Isomerization and Racemization of Menthols

The isomerization and racemization of menthol isomers have been investigated with copper chromite and Raney nickel catalyst or sodium mentholates. The equilibrium concentration has been found to correspond to 55~56% of menthol with the catalytic isomerization, whereas to 74~75% of menthol with sodium mentholates. From these data, the free energy difference between equatorial and axial group in menthols is calculated to be about 0.5~0.6 Kcal./mole for hydroxyl and 1.4~1.5 Kcal./mole for methyl at 200°C.     

Design,synthesis and pharmacology of aortic-selective acyl-CoA: Cholesterol O-acyltransferase (ACAT/SOAT) inhibitors

We describe our molecular design of aortic-selective acyl-coenzyme A:cholesterol O-acyltransferase (ACAT, also abbreviated as SOAT) inhibitors, their structure–activity relationships (SARs) and their pharmacokinetic (PK) and pharmacological profiles. The connection of two weak ligands—N-(2,6-diisopropylphenyl)acetamide (50% inhibitory concentration [IC₅₀]?=?8.6?μM) and 2-(methylthio)benzo[d]oxazole (IC₅₀?=?31?μM)—via a linker comprising a 6 methylene group chains yielded a highly potent molecule, 9-(benzo[d]oxazol-2-ylthio)-N-(2,6-diisopropylphenyl)nonanamide (3h) that exhibited high potency (IC₅₀?=?0.004?μM) toward aortic ACAT. This head-to-tail design made it possible to markedly enhance the activity to 2150- to 7750-fold and to discriminate the isoform-selectivity based on the double-induced fit mechanism. At doses of 1 and 3?mg/kg, 3h significantly decreased the lipid-accumulation areas in the aortic arch to 74 and 69%, respectively without reducing the plasma total cholesterol level in high fat- and cholesterol-fed F₁B hamsters. Here, we demonstrate the antiatherosclerotic effect of 3hin vivo via its direct action on aortic ACAT and its powerful modulator of cholesterol level. This molecule is a potential therapeutic agent for the treatment of diseases involving ACAT-1 overexpression.     

Synthetic construction of sugar-amino acid hybrid polymers involving globotriaose or lactose and evaluation of their biological activities against Shiga toxins produced by Escherichia coli O157:H7

Synthetic assembly of sugar moieties and amino acids in order to create “sugar-amino acid hybrid polymers” was accomplished by means of simple radical polymerization of carbohydrate monomers having an amino acid-modified polymerizable aglycon. Amines derived from globotriaoside and lactoside as glycoepitopes were condensed with known carbobenzyloxy derivatives, including Z-Gly, Z-l-Ala and Z-β-Ala, which had appropriate spacer ability and a chiral center to afford fully protected sugar-amino acid hybrid compounds in good yields. After deprotection followed by acryloylation, the water-soluble glycomonomers were polymerized with or without acrylamide in the presence of a radical initiator in water to give corresponding copolymers and homopolymers, which were shown by SEC analysis to have high molecular weights. Evaluation of the biological activities of the glycopolymers against Shiga toxins (Stxs) was carried out, and the results suggested that glycopolymers having highly clustered globotriaosyl residues had high affinity against Stx2 (K_D?=?2.7～4.0?µM) even though other glycopolymers did not show any affinity or showed very weak binding affinity. When Stx1 was used for the same assay, all of the glycopolymers having globotriaosyl residues showed high affinity (K_D?=?0.30～1.74?µM). Interestingly, couple of glycopolymers having lactosyl moieties had weaker binding affinity against Stx1. In addition, when cytotoxicity assays were carried out for both Stxs, glycopolymers having highly clustered globotriaosyl residues showed higher affinity than that of the copolymers, and only highly clustered-type glycopolymers displayed neutralization potency against Stx2.