Synthesis of 12-deoxyroyleanone, cryptoquinone, 11,14-dihydroxy-8,11,13-abietatrien-7-one, and related derivatives from dehydroabietic acid

Naturally occurring abietane quinones and hydroquinone, namely, 12-deoxyroyleanone (1a), cryptoquinone (4a), and 11,14-dihydroxyabieta-8,11,13-trien-7-one (5a), together with the epimers of tryptoquinones D (2) and F (3), were first synthesized from dehydroabietic acid (6).     

Synthesis of 4-hydroxyderricin and related derivatives

Naturally occurring chalcones, namely 4-hydroxyderricin (1), xanthoangelol H (2), deoxyxanthoangelol H (3), and deoxydihydroxanthoangelol H (4), were first synthesized and evaluated for antibacterial activities.     

Eigenfrequency spacing analysis and eigenmode breakdown for semi-stadium-type 2-D fields

This paper describes eigenfrequency statistics including modal patterns and degrees of freedom for a semi-stadium-type 2-D field. The authors numerically investigated sound fields surrounded by 2-D semi-stadium-type boundaries as examples of boundaries where chaotic properties are hidden, in order to understand the characteristics of complex sound fields and to gain new insight into sound-field design. One limit of the semi-stadium boundaries is a rectangular boundary that gives a regular field, while another limit is a stadium boundary in which the chaotic property emerges. The numerical results show that eigenfrequency spacing in all the cases can be expressed as a family of Γ distributions extended to a non-integer degree of freedom. This fractal degree of freedom can be interpreted as the degree of freedom of the sound field. For the regular limit case, i.e., a rectangular case, the distribution is the exponential distribution with the freedom of unity, while in the chaotic case, i.e., the stadium case, it is the Wigner distribution with a degree of freedom of two. The authors, however, analyze the semi-stadium sound fields. The analysis of the fluctuations in the distribution function for the eigenfrequencies showed that the skewness decreases as the boundary approaches the stadium condition. Modal patterns also clearly showed breaks of the regular pattern of nodal lines in a rectangular case as the boundary was deformed from the rectangular to the stadium condition. The breaks of the modal pattern could be also confirmed by decreasing of the skewness for the sound pressure distribution.     

Preparation and radical ring-opening polymerization of 2-substituted-4-methylene-1,3-dioxolanes

2-Methyl-2-phenyl-4-methylene-1,3-dioxolane ( IIa ), 2-ethyl-2-phenyl-4-methylene-1,3-dioxolane ( IIb ), 2-phenyl-2-(n-propyl)-4-methylene-1,3-dioxolane ( IIc ), 2-phenyl-2-(i-propyl)-4-methylene-1,3-dioxolane ( IId ), 2-(n-heptyl)-2-phenyl-4-methylene-1,3-dioxolane ( IIe ), 2-methyl-2-(2-naphthyl)-4-methylene-1,3-dioxolane ( IIf ), and 2,2-diphenyl-4-methylene-1,3-dioxolane ( IIg ) were prepared and polymerized in the presence of a radical initiator. IIa–IIf were found to undergo vinyl polymerization with ring-opening reaction accompanying the elimination of ketone groups in bulk. IIg was found to undergo the quantitative ring-opening reaction accompanying the elimination of benzophenone in solution to obtain polyketone without any side reaction.     

Synthesis of Biodegradable Hydrogel by Radical Ring‐Opening Polymerization of 2‐Methylene‐1,3,6‐Trioxocane

2‐Methylene‐1,3,6‐trioxocane (MTC), maleic anhydride (MA), and poly(ethylene glycol diacrylate) 400 (PEGD) or divinyl adipate (DVA) were terpolymerized in the presence of a radical initiator. Though the obtained gels did not absorb deionized water, the gels could absorb deionized water and saline after hydrolyzing the MA carboxylate anhydride functionality. The absorbing ratios of deionized water and saline were high. The biodegradability of the hydrogels after hydrolysis was found to be good by a biochemical oxygen demand (BOD)‐tester using soil.     

Aerobic oxidation of 8,11,13-abietatrienes catalyzed by N-hydroxyphthalimide combined with 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) and its application to synthesis of naturally occurring diterpenes

Methyl 8,11,13-abietatriene-18-oate (1b) and 7-oxo-8,11,13-abietatrienes 10 and 15 were converted into 15-hydroperoxy-7-oxo-8,11,13-abietatrienes 13 and 16 by aerobic oxidation catalyzed by N-hydroxyphthalimide (NHPI) combined with 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70) at room temperature, and several abietane and podocarpane terpenes were synthesized from 13 and 16.     

Microwave-Assisted Beckmann Rearrangement of Aryl Ketoximes Catalyzed by In(OTf)3 in Ionic Liquid

Abstract

Carbonyl compounds were regenerated from corresponding dithioacetals via refluxing with FeCl₃/KI and methanol as a solvent.