Acidity study on some pyridazines
The tautomeric, conformational equilibrium positions, and pKa values of some pyridazine derivatives 1–17 have been examined by means of semi empirical AM1 COSMO calculations in aqueous solution (ɛ=78.4). The results obtained from the calculations have been compared with the experimental findings.
An enantiocontrolled synthesis pathway has been developed to provide formation of tricyclic amine 7, representing the ABC ring system of the complex alkaloid daphnicyclidin A (1). Our efforts describe preparation of the Z-hexahydro-(1H)-azocine 29 and cyclization to construct the novel 4-azabicyclo[5.3.2]dodecane 31. Transannular reductive amination following the deprotection of 31 gave the desired tertiary amine 7.