Enantioselective Peptide Synthesis by Using the Optically Active Polymer Containing the 1-Benzyl-3-Hydroxy-5-Isobutyl-Hydantoin Structure

The polymer containing the 1-benzyl-3-hydroxyhydantoin structure was prepared from styrene and 1-chloromethylhydantotin in order to achieve not only the act as acyl activating polymeric ester but the selective reaction using the D, L-amino acid seter. For the enantioselective peptide senthesis, the 1-benzyl-3-hydroxyhydantoin as a model compound and the 1-bernzyl-3-hydroxyhydantoin type polymer were allowed to act by two methods-the active ester method and the additive method using N, N\u27-dicyclohexylcarbodiimide (DCC). Optical yield was appreciated in 45%

Polymers Having Stable Radicals : Electrochemical and Chemical Behaviors of the Polymer Having Nitroxyls.

As a part of this series on polymers having stable radicals, evaluation of oxidation-reduction potentials by polarography and oxidative reactivities toward hydrazine and hydrazobenzene has been dealt with on nitroxyl stable radicals. Poly (4-methacryloyloxy-2, 2, 6, 6-tetramethylpiperidine-1-oxyl) (III) as a polymer having stable radicals, and its prototypes, 4-oxy-2, 2, 6, 6-tetramethylpiperidine-1-oxyl (I) and 4-isobutyroyloxy-2, 2, 6, 6-tetramethylpiperidine-1-oxyl (II), have been employed for purpose of the study. The electrode reactions of (I) in a range of pH. 8.0-10.1 in aqueous media were observed to be quasi-reversible and the reduction half-wave potentials (E_) being between 0.120-0.200 V (vs. SCE) depending on pH.. In the other pH. regions, the reactions seemed to be irreversible and the reduction halfwave potentials depended uPon pH. as well. In addition, polarographic data in a non-aqueous medium ensured that all the nitroxyls (I), (II) and (III) might have the same redox potential values. The oxidation reactions, using (I), (II), and (III), on hydrazine and hydrazobenzene have been performed, of which extent was pursued spectrophotometrically. From the kinetics, it was elucidated that, (1) the reactions were bimolecula, (2) the rate determinant steps were in the first hydrogen abstraction and, (3) the reactions with hydrazine were reaction controlled (ΔE ; 11.2-11.3 Kcal/mol) while the reactions with hydrazobenzene were diffusion controlled (ΔE ; 5.9-3.9 Kcal/mol). Thermodynamic analysis indicated that the case of reaction with hydrazobenzene differed mechanistically whether the reactant was monomeric (II)or polymeric (III) (ΔS^‡ : -17.9 e. u., (II) ; -21.8 e.u., (III), at 20℃ in THF)and that a steric hindrance presumably took place in the latter

Optically Active 1-Hydroxy-3-Substituted Succinimides for Enantioselective Peptide Synthesis

Optically active 1-hydroxy-3-substituted succinimides were prepared in good yield. The enantioselectivity was evaluated based on specific rotation of dipeptides. 1-Hydroxy-3-substituted succinimide esters of Z-alanine were treated with D, L-ethyl alaninate to indicate 70 and 90% diastereomeric excess of L-L and D-D isomers respectively

Acetohydroxamic Acid for Peptide Synthesis

The ester derivatives of acetohydroxamic acid md N, N-diacetyl hydroxylamine, N, O-diacetyl hydroxylamine and triacetyl hydroxylamine were assured to be capable of being used as activated esters. At first, evaluation of acyl activating ability was made by reacting the above compounds with amine, and it was shown that all of them worked to yield amides with excellent conversion and that, among them, triacetyy hydroxylamine was most powerfull, where acetylation of amines went through its imide carbonyl group. Furthemore, dipeptide synthesis was found to accomplish without any racemization and in a good yield by use of acetohydroxamic acid. Next syntheses of polymers containing hydroxamic acid structure were carried out by the following routes. (a) methyl methacrylate was copolymerized with N-methacrylobenzyloxyamine and the copolymer obtained was debenzylated, (b) N-methacrylo-N, O-diacetyl hydroxylamine was polymerized, followed by hydrolysis and copolymers with styrene or methyl methacrylate were deacylated. The polymer obtained by route (a) was converted to the activated polymer ester of N-blocked diglycine and removal of the protecting group would provide a method for preparation of cyclic diglycine

Association between the course of hypnotics treatment for insomnia and work functioning impairment in Japanese workers.

Study objectivesThis cross-sectional study analyzed the effect of treatment with hypnotics for sleep disorders, particularly insomnia, on daytime work functioning by phase of treatment in Japanese workers.MethodsSubjects were respondents (n = 36,375) to a questionnaire survey conducted in 2015 to assess work functioning impairment in 15 companies in Japan. The questionnaire results were analyzed together with the respondents' healthcare data extracted from public health insurance claims. Work functioning impairment was measured using the Work Functioning Impairment Scale (WFun). The status of treatment for insomnia was determined using data on diseases and prescribed drugs extracted from health insurance claims from the past 16 months. The odds ratio of severe work functioning impairment according to on-treatment duration and off-treatment duration was estimated using logistic regression analysis.ResultsThe risk of severe work functioning impairment was significantly higher in subjects with insomnia who were being treated with hypnotics for 1 month or longer compared to non-insomnia subjects. This increased risk tended to be reduced with longer on-treatment duration. For subjects who had previously received hypnotics treatment for insomnia, the risk of severe work functioning impairment was significantly increased in all subgroups stratified by time from discontinuation of the prescription. This increased risk tended to be reduced with longer off-treatment duration.ConclusionsWorkers who are or were receiving hypnotics to treat insomnia may have a higher risk of daytime functioning impairment. Those with protracted insomnia require careful assessment of the risks and benefits of prescription hypnotics