Einfluß der syn-1,3-diaxialen wechselwirkung auf konformationsgleichgewichte der 2,4-diamino-2,4-didesoxy-α-d-idopyranose

Conformational equilibria of derivatives of 2,4-diamino-2,4-dideoxy-α-d-idopyranose are investigated. In the case of methyl 2,4-diacetamido-3,6-di-O-acetyl-2,4-dideoxy-α-d-idopyranoside, the proportion of the ¹C₄ conformation is between 7 and 44%, depending upon the solvent, and increases with increasing polarity of the solvent. Methyl 2,4-di(N-acetyl-N-acylamino)-3,6-di-O-acyl-2,4-dideoxy-α-d-idopyranosides show such strong steric 1,3-diaxial interaction that the proportion of the ¹C₄ conformation is 93%. Methyl 2,4-diamino-2,4-dideoxy-α-d-idopyranoside and its bis(ammonium) salt show strong 1,3-diaxial interactions of polar nature, resulting in an increase of the ¹C₄ conformation up to 74% and 84%, respectively.