2-BENZYL-5-METHYL-2H-PYRAZOL-3-YLAMINE synthesis

7synthesis methods

Product Name:2-BENZYL-5-METHYL-2H-PYRAZOL-3-YLAMINE
CAS Number:1134-82-3
Molecular formula:C11H13N3
Molecular Weight:187.24

2469-99-0
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555-96-4 Synthesis

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1134-82-3
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Yield:1134-82-3 45%

Reaction Conditions:

Stage #1: Cyanoaceton;Benzylhydrazinewith hydrogenchloride in water at 70 - 105;
Stage #2: with sodium hydroxide pH=6;Cooling with ice;

Steps:

2.a

To (phenylmethyl)hydrazine (100g, 0.513mol) in 220ml of H₂O at 70 ⁰C was added 3-oxobutanenitrile sodium salt (48.62g, 0.463mol) in one portion, and then 110 ml of H₂O and 177ml of the cone. HCI . The reaction mixture was heated at 105 ⁰C for 30mins. LC/MS showed product. The reaction mixture was cooled to rt, then chilled in ice-water bath, and pH was adjusted to 6 using 50%w NaOH. A waxy solid was collected. To this solid was added EtOAc (50ml) and hexane (100ml). The resulting solution was cooled at -20 ⁰C to give 12.Og solid (14% yield). The mother liquid was concentrated and purified by silica gel column (3/10/0.5(v/v/v)=EtOAc/ DCIWMeOH) to give 38.6g of 2a as a solid (45%).

References:

WO2009/32652,2009,A1 Location in patent:Page/Page column 9; 35-36

1118-61-2 Synthesis