تفاعل #61557

معادلة التفاعل

water

5-(tert-Butyl-diphenyl-silanyloxymethyl)-2H-pyrazole-3-carboxylic acid ethyl ester

2-Bromo-N-(5-chloro-pyridin-2-yl)-acetamide

→

desired product

5-(tert-Butyl-diphenyl-silanyloxymethyl)-1-[(5-chloro-pyridin-2-ylcarbamoyl)-methyl]-1H-pyrazole -3-carboxylic acid ethyl ester

المذيبات

DMF

ظروف التفاعل

المعالجة

1. 1
   استخلاصthe mixture was extracted with ethyl acetate (2×50 ml)
2. 2
   تجفيفThe combined organic layers were dried over MgSO4
3. 3
   ترشيحfiltered
4. 4
   تركيزconcentrated under reduced pressure
5. 5
   workup.ADDITIONInspection of the TLC and HPLC/MS indicated that a 1:1 mixture of the desired product together with the regioisomeric 5-(tert-Butyl-diphenyl-silanyloxymethyl)-2-[(5-chloro-pyridin-2-ylcarbamoyl)-methyl]-2H-pyrazole-3-carboxylic acid ethyl ester
6. 6
   أخرىPurification of this mixture on silica gel eluting with a gradient on n-heptane/ethylacetate

الإجراء التجريبي

To a solution of 5 g 5-(tert-Butyl-diphenyl-silanyloxymethyl)-2H-pyrazole-3-carboxylic acid ethyl ester in 10 ml DMF 4 g Cs2CO3 and 3 g 2-Bromo-N-(5-chloro-pyridin-2-yl)-acetamide were added and the mixture was stirred for 3 h. Then 10 ml of water were added and the mixture was extracted with ethyl acetate (2×50 ml). The combined organic layers were dried over MgSO4, filtered and concentrated under reduced pressure. Inspection of the TLC and HPLC/MS indicated that a 1:1 mixture of the desired product together with the regioisomeric 5-(tert-Butyl-diphenyl-silanyloxymethyl)-2-[(5-chloro-pyridin-2-ylcarbamoyl)-methyl]-2H-pyrazole-3-carboxylic acid ethyl ester was present. Purification of this mixture on silica gel eluting with a gradient on n-heptane/ethylacetate yielded the desired product as the faster eluting less polar isomer.

المصدر