- Process for the preparation of ε-caprolactam
-
Process for the preparation of ε-caprolactam, in which in a step (a) a compound with the general formula: O=CH—(CH2)4—C(O)—R??(1) in which R is —OH, —NH2or O—R′, in which R′ is an organic group with 1 to 10 carbon atoms, is contacted with ammonia and hydrogen in a suitable solvent at elevated pressure in the presence of a hydrogenation catalyst to a mixture of primary amino compounds and ε-caprolactam, followed by a separate second step (b) in which the primary amino compounds are reacted to ε-caprolactam, wherein the solvent in step (a) is an aqueous medium, including water, the yield to ε-caprolactam in step (a) is more than 10%, calculated on the initial molar amount of the compound according to formula (1), that ε-caprolactam is separated from the aqueous mixture obtained in step (a) by extraction and that the aqueous mixture resulting from the extraction, containing the primary amino compounds, is used in step (b).
- -
-
Page column 11,12
(2008/06/13)
-
- New renin inhibitors containing aliphatic or aromatic amides at the C-terminus
-
Five renin inhibitors, Iva-Pro-Phe(4-OMe)-MeLeu-Sta-εAhx-IAA (18), Iva-εAhx-Phe(4-OMe)-MeLeu-Sta-εAhx-IAA (23), H-εAhx-Phe(4-OMe)-His-Sta-εAhx-FBZA (36), H-εAhx-Phe(4-OMe)-His-Sta-εAhx-MBZA (45), and H-Phe (4-OMe)-His-Sta-εAhx-FBZA (48) have been synthesized in search of structures of improved biological properties. All synthesized inhibitors were resistant to chymotrypsin activity. Inhibitors 18 and 23 were insoluble in buffers, pH 7.4 and 2.0, 36, 45 and 48 were very good soluble in buffer pH 2.0 and poorly in buffer pH 7.4. Experimentally determined 1-octanol/pH 7.4 buffer partition coefficients (log P) of 36, 45 and 48 were above 1. Log P values of 18, 23, 36, 45 and 48 were 6.57, 6.91, 2.48, 2.09 and 2.00 respectively. The inhibitory potency in vitro of 18, 23, 36, 45 and 48 expressed as IC50 was 7.5 · 10-5, 5.0 · 10-6, 7.5 · 10-3, 1.0 · 10-4 and 2.5 · 10-5 M/l respectively.
- Paruszewski,Jaworski,Tautt,Dudkiewicz
-
p. 206 - 209
(2007/10/03)
-
- HYDROLYSIS OF ESTERS OF N-RETINYLIDENEAMINO ACIDS
-
The hydrolysis rate of the ester bond in the molecules of methyl esters of the N-retinylidene derivatives of aliphatic amino acids depends on their chain lengths.The higher reaction rates for the derivatives of γ-aminobutyric and δ-aminovaleric acids are explained by intramolecular catalysis.
- Karpenko, E. P.,Mitsner, B. I.,Zvonkova, E. N.,Evstigneeva, R. P.
-
p. 1669 - 1673
(2007/10/02)
-