Showing papers by "Islamic Azad University published in 1996"
TL;DR: In this paper, a one-pot synthesis of highly functionalized ketenimines by reaction of alkyl isocyanides with dialkyl acetylenedicarboxylates in presence of 1,3-diphenylpropan-1, 3-dione is reported.
Abstract: A one-pot synthesis of highly functionalized ketenimines by reaction of alkyl isocyanides with dialkyl acetylenedicarboxylates in presence of 1,3-diphenylpropan-1,3-dione is reported.
18 citations
TL;DR: In this article, semi-empirical SCF MO calculations are used to investigate the conformational properties of five-to eight-membered ring sulfur diimides. But the energy barrier for interconversion of C 2 and C s conformations is only 7.5 kJ mol −1.
Abstract: MNDO semiempirical SCF MO calculations are used to investigate the conformational properties of five- to eight-membered ring sulfur diimides ( 1–4 ). Dimethylene sulfur diimide ( 1 ) is planar with C 2 v symmetry. The plane symmetrical puckered conformation of trimethylene sulfur diimide ( 2 ) is calculated to be only 6.4 kJ mol −1 more stable than the planar C 2 v transition-state geometry. Tetramethylene sulfur diimide ( 3 ) has two energy-minimum conformations with the envelope ( C 2 ) form, being 2.5 kJ mol −1 more stable than the half-chair ( C s ) geometry. The calculated energy barrier for interconversion of C 2 and C s conformations is only 7.5 kJ mol −1 . Two energy-minimum conformations with similar energies were found for pentamethylene sulfur diimide ( 4 ), separated by a relatively high (29.6 kJ mol −1 ) energy barrier.
5 citations
Journal Article•
TL;DR: Among isolated bacteria, lactobacilli (37 isolates) had stronger activity against gram-negative pathogens, and S. aureus was more sensitive to lactococci than lactOBacilli, which provides a natural mean of preservation.
Abstract: 71 samples of milk and dairy products were collected from 18 cities throughout Iran. 93 strains of lactic acid bacteria (LAB) were isolated and assayed against four opportunistic patho gens including E. coli, proteus and klebsiella as gram-negative and S. aureus as a gram-positive organism. All indicators (organisms) were hospital strains. Among isolated bacteria, lactobacilli (37 isolates) had stronger activity against gram-negative pathogens. 37 isolates were lactococci out of which 9 strains were leuconostocs and seven strains were S.jaecalis. S. aureus was more sensitive to lactococci than lactobacilli. Only one isolate of leuconostoc inhibited the growth of gram-negative indicators, but five isolates inhibited S. aureus. The use of bacteriocin-producing lactic acid bacteria in dairy products provides a natural mean of preservation.
1 citations
TL;DR: In this paper, semi-empirical AM1 MO calculations for important conformations of oxocane and 1,3-dioxocane (2) are reported.
Abstract: AM1 semi-empirical SCF MO calculations are reported for important conformations of oxocane (1) and 1,3-dioxocane (2). The boat-chair conformation of1 (BC-1) is found to be the most stable form, whereas the crown family conformation is calculated to be 3.7 kJ·mol−1 less stable. The boat-boat form of1 is 15.9 kJ·mol−1 less stable thanBC-1. The boat-chair conformation of2 (BC-1,3) is calculated to be the most stable form of 1,3-Dioxocane. The crown-family conformation and the boat-boat geometry of this compound are 4.2 and 8.3 kJ mol−1 less stable thanBC-1,3.
1 citations