The earliest successes were nature-identical materials such as coumarin, heliotropin and vanillin, all of which were used in 1889’s Jicky. Bertagnini’s aldehydes were already known at this time but it was their successful use in 1921 by Ernest Beaux (to provide a new top note character manifested in Chanel No. 5) that really stimulated the search for other novel fragrance ingredients.
There are many reasons why this search continues. In addition to originality of odor, cost, security of supply and performance in difficult media (such as laundry detergent), safety and sustainability are becoming increasingly important as plant-derived ingredients are being lost from the perfumer’s palette through unsustainable production (e.g., sandalwood, rosewood) or safety issues (e.g., sasafrass, fig leaf).
Screening of potential new ingredients requires time and involves expense in materials and equipment because in order for a material to pass an initial odor screen it is evaluated in a range of consumer products such as soap, laundry detergent, shampoo, conditioner, etc. Obviously, it is desirable to evaluate as few materials as possible and therefore the fragrance chemist will seek to synthesize only those materials with a high chance of passing the screening criteria. This is where rational design comes into play. Rational design uses our knowledge and understanding of fragrance in order to predict molecules with a better than random chance of making the grade as perfumery materials.