《Unusual amino acids VI. Substituted arylamino acids by asymmetric hydrogenation of N-Cbz and N-Boc protected dehydroamino acid derivatives》 was published in Chirality in 1996. These research results belong to Krause, H. W.; Kreuzfeld, H.-J.; Schmidt, U.; Dobler, Ch.; Michalik, M.; Taudien, S.; Fischer, Ch.. Category: esters-buliding-blocks The article mentions the following:
Substituted N-Cbz and N-Boc protected (arylamino)acrylic acids and esters were prepared and used in asym. hydrogenations catalyzed by PROPRAPHOS-Rh. Stereoselectivities >90% ee could be achieved, the rate of which is dependent on the position of the substituent in the aromatic ring. The N-Boc derivatives provide advantages compared with the N-Cbz analogs. The amino acid derivatives were fully characterized by 19F, 13C, and 1H NMR. In the part of experimental materials, we found many familiar compounds, such as H-D-Phe(4-NO2)-OMe.HCl(cas: 67877-95-6Category: esters-buliding-blocks)
H-D-Phe(4-NO2)-OMe.HCl(cas: 67877-95-6) belongs to esters. Esters are more polar than ethers but less polar than alcohols. Category: esters-buliding-blocks They participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding confers some water-solubility.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics