3-[Benzyl-(3,5-dimethyl-pyrazol-1-ylmethyl)-amino]-propionitrile

The products of aza-type Michael addition, i.e., β-amino carbonyl compounds and their derivatives, are often used as peptide analogs or precursors of optically active amino acids, amino alcohols, diamines, and lactams [1]. Moreover, β-amino carbonyl functionalities are ubiquitous motifs in natural products such as alkaloids and polyketides [2]. Herein, we report the synthesis of new product using aza-type Michael reactions under mild conditions.

A mixture of 3-(benzylamino)propionitrile 1 [3] (1g, 6.25mmol) and 1-hydroxymethyl-3,5-dimethyl pyrazole 2 [4] (0.79g, 6.25 mmol) in 20 ml of acetonitrile was stirred at room temperature for four days, then the mixture was dried with Na₂SO₄ and filtered. The solvent was evaporated under reduced pressure. The product 3 obtained with a 97% yield as yellow oil.

¹H-NMR (300 MHz, CDCl₃): δ= 7.31-7.37 (CHarom, 5H, m); 4.80 ( N-CH₂-N, 2H, s); 3.75 (C₆H₅-CH₂,2H, s); 2.98-3.02 (CH₂-CH₂-CN, 2H, t, J = 7.66 Hz) ; 2.31-2.35 ( N-CH₂, t, J = 7.66 Hz); 2.22 ( CH₃, 3H, s) and 2.15 ( CH₃, 3H, s).

¹³C-NMR (CDCl₃, 75 MHz): δ= 148.18 (l); 140.5 (j); 138.12 (e); 129.11 (f); 128.99 (g); 128.03 (h); 119.27 (a); 106.35 (k); 66.56 (i); 56.94 (d); 48.24 (c); 17.23 (b); 13.95 (m); 11.46 (n).

EI-MS (70 eV, m/z): 173 (17.4); 171; 119; 95; 91 (100).