Dearomatizing Anionic Cyclization and Novel Skeletal Rearrangement:  High Yield Formation of Multiply Substituted Bicyclic or Polycyclic Spirocyclopentadienes and Phenanthrene Derivatives from 4-Aryl 1-Lithio-1,3-butadienes

2007 ◽  
Vol 72 (9) ◽  
pp. 3484-3491 ◽  
Author(s):  
Lantao Liu ◽  
Zhihui Wang ◽  
Fei Zhao ◽  
Zhenfeng Xi
1993 ◽  
Vol 58 (12) ◽  
pp. 2924-2935 ◽  
Author(s):  
Jane H. Jones ◽  
Bohumil Štíbr ◽  
John D. Kennedy ◽  
Mark Thornton-Pett

Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11] in boiling toluene solution results in an elimination of the platinum centre and cluster closure to give the ten-vertex closo species [6-(PMe2Ph)-closo-1-CB9H9] in 85% yield as a colourles air stable solid. The product is characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Crystals (from hexane-dichloromethane) are monoclinic, space group P21/c, with a = 903.20(9), b = 1 481.86(11), c = 2 320.0(2) pm, β = 97.860(7)° and Z = 8, and the structure has been refined to R(Rw) = 0.045(0.051) for 3 281 observed reflections with Fo > 2.0σ(Fo). The clean high-yield elimination of a metal centre from a polyhedral metallaborane or metallaheteroborane species is very rare.


2011 ◽  
Vol 57 (No. 6) ◽  
pp. 264-270 ◽  
Author(s):  
J. Pokorný ◽  
J. Pulkrábek ◽  
P. Štranc ◽  
D. Bečka

This paper evaluates the influence of genotype on the photosynthetic activity of hops in the period critical for generating yield. Results over three years from measuring the photosynthesis rate statistically show an increase in the photosynthetic activity of hop plants in the flowering stage. The average photosynthetic rates from measurements on the second date (BBA 65) in the years 2007, 2008, and 2009 increased by 17.9%, 45.6%, and 49.2%, respectively. Different photosynthesis curve trends during the final stage of ontogenesis of the plants indicate the maturity level of each hop genotype. As regards the genotypes for which photosynthesis did not reduce significantly, it may be assumed that such plants had not reached technical maturity. The results from the three-year study also show that any promising genotype, with respect to the photosynthesis rate and yield, is the result of breeding of new varieties with greater resistance to drought and high temperatures. Very good results in photosynthetic activity were reached by the new varieties exhibiting high yield and a similar chemical composition to Saaz hop and those sharing the same origins to Saaz, showing a higher content of bitter substances. In 2008 and 2009, all three new forms reached yield levels of 2.35 to 3.12 t/ha of dry hops.


ChemInform ◽  
1990 ◽  
Vol 21 (51) ◽  
Author(s):  
C. H. ZAMBRANO ◽  
A. K. MCMULLEN ◽  
L. M. KOBRIGER ◽  
P. E. FANWICK ◽  
I. P. ROTHWELL

2001 ◽  
Vol 24 (2) ◽  
Author(s):  
Taichi Nakano ◽  
Sigeyuki Nöda ◽  
Nao-aki A-ihara ◽  
Hirohide Yamashita ◽  
Takashi Miyamoto ◽  
...  

RSC Advances ◽  
2012 ◽  
Vol 2 (4) ◽  
pp. 1292-1295 ◽  
Author(s):  
Chun-Xia Zhao ◽  
Lei Yu ◽  
Anton P. J. Middelberg

1997 ◽  
Vol 62 (10) ◽  
pp. 1577-1584 ◽  
Author(s):  
Petr Štěpnička ◽  
Ivana Císařová ◽  
Jan Sedláček ◽  
Jiří Vohlídal ◽  
Miroslav Polášek

Exclusive, high-yield formation of the cyclotrimers of ethynylferrocene (1) was observed when TaCl5 in benzene was employed as catalyst. Analysis of the resulting isomer mixture by means of HPLC and 1H NMR revealed the presence of 1,3,5-triferrocenylbenzene (sym-2) and 1,2,4-triferrocenylbenzene (asym-2) in the ratio of 4 : 6. A small amount of pure sym-2 isomer was isolated, and its solid-state structure was established by single-crystal X-ray diffraction. The molecules of sym-2 possess a distorted up-up-down arrangement of the ferrocenyl groups attached to the benzene ring.


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