ChemicalBook CAS DataBase List 6-Chloro-1H-pyrazolo[4,3-c]pyridine

6-Chloro-1H-pyrazolo[4,3-c]pyridine synthesis

9synthesis methods

Product Name:6-Chloro-1H-pyrazolo[4,3-c]pyridine
CAS Number:1206979-33-0
Molecular formula:C6H4ClN3
Molecular Weight:153.57

4,6-Dichloropyridine-3-carbaldehyde (3.7 g, 32 mmol), hydrazine (3.5 mL, 110 mmol) and N,N-diisopropylethylamine (20 mL) were combined in DMA (100 mL) and stirred at 80° C. for four hours. Then, the solution was cooled to room temperature, diluted with EtOAc, and washed three times with water and then with brine. The organic solution was concentrated and the resulting mixture was precipitated from dichloromethane to give 6-chloro-1H-pyrazolo[4,3-c]pyridine. Yield 2 g (41%). LCMS (ESI): calc. C6H4ClN3=153; obs. M+H=154.

6-Chloro-1H-pyrazolo[4,3-c]pyridine synthesis

1060811-62-2
136 suppliers
$15.00/100mg

1206979-33-0
167 suppliers
$17.00/250mg

Yield:1206979-33-0 53.4%

Reaction Conditions:

with hydrazine hydrate in 1,2-dimethoxyethane at 75; for 16 h;

Steps:

C.4 Step 4: 6-Chloro-lH-pyrazolo[4,3-c]pyridine 53.4%
To a stirred solution of 4,6-dichloronicotinaldehyde (3 x 1.0 g, 1.0 eq) in DME (3 x 14 mL), hydrazine hydrate (3 x 1.14 g, 4.0 eq, 99%) was added slowly in a vial. The vial was sealed and the contents heated at 75°C for 16 h. After TLC showed completion, the mixture was cooled to rt and diluted with water (3 x 10 mL) and EtOAc (3 x 10 mL). After combining all 3 mixtures, the layers were separated and the organic layer was washed with brine (20 mL), dried over anhydrous sodium sulphate, filtered and concentrated. The resulting crude was purified by flash chromatography (Combiflash - Redisep, 12 g) using MeOH in DCM as eluent. The desired product was eluted at 1% MeOH in DCM. The fractions with product were concentrated to obtain pure 6-chloro- lH-pyrazolo[4,3-c]pyridine as yellow solid (1.4 g, 53.43%, from 3 batches). 1H NMR (400 MHz, DMSO-d₆): δ 13.608 (s, 1H), 8.946 (s, 1H), 8.350 (s, 1H), 7.652 (s, 1H). LCMS calculated for (M) 423.15 and found (M+H) 424.23.

References:

ASANA BIOSCIENCES, LLC;VENKATESAN, Aranapakam M.;SMITH, Roger A.;THOMPSON, Scott K.;LAPING, Nicholas;KULKARNI, Bheemashankar;HALLUR, Gurulingappa;VISWANADHAN, Vellarkad N.;PENDYALA, Muralidhar;KETHIRI, Raghava Reddy;TYAGI, Rajiv;SIVANANDHAN, Dhanalakshmi;BAKTHAVATCHALAM, Rajagopal WO2015/38417, 2015, A1 Location in patent:Page/Page column 78

FullText