Synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles in water using p-dodecylbenzenesulfonic acid as catalyst

1H‐NMR, Photophysical, and pH Studies of 4‐(4,5‐Diphenyl‐1H‐imidazol‐2‐yl)benzaldehyde through Experimental and DFT Theoretical Analysis

“…The main halochromic compounds classes are: phthalides, [6] coumarin, [7] azo dyes, [8] and Imidazole derivatives [9,10] etc., In particular, the imidazole derivatives have been shown as impressive fluorophores due to their larger π-conjugated structure and acidity nature of the NH-group. These optical properties have been exploited in different applications like photographic materials, luminescent materials, two-photon absorption applications, two-photon fluorescence microscopy, high density storage and 3D microfabrication, Non Linear Optics (NLO), Dye Sensitized Solar Cells (DSSC), Organic Light Emitting Diodes (OLEDs) and molecular switches, etc., [11][12][13] The well-known 4-(4,5-diphenyl-1H-imidazol-2-yl)benzaldehyde (DPI-BA) ( Figure 1) has been condensed with various functional groups to make a different push-pull chromophore motifs such as D-π-A, D-π-D or A'-π-A, Y-shaped so on. [14][15][16] On the other hand, the NMR technique together with quantum chemical methods have been used to screen halochromic or sensor behavior for different substances such as 5fluorouracil, [17] 2-aminoethyl dihydrogen phosphate zwitterion, [18] 1,3-dimethylbarbituric acid, [19] 5-methoxy-1H-benzo[d]imidazole-2(3H)-thione, [20] etc., to propose the anionic and [ 1.…”

Co(II) anchored glutaraldehyde crosslinked magnetic chitosan nanoparticles (MCS) for synthesis of 2,4,5‐trisubstituted and 1,2,4,5‐tetrasubstituted imidazoles

“…This work 40 min 78 [27] 720-900 min 82 [28] 240 min 81 [29] 240 min 86 [30] 45 min 87 [60] SCHEME 4 Proposed mechanism of the reaction …”

“…[21] 90 min 88 [30] 720-900 min 92 [28] 540 min 90 [26] 55 min 96 [31] 20 min 94 [32] 30 min 80 [27] 12 h 90 [63] 120 min 95 [33] 240 min 81 [29] 45 min 87 [60] 4b [26] 120 min 93 [33] 35 min 76 [27] 720-900 min 86 [32] 240 min 70 [29] 5a MCS-GT@Co(II)/EtOH, refluxing (5 mg) SiO 2 -cl/solvent free, 80°C (250 mg) DABCO/t-BuOH (10 ml), 60-65°C (0.7 mol%) DBSA/H 2 O, refluxing (20 mol%) PEG-400/110°C (1.5 g) Nano-crystalline sulfated zirconia (SZ)/EtOH/refluxing (25 mg)…”

“…[25] A variety of catalysts have been reported for the synthesis of multisubstituted imidazoles. [19,21,[26][27][28][29][30][31][32][33] Many of these methods suffer disadvantages like harsh reaction conditions, difficult work-up procedure with large amount of toxic waste generated, use of expensive catalysts and reagents, separation of catalyst from reaction mixture, low yield of product, prolonged reaction time, moisture-sensitive catalyst, high temperature conditions, occurrence of side reactions leading to the formation of side products (including reversed aldol condensation and oxazole formation), lack of generality, in some cases use of more than one step for the formation of product, and strongly acidic conditions. So the development of a simple, clean, efficient, high-yielding, environmentally friendly approach to the formation of products with recyclable and reusable catalysts is still desirable and much in demand.…”

One Pot Synthesis of Multiaryl Imidazoles Catalyzed by Modified Active Carbon Surported FeCl3

“…制备 2,4,5-三取代咪 唑及 1,2,4,5-四取代咪唑类化合物的反应条件类似, 通 常由邻二酮、醛或胺为原料, 醋酸铵等为氮源通过多组 分 一 锅 法 合 成 . 采 用 的 催 化 剂 既 有 均 相 催 化 剂 如 KH 2 PO 4 [4] 、ZrOCl 2 •8H 2 O [5] 、杂多酸 [6] 、(C 4 H 9 ) 4 Br [7] 、 PEG-400 [8] 、InCl 3 •3H 2 O [9] 、InF 3 [10] 、分子碘 [11] 、烷基苯 磺酸 [12] 、离子液体 [13,14] 、铁磁流体 [15] 等, 也有负载型催 化剂如 SiO 2 -TiCl 4 [16] 、Al 2 O 3 -NiCl 2 [17] 、硅胶-NaHSO 4 [18] 、 SBA-15-TFE [19] 、 粘土负载钛化合物 [20] 、 高聚物催化剂 [21] 等. 尤其是近年来, 纳米材料负载催化剂在合成多取代 咪唑类化合物中得到广泛应用, 如纳米硅负载有机 酸 [22] 、水合氧化铝纳米颗粒 [23] 、纳米晶体 MgAl 2 O 3 [24] 、 纳米 Fe 3 O 4 负载离子液体 [25] 等.…”