Makoto Kirisawa

Acetylenes from Panax quinquefolium

Abstract Two new C 17 -polyacetylenes and a C 14 -polyacetylene were isolated from dried roots of Panax quinquefolium . Their structures were determined by their 1 H NMR, 13 C NMR and mass spectral data. The cytotoxic activity of C 17 -polyacetylenes against leukemia cells (L 1210) was ca 20 times that of the C 14 -polyacetylene.

Anionic cyclophanes as hosts for cationic aromatic guests

Abstract Negatively-charged cyclophanes ( 2a,2b ) having eight carboxylate groups on the aromatic rings were designed and synthesized. It is shown that they work as hosts that form inclusion complexes selectively with positively-charged aromatic compounds as guests in alkaline water.

Studies on the alkaloids from Aconitum karakolicum rap.

A new C 2 0-diterpene alkaloid, karakomine (1) along with two known compounds, sangorine (2) and neoline (3), have been isolated from the roots of Aconitum karakolicum Rap. The structure of Karakomine was determined by 1D and 2D nmr spectroscopic analyses.

Synthesis of a novel water-soluble cyclophane having eight carboxymethylthiomethyl groups on the aromatic rings

A novel cyclophane (9) having eight carboxyl groups that are attached on the aromatic rings via a spacer (-CH 2 SCH 2 -) was designed and synthesized as a host for cationic, anionic, and neutral aromatic guests in alkaline water. Macrocyclization of 7 with 6 was carried out under high dilution condition to give the objective 8 in 17% yield

Inclusion Complex Formation between a Novel Anionic Cyclophane and Cationic Aromatic Guests in Aqueous Solution

1 H-Nmr spectral studies have shown that a negatively charged cyclophane (2) having eight carboxylate groups that are bonded directly on the aromatic rings forms 1:1 inclusion complexes selectively with positively charged aromatic comounds as guests in alkaline water

Preparation and performance of plasticizers for poly(vinyl chloride) from products of thermal decomposition of waste polystyrene

Abstract 2,4-Diphenylbutyl-2,4-diphenylbutyrate (DPBDPB) and 2,4,6-triphenylhexyl-2,4,6-triphenylhexoate (TPHTPH), plasticizers for poly(vinyl chloride), were synthesized from the products of thermal decomposition of waste polystyrene. Their heat stabilities were studied by thermogravimetric analysis and differential thermal analysis, and compared with those of typical plasticizers for PVC such as dibutyl phthalate (DBP), dihexyl phthalate (DHP) and bis(2-ethylhexyl) phthalate (DOP). DPBDPB and TPHTPH showed much higher heat resistance than DOP. PVC was plasticized with a mixed system consisting of DOP as the primary plasticizer and DPBDPB as the secondary. It became clear that DPBDPB is an excellent heat-resistant plasticizer which does not affect the compatibility of PVC with DOP.