1,4-Diaza[2.2.2]bicyclooctane 1,4-Diazabicyclo[2.2.2]octane 1,4-Diazobicyclo[2.2.2]octane 1,4-Ethylenepiperazine 280-57-9 Bicyclo[2.2.2]-1,4-diazaoctane D 33LV Dabco Dabco 33LV N,N'-endo-Ethylenepiperazine NSC56362 Triethylenediamine