Preparation of dopaminergic N-alkyl-benzyltetrahydro-isoquinolines using a ‘one-pot’ procedure in acid medium Original Research Article

The preparation of N-methyl-BTHIQ () from N-phenylethyl-phenacetamide () by cyclization, reduction and N-alkylation in acid medium has been achieved in good yield in a ‘one-pot’ procedure. Acylation of imine () intermediate afforded the Z and E stereoselectivity in the enamide formation. 6-Hydroxy-BTHIQ () shows selectivity for D2 dopamine receptors, while its N-methylated homologue () displays higher affinities for both D1 and D2 receptor types, with an unexpected increase in D1 dopamine receptor affinity.