- 2,5-diphenyl-oxazole preparation method
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The invention relates to a method for preparing scintillation pure grade 2,5-diphenyl oxazole (DPO or PPO for short). The method comprises the following steps: by taking benzoyl glycine as a raw material, performing multiple steps of reaction such as acylating chlorination, Frieldel-Crafts and ring formation, purifying middle products of each step without being separated, and preparing 2,5-diphenyl oxazole by using a one-pot method. An obtained product can be rectified and purified, the requirements of a scintillator cannot be met but metal oxide heating treatment is needed, and thus a 2,5-diphenyl oxazole product for scintillation fluor can be obtained. As the one-pot method is adopted to prepare 2,5-diphenyl oxazole, the reaction steps are reduced, the operation process is simplified, the production efficiency is improved, a purification method is simple, convenient and effective, and on-scale industrialization production is achieved.
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Paragraph 0026; 0027; 0036; 0037
(2019/02/04)
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- Synthesis of dipeptides using polymer bound hydroxamic esters - A comparative study of reactivity
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Poly(Methyl methaery late) and polystyrene supported hydroxamic esters have been prepared and developed as a new class of recyclable solid phase acylating reagents for the synthesis of peptides. The crosslinking agents used are DVB (divinyl benzene). EGDM
- Sophiamma,Sreekumar
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p. 995 - 999
(2007/10/03)
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- SYNTHESIS OF LUMINOPHORIC DERIVATIVES OF PBD BASED ON 2,5-DIARYL SUBSTITUTED THIAZOLES AND OXAZOLES
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The Friedel-Crafts acylation of 2-(biphenyl-4-yl)-5-phenyl-1,3,4-oxadiazole (PBD) with hippuryl chloride has been used to prepare the derivative V which on cyclization with POCl3 or P4S10 gives the respective oxazole (or thiazole) derivative of PBD, XIa or XIb.The reaction of carboxylic acid II with 4-(ω-aminoacetyl)biphenyl in the presence of CDI gives N-acyl-α-aminoketone VII; the analogous compound VI has been prepared by acylating ω-aminoacetophenone with acyl chloride III.The cyclization of these compounds gives bifluorophores Xa - Xd.
- Lhotak, Pavel,Kurfuerst, Antonin
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p. 2720 - 2728
(2007/10/02)
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- Process for the preparation of 2-(2-thienyl)-ethylamine and derivatives thereof
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The present invention provides a process for the preparation of 2-(2-thienyl)-ethylamine and derivatives thereof having the general formula: STR1 wherein R1 and R2 are hydrogen or taken together form a phenyl ring.
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- Acylaminoacetyl Derivatives of Active Methylene Compounds. 1. The Cyclization of the Benzoylaminoacetyl Derivatives to α-Substituted Tetramic Acids (1)
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Hippuric acid was converted to α-Y-substituted tetramic acids (Y = -CN, -CO2R and -COCH3) according to the following general scheme of reactions: a) preparation of the hippuric acid chloride or of its p-nitrophenyl ester; b) C-acylation of an active methy
- Igglessi-Markopoulou, Olga,Sandris, Constantine
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p. 883 - 890
(2007/10/02)
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