1H-Benzimidazole-2-carboxaldehyde

1H-benzimidazole-2-carbaldehyde is a benzimidazolecarbaldehyde.

15 mL (276 mmol, 6.6 eq) of concentrated sulfuric acid was slowly added dropwise to 8.40 g (41.8 mmol) of compound L5, Yellow bubbles, 10min after the drop is completed, At this time compound L5 is completely dissolved, The oil bath was heated at 80 ° C for 1 h and the reaction was stopped. Cold to room temperature, Add 150mL ice water, 4N NaOH aqueous solution adjusted to pH 7, At this time the original transparent solution in the precipitation of yellow solid, Filter, drying, Get 5.21g, The yield was 85.3percent. To give 1H-benzimidazole-2-formaldehyde, Compound code L6.200 mesh hydroxyapatite powder, 0.008g as catalystUse 52 mL of hot water as solvent, The reaction was carried out with 0.1 mol o-phenylenediamine and 0.11 mol glyoxylic acid as raw materials. The reaction time was 6 hours and the reaction temperature was 52°C.After the reaction is over, Hot filter, Cool the filtrate to 2 °CWhite crystals precipitated, Filtered to obtain crystals, 35 °C vacuum drying overnight, That is, benzimidazole-2-formaldehyde 11.9g, yield 81percent, Purity 99.6percent, The procedure for gram scale oxidation of (1H-benzo[d]imidazol-2-yl)methanol to 1H-benzo[d]imidazole-2-carbaldehydewas as follows: (1H-benzo[d]imidazol-2-yl)methanol (0.1 mol, 14.8 g) and [Ru(bpbp)(pydic)] (0.001 mmol, 7.32 × 10−3 g) wereadded into a reactor. The reactor containing this mixture was heatedto 50 °C in an oil bath under vigorous stirring and then 30percent H2O2(30 mL, 0.3 mol) was slowly dropwise over a period of 30 min. The mixture was stirred for 5 h. After filtering, the solution wasevaporation under reduced pressure at 50 °C. Pure 1H-benzo[d]imidazole-2-carbaldehyde (0.07 mmol, 10.2 g) was obtained with ayield of 70percent after recrystallisation from 30percent H2SO4 solution. Theproduct, 1H-benzo[d]imidazole-2-carbaldehyde, was identified byits 1H NMR spectrum.The method for synthesizing 2-aldehyde benzimidazole in this example is as follows2-Hydroxymethylbenzimidazole (0.1 mol, 14.8 g)The rhodium complex (10-4 mol, 0.0577 g) in was added to the reaction vessel.Hydrogen peroxide (30percent, 0.3 mol, 9.1 ml) was slowly added to the reaction vessel with stirring.The reaction temperature was controlled at 50°C for several hours.The reaction solution was concentrated under reduced pressure, Obtain a solid product, The solid product was dissolved in dichloromethane and subjected to silica gel column chromatography.Get pure product2-aldehyde benzoimidazole 8.32 g, Yield 57percent.General procedure: To a stirred solution of the (1H-benzo[d]imidazol-2-yl)methanol from above (2.6 mmol) in dryCH2Cl2/MeOH (6:1, 3.5 mL) was added activated manganese dioxide (85percent purity, <5 micron, 2.328 g, 22.8 mmol)and the suspension stirred overnight, at which point the black slurry was filtered through a cake of celite andwashed with MeOH (3x5 mL). The combined washings were concentrated to afford a dark brown solid.Purification of the crude product by column chromatography on silica gel (CH2Cl2:MeOH, 98:2 to 95:5) affordedthe title compound 1H-benzo[d]imidazole-2-carbaldehyde (2i) (0.245 g, 51percent).1.

Molecular Weight:146.15
XLogP3:1.1
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:146.048012819
Monoisotopic Mass:146.048012819
Topological Polar Surface Area:45.8
Heavy Atom Count:11
Complexity:160
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes