ChemInform Abstract (44 refs. up to 1987).

An enantioselective iodolactonization reaction of allenoic acids has been developed using a trisimidazoline catalyst and I2. Our mechanistic study suggests the involvement of a π-allyl cation intermediate in this reaction system.

No abstract

Various -alkoxy oximes are converted with collidine to form a collidinium salt intermediate, which reacts with cuprates (II) or (V) to give the corresponding nitriles. -(FUJIOKA*, H.; MATSUMOTO, N.; OHTA, R.; YAMAKAWA, M.; SHIMIZU, N.; KIMURA, T.; MURAI, K.; Tetrahedron Lett. 56 (2015) 21, 2656-2658, http://dx.

Vitamin K deficiency is a relatively common condition in neonates. However, the role of vitamin K in neonatal bone metabolism remains to be determined. Osteocalcin (OC) is the most abundant noncollagenous protein in bone, and is regulated to be ␥-carboxylated by vitamin K. In this study, we measured ␥-carboxylated osteocalcin (Gla-OC) and non-or undercarboxylated osteocalcin (Glu-OC) separately, and examined the effects of vitamin K on osteocalcin metabolism. Eighteen full-term healthy neonates were enrolled in this study. In the cord and d-5 blood samples, the OC levels were determined by three different methods to examine the intact OC by immunoradiometric assay (IRMA), Gla-OC, and Glu-OC. Serum vitamin K fractions, hepaplastin test, and type 1 procollagen carboxyl extension peptide were also determined. Urine samples were also collected from the first voiding and on d 5 to determine urinary pyridinoline, deoxypyridinoline, and ␥-carboxylated glutamic acid. Serum levels of phylloquinone (PK) and menaquinone (MK)-4 increased on d 5 following vitamin K administration and increased intake in breast milk and/or formula. The OC levels determined by IRMA did not change between cord and d-5 blood samples, but the Gla-OC level increased remarkably and Glu-OC reduced to a negligible level. OC in cord blood is mainly Glu-OC, and Glu-OC is replaced with Gla-OC within 5 d of life after vitamin K supplement. The IRMA assay fails to distinguish Gla-OC from Glu-OC and caution is needed to estimate bone turnover with this method in the perinatal period. (Pediatr Res 52: 656-659, 2002) Abbreviations OC, osteocalcin Gla-OC, ␥-carboxylated osteocalcin Glu-OC, non-or undercarboxylated osteocalcin IRMA, immunoradiometric assay PK, phylloquinone MK, menaquinone PICP, type 1 procollagen carboxyl extension peptide ␥-Gla, ␥-carboxylated glutamic acid Pyr, pyridinoline D-Pyr, deoxypyridinoline