Hydrogen bond assisted synthesis of azacyclophanes from l-tyrosine derivatives

Spectroscopic and computational studies reveal that a dimer of two units of l-tyrosine derivatives, joined by intermolecular hydrogen bonds, acts as a template in the synthesis of azacyclophanes from l-tyrosine derivatives and formaldehyde via double Mannich type reaction. When the reaction is performed with l-tyrosine, the absence of this template leads to linear products. A new azacyclophane (benzoxazinephane) was synthesized by condensation of l-tyrosine isopropyl ester and formaldehyde.