Synthesis, characterization and crystal structures of two new phenolic mannich bases

Two new Mannich bases, 5-methyl-2-((4-(pyridin-2-yl)piperazin-1-yl)methyl)phenol (1) and 5-methyl-2-((4-(4-nitrophenyl)piperazin-1-yl)methyl)phenol (2), were prepared and characterized structurally with elemental analysis, IR UV and NMR spectroscopic techniques as well as single crystal X-ray diffraction. Compound I crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 6.6726(2) [Angstrom], b = 17.0542(6) [Angstrom], c = 13.3222(4) [Angstrom], [beta] = 100.832(1)[degrees], V = 1489.00 (8) [[Angstrom].sup.3], Z = 4, [R.sub.1] = 0.0408, [wR.sub.2] = 0.1143. Compound II crystallizes in the monoclinic space P21 with unit cell dimensions a = 5.9519(2) A, b = 17.3315(8) [Angstrom] c = 15.7237(7) [Angstrom] [beta] = 90.348(2)[degrees], V = 1621.95(12) [[Angstrom].sup.3], Z = 4, [R.sub.1] = 0.0353, [wR.sub.2] = 0.0965. Both compounds have their structures stabilized by hydrogen bonding and [micro]...[micro] interactions. KEY WORDS: Mannich base, Piperazine, X-ray diffraction, Hydrogen bonds