Aspartame dipeptide analogues: Effect of number of side-chain methylene group spacers and C-alpha-methylation in the second position

Our model of the active site of the sweet taste receptor is shown to be consistent with the aspartame analogues in which the L-Phe(2) residue is replaced by L-(alpha Me)Phg, L-(alpha Me)Phe or L-(alpha Me)Hph. The analogues containing either the first or the third C-alpha-methylated, phenyl-containing residue in the second position of the dipeptide were synthesized and found to be approximately as sweet as aspartame itself and its L-(alpha Me)Phe(2) analogue. (C) 1997 Elsevier Science Ltd