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11.
Allylation of carbonucleophiles with allylic carbamates under neutral conditions has been studied. The C-allylation of carbonucleophile is competitive with the N-allylation of amines, and the structure of amines is crucial for the selectivity. Bulky secondary amines gave the best results. Also a new method of protection-deprotection of amines as carbamates has been developed. Smooth deprotection is possible by the palladium-catalyzed reaction of allyl carbamates with formic acid. This method is particulary useful for primary amines, including optically active amino acids. 相似文献
12.
The possibility of radioisotope X-ray absorptiometry to determine the particle size of powder in conjunction with sedimentation was investigated. The experimental accuracy was primarily determined by Cow and X-ray intensity. where Co'=weight concentration of the particle in the suspension w'=(micron/rho)l/(mu/rho)s-rhol/rhos rho; density micron/rho; mass absorption coefficient, suffix l and s indicate dispersion and particle, respectively. The radiosiotopes, Fe-55, Pu-238 and Cd-109 have high w-values over the wide range of the atomic number. However, a source of high micron value such as Fe-55 is not suitable because the optimal X-ray transmission length, Lopt is decided by the expression, micronlLopt approximately 2/(1+C'ow') by using Cd-109 AgKX-ray source, the weight size distribution of particles from the heavy elements such as PbO2 to light elements such as Al2O3 or flyash was determined. 相似文献
13.
Dehydrroxy-trans-resorcylide () was synthesized by efficient intramolecular alkylation of the protected cyanohydrin. The butadiene telomer obtained by the palladium catalyzed reaction of butadiene with acetic acid was used as a suitable block of the carbocycle. 相似文献
14.
Angiotensin I‐converting enzyme (ACE) inhibitory peptide was isolated from the hen ovotransferrin hydrolysate using chymotryptic hydrolysis by two steps of reverse‐phase high‐performance liquid chromatography. The amino sequence of this novel peptide was identified as Lys‐Val‐Arg‐Glu‐Gly‐Thr‐Thr‐Tyr that inhibited ACE activity in vitro in a concentration‐dependent manner with an effective concentration (IC50) of 102.8 μM. Also, this inhibition was identified as noncompetitive using the Lineweaver‐Burk plot. Moreover, the antihypertensive action of this novel peptide was investigated by an intravenous injection into spontaneously hypertensive rats (SHR). A dose‐dependent reduction of systolic blood pressure by this peptide was observed after 40 min of treatment and it decreased the blood pressure markedly at the maximal dose (1 nmol/mL/kg). The maximal blood pressure lowering activity of this peptide was calculated as 163% of captopril (10 pmol/mL/kg) that was used as positive control. In conclusion, the obtained data suggests that Lys‐Val‐Arg‐Glu‐Gly‐Thr‐Thr‐Tyr has an ability to inhibit ACE activity and decrease the systolic blood pressure in hypertensive animals. 相似文献
15.
16.
Oxetanes were reacted with lithium enolates generated from esters or amides in the presence of boron trifluoride etherate to give δ-hydroxyesters or amides in high yield, which were hydrolyzed and converted to δ-lactones. 相似文献
17.
Fumihiko Hasumi Yasumitsu Miyamoto Ichiro Okura 《Applied biochemistry and biotechnology》1995,55(1):1-4
Glutamate synthesis by reductive amination of 2-oxoglutarate was performed by the combination of NADH regeneration system
and glutamate dehydrogenase (GluDH). The conversion of 2-oxoglutamate to glutamate was 98% after 3 h, and the turnover number
of NAD+was 17. 相似文献
18.
19.
Ichiro Matsuo 《Tetrahedron letters》2005,46(24):4197-4200
Triglucosylated high-mannose-type tetradecasaccharide (Glc3Man9GlcNAc2), the oligosaccharide part of the donor substrate of oligosaccharyl transferase (OST) complex, and diglucosylated tridecasaccharide (Glc2Man9GlcNAc2) were synthesized. These oligosaccharides were assembled in a convergent and stereoselective manner. Undecasaccharide 5 was employed as the common intermediate, and coupling with trisaccharide (4) and disaccharide (3) donor afforded fully protected tetradeca-(17) and tridecasaccharide (16), respectively. These oligosaccharides were deprotected to give Glc3Man9GlcNAc2 and Glc2Man9GlcNAc2, respectively. 相似文献
20.
Fumihiko Hasuni Katsunori Fukuoka Shuichi Adachi Yasumitsu Miyamoto Ichiro Okura 《Applied biochemistry and biotechnology》1996,56(3):341-344
Alanine synthesis by reductive amination of pyruvate was performed by the combination of NADH regeneration system and alanine
dehydrogenase (AlaDH). The conversion of pyruvate to alanine was 99% after 1 h. Leucine synthesis was also carried out by
the combination of NADH regeneration system and leucine dehydrogenase (LeuDH). The conversion of 4-methyl-2-oxovalerate to
leucine was 60% after 1.5 h. 相似文献