Characteristic terahertz absorption spectra of paramylon and paramylon-ester compounds.

Paramylon is a long-chain polysaccharide, composed of glucose units connected via β-(1,3) glycosidic bonds, that spontaneously forms a three-strand helical bundle. Paramylon-esters can be made by partially or fully replacing saccharide chain hydroxide groups with carboxylic functional groups, such as stearoyl (CH(CH)CO) and palmitoyl (CH(CH)CO). The paramylon-ester with carboxylic acids has superior characteristics, including high thermal resistance, stability and transparency under visible light, which are necessary for thermoplastic applications.

Water-Soluble -Docecaborate-Containing Pteroyl Derivatives Targeting Folate Receptor-Positive Tumors for Boron Neutron Capture Therapy.

Water-soluble pteroyl--dodecaborate conjugates (PBCs 1-4), were developed as folate receptor (FRα) targeting boron carriers for boron neutron capture therapy (BNCT). PBCs 1-4 had adequately low cytotoxicity with IC values in the range of 1~3 mM toward selected human cancer cells, low enough to use as BNCT boron agents. PBCs 1-3 showed significant cell uptake by FRα positive cells, especially U87MG glioblastoma cells, although the accumulation of PBC 4 was low compared with PBCs 1-3 and L-4-boronophenylalanine (L-BPA).

Molecular vibration and Boson peak analysis of glucose polymers and ester via terahertz spectroscopy.

Complex permittivity spectra were obtained herein by performing broadband terahertz (THz) spectroscopy on cellulose, paramylon, and paramylon ester. Absorption peaks observed for cellulose and paramylon at approximately 3 THz are attributed to hydrogen bonds. In addition, a broad absorption peak around 2 THz was observed for all the polymers, demonstrating a general feature of polymer glasses derived from weak interatomic van der Waals forces.

Metal catalyst-free substitution of allylic and propargylic phosphates with diarylmethyl anions.

Substitution of secondary allylic phosphates with the anions derived from Ar2CH2 with BuLi or LDA proceeded regioselectively and stereoselectively without a metal catalyst, affording inversion products in good yield. Similarly, propargylic phosphates gave propargylic products selectively.

Synthesis of the PMB ether of 5,6-epoxyisoprostane E2 through aldol reaction of the α-bromocyclopentanone.

5,6-Epoxyisoprostane E2 was synthesized via bromohydrination of the cyclopentene and aldol reaction of the α-bromocyclopentanone with the epoxyaldehyde. High regioselectivity in the bromohydrination was attained with recrystallized NBS and pyridine in aqueous DMSO. The enolate for the aldol reaction was generated by adding t-BuLi to the mixture of the α-bromocyclopentanone and ZnI2.

Synthesis of cyclobakuchiols A, B, and C by using conformation-controlled stereoselective reactions.

Cyclohexanone with the pMeOC6H4 and CH2=C(Me) substituents at the C3 and C4-positions was prepared from (+)-β-pinene and converted to the allylic picolinate by a Masamune-Wittig reaction followed by reduction and esterification. Allylic substitution of this picolinate with Me2CuMgBr·MgBr2 in the presence of ZnI2 proceeded with γ regio- and stereoselectively to afford the quaternary carbon center on the cyclohexane ring with the CH2=CH and Me groups in axial and equatorial positions, respectively. This product was converted to cyclobakuchiol A by demethylation and to cyclobakuchiol C by epoxidation of the CH2=C(Me) group.

Magnesium methoxide-induced chemiluminescent decomposition of bicyclic dioxetanes bearing a 2'-alkoxy-2-hydroxy-1,1'-binaphthyl-7-yl moiety.

Bicyclic dioxetanes 2a-c bearing a 2'-alkoxy-2-hydroxy-1,1