Zheng, Xiaozhang et al. published their research in Chirality in 2000 | CAS: 87694-53-9

(S)-tert-Butyl (1-(methoxy(methyl)amino)-1-oxo-3-phenylpropan-2-yl)carbamate (cas: 87694-53-9) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Reference of 87694-53-9

Unprecedented crystallization and X-ray crystal structure of racemic Nα-(t-butyloxycarbonyl)-L-phenylalanine N-methoxy-N-methylamide was written by Zheng, Xiaozhang;Donkor, Isaac O.;Miller, Duane D.;Ross, Charles R. II. And the article was included in Chirality in 2000.Reference of 87694-53-9 This article mentions the following:

Weinreb amide Boc-Phe-N(Me)OMe was synthesized from Boc-Phe-OH and O,N-dimethylhydroxylamine hydrochloride using iso-Bu chloroformate with the coupling agent being carbonyldiimidazole or ethylcarbodiimide. An optically active oil was isolated along with an optically inactive solid irresp. of the type of coupling agent used. Single crystal x-ray anal. of the solid revealed that it is a racemate. The mol. packing of the crystals reflect the stability of the racemate as opposed to an enantiomerically pure solid. In the experiment, the researchers used many compounds, for example, (S)-tert-Butyl (1-(methoxy(methyl)amino)-1-oxo-3-phenylpropan-2-yl)carbamate (cas: 87694-53-9Reference of 87694-53-9).

(S)-tert-Butyl (1-(methoxy(methyl)amino)-1-oxo-3-phenylpropan-2-yl)carbamate (cas: 87694-53-9) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Reference of 87694-53-9

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics