Phenylalanine-N-methylamide

Ammonium formate Phenylalanine-N-methylamide Formaldehyde Dicyclohexylcarbodiimide... 

The [4-hydroxy-2R-isobutyl-3-ethenylsuccinyl]-L-phenylalanine-N-methylamide (400.0 mg, 1.16 mmol) was dissolved in thiophenethyol and the mixture stirred in the dark under nitrogen at 60°C for 2 days. Ether was added to the cooled reaction mixture and the precipitated product collected by filtration. 

The solid was washed with large volumes of ether and dried under vacuum to give the [4-N-hydroxy-2R-isobutyl-3S-(thienylthiomethyl)succinyl]-L-phenylalanine-N-methylamide (320.0 mg, 0.73 mmol, 63%), melting point 184°-186°C. 

The [4-N-hydroxy-2R-isobutyl-3S-(thienylthiomethyl)succinyl]-L-phenylalanine-N-methylamide and hydroxy benztriazole were dissolved in DCM/DMF (4 1) and the mixture cooled to 0°C before adding N-(dimethylaminoethyl)-N -ethylcarbodiimide and N-methylmorpholine. The mixture was stirred at 0°C or 1 h to ensure complete formation of the activated ester. Hydroxylamine hydrochloride and NMM were dissolved in DMF then this mixture added dropwise to the cooled solution of the activated ester. After 1 h the reaction was poured into ether/water (1 1) whereupon the desired product precipitated as white crystals. These were collected by filtration, further washed with ether and water then dried under vacuum at... 

C. So the [4-(N-hydroxyamino)-2R-isobutyl-3S-(thienylthiomethyl) succinyl]-L-phenylalanine-N-methylamide was obtained, melting point 236°-238°C (recrystallised from methanol/ water 1 1). 

N-Acetyl-DL-phenylalanine-N-methylamide, 40B, 457 N-Acetyl-L-phenylalanine-N-methylamide, 43B, 608 N-Acetyl-L-tyrosinemethylamide, 39B, 362 40B, 456 Cyclo(L-seryl-L-tyrosyl) monohydrate, 39B, 360 Methyl L-pyroglutamyl-L-histidine, 39B, 362 N(a)-Acetyl-aza-a-homo-phenylalanine methylamide, 45B,... 

The energetics of Phe provide an excellent example of this phenomenon. In our molecular dynamics simulation of vasopressin, we found that Phe underwent conformational transitions between three regions of conformational space the 7 (, = -80, -1-80), a, (, i/i = -E80, -80) conformations(64). These conformations in the isolated residue, taken as the N-acetyl, N -methylamide blocked phenylalanine, are well separated energetically as can be seen in Table I. The C7 is 3.1 Kcal more stable than the 7 , and 4.7 Kcal more stable than the a,. In order to compare the relative stabilities of these phenylalanine conformations in the... 

Hiraoki et al. investigated the phenyl ring dynamics of poly(L-phenylalanine) using H-NMR, showing that it is characterized by a fairly broad distribution of correlation times. The mean correlation time of this distribution was 1.2 x 10 Hz at 25°C, which is close to that of the fast motional component of the B. mori and S.c. ricini silk fibroins. The Tyr ring flip in the pentapeptide [Leu ] enkephalin was reported to be 5.6 x 10 Hz at 25°C, which is close to that of the slow motional component observed here for silk fibroin. On the other hand, the ring motion in crystalline N-acetyl-L-Asp-L-Pro-L-Tyr-N -methylamide was found to be 1.1 X 10 Hz at 27°C, close to that of the fast motional component of the silk fibroins. 

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