Extracurricular laboratory: Synthetic route of 5414-21-1

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 5-Bromovaleronitrile, and friends who are interested can also refer to it.

Reference of 5414-21-1, As we all know, there are many different methods for the synthesis of a compound, and people can choose the synthesis method that suits their own laboratory according to the actual situation. 5414-21-1 name is 5-Bromovaleronitrile, This compound is widely used in many fields, so it is necessary to find a new synthetic route. The downstream synthesis method of this compound is introduced below.

Sodium hydride paste (6.16 g. of 61% w/w suspension in liquid paraffin) was added portionwise over 30 minutes to a solution of 3-nitropyrazole (17.4 g.) in dry DMF (150 ml.) with external ice cooling to maintain the temperature at 20-30. The mixture was stirred for 45 minutes and to the almost clear solution was added 5-bromovaleronitrile (25 g.) over 30 minutes, at 25-30, and the mixture was stirred for 4 hours. Water (450 ml.) and EtOAc (450 ml.) were added and the upper layer was separated, dried (MgSO4) and evaporated in vacuo to an oil which was a mixture of 5-(3-nitropyrazol-1-yl)valeronitrile and 5-(5-nitropyrazol-1-yl)valeronitrile. The oil was divided into two 15 g. portions which were fractionated on a silica column (3.5 cm diameter*100 cm long) eluted at 2 atmospheres by EtOAc/60-80 petroleum ether (3:7 v/v). The 1,5 isomer was eluted first followed by the 1,3 isomer. The 5-(3-nitropyrazol-1-yl)valeronitrile had m.p. 32-33. To a solution of 5-(3-nitropyrazol-1-yl)valeronitrile (9.16 g.) in dry THF (200 ml.) was added 5% w/w palladium on carbon (1.8 g.). The mixture was stirred at 20 under an atmosphere of hydrogen. 3.2 Liters of hydrogen were absorbed over 4 hours. The catalyst was filtered off and the filtrate was evaporated in vacuo to give 5-(3-aminopyrazol-1-yl)valeronitrile as an oil.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 5-Bromovaleronitrile, and friends who are interested can also refer to it.

Reference:
Patent; ICI Americas Inc.; Imperial Chemical Industries PLC; US4496564; (1985); A;,
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts