisco Aguilar-Parrilla ◽  
María Minguet-Bonvehí ◽  
...  

1986 ◽  
Vol 41 (6) ◽  
pp. 722-730 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Eduard Michels ◽  
Jürgen Kaub

11-Isopropylidene-bicyclo[4.4.1]undeca-2,4,8-triene (IBU, 1A) and five alkyl substituted de­rivatives (1B-1F) contain a conjugated diene unit and two isolated CC-double bonds, one exocyclic and one incorporated into the bicvclus, each suited for complexation to transition metals. With [Cr(CO)3(CH3CN)3] (2) 1A-1F form [Cr(CO)3(η6-IBU)] complexes (3A−3F). in which the IBU ligands are coordinated to the chromium via the diene unit and the exocyclic CC-double bond. The corresponding [Mo(CO)3(η6-IBU)] complexes (5A−5F) are obtained from the reactions of [Mo(CO)3(diglyme)] (4) with 1A−1F. In addition, the isomeric [Mo(CO)3(η6-IBU)] complexes (6A−6D) are formed, in which the IBU ligands are bound to molybdenum via the three cyclic CC-double bonds. The complexes 3A−3F, 5A−5F and 6A−6D were studied by IR and NMR spectroscopy (1H. 13C) and characterized by C, H elemental analyses. The crystal and molecular structure of 1A was determined by X-ray structure analysis.


2019 ◽  
Vol 264 ◽  
pp. 01005
Author(s):  
Masahiro Inagaki ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida ◽  
Yuji Kashima

In this study, rolling contact fatigue (RCF) tests were performed in order to investigate the effect of groove radius on the life of PEEK-PTFE hybrid radial bearings. Furthermore, solid state NMR spectroscopy was performed in order to investigate the molecular structure of PEEK. It was found that groove radius shape was related to limitations of the bearings, and the molecular structure of the PEEK was not changed by the temperature rise in this test. Furthermore, thermal failure of the PEEK was not affected by oxidation during RCF test.


2007 ◽  
Vol 62 (12) ◽  
pp. 1509-1513 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Oleg L. Tok ◽  
Wolfgang Milius

The 1 : 1 reactions of triphenylborane 1 with monoalkyn-1-yltin compounds Me3Sn-C≡C-R1 2 [R1 = tBu (a), Ph (b), ferrocenyl (c), Si(H)Me2 (d), SnMe3 (e)] afford mainly (> 80 %) the corresponding alkene derivatives 3 by 1,1-phenylboration. Exchange B-Ph/Sn-C≡C-R1 takes place as a side reaction. The corresponding 1 : 2 reaction with 2b leads to the dialkenylborane 4b (R1 = Ph), of which the molecular structure could be determined by X-ray analysis. In contrast, the 1 : 2 reaction with 2e gave an allene derivative 5e. The solution-state structures of compounds 3 - 5 have been confirmed by 1H, 11B, 13C and 119Sn NMR spectroscopy.


2008 ◽  
Vol 63 (3) ◽  
pp. 275-279 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Ezzat Khan ◽  
Rhett Kempe

Protodeborylation of triorganoboranes, usually carried out under mild reaction conditions using an excess of acetic acid, affords 1,5-dialkyl-3,7-dimethyl-4,8,9-trioxa-2,6-dioxonia-1,5-diboratabicyclo [3.3.1]nona-2,6-dienes OB(R)OC(Me)OB(R)OC(Me)O [1 (R = Et), 2 (R = cyclooctyl)]. Acetoxy(dialkyl) boranes and di(acetoxy)alkylboranes were not formed in an appreciable amount. Compounds 1 and 2 were characterized by NMR spectroscopy (1H, 11B, 13C NMR) in solution, the molecular structure of 2 was determined by X-ray analysis. The gas-phase geometry of 1 was optimized by calculations [B3LYP/6-311+G(d, p) level of theory], and its NMR parameters were also calculated at the same level of theory.


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