1,5-diazo-bicyclo{4.3.0}5-nonene in tetrahydrofuran exothermic react.; evapn. of mixt.; intermediates dissolved in tetraglyme and treated with 1,5-diazo-bicyclo(4.3.9)5-nonene; vac. distn. to receiver cooled by dry ice;

1,5-diazabicyclo{4.3.0}non-5-ene in further solvent(s) in tetraglyme;

1: n-heptane 2: tetrahydrofuran View Scheme