[ CAS No. 53052-06-5 ]

Name: 53052-06-5|Oxazolo[4,5-b]pyridine-2(3H)-thione|98%
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SKU: A149223
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Quality Control of [ 53052-06-5 ]

COA NMR CNMR HPLC LC-MS

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SDS Specification

Alternatived Products of [ 53052-06-5 ]

Product Details of [ 53052-06-5 ]

CAS No. :	53052-06-5	MDL No. :	MFCD01089040
Formula :	C₆H₄N₂OS	Boiling Point :	-
Linear Structure Formula :	-	InChI Key :	BRSZJWYJYOGBGK-UHFFFAOYSA-N
M.W :	152.17 g/mol	Pubchem ID :	658727
Synonyms :

Calculated chemistry of [ 53052-06-5 ]

Physicochemical Properties

Num. heavy atoms :	10
Num. arom. heavy atoms :	9
Fraction Csp3 :	0.0
Num. rotatable bonds :	0
Num. H-bond acceptors :	2.0
Num. H-bond donors :	1.0
Molar Refractivity :	39.19
TPSA :	73.91 Å²

Pharmacokinetics

GI absorption :	High
BBB permeant :	Yes
P-gp substrate :	No
CYP1A2 inhibitor :	Yes
CYP2C19 inhibitor :	No
CYP2C9 inhibitor :	No
CYP2D6 inhibitor :	No
CYP3A4 inhibitor :	No
Log Kp (skin permeation) :	-6.52 cm/s

Lipophilicity

Log Po/w (iLOGP) :	1.36
Log Po/w (XLOGP3) :	1.0
Log Po/w (WLOGP) :	1.89
Log Po/w (MLOGP) :	0.07
Log Po/w (SILICOS-IT) :	3.07
Consensus Log Po/w :	1.48

Druglikeness

Lipinski :	0.0
Ghose :	None
Veber :	0.0
Egan :	0.0
Muegge :	1.0
Bioavailability Score :	0.55

Water Solubility

Log S (ESOL) :	-2.08
Solubility :	1.27 mg/ml ; 0.00833 mol/l
Class :	Soluble
Log S (Ali) :	-2.14
Solubility :	1.1 mg/ml ; 0.00723 mol/l
Class :	Soluble
Log S (SILICOS-IT) :	-2.63
Solubility :	0.353 mg/ml ; 0.00232 mol/l
Class :	Soluble

Medicinal Chemistry

PAINS :	0.0 alert
Brenk :	1.0 alert
Leadlikeness :	1.0
Synthetic accessibility :	2.37

Safety of [ 53052-06-5 ]

Signal Word:	Warning	Class:	N/A
Precautionary Statements:	P261-P305+P351+P338	UN#:	N/A
Hazard Statements:	H302-H315-H319-H335	Packing Group:	N/A
GHS Pictogram:

Application In Synthesis of [ 53052-06-5 ]

* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.

Upstream synthesis route of [ 53052-06-5 ]
Downstream synthetic route of [ 53052-06-5 ]

[ 53052-06-5 ] Synthesis Path-Upstream 1~8

1
[ 53052-06-5 ]
[ 60832-72-6 ]

Reference： [1] Journal fuer Praktische Chemie (Leipzig), 1989, vol. 331, # 1, p. 167 - 170

2
[ 16867-03-1 ]
[ 140-89-6 ]
[ 53052-06-5 ]

Yield	Reaction Conditions	Operation in experiment
86.95%	at 110℃;	Step 1: Preparation of oxazolo[4,5-b]pyridine-2-thiol A solution of 2-aminopyridin-3-ol (5.0g, 45.45 mmol) and potassium ethyl xanthate (8.0g, 49.99 mmol) in pyridine (50mL) was heated at 110°C overnight. The reaction mixture was cooled to 0°C, added ice water and acidified with Cone. HCl. The solid was filtered and dried under vacuum to afford the title compound (6.0g, 86.95percent). 1HNMR (DMSO-d₆, 300MHz): δ 8.24-8.22 (d, 1H), 7.90-7.87 (d, 1H), 7.30-7.26 (m, 1H). LCMS: m/z: 153.0 (M+l) ⁺.
86.95%	at 110℃;	A solution of 2-aminopyridin-3-ol (5.0 g, 45.45 mmol) and potassium ethyl xanthate (8.0 g, 49.99 mmol) in pyridine (50 mL) was heated at 1100 C. overnight. The reaction mixture was cooled to 00 C., added ice water and acidified with Conc. HC1. The solid was filtered and dried under vacuum to afford the title compound (6.0 g, 86.95percent). 10206] ‘HNMR (DMSO-d5, 300 MHz): ö 8.24-8.22 (d, 1H), 7.90-7.87 (d, 1H), 7.30-7.26 (m, 1H). LCMS: mlz:153.0 (M+1).

Reference： [1] Patent: WO2015/104688, 2015, A1, . Location in patent: Page/Page column 36
[2] Patent: US2016/340366, 2016, A1, . Location in patent: Paragraph 0205; 0206
[3] Monatshefte fur Chemie, 2011, vol. 142, # 9, p. 895 - 899
[4] Journal of Organic Chemistry, 1995, vol. 60, # 17, p. 5721 - 5725
[5] European Journal of Medicinal Chemistry, 2005, vol. 40, # 1, p. 15 - 23
[6] Bioorganic and Medicinal Chemistry, 2008, vol. 16, # 1, p. 114 - 125
[7] Patent: EP1308439, 2003, A1,

3
[ 75-15-0 ]
[ 16867-03-1 ]
[ 53052-06-5 ]

Yield	Reaction Conditions	Operation in experiment
67%	With potassium hydroxide In ethanol for 10 h; Reflux	In a 100 ml round bottom flask was placed 2- amino-3-hydroxy pyridine (2.20g, 20 mmol) and 40 ml of absoluteethanol was added and the mixture was stirred for 15minutes. In the meanwhile, 2.0g (29 mmol) KOH pelletswere powdered and transferred into the flask followed by theaddition of 15 ml of carbon disulfide. The resulting mixturewas refluxed over an oil bath for 8 hours when a yellowprecipitate appeared. The contents of the flask were cooledto room temperature. The solvent was rotary evaporated andthe residue was transferred in to a beaker and 75 ml of waterwas added followed by neutralization with acetic acid. Theprecipitated product was filtered under vacuum and washedwith 3x50 ml of water and dried under vacuum over night toyield 2.1g of light yellow solid product (yield, 65percent).

Reference： [1] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 5, p. 2075 - 2078
[2] Advanced Synthesis and Catalysis, 2017, vol. 359, # 11, p. 1837 - 1843
[3] Letters in Organic Chemistry, 2010, vol. 7, # 7, p. 519 - 527
[4] Archiv der Pharmazie, 2017, vol. 350, # 8,

4
[ 16867-03-1 ]
[ 53052-06-5 ]

Reference： [1] Patent: US4351832, 1982, A,

5
[ 16867-03-1 ]
[ 137-26-8 ]
[ 53052-06-5 ]

Reference： [1] Green Chemistry, 2017, vol. 19, # 23, p. 5591 - 5598

6
[ 53052-06-5 ]
[ 74-88-4 ]
[ 169205-95-2 ]

Yield	Reaction Conditions	Operation in experiment
93.75%	With potassium carbonate In ethyl acetate at 20℃;	Step 2: Preparation of 2-(methylthio)oxazolo[4,5-b]pyridine To a stirred solution of oxazolo[4,5-b]pyridine-2-thiol (3.0g, 19.73 mmol) in ethyl acetate (30mL) was added potassium carbonate (3.81g, 27.62 mmol) and methyl iodide (3.08g, 21.71 mmol) and stirred at RT overnight. The reaction mixture was diluted with water (100ml), extracted with ethyl acetate (2x50mL), dried over sodium sulphate and concentrated to afford the title compound (3.0g, 93.75percent). 1HNMR (CDCI₃, 300MHz): δ 8.46-8.44 (d, 1H), 7.71-7.68 (d, 1H), 7.20-7.15 (m, 1H), 2.81 (s, 3H). LCMS: m/z: 167.0(M+1) ⁺.
93.75%	With potassium carbonate In ethyl acetate at 20℃;	To a stirred solution of oxazolo[4,5-b]pyridine-2- thiol (3.0 g, 19.73 mmol) in ethyl acetate (30 mL) was added potassium carbonate (3.81 g, 27.62 mmol) and methyl iodide (3.08 g, 21.71 mmol) and stirred at RT overnight. The reaction mixture was diluted with water (100 ml), extracted with ethyl acetate (2x50 mL), dried over sodium sulphate and concentrated to afford the title compound (3.0 g, 93 .75percent).10208] ‘HNMR (CDC13, 300 MHz): ö 8.46-8.44 (d, 1H),7.71-7.68 (d, 1H), 7.20-7.15 (m, 1H), 2.81 (s, 3H). LCMS:mlz: 167.0 (M+1)+.

Reference： [1] Patent: WO2015/104688, 2015, A1, . Location in patent: Page/Page column 36
[2] Patent: US2016/340366, 2016, A1, . Location in patent: Paragraph 0207; 0208
[3] Journal of Organic Chemistry, 1995, vol. 60, # 17, p. 5721 - 5725
[4] Ultrasonics Sonochemistry, 2010, vol. 17, # 5, p. 783 - 788
[5] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 5, p. 2075 - 2078
[6] Advanced Synthesis and Catalysis, 2017, vol. 359, # 11, p. 1837 - 1843
[7] European Journal of Medicinal Chemistry, 2005, vol. 40, # 1, p. 15 - 23
[8] Bioorganic and Medicinal Chemistry, 2008, vol. 16, # 1, p. 114 - 125

7
[ 53052-06-5 ]
[ 74-88-4 ]
[ 169205-95-2 ]

Yield	Reaction Conditions	Operation in experiment
83%	With potassium carbonate In N,N-dimethyl-formamide for 2 h;	2-(Mβthv)thio)ri,31oxazolor4,5-biPyridine; A 250 mL RB flask, equipped with a magnetic stirring bar and nitrogen gas inlet, was charged with [1,3]oxazolo[4,5-b]pyridine-2(3H)-thione (5.00 g, 32.9 mmol), potassium carbonate (4.54 g, 32.8 mmol), and 80 mL of anhydrous DMF. Then iodomethane (2.45 mL, 5.57 g, 39.3 mmol) was added dropwise to the stirring reaction mixture under nitrogen. The mixture was stirring for 2 h, then diluted with 300 mL of water, and extracted with EtOAc (4x150 mL). The combined organic extract was washed with water (3x100 mL), then with brine (100 mL), dried over Na₂SO₄ and evaporated to give 4.53 g (83 percent) of 2- (methylthio)[1,3]oxazolo[4,5-b]pyridine as a tan solid. LCMS m/z (M+H): 167.1. ¹H NMR (300 MHz, DMSO-d₆): δ 8.44 (1H), 8.08 (1H), 7.35 (1H), 2.81 (3H).

Reference： [1] Patent: WO2006/51410, 2006, A1, . Location in patent: Page/Page column 45
[2] Chemistry of Heterocyclic Compounds, 1999, vol. 35, # 1, p. 84 - 86

8
[ 186581-53-3 ]
[ 53052-06-5 ]
[ 169205-95-2 ]

Reference： [1] Chemistry of Heterocyclic Compounds, 1999, vol. 35, # 1, p. 84 - 86

[ 53052-06-5 ] Synthesis Path-Downstream 1~59

1
[ 6959-48-4 ]
[ 53052-06-5 ]
[ 88594-61-0 ]

Reference： [1]Journal of Medicinal Chemistry,1987,vol. 30,p. 547 - 551

2
[ 53052-06-5 ]
[ 60832-72-6 ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

3
[ 16867-03-1 ]
[ 140-89-6 ]
[ 53052-06-5 ]

Yield	Reaction Conditions	Operation in experiment
86.95%	With pyridine; at 110.0℃;	Step 1: Preparation of oxazolo[4,5-b]pyridine-2-thiol A solution of 2-aminopyridin-3-ol (5.0g, 45.45 mmol) and potassium ethyl xanthate (8.0g, 49.99 mmol) in pyridine (50mL) was heated at 110C overnight. The reaction mixture was cooled to 0C, added ice water and acidified with Cone. HCl. The solid was filtered and dried under vacuum to afford the title compound (6.0g, 86.95%). 1HNMR (DMSO-d6, 300MHz): delta 8.24-8.22 (d, 1H), 7.90-7.87 (d, 1H), 7.30-7.26 (m, 1H). LCMS: m/z: 153.0 (M+l) +.
86.95%	With pyridine; at 110.0℃;	A solution of 2-aminopyridin-3-ol (5.0 g, 45.45 mmol) and potassium ethyl xanthate (8.0 g, 49.99 mmol) in pyridine (50 mL) was heated at 1100 C. overnight. The reaction mixture was cooled to 00 C., added ice water and acidified with Conc. HC1. The solid was filtered and dried under vacuum to afford the title compound (6.0 g, 86.95%). 10206] ?HNMR (DMSO-d5, 300 MHz): oe 8.24-8.22 (d, 1H), 7.90-7.87 (d, 1H), 7.30-7.26 (m, 1H). LCMS: mlz:153.0 (M+1).
74%	In ethanol; for 24h;Reflux;	A mixture of 2-amino-pyridin-3-ol (1) (2.00 g, 18.16 mmol) and potassium ethyl xanthate (2.91 g, 18.16 mmol) in ethanol (40 mL) was heated under reflux for 24 h. The solvent was removed in vacuo and water (30 mL) was added. The mixture was acidified with AcOH to pH 5. The resultant precipitate was filtered, washed with water (20 mL) and dried to give oxazolo[4,5-b]pyridine-2-thiol (2) (2.05 g, 74% yield). 300 MHz 1H-NMR (DMSO-d6, ppm): 8.21 (dd, J=5.2, 1.3 Hz, 1H) 7.85 (dd, J=8.1, 1.3 Hz, 1H) 7.25 (dd, J=8.1, 5.2 Hz, 1H).

With hydrogenchloride; In pyridine; water;

(1) 2-Amino-3-hydroxypyridine (5.51 g) was dissolved in pyridine (100 mL), and potassium ethylxanthate (8.82 g) was added thereto. The mixture was refluxed for 2 hr. Iced water (400 mL) was added to the reaction mixture, and concentrated hydrochloric acid (40 mL) was added thereto. The mixture was extracted with chloroform and the extract was washed with brine and concentrated under reduced pressure to give 1,3-oxazolo[4,5-b]pyridine-2-thiol (5.13 g) as a pale-brown powder.

Reference： [1]Patent: WO2015/104688,2015,A1 .Location in patent: Page/Page column 36
[2]Patent: US2016/340366,2016,A1 .Location in patent: Paragraph 0205; 0206
[3]Monatshefte fur Chemie,2011,vol. 142,p. 895 - 899
[4]Patent: US2019/367499,2019,A1 .Location in patent: Paragraph 0166
[5]Journal of Organic Chemistry,1995,vol. 60,p. 5721 - 5725
[6]European Journal of Medicinal Chemistry,2005,vol. 40,p. 15 - 23
[7]Bioorganic and Medicinal Chemistry,2008,vol. 16,p. 114 - 125
[8]Patent: EP1308439,2003,A1

4
[ 53052-06-5 ]
[ 74-88-4 ]
[ 169205-95-2 ]

Yield	Reaction Conditions	Operation in experiment
93.75%	With potassium carbonate; In ethyl acetate; at 20.0℃;	Step 2: Preparation of 2-(methylthio)oxazolo[4,5-b]pyridine To a stirred solution of <strong>[53052-06-5]oxazolo[4,5-b]pyridine-2-thiol</strong> (3.0g, 19.73 mmol) in ethyl acetate (30mL) was added potassium carbonate (3.81g, 27.62 mmol) and methyl iodide (3.08g, 21.71 mmol) and stirred at RT overnight. The reaction mixture was diluted with water (100ml), extracted with ethyl acetate (2x50mL), dried over sodium sulphate and concentrated to afford the title compound (3.0g, 93.75%). 1HNMR (CDCI3, 300MHz): delta 8.46-8.44 (d, 1H), 7.71-7.68 (d, 1H), 7.20-7.15 (m, 1H), 2.81 (s, 3H). LCMS: m/z: 167.0(M+1) +.
93.75%	With potassium carbonate; In ethyl acetate; at 20.0℃;	To a stirred solution of oxazolo[4,5-b]pyridine-2- thiol (3.0 g, 19.73 mmol) in ethyl acetate (30 mL) was added potassium carbonate (3.81 g, 27.62 mmol) and methyl iodide (3.08 g, 21.71 mmol) and stirred at RT overnight. The reaction mixture was diluted with water (100 ml), extracted with ethyl acetate (2x50 mL), dried over sodium sulphate and concentrated to afford the title compound (3.0 g, 93 .75%).10208] ?HNMR (CDC13, 300 MHz): oe 8.46-8.44 (d, 1H),7.71-7.68 (d, 1H), 7.20-7.15 (m, 1H), 2.81 (s, 3H). LCMS:mlz: 167.0 (M+1)+.

Reference： [1]Patent: WO2015/104688,2015,A1 .Location in patent: Page/Page column 36
[2]Patent: US2016/340366,2016,A1 .Location in patent: Paragraph 0207; 0208
[3]Journal of Organic Chemistry,1995,vol. 60,p. 5721 - 5725
[4]Ultrasonics Sonochemistry,2010,vol. 17,p. 783 - 788
[5]Bioorganic and Medicinal Chemistry Letters,2012,vol. 22,p. 2075 - 2078
[6]Advanced Synthesis and Catalysis,2017,vol. 359,p. 1837 - 1843
[7]European Journal of Medicinal Chemistry,2005,vol. 40,p. 15 - 23
[8]Bioorganic and Medicinal Chemistry,2008,vol. 16,p. 114 - 125

5
[ 53052-06-5 ]
2-(4-propyl-piperazin-1-yl)-oxazolo[4,5-b]pyridine [ No CAS ]

Reference： [1]European Journal of Medicinal Chemistry,2005,vol. 40,p. 15 - 23

6
[ 53052-06-5 ]
imidazo[1',2':2,3]oxazolo[4,5-b]pyridine [ No CAS ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

7
[ 53052-06-5 ]
3-amino-1,2,4-triazolo[3',4':2,3]oxazolo[4,5-b]pyridine [ No CAS ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

8
[ 53052-06-5 ]
imidazo[1',2':2,3]oxazolo[4,5-b]pyridine-3-one [ No CAS ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

9
[ 53052-06-5 ]
[ 300672-80-4 ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

10
[ 53052-06-5 ]
(3H-oxazolo[4,5-b]pyridin-2-ylideneamino)-acetic acid ethyl ester [ No CAS ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

11
[ 53052-06-5 ]
3-phenyl-1,2,4-triazolo[3',4':2,3]oxazolo[4,5-b]pyridine [ No CAS ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

12
[ 53052-06-5 ]
3-nicotinyl-1,2,4-triazolo[3',4':2,3]oxazolo[4,5-b]pyridine [ No CAS ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

13
[ 53052-06-5 ]
[ 300672-86-0 ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

14
[ 53052-06-5 ]
[ 300672-82-6 ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

15
[ 53052-06-5 ]
[ 300672-84-8 ]

Reference： [1]Synthetic Communications,2000,vol. 30,p. 3423 - 3438

16
[ 53052-06-5 ]
2-(1-Piperidinyl)oxazolo<4,5-b>pyridine [ No CAS ]

Reference： [1]Journal of Organic Chemistry,1995,vol. 60,p. 5721 - 5725

17
[ 53052-06-5 ]
[ 128456-15-5 ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

18
[ 53052-06-5 ]
2-(3,4-Dimethyl-4-imidazolin-2-on-1-yl)-3-hydroxypyridin [ No CAS ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

19
[ 53052-06-5 ]
2-(3-Ethyl-4-methyl-4-imidazolin-2-on-1-yl)-3-hydroxypyridin [ No CAS ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

20
[ 53052-06-5 ]
3-(Acetylaminomethyl)-oxazolo<4,5-b>pyridin-2-on [ No CAS ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

21
[ 53052-06-5 ]
[ 128456-16-6 ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

22
[ 53052-06-5 ]
2-(4-Methyl-3-propyl-4-imidazolin-2-on-1-yl)-3-hydroxypyridin [ No CAS ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

23
[ 53052-06-5 ]
2-(3-Butyl-4-methyl-4-imidazolin-2-on-1-yl)-3-hydroxypyridin [ No CAS ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

24
[ 53052-06-5 ]
2-(3-Benzyl-4-methyl-4-imidazolin-2-on-1-yl)-3-hydroxypyridin [ No CAS ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

25
[ 53052-06-5 ]
2-(3-Cyclohexyl-4-methyl-4-imidazolin-2-on-1-yl)-3-hydroxypyridin [ No CAS ]

Reference： [1]Journal fur praktische Chemie (Leipzig 1954),1989,vol. 331,p. 167 - 170

26
[ 225942-11-0 ]
[ 53052-06-5 ]
[ 225941-50-4 ]

Yield	Reaction Conditions	Operation in experiment
72%	With sodium chloride; potassium carbonate; In N,N-dimethyl-formamide;	Example 37 (Compound No. 1237 in Table) Production of 6-(oxazolo[4,5-b]pyridin-2-ylthio)-N-[2,4-bis(methylthio)-6-methyl-3-pyridyl]hexanamide: To a DMF (4 ml) solution of 6-bromo-N-[2,4-bis(methylthio)-6-methyl-3-pyridyl]hexanamide (100 mg, 0.27 mmol) and 2-mercaptoxazolo[4,5-b]pyridine (40 mg, 0.27 mmol) were added 18-crown-6 (7 mg, 0.03 mmol) and potassium carbonate (40 mg, 0.29 mmol), and the mixture was stirred at 80C for 4 hours. The reaction mixture was diluted with water, and then extracted with ethyl acetate. The organic layer was washed with water and then with a saturated aqueous solution of sodium chloride, and dried over magnesium sulfate. Subsequently, the solvent was distilled off, and the resulting crude product was purified through preparative thin-layer chromatography (eluent - hexane: acetone = 2:1) to obtain 85 mg (yield 72%) of the desired compound as a colorless powdery crystal. Melting point: 132 - 133C IR (KBr) cm-1: 3435, 3243, 2923, 1655, 1493, 1404.
72%	With potassium carbonate;18-crown-6 ether; In DMF (N,N-dimethyl-formamide); at 80.0℃; for 4h;	[00549] To a DMF (4 ml) solution of 6-bromo-N-[2,4-bis(methylthio)-6-methyl-3-pyridyl]hexanamide (100 mg, 0.27 mmol) and 2-mercaptoxazolo[4,5-b]pyridine (40 mg, 0.27 mmol) were added 18-crown-6 (7 mg, 0.03 mmol) and potassium carbonate (40 mg, 0.29 mmol), and the mixture was stirred at 80 C. for 4 hours. The reaction mixture was diluted with water, and then extracted with ethyl acetate. The organic layer was washed with water and then with a saturated aqueous solution of sodium chloride, and dried over magnesium sulfate. Subsequently, the solvent was distilled off, and the resulting crude product was purified through preparative thin-layer chromatography (eluent-hexane:acetone=2:1) to obtain 85 mg (yield 72%) of the desired compound as a colorless powdery crystal. [00550] Melting point: 132-133 C. [00551] IR (KBr) cm-1: 3435, 3243, 2923, 1655, 1493, 1404. [00552] 1H-NMR (d6-DMSO) delta: 1.53-1.63 (2H, m), 1.65-1.76 (2H, m), 1.83-1.93 (2H, m), 2.27-2.35 (2H, m), 2.40 (3H, s), 2.42 (3H, s), 2.45 (3H, s), 3.40 (2H, t, J=7.3 Hz), 6.86 (1H, s), 7.30 (1H, dd, J=8.1, 4.9 Hz), 7.97 (1H, dd, J=8.1, 1.3 HZ), 8.42 (1H, dd, J=4.9, 1.3 HZ), 8.83 (1H, br s). [00553] EIMS m/z (relative intensity): 447 (M+-1), 400 (100). [00554] Elemental analysis: as C20H24N4O2S3; calculated: C, 53.55; H, 5.39; N, 12.59; S, 21.44. found: C, 53.72; H, 5.39; N, 12.41; S, 21.51.

Reference： [1]Patent: EP979823,2000,A1
[2]Patent: US6849647,2005,B1 .Location in patent: Page/Page column 119-120

27
[ 199592-72-8 ]
[ 53052-06-5 ]
[ 213684-58-3 ]

Yield	Reaction Conditions	Operation in experiment
27%	With potassium carbonate; In N,N-dimethyl-formamide;	Example 1 Production of 6-(oxazolo[4,5-b]pyridin-2-ylthio)-N-(2,6-diisopropylphenyl)hexanamide Potassium carbonate (64 mg, 0.47 mmol) and 18-crown-6 (11 mg, 0.04 mmol) were added to a solution of <strong>[53052-06-5]2-mercaptooxazolo[4,5-b]pyridine</strong> (64 mg, 0.42 mmol) and 6-bromo-N-(2,6-diisopropylphenyl)hexanamide (150 mg, 0.42 mmol) in DMF (3 ml), and the resulting mixture was stirred at 80 C. for4 hours. After there action solution was diluted with water, the organic layer was extracted with ethyl acetate. The organic layer was washed with water and dried over anhydrous magnesium sulfate, from which the solvents were distilled off. The residue was purified by silica gel column chromatography (elution solvents: hexane:ethyl acetate=2:1); the resulting crystal was recrystallized from ethyl acetate-hexane, to recover the objective compound of 49 mg (at a yield of 27%) as a colorless needle-like crystal. Melting Point: 94-95 C. IR (KBr) cm-1: 3230, 2965, 1646, 1497, 1403. 1H-NMR (d6-DMSO) delta: 1.14 (12H, d, J=6.8 Hz), 1.52-1.68 (2H, m), 1.68-1.82 (2H, m), 1.82-1.97 (2H, m), 2.33-2.45 (2H, m), 3.11 (2H, sept, J=6.8 Hz), 3.43 (2H, t, J=7.0 Hz), 7.12 (1H, d, J=8.1 Hz), 7.12 (1H, d, J=6.6 Hz), 7.22 (1H, dd, J=8.1, 6.6 Hz), 7.31 (1H, dd, J=8.1, 4.8 Hz), 7.98 (1H, dd, J=8.1, 1.5 Hz), 8.42 (1H, d, J=4.8 Hz), 8.72 (1H, br s). EIMS m/z (relative intensity): 425 (M+), 407 (100). Elementary Analysis: C24H31N3O2S Required: C, 67.73; H, 7.34; N, 9.87; S, 7.53. Found: C, 67.68; H, 7.33; N, 9.86; S, 7.57.
27%	With 18-crown-6 ether; potassium carbonate; In N,N-dimethyl-formamide; at 80.0℃; for 4h;	To a stirred solution of oxazolo[4,5-b]-pyridine-2-thiol (21a) (64?mg, 0.42?mmol) and 2e (150?mg, 0.42?mmol) in DMF (3 mL) were added K2CO3 (64?mg, 0.47?mmol) and 18-crown-6 (11?mg, 0.04?mmol). The reaction mixture was stirred at 80 C for 4?h and diluted with water and AcOEt. The organic layer was washed with water and dried over MgSO4. After filtration, the solvent was concentrated in vacuo. The residue was purified by silica gel column chromatography, and eluted with AcOEt/n-hexane (1:2) to give a solid, which was recrystallized from AcOEt/n-hexane to afford 22a (49?mg, 27%) as colorless needles. Mp 94-95?C; IR (KBr) cm-1: 3230, 2965, 1646, 1497, 1403; 1H-NMR (DMSO-d6) delta: 1.14 (12H, d, J?=?6.8?Hz), 1.52-1.68 (2H, m), 1.68-1.82 (2H, m), 1.82-1.97 (2H, m), 2.33-2.45 (2H, m), 3.11 (2H, sept, J?=?6.8?Hz), 3.43 (2H, t, J?=?7.0?Hz), 7.11 (1H, d, J?=?8.1?Hz), 7.12 (lH, d, J?=?6.6?Hz), 7.22 (lH, dd, J?=?8.1, 6.6?Hz), 7.31 (1H, dd, J?=?8.1, 4.8?Hz), 7.98 (1H, dd, J?=?8.1, 1.5?Hz), 8.42 (1H, d, J?=?4.8?Hz), 8.72 (lH, br s); EIMS m/z: 425 (M+); Anal. Calcd for C24H31N3O2S: C, 67.73; H, 7.34; N 9.87; S, 7.53. Found: C, 67.68; H, 7.33; N, 9.86; S, 7.57.

Reference： [1]Patent: US6362208,2002,B1
[2]Bioorganic and Medicinal Chemistry,2018,vol. 26,p. 4001 - 4013

Yield	Reaction Conditions	Operation in experiment
		(1-5) Synthesis of Dye (D-1) In an amount of 100 mg of the 4-(2-carbamoylethyl)-2-methylthiooxazolo[4,5-b]pyridinium bromide synthesised in Synthesis Example (1-3) and 40 mg of the 1,4-dimethylquinolinium p-toluenesulfonate synthesised in Synthesis Example (1-4) were dissolved in 4 mL of dimethylformamide and added with 0.5 mL of triethylamine at room temperature. After a reaction was allowed at a room temperature for 1 hour, the reaction mixture was added with 0.5 mL of triethylamine and allowed to react at 80C for 1 hour. The reaction mixture was subjected without treatment to silica gel column chromatography, and yellow fractions were collected to obtain the target substance. The purification by chromatography was repeated to obtain 2 mg of the desired substance.

29
[ 16867-03-1 ]
MeOCS₂ K [ No CAS ]
[ 53052-06-5 ]

Yield	Reaction Conditions	Operation in experiment
	With carbon disulfide; potassium hydroxide; In methanol; water;	EXAMPLE 15 6,7-Dimethoxy-2-[4-(oxazolo[4,5-b]pyridin-2-yl)-1-piperazinyl]-4-quinazolinamine (Ia: R3 =oxazolo[4,5-b]pyridin-2-yl; R4, R5, R6 and R9 =H; R7 and R8 =OMe; and n=1) A mixture of 2-amino-3-hydroxypyridine and MeOCS2 K [prepared from potassium hydroxide (6.2 g), methanol (96 ml), water (17.4 ml) and carbon disulfide (7.1 g)] was refluxed for 20 hr and filtered. The filtrate was neutralized with acetic acid and the resulting precipitate was collected, washed with water and dried to give 2-mercapto-oxazolo[4,5-b]pyridine (8.2 g).

