Stereoselective synthesis of the Halaven C14-C26 fragment from D-quinic acid: crystallization-induced diastereoselective transformation of an α-methyl nitrile.

Crystallization-induced diastereoselective transformation (CIDT) of an α-methyl nitrile completes an entirely non-chromatographic synthesis of the halichondrin B C14-C26 stereochemical array. The requisite α-methyl nitrile substrate is derived from D-quinic acid through a series of substrate-controlled stereoselective reactions via a number of crystalline intermediates that benefit from a rigid polycyclic template. Therefore, all four stereogenic centers in the Halaven C14-C26 fragment were derived from the single chiral source D-quinic acid.

Anesthetic implications of emergent Cesarean section in a parturient with Noonan syndrome and bacterial endocarditis.

Noonan syndrome is a relatively common genetically transmitted disorder characterized by facial, cardiac, and musculoskeletal abnormalities. The management of a 27 year old woman with Noonan syndrome at 23 weeks' gestation, presenting with premature labor, who required an emergent Cesarean section for placental abruption, is discussed. In addition to Noonan syndrome, this patient had bacterial endocarditis involving the mitral and aortic valves.

Cyclooctatrienes from pyran-2-ones via a tandem [4+4]-photocycloaddition/decarboxylation process.

Irradiation of pyran-2-ones bearing pendent furans in aqueous MeOH followed by heating furnished fused bicyclic products containing a cyclooctatriene ring.

Validity of the VmaxST portable metabolic measurement system.

The aim of this study was to assess and compare the validity of the portable VmaxST telemetry metabolic measurement device with that of a standard measurement system (Vmax29). Thirty asymptomatic, moderately active males provided written, informed consent and completed two maximal graded treadmill exercise tests (Bruce) using the VmaxST and the Vmax29 metabolic measurement systems. Tests were performed in random order on separate days to obtain peak values for time to exhaustion, heart rate, systolic and diastolic blood pressure, oxygen consumption (VO2), carbon dioxide production (VCO2), ventilation (VE), and respiratory exchange ratio (RER).

Macrocyclic ketone analogues of halichondrin B.

Structurally simplified macrocyclic ketone analogues of halichondrin B were prepared by total synthesis and found to retain the potent cell growth inhibitory activity in vitro, stability in mouse serum, and in vivo efficacy of the natural product.