4-[5-(4,4,5,5-TETRAMETHYL-[1,3,2]DIOXABOROLAN-2-YL)-PYRIDIN-2-YL]-PIPERAZINE-1-CARBOXYLIC ACID TERT-BUTYL ESTER

4-[5-(4,4,5,5-TETRAMETHYL-[1,3,2]DIOXABOROLAN-2-YL)-PYRIDIN-2-YL]-PIPERAZINE-1-CARBOXYLIC ACID TERT-BUTYL ESTER Property

Melting point:

165-169 °C

Boiling point:

515.9±50.0 °C(Predicted)

Density 

1.14±0.1 g/cm3(Predicted)

storage temp. 

Keep in dark place,Sealed in dry,Room Temperature

form 

solid

pka

8.41±0.31(Predicted)

Appearance

White to off-white Solid

InChI

InChI=1S/C20H32BN3O4/c1-18(2,3)26-17(25)24-12-10-23(11-13-24)16-9-8-15(14-22-16)21-27-19(4,5)20(6,7)28-21/h8-9,14H,10-13H2,1-7H3

InChIKey

JWUBVPJWWYYRLJ-UHFFFAOYSA-N

SMILES

N1(C(OC(C)(C)C)=O)CCN(C2=NC=C(B3OC(C)(C)C(C)(C)O3)C=C2)CC1

CAS DataBase Reference

496786-98-2(CAS DataBase Reference)

Safety

Hazard Codes 

Xi

Safety Statements 

22-24/25

WGK Germany 

3

HazardClass 

IRRITANT

HS Code 

2933998090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P304+P340IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P405Store locked up.

4-[5-(4,4,5,5-TETRAMETHYL-[1,3,2]DIOXABOROLAN-2-YL)-PYRIDIN-2-YL]-PIPERAZINE-1-CARBOXYLIC ACID TERT-BUTYL ESTER Chemical Properties,Usage,Production

Uses

6-(4-Boc-piperazin-1-yl)pyridine-3-boronic Acid Pinacol Ester is used as a reactant in the preparation of fluorogenic probes used to distinguish chemical warfare agents and their mimics.

Synthesis

Under nitrogen protection, 4-Boc-1-(5-bromo-2-pyridyl)piperazine (125 g, 366 mmol) was dissolved in DMF (1.30 L), and bipinacolate pinacol ester (186 g, 732 mmol), palladium acetate (4.09 g, 18.3 mmol), triphenylphosphine (19.2 g, 73.2 mmol) and potassium acetate ( 108 g, 1.10 mol). The reaction mixture was stirred at 80 °C overnight. After completion of the reaction, it was cooled to room temperature and the solid was collected by filtration. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica gel fast column chromatography (eluent: ethyl acetate/petroleum ether, 1:50 v/v) to afford the target product tert-butyl 4-[5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)piperidin-2-yl]piperazine-1-carboxylate (90c) as a white solid (80.0 g, yield 56%). Mass spectrum (LCMS, ESI positive ion mode): calculated value C20H32BN3O4 [M+H]+ 390.2, measured value 390.2.

References

[1] Patent: US2014/364414, 2014, A1. Location in patent: Paragraph 0945; 0950-0951
[2] Journal of Medicinal Chemistry, 2012, vol. 55, # 11, p. 5361 - 5379
[3] Patent: US2013/225548, 2013, A1. Location in patent: Paragraph 0531; 0632
[4] Patent: CN104650049, 2018, B. Location in patent: Paragraph 0426; 0427