Oxazolo[4,5-b]pyridin-2(3H)-one

Tan Solid

Oxazolo[4,5-b]pyridin-2(3H)-one is a lactone. It derives from a hydride of an oxazolo[4,5-b]pyridine.

As shown in step 4-i of Scheme 4, l, l '-carbonyldiimidazole (57.4 g, 354.2 mmol) was added to a solution of 2-amino-3-hydroxypyridine (26.0 g, 236.1 mmol, obtained from Aldrich Chemical Co.) in THF (400 mL). The resulting reaction mixture was stirred at 70 As shown in step 4-i of Scheme 4, 1, 1'-carbonyldiimidazole (57.4 g, 354.2 mmol) was added to a solution of 2-amino-3-hydroxypyridine (26.0 g, 236.1 mmol, obtained from Aldrich Chemical Co.) in THF (400 mL). The resulting reaction mixture was stirred at 70 Carbonyldiimidazole (600 mmol) was added in several batches to a solution of 2-aminopyridin-3- ol (400 mmol) in tetrahydrofuran (600 ml) and the reaction was heated at reflux for 1 h. The mixture was concentrated and the residue was diluted with dichloromethane (500 ml). The solution was extracted with 1.5 N sodium hydroxide (3 x 200 ml). The pH of the aqueous layer was adjusted to 5 with 2 N hydrochloric acid and the precipitaed solids were collected by filtration to provide oxazolo[4, 5-b]pyridin- 2(3H)-one in 79percent yield as a grey solid.Intermediate 30: Synthesis of 3-oxo-3, 4-dihydro-2H-pyrido[3, 2-b][l, 4]oxazine-7-sulfonyl chloride.CCIICCHHIntermediate 30: Synthesis of 3-oxo-3, 4-dihydro-2H-pyrido[3, 2-b][l, 4]oxazine-7-sulfonyI chloride.CICH, COCI Pd/C, H- NaHCO, 1. Synthesis of oxazolo[4, 5-b]pyridin-2(Into a 3-L 3-necked round-bottom flask, was placed a solution of 2-aminopyridin-3-ol (100 g, 908.15 mmol, 1.00 equiv), 1-[(1H-imidazol-1-yl)carbonyl]-1H-imidazole (221.3 g, 1.36 mol, 1.50 equiv) in THF (1000 mL). A suspension of carbonyl diimidazole (118.2 mmol, 19.1 g) and 2-amino-3-hydroxy-pyridine (90.9 mmol, 10.00 g) in THF (100 mL) was heated at reflux for 1.5 hours. (0767) The mixture was cooled and concentrated under reduced pressure. The residue was taken up in dichloromethane and extracted with 2M aqueous sodium hydroxide solution. The aqueous phase was cooled (ice/water bath) and (0768) acidified to pH5 with concentrated hydrochloric acid. (0769) The resulting precipitate was isolated by filtration, washed with water and THF then dried under suction to give the title compound as a grey powder (8.81 g, 71percent).To a stirred solution of 2-amino 3-hydroxy pyridine 1 (2 g, 16.26 mmol) in THF (20 ml ) was added CDI (2.63 g , 16.26 mmol )and the total reaction mass stirred at reflux temperature for 16 h. Reaction mass was cooled to room temperature, THF was distilled and the crude material was partitioned between water and ethyl acetate. The organic layer was separated, dried over sodium sulphate and concentrated under vacuum to afford the desired compound 2 (0.5 g )In 2L to three-opening bottle 810g30percent of aqueous sodium hydroxide solution and 110g2-amino-3-hydroxy-pyridine, stirring to dissolve, will 340g triphosgene is dissolved in 600 ml of toluene and 300 ml chloroform solution; to the slow heating three-mouth bottle 80 °C rear, dropping the toluene and the chloroform solution of triphosgene, the reaction temperature is controlled at 74 the [...] 88 °C between, the end of the dropping reaction 8 hours; cooling to the 20 [...] 30 °C, reaction with hydrochloric acid or sodium hydroxide to adjust PH value is neutral, to continue to lower the temperature to 10 °C the following, a filter, a water washing of the filter cake, drying the white solid obtained oxazole [4, 5-b] pyridine -2 (3H) ketone 91.4g, the yield is 86.2percent, after separating the filtrate, dry recovery of toluene and chloroformStep-1 [0134] To a stirred solution of 2-amino 3-hydroxy pyridine 1 (2 g, 16.26 mmol) in THF (20 ml) was added CDI (2.63 g, 16.26 mmol) and the total reaction mass stirred at reflux temperature for 16 h. Reaction mass was cooled to room temperature, THF was distilled and the crude material was partitioned between water and ethyl acetate. The organic layer was separated, dried over sodium sulphate and concentrated under vacuum to afford the desired compound 2 (0.5 g)

A benzoxazolone analogue that may be used to inhibit the nitric oxide synthases (NOS).

Molecular Weight:136.11
XLogP3:0.4
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Exact Mass:136.027277375
Monoisotopic Mass:136.027277375
Topological Polar Surface Area:51.2
Heavy Atom Count:10
Complexity:160
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes