Azobenzene moieties were incorporated into a synthetic receptor allowing its affinity for the guanidinium cation to be modulated ten-fold by photoirradiation and/or heating.

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Chiral monoaza-15-crown-5 ethers (1, 2) were prepared from (R)-(-)-2-amino-1-butanol in high yield. The chiral monoaza-15-crown-5 ethers were purified directly as NaClO(4) complexes. Molecular recognition by these chiral monoaza-crown ethers of (R)- and (S)-PhEtHClO(4) and (R)- and (S)-NapEtHClO(4) as characterized by UV-vis spectroscopy. The order of enantiomeric selectivity is (R)- > (S)- PhEtHClO(4) and (S)- > (R)-NapEtHClO(4) for 1. In the case of 2 it was (R)- > (S)-PhEtHClO(4) and (R)- > (S)- NapEtHClO(4). The cavity of macrocycle and steric hindrance of the benzene units appears to play an important role in recognition.

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We synthesized a series of novel macrocycles with diamide-diester groups (S,S)-1, (S,S)-2, (S,S)-3, and (R,R)-1, derived from dimethyloxalate and amino alcohols by high dilution technique, and evaluated enantiomeric recognition properties of these macrocycles toward primary alkyl ammonium salts by 1H NMR titration. Taking into account the host employed, important differences were observed in the Ka values of (R)-Am and (S)-Am for (S,S)-1 and (R,R)-1 hosts, KS/KR = 5.55 and KR/KS = 3.65, Delta Delta Go = 0.43 and -0.32 kJ mol-1, respectively. There seems a general tendency for the host to include the guests with the same absolute configuration.

This study represents a facile synthesis of building blocks (1–3) of crown ethers and amine precoursers (4a‐d). The study also involves synthesis of mono and dibenzo N, N‐disubstituted diaza 18‐crown‐6 derivatives with high yield without chromatographic purification and high vacuum distillation. The complex ability of host the ethers was evaluated in terms of structural modification.