8-Hydroxyquinoline-2-carboxaldehyde

yellow crystalline powder

3, 3′-(1E, 1′E)-(propane-1, 3-diylbis(azan-1-yl-1-ylidene))bis (methan-1-yl-1-ylidene)diquinolin-8-ol (H2PBIQ). A mixture of 8-hydroxyl-2-methylquinoline (4 g, 25 mmol), selenium dioxide (3.5 g, 31 mmol), H2O(3mL), 1, 4-diethylene dioxide (300 mL) was stirred at 80 °C for 24 h under the protectionof nitrogen. After cooling, the mixture wasfiltered and thefiltrate evaporated. Thesolid was purified by silica-gel column chromatography (developing solvent—petroleum ether:ethyl acetate, 95:5, v/v) to yield pure yellow needle crystalof 2-Formyl-8-hydroxyquinoline. Yield = 90percent;1H NMR (400 MHz, CDCl3):δ10.25 (s, 1H), 8.35 (d, J = 8.5 Hz, 1H), 8.18 (s, 1H), 8.09 (d, J = 8.5 Hz, 1H), 7.66 (t, J = 8.0 Hz, 1H), 7.46 (d, J = 8.2 Hz, 1H), 7.31 (d, J = 7.7 Hz, 1H).4.1.8 A solution of 2-methyl-quinolin-8-ol (536 mg, 3.37 mmol) in dioxane (8 mL) was added dropwise over 3 h into a stirred mixture of Se02 (665 mg, 5.99 mmol) in dioxane (25 mL) at 50 [- 55 C.] The resulting mixture was then heated at 80 [C] for 16 h, cooled, and the solids filtered off. The filtrate was concentrated and the residue purified by column chromatography on silica [(DICHLOROMETHANE/MEOH, ] 1: 0-40: 1). This afforded 8-hydroxy-quinoline-2-carboxaldehyde 4 as a straw-coloured solid (358 mg, 61percent). 4 :1H NMR [(CDC13)] : 8 10.24 (s, 1 H), 8.34 (d, [J=8.] 6, 1 H), 8.22 (br, 1 H), 8.07 (d, [J=8.] 6, [1] H), 7.64 (dd, [J=7.] 5 and 8.0, 1 H), 7.44 [(D, ] [J=8.] 0, 1 H), 7.30 (d, [J=7.] 5, [1] H). The mixture of 4 (100 mg, 0.578 mmol), NaOAc (63 mg, mmol), hydroxylamine hydrochloride (60 mg, 0.863 mmol) and water (5 mL) was heated at [100 C] for 15 min. The precipitate was isolated by filtration. This provided the title oxime [(ID] 969) [DL] as an off-white solid (87 mg, [80percent) ; SPECTRAL] data of this compound are shown in Table 2.8-hydroxy-2-methylquinoline (2.00 g, 12.5 mmol), selenium dioxide (1.74 g, 15.6 mmol) and 50 mL of 1, 4-dioxane were mixed and stirred in a 100 mL round bottom flask. The resulting solution was refluxed for 24 h. The reaction was monitored until completion by TLC method. The reaction mixture was then filtered off and the selenium metal was washed with dichloromethane. The combined filtrates were evaporated off under reduced pressure. The crude product was purified by column chromatography on silica gel to give pure 2 as a yellow needle crystal (1.30 g, 59.9percent yield). 2-Methyl-8-hydroxyquinoline (50 mmol, 8 g)150 mL of 1, 4-dioxane and 6 mL of water was placed in a 70 ° C oil bath to completely dissolve it. A previously prepared solution of SeO 2 (63 mmol, 7 g) in 4 mL of water And 100mL of 1, 4-dioxane was slowly added dropwise to the mixed solution, until the temperature was raised to 100 , the temperature was heated to continue to reflux for 3h, the reaction was stopped, cooled to room temperature, vacuum filtration In addition to the solvent, and then extracted with ethyl acetate multiple times (at least 3 times), and finally the extract was dried to give a red oily substance, to the red oily substance was added cyclohexane, gently shaking, this will produce yellowish Xu Material, dissolvedThe liquid also becomes a light yellow, the yellowish flocculent material together with the light yellow serum in a freezer to allow it to cool slowly crystallized, and then thawed at room temperature, filtered to give 2- Aldehyde-8-hydroxyquinoline, the yield was about 52percent.0.32 g of 2-methyl-8-hydroxyquinoline (2 mmol) was dissolved in 20 mL of dioxane.After heating to 60 ° C, 0.27 g of SeO 2 was weighed and added to the above solution, and then the temperature was raised to 80 ° C, and the reaction mixture was heated under reflux for 10 hours under the protection of nitrogen.After completion of the reaction, the reaction solution was cooled to room temperature, and the resulting precipitate was washed with 8 mL of dioxane and 8 mL of dichloromethane.Filter and dry in vacuo.The crude product was purified by silica gel chromatography eluting with petroleum ether: ethyl acetate=9:1 (v:v).The eluate was concentrated to give 0.14 g of pale yellow compound. The yield was 40.5percent.Example 9-Preparation of 2-N-substituted alcohol-8-hydroxyquinoline - Preparation of 2- -stifostittedalcohol-S-hydiroxyqiiiiioiiiie Reagents and conditions: (a) SeO dioxane, 50 to 80 °C; (b) N-methypropagylaraine or 2- (pipera .in-1 -yl) ethano or NHaiCHa )n-i OH, NaBH(OAc);;, l, 2~dkhloroeihane, rt. Method: A solution of 8-hydroxy-2A solution of 8-hydroxy-2-methylquinoline (6.0 g, 37.7 mmol) in dioxane (15 ml) was added dropwise to a solution of SeO2 (6.3 g, 56.8 mmol) (80 ml) was added and the mixture was heated to80 ° C for another 20 hours. The resulting mixture is filtered. The filtrate was concentrated and the residue was purified by column chromatography using Hex / EA = (15: 1 to 10: 1) to obtain 8-hydroxyquinoline-2-carboxaldehyde (2.45 g, 38percent) derivative As an intermediate. The intermediate is converted to an N-substituted compound using a reductive amination reaction with an amine alcohol, an amine alkyne or other heterocycle to provide a series of compounds. 8-alkoxy-2-methylquinoline was oxidized to provide 8-alkoxyquinoline-2-carboxaldehyde derivatives, and then the compounds M to O were obtained in the same manner.

The structural unit of the synthetic complexing agent.

Molecular Weight:173.17
XLogP3:1.6
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:173.047678466
Monoisotopic Mass:173.047678466
Topological Polar Surface Area:50.2
Heavy Atom Count:13
Complexity:195
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes