Two diastereomers of 2-[[β-(N-phenylamino)-α-methylphenethyl]-methylamino]-N,N-dimethylacetamide

The structures of two diastereomers ((1 R ,2 R ) and (1 R ,2 S )) of the title compound have been determined. The molecular conformation of the (1 R ,2 R ) isomer is heavily influenced by strong intramolecular hydrogen bonding between the secondary and tertiary amine groups (N(1)…N(2) 2.629(8) Å; N(4)…N(5) 2.628(8) Å). In the (1 R ,2 S ) isomer no intramolecular interaction is observed, but somewhat weaker intermolecular hydrogen bonding does occur between the secondary amine and the carbonyl group of a neighboring molecule (N(1)…O(1) 2.960(6) Å) related by a 2 1 screw operation along the a -axis ( x 1/4 0 ). No close intermolecular contacts are observed for the (1 R ,2 R ) isomer. Crystal data for (1 R ,2 R ); monoclinic, P 2 1 (No. 4), a =18.588(5), b =16.743(4), c =6.062(1) Å, β=97.26(2) o , V =1871.5(8) A 3 , Z=4, D cale =1.16 g/cm 3 . Crystal data for (1 R ,2 S ): orthorhombic, P 2 1 2 1 2 1 (No. 19), a =8.008(2), b =9.985(3), c =23.458(5)Å, V =1875.8(6) Å 3 , Z=4, D cale =1.15 g/cm 3 .