The diversity of products in the reaction of diethyl azodicarboxylate (DEAD)/diisopropyl azodicarboxylate (DIAD) and activated acetylenes with PIII compounds bearing oxygen or nitrogen substituents ...is discussed. New findings that are useful in understanding the nature of intermediates involved in the Mitsunobu reaction are highlighted. X-ray structures of two new compounds (2-t-Bu-4-MeC6H3O)P (μ-N-t-Bu)2P+(NH-t-Bu)N(CO2-i-Pr)(HNCO2-i-Pr)(Cl-)(2-t-Bu-4-MeC6H3OH)(23)and CH2(6-t-Bu-4-Me-C6H2O)2P(O)C(CO2Me)C-(CO2Me)CClNC(O)Cl (33) are also reported. The structure of23 is close to one of the intermediates proposed in the Mitsunobu reaction.
Aminophosphoranes 2 and 4−9 with a cyclohexylamino substituent and ring sizes varying from five to eight have been synthesized by oxidative addition reactions of cyclic aminophosphites with diols or ...1,2-diketones. The reactivities of these phosphoranes are compared with those of the corresponding cyclic aminophosphites. The difference in hydrolytic pathways between amino- and analogous phenoxyphosphoranes is discussed. X-ray structures of two sets of compounds, (a) (C6H11NH)P(OCH2CMe2CH2O) (1) and (C6H11NH)P(OCH2CMe2CH2O)(1,2-O2C6Cl4) (2) and (b) (C6H11NH)P{O-(t-Bu)2C6H2)2CH2} (3) and (C6H11NH)P{(O-(t-Bu)2C6H2)2CH2}(1,2-O2C6H4)·1/2Et2O (4·1/2Et2O) have been determined and geometrical parameters compared between the P(III) and the corresponding P(V) compounds. In 1, the six-membered ring has a chair conformation with the amino group axial; in 2, the six-membered ring is located apical-equatorial in a trigonal bipyramidal geometry and has a boat conformation. The eight-membered ring has a boat-chair conformation in 3, whereas the same ring has a tub conformation in 4.
1- Methylcyclopropene (1-MCP) has been identified as a safe chemical tested successfully in extending shelf life while maintaining quality of plant products. 1-MCP, at very low concentrations, ...usually blocks ethylene receptors and then inhibits the action of ethylene delaying further ripening and senescence. Several studies have been conducted elsewhere for delaying ripening of different banana cultivars such as Cavendish, Prata, Tella Chakkerakeli, Beragan and Kolikuttu. Physiological reactions related with ripening of banana are delayed by inhibition of ethylene perception, while ethylene synthesis of banana fruit can be regulated at suppressed levels of ACS and ACO by 1-MCP. The effectiveness of 1-MCP on bananas varies with the maturity of the fruit. Fumigation, the conventional application method, has some limitations, particularly long exposure duration, uneven ripening and green ripening in bananas. Application of 1-MCP in aqueous form is recently developed to minimize these limitations. Micro-bubbling and controlled release packaging technologies are effective tools of application of 1-MCP on bananas. This review compiles and critically analyses the existing knowledge on the technological use of 1-MCP, clarifies inconsistencies in different publications.
Without appropriate stitching of scan chains, even with good diagnosis algorithm and diagnostic pattern generation, the chain diagnostic resolution may still be bad. In this paper, we propose a novel ...pattern-independent diagnosis and layout aware (DLA) scan chain stitching method: 1) the resolution is improved by increasing and properly distributing the sensitive scan cells, which can capture useful diagnostic information under both single- and multiple-fault situations; and 2) the scan cell layout placement is taken into account to reduce routing overhead and hence preserve the chip performance. Experiments using two different techniques to diagnose ISCAS'89/ITC'99 benchmark circuits with/without embedded scan compaction show the effectiveness of the proposed method in improving the diagnostic resolution. Impacts on chip performance, embedded scan compaction, transition fault coverage, and test power dissipation are negligible. The proposed method is also successfully applied to an industry circuit manufactured with 20-nm technology. The silicon results show 7× average resolution improvement comparing to without using the DLA scan chain stitching.
The functionalization of materials for ultrasensitive detection of heavy metal ions (HMIs) in the environment is crucial. Herewith, we have functionalized inexpensive and environmentally friendly Fe
...O
nanoparticles with D-valine (Fe
O
-D-Val) by a simple co-precipitation synthetic approach characterized by XRD, FE-SEM, and FTIR spectroscopy. The Fe
O
-D-Val sensor was used for the ultrasensitive detection of Cd
, Pb
, and Cu
in water samples. This sensor shows a very low detection limit of 11.29, 4.59, and 20.07 nM for Cd
, Pb
, and Cu
, respectively. The detection limits are much lower than the values suggested by the world health Organization. The real water samples were also analyzed using the developed sensor.
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