Thorleif Anthonsen

Addition of diazomethane and sulfur ylides to the oxo-group in derivatives of ketoses and aldoses : I. Reactions of 2,3-O-isopropylidene-D-glyceraldehyde

Abstract The reaction between 2,3-O-isopropylidene- D -glyceraldehyde and diazomethane, dimethylsulfonium methylide and dimethyloxosulfonium methylide has been studied. The sulfur ylides yield two epimeric epoxides, 1,2-anhydro-3,4-O-isopropylidene- D -erythritol and 1,2-anhydro-3,4-O-isopropylidene- D -threitol, with a slight preference for the erythro isomer. The reaction with diazomethane yields in addition to the epoxides a methyl ketone, 1-deoxy-3,4-O-isopropylidene- D -glycero-tetrulose. The relative yields of the three products have been discussed on the basis of mechanisms previously proposed for the reactions. The yield of methyl ketone was lowest when the reaction was carried out in pure diethyl ether solution. This solvent also gives the greatest preference for the erythro isomer of the two epoxides. Constitution and stereochemistry for the three products have been shown by synthesis.

Two new dihydrochalcones from Myrica gale

Abstract From the fruits of Myrica gale the isolation of 2′,6′dihydroxy-4′-methoxy-3′,5′-dimethyldihydrochalcone and 4,4,6-trimethyl-2-(3-phenylpropionyl)-cyclohexane-1,3,5-trione is described. The constitutions have been deduced from spectroscopic data and confirmed by synthesis.

Addition of diazomethane and sulfur ylides to the carbonyl group in derivatives of ketoses and aldoses-III: Reactions of 1,2-dideoxy-4,5-O-isopropylidene-d-glycero-3-pentulose

Abstract The reactions of diazomethane and dimethyloxo-sulfonium methylide with 1,2-dideoxy-4,5- O -isopropylidene- d - glycero -3-pentulose were studied. The sulfur ylide yielded two epimeric epoxides while diazomethane in addition furnished a homologous ketone. The reaction with diazomethane was carried out with varying concentrations of methanol in the reaction medium, and the relative yields of the three products were determined in each case. The results were explained on the basis of a two-step reaction mechanism proposed earlier. Steric effects and complexation between the positive nitrogen and one of the oxygens were inferred to be important.

Synthetic and spectroscopic studies of 2-C-methyl-erythritol and 2-C-methyl-threito

Abstract The synthesis of 2- C -methyl- d,l -threitol and two isopropylidene derivatives of 2- C -methyl- d -erythritol is described. 1 H and 13 C NMR spectra of these and several related compounds are discussed.

13-Oxomyricanol, a new [7.0]-metacyclophane from Myrica nagi

Abstract A new [7.0]-metacyclophane has been isolated from the root bark of Myrica nagi. On the basis of spectroscopy the constitution of the new compound is proposed to be 13-oxomyricanol. A new [7.0]-metacyclophane has been isolated from the root bark of Myrica nagi. On the basis of spectroscopy the constitution of the new compound is proposed to be 13-oxomyricanol.