Synthesis of substituted ethenylpyrazines and dialkylpyridines and their sensory properties

Ethenylpyrazines and substituted pentylpyridines are potent flavouring materials. For a more detailed evaluation of their sensory properties, we synthesized 2-ethenyl-3-ethylpyrazine (1), 2,3-diethenyl-5-methylpyrazine (2), 2-prop-2-enylpyrazine (3), 5-ethenyl-2-methoxy-pyrazine (4), 3-ethenyl-2-ethoxypyrazine (5), 3-methyl-2-pentylpyridine (6), 5-methyl-2-pentylpyridine (7), 6-methyl-2-pentylpyridine (8) and 4-pentylpyridine (9). An expert panel evaluated these compounds as having intense green and herbal notes. © 1997 John Wiley & Sons, Ltd.