scholarly journals Molecular structure and intramolecular hydrogen bonding in 2-hydroxybenzophenones: A theoretical study

2014 ◽  
Vol 126 (4) ◽  
pp. 919-929 ◽  
Author(s):  
MANSOUREH ZAHEDI-TABRIZI ◽  
SAYYED FARAMARZ TAYYARI ◽  
FARIDEH BADALKHANI-KHAMSEH ◽  
REIHANEH GHOMI ◽  
FATEMEH AFSHAR-QAHREMANI
10.1002/jcc.2 ◽  
1996 ◽  
Vol 17 (16) ◽  
pp. 1804-1819 ◽  
Author(s):  
Attila Kov�cs ◽  
Istv�n Kolossv�ry ◽  
G�bor I. Csonka ◽  
Istv�n Hargittai

1996 ◽  
Vol 52 (1) ◽  
pp. 145-150 ◽  
Author(s):  
T. R. Govindachari ◽  
Geetha Gopalakrishnan ◽  
S. S. Rajan ◽  
V. Kabaleeswaran ◽  
L. Lessinger

Azadirachtin-H, isolated from the seed kernels of Azadirachta indica (neem), crystallizes in space group I4, Z = 8, with disordered ethyl acetate solvent filling channels along the fourfold rotation axes. The crystal structure determination showed that the previously reported molecular structure deduced from NMR studies was correct except for the stereochemistry at C(11). Azadirachtin-H, which belongs to a group of C-seco-tetranortriterpenoids (C-seco-limonoids) of great interest for their insect antifeedant and ecdysis-inhibiting activity, has some unusual features: the absence of a carbomethoxy group at C(11); the presence of a cyclic hemiacetal function at C(11); the α-orientation of the hydroxyl group on C(11), opposite to that in all other known azadirachtins with a hydroxyl group on C(11), except azadirachtin-I. There is no intramolecular hydrogen bonding. In this crystal the rotation of the two major moieties of the azadirachtin-H molecule about the single connecting C(8)—C(14) bond is quite different from that in azadirachtin-A, whose crystal structure has recently been determined.


2015 ◽  
Vol 80 (21) ◽  
pp. 10521-10535 ◽  
Author(s):  
Mark Sigalov ◽  
Bagrat Shainyan ◽  
Nina Chipanina ◽  
Larisa Oznobikhina ◽  
Natalia Strashnikova ◽  
...  

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