Charles Heidelberger asked Robert Duschinsky and Robert Schnitzer at Hoffman - La Roche to synthesize fluorouracil .
Charles Heidelberger had earlier found that fluorine in fluoroacetic acid inhibited a vital enzyme .
Charles Heidelberger , who had earlier found that fluorine in fluoroacetic acid inhibited a vital enzyme , asked Robert Duschinsky and Robert Schnitzer at Hoffman - La Roche to synthesize fluorouracil .