Research on Chemical Intermediates ( IF 2.8 ) Pub Date : 2022-02-01 , DOI: 10.1007/s11164-021-04655-9 Dawei Zhang 1 , Ailing Liu 1 , Yang Lv 1 , Lu Ren 2 , Yumin Zhang 3 , Qiang Gu 3
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Abstract
An efficient synthesis of 1,3,5-trisubstituted-1H-pyrazoles was developed via cyclocondensation in 78–92% yields starting from α,β-unsaturated aldehydes/ketones with substituted phenylhydrazine using vitamin B1 as a catalyst, and was characterized by HR-MS, FT-IR, 1H NMR and 13C NMR spectroscopy. The reaction has simple operation, metal-free catalysis, acid or base free catalysis. As a green catalyst, vitamin B1 was found to possess favorable catalytic activity and reusability for the condensation reaction. 1,3,5-trisubstituted-1H-pyrazole shows from orange-red to cyan in different solvents when the electron withdrawing group is attached to acetophenone (taking compound 5i as an example). Compound 5i as a metal ion fluorescent probe has excellent selectivity for Ag+ detection. The crystal structure of the compound 3-(4-chlorophenyl)-1,5-diphenyl-4,5-dihydro-1H-pyrazole (5b) in the orthorhombic space group Pca 21 was presented and formed racemic crystals.
Graphical abstract
中文翻译：
维生素B1催化1,3,5-三取代-4,5-二氢-1H-吡唑的合成及其荧光性质
摘要
1,3,5-三取代-1 H-吡唑的高效合成是通过以维生素 B 1为催化剂的α , β-不饱和醛/酮与取代苯肼开始的缩合反应，收率为 78-92% ，并对其进行了表征通过 HR-MS、FT-IR、1 H NMR 和13 C NMR 光谱。该反应操作简单，无金属催化，无酸或碱催化。作为一种绿色催化剂，维生素B 1被发现具有良好的催化活性和缩合反应的可重复使用性。1,3,5-三取代-1 H当吸电子基团与苯乙酮相连时，-吡唑在不同溶剂中呈现橙红色至青色（以化合物5i为例）。化合物5i作为金属离子荧光探针对Ag +检测具有优异的选择性。化合物3-(4-氯苯基)-1,5-二苯基-4,5-二氢-1H-吡唑( 5b )的晶体结构呈正交空间群Pca 21并形成外消旋晶体。
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