نتایج جستجو برای: β diketones
تعداد نتایج: 177869 فیلتر نتایج به سال:
عاملهای شناختی، شخصیتی و موقعیتی متعددی یافت شده است که می توانند با پرخاشگری ارتباط داشته باشند. فهم چگونگی ارتباط درونی این عاملها برای پیش بینی، سنجش، و درمان پرخاشگری زندانیانی که سابقه رفتارهای پرخاشگرانه را دارند، بسیار اساسی است. پژوهشهای قبلی نقش بالقوه ای را برای توانایی حل مساله اجتماعی بعنوان یک میانجیگر بین تکانشگری و پرخاشگری پیشنهاد کرده اند. ( موران و همکاران، 2002). علاوه بر این...
1,2-Diketones have been reacted in one-pot method with 1,2-diamines at room temperature with ZnO nanoparticles as a catalyst. ZnO nanoparticles as an available and reusable catalyst is used for the synthesis of Quinoxalinein improved yields.
Recently described scientific literature has identified the airborne presence of 2,3-butanedione (diacetyl) and 2,3-pentanedione at concentrations approaching or potentially exceeding the current American Conference of Industrial Hygienists' (ACGIH) Threshold Limit Values (TLVs) at commercial coffee roasting and production facilities. Newly established National Institutes of Occupational Safety...
A simple, chemoselective transfer hydrogenation of aryl aldehydes with the aid of Amberlite((R)) resin formate (ARF), a stable H-donor, in the presence of catalytic ruthenium trichloride is described. Aromatic aldehydes and 1,2-diketones are reduced efficiently and selectively, while aryl ketones remain unchanged. Several other potentially reducible groups attached to the aromatic moiety are un...
Silica supported phosphorus pentoxide (P2O5·SiO2) is an efficient catalyst for synthesis of 1,3,5-substituted pyrazoles via the condensation of 1,3-diketones and hydrazines. Simplicity of procedure, mild condition, being solvent-free, high yields, and easy workup are some advantages of this protocol.
In present paper a simple procedure for the synthesis of enaminones without catalyst from 1,3-diketones that reacted with primary or secondary amines in ethanol as solvent, as well as the reaction of enaminones with unsaturated esters such as dimethyl acetylene dicarboxylate are reported.
in present paper a simple procedure for the synthesis of enaminones without catalyst from 1,3-diketones that reacted with primary or secondary amines in ethanol as solvent, as well as the reaction of enaminones with unsaturated esters such as dimethyl acetylene dicarboxylate are reported.
Over the last decade, concerns have been raised about potential respiratory health effects associated with occupational exposure to the flavoring additives diacetyl and 2,3-pentanedione. Both of these diketones are also natural components of many foods and beverages, including roasted coffee. To date, there are no published studies characterizing workplace exposures to these diketones during co...
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