Reference： [1]Patent: US4351832,1982,A

30
[ 53052-06-5 ]
[ 84050-22-6 ]
6,7-Dimethoxy-2-[4-(oxazolo[4,5-b]pyridin-2-yl)-1-piperazinyl]-4-quinazolinamine [ No CAS ]

Yield	Reaction Conditions	Operation in experiment
	With triethylamine; In hydrogenchloride; butan-1-ol;	A suspension of the latter compound (5.0 g), 4-amino-2-piperazinyl-6,7-dimethoxyquinazoline hydrochloride (10.7 g), triethylamine (13.3 g) in butanol (500 ml) was refluxed for 20 hr and cooled. The precipitate was collected and dissolved in 2 N hydrochloric acid. The solution was basified with 2 N sodium hydroxide and the precipitate was collected, washed with water, dried (8.2 g) and crystallized from methanol to give the title compound: mp>250 C; ir (nujol) 3460 and 3350 cm-1; uv max (MeOH) 248 (epsilon=62,600), 299 (epsilon=27,000) and 341 nm (epsilon=6,410); nmr (DMSO-d6) delta 3.85 (m, 14H), 7.15 (s, 2H) and 7.4 (m, 5H); and Anal. Calcd. for C20 H21 N7 O3: C, 58.96% H, 5.19% N, 24.07% and Found: C, 58.72% H, 5.35% N, 23.93%.

Reference： [1]Patent: US4351832,1982,A

31
[ 75-15-0 ]
[ 16867-03-1 ]
[ 53052-06-5 ]

Yield	Reaction Conditions	Operation in experiment
71%	With potassium hydroxide; In ethanol; at 90.0℃; for 2h;	A solution of 2-aminopyri din-3 -ol (3.00 g, 27.24 mmol), carbon disulfide (41.45 g, 544.8 mmol), and potassium hydroxide (5.40 g, 96.24 mmol) in ethanol (50 mL) was stirred for 2 h at 90 C. The reaction was then quenched by the addition of 150 mL of water. The resulting solution was extracted with 3x150 mL of ethyl acetate. The pH value of the combined aqueous layers was adjusted to 6 with 6 M aqueous HC1 solution and then extracted with 3x150 mL of ethyl acetate. The organic layers were combined and dried over anhydrous sodium sulfate, filtered, and concentrated to give oxazolo[4,5-b]pyridine-2-thiol (3.0 g, 71%) as a red solid. MS: (ESI, m/z): 153[M+H]+.
67%	With potassium hydroxide; In ethanol; for 10h;Reflux;	In a 100 ml round bottom flask was placed 2- amino-3-hydroxy pyridine (2.20g, 20 mmol) and 40 ml of absoluteethanol was added and the mixture was stirred for 15minutes. In the meanwhile, 2.0g (29 mmol) KOH pelletswere powdered and transferred into the flask followed by theaddition of 15 ml of carbon disulfide. The resulting mixturewas refluxed over an oil bath for 8 hours when a yellowprecipitate appeared. The contents of the flask were cooledto room temperature. The solvent was rotary evaporated andthe residue was transferred in to a beaker and 75 ml of waterwas added followed by neutralization with acetic acid. Theprecipitated product was filtered under vacuum and washedwith 3x50 ml of water and dried under vacuum over night toyield 2.1g of light yellow solid product (yield, 65%).

Reference： [1]Bioorganic and Medicinal Chemistry Letters,2012,vol. 22,p. 2075 - 2078
[2]Patent: WO2019/204550,2019,A1 .Location in patent: Paragraph 00149
[3]Advanced Synthesis and Catalysis,2017,vol. 359,p. 1837 - 1843
[4]Letters in Organic Chemistry,2010,vol. 7,p. 519 - 527
[5]Archiv der Pharmazie,2017,vol. 350

32
[ 53052-06-5 ]
[ 1231933-82-6 ]

Reference： [1]Bioorganic and Medicinal Chemistry Letters,2012,vol. 22,p. 2075 - 2078

33
1-(4-bromo-2-fluorobenzyl)piperazine [ No CAS ]
[ 53052-06-5 ]
2-(4-(4-bromo-2-fluorobenzyl)piperazin-1-yl)oxazolo[4, 5-b]pyridine [ No CAS ]

Yield	Reaction Conditions	Operation in experiment
72%	In toluene; at 150.0℃; for 16h;	In a 100ml round bottom flask was placed 0.604g (4mmol) of benzoxazole and 0.688g (8 mmol) of anhydrouspiperazine or substituted piperazine derivative. 50 ml of drytoluene was added to this mixture and the contents werestirred and refluxed over an oil bath maintained at 150C for16-18 hours. After this period, the mixture was cooled andthe solvent was rotary evaporated and the residue wassubjected to column chromatography over silica gel usingmethanol/methylene chloride (20/80) to furnish the titledcompounds.

Reference： [1]Letters in Organic Chemistry,2010,vol. 7,p. 519 - 527

34
[ 18903-01-0 ]
[ 53052-06-5 ]
(E)-2-(4-cinnamylpiperazin-1-yl)oxazolo[4,5-b]pyridine [ No CAS ]

Yield	Reaction Conditions	Operation in experiment
81%	In toluene; at 150.0℃; for 16h;	In a 100ml round bottom flask was placed 0.604g (4mmol) of benzoxazole and 0.688g (8 mmol) of anhydrouspiperazine or substituted piperazine derivative. 50 ml of drytoluene was added to this mixture and the contents werestirred and refluxed over an oil bath maintained at 150C for16-18 hours. After this period, the mixture was cooled andthe solvent was rotary evaporated and the residue wassubjected to column chromatography over silica gel usingmethanol/methylene chloride (20/80) to furnish the titledcompounds.

Reference： [1]Letters in Organic Chemistry,2010,vol. 7,p. 519 - 527

35
[ 18903-01-0 ]
[ 53052-06-5 ]
(E)-2-(4-cinnamylpiperazin-1-yl)benzo[d]oxazole [ No CAS ]

Yield	Reaction Conditions	Operation in experiment
64%	In toluene; at 150.0℃; for 16h;	In a 100ml round bottom flask was placed 0.604g (4mmol) of benzoxazole and 0.688g (8 mmol) of anhydrouspiperazine or substituted piperazine derivative. 50 ml of drytoluene was added to this mixture and the contents werestirred and refluxed over an oil bath maintained at 150C for16-18 hours. After this period, the mixture was cooled andthe solvent was rotary evaporated and the residue wassubjected to column chromatography over silica gel usingmethanol/methylene chloride (20/80) to furnish the titledcompounds.

Reference： [1]Letters in Organic Chemistry,2010,vol. 7,p. 519 - 527

36
[ 110-85-0 ]
[ 53052-06-5 ]
[ 113520-22-2 ]

Yield	Reaction Conditions	Operation in experiment
83%	In toluene; at 150.0℃; for 16h;	In a 100ml round bottom flask was placed 0.604g (4mmol) of benzoxazole and 0.688g (8 mmol) of anhydrouspiperazine or substituted piperazine derivative. 50 ml of drytoluene was added to this mixture and the contents werestirred and refluxed over an oil bath maintained at 150C for16-18 hours. After this period, the mixture was cooled andthe solvent was rotary evaporated and the residue wassubjected to column chromatography over silica gel usingmethanol/methylene chloride (20/80) to furnish the titledcompounds.

Reference： [1]Letters in Organic Chemistry,2010,vol. 7,p. 519 - 527

37
[ 53052-06-5 ]
6'-amino-N-(2-morpholinooxazolo[4,5-b]pyridin-6-yl)-[2,3'-bipyridine]-6-carboxamide [ No CAS ]

Reference： [1]Patent: WO2015/104688,2015,A1
[2]Patent: US2016/340366,2016,A1

38
[ 53052-06-5 ]
2-morpholinooxazolo[4,5-b]pyridine [ No CAS ]

Reference： [1]Patent: WO2015/104688,2015,A1

39
[ 53052-06-5 ]
2-morpholino-6-nitrooxazolo[4,5-b]pyridine [ No CAS ]

Reference： [1]Patent: WO2015/104688,2015,A1
[2]Patent: US2016/340366,2016,A1

40
[ 53052-06-5 ]
2-morpholinooxazolo[4,5-b]pyridin-6-amine [ No CAS ]

Reference： [1]Patent: WO2015/104688,2015,A1
[2]Patent: US2016/340366,2016,A1

41
[ 53052-06-5 ]
6-bromo-N-(2-morpholinooxazolo[4,5-b]pyridin-6-yl)picolinamide [ No CAS ]

Reference： [1]Patent: WO2015/104688,2015,A1
[2]Patent: US2016/340366,2016,A1

42
[ 53052-06-5 ]
tert-butyl (6-((2-morpholinooxazolo[4,5-b]pyridin-6-yl)carbamoyl)-[2,3'-bipyridin]-6'-yl)carbamate [ No CAS ]

Reference： [1]Patent: WO2015/104688,2015,A1
[2]Patent: US2016/340366,2016,A1

43
[ 53052-06-5 ]
C₁₆H₁₄N₄O₃S [ No CAS ]

Reference： [1]Advanced Synthesis and Catalysis,2017,vol. 359,p. 1837 - 1843

44
[ 53052-06-5 ]
C₁₈H₁₆N₄O₃S [ No CAS ]

Reference： [1]Advanced Synthesis and Catalysis,2017,vol. 359,p. 1837 - 1843

45
[ 53052-06-5 ]
C₁₁H₈N₄O [ No CAS ]

Reference： [1]Advanced Synthesis and Catalysis,2017,vol. 359,p. 1837 - 1843

46
[ 53052-06-5 ]
1-[4-(4-methoxybenzoyl)piperazin-1-yl]-2-[1,3]-oxazolo[4,5-b]pyridin-2-ylsulfanyl}ethan-1-one [ No CAS ]