Prevalence and predictors of lower extremity atherosclerotic disease amongst high-risk patients using ankle brachial index.

INTRODUCTION: The prevalence of lower extremity artery disease (LEAD) continues to increase worldwide. This is expected to translate into logarithmic rise in lower-limb amputations especially in the developing world. Majority of patients suffering from LEAD remain asymptomatic until late and are vulnerable to limb-threatening complications unless actively screened and treated. METHODS: This was a prospective, single-center, observational study to determine the prevalence and predictors of LEAD. Patients with known atherosclerotic vascular disease (but not known LEAD) or those at risk were enrolled. All underwent ankle brachial index (ABI) measurement as per the standard protocol. A threshold of ABI ≤0.90 was taken to diagnose LEAD. RESULTS: A total of 1000 patients were enrolled. The mean age of the group was 61.4 ± 10.0 years and the prevalence of LEAD was 10.2%. Amongst those who had LEAD, the majority of patients (69.6%) had no symptoms. The prevalence of LEAD in diabetic population in our study was 13.2% and it was 30.9% in coronary artery disease patients . Factors independently linked to LEAD on regression analysis included advanced age, presence of diabetes, smoking history, lower serum HDL and a lower ejection fraction. CONCLUSIONS: The vast majority of patients suffering from LEAD are asymptomatic. Early diagnoses and institution of appropriate medical and physical therapy can prevent excess morbidity and mortality due to LEAD. Factors independently linked to LEAD are advanced age, presence of diabetes, smoking history, lower serum HDL and a lower ejection fraction. The presence of either of these should signal undertaking of appropriate steps to unmask underlying LEAD.

Palladium-catalyzed synthesis of α-aryl acetophenones from styryl ethers and aryl diazonium salts via regioselective Heck arylation at room temperature.

Preparation of α-aryl acetophenones from styryl ethers and aryldiazonium salts is described. The reaction is catalyzed by palladium acetate at room temperature in the absence of ligand and base. The developed method is highly attractive in terms of reaction conditions, substrate scope, functional group tolerance and yields. Synthetic applications of the present method are demonstrated by preparing α-aryl indoles and 3-aryl isocoumarin from styryl ethers.

Development of Routes for the Stereoselective Preparation of ß-Aryl-C-glycosides via C-1 Aryl Enones.

A wide range of enones derived from d-glucal, d-galactal, l-rhamnal, d-rhamnal, and l-arabinal underwent Heck-coupling with various arylboronic acids bearing electron-donating and -withdrawing groups in the presence of palladium acetate and 1,10-phenanthroline. These reactions provided synthetically useful C-1 aryl enones in good yields. Many sensitive functional groups as well as protecting groups present in arylboronic acids and enones, respectively, remained intact under optimized conditions. The stereoselective hydrogenation of C-1 aryl enones with Pd-C/H2 provides the ß-isomer of 2-deoxy-aryl-C-glycosides in excellent yield. The C-1 aryl enones were also used as precursors for the synthesis of 2-hydroxy-ß-aryl-C-glycosides. Regioselective C-2 halogenations and vinylations of C-1 aryl enones were achieved in excellent yields.

Palladium catalyzed stereocontrolled synthesis of C-aryl glycosides using glycals and arenediazonium salts at room temperature.

A stereocontrolled synthesis of aryl-C-glycosides was achieved using glycals and aryldiazonium salts in the presence of palladium acetate. A wide range of glycals including d-glucal, d-galactal, l-rhamnal, d-xylal and d-ribal underwent C-arylation at the anomeric carbon in the presence of different aryldiazonium tetrafluoroborates and gave synthetically useful 2,3-deoxy-3-keto-α-aryl-C-glycosides in good to excellent yields. Broad substrate scope, simple operation and room temperature reactions make this protocol very attractive in organic synthesis.

Tris(pentafluorophenyl)borane-Promoted Stereoselective Glycosylation with Glycosyl Trichloroacetimidates under Mild Conditions.

Tris(pentafluorophenyl)borane-promoted stereoselective glycosylation with trichloroacetimidate glycosyl donors is described. The reactions proceed efficiently with a wide range of acceptors, from sugar to nonsugar, under mild conditions in the presence of a catalytic amount of B(C6F5)3. The perbenzylated glucosyl α-imidate provides ß-selective glycosides in 70-92% yields.

Urea-hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones.

A practical method for the selective and controlled oxidation of thioglycosides to corresponding glycosyl sulfoxides and sulfones is reported using urea-hydrogen peroxide (UHP). A wide range of glycosyl sulfoxides are selectively achieved using 1.5 equiv of UHP at 60 °C while corresponding sulfones are achieved using 2.5 equiv of UHP at 80 °C in acetic acid. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide.