This disclosure relates to flavour modification and to compounds of formula (I)whereinR1 is selected from C2-C20 alkyl, and C6-C25 alkenyl, and a) R2 and R3 together are —C(O)CH2CH2—; orb) R3 is hydrogen and R2 is —CH2CH2C(O)NHCH2CH3,useful in modifying flavours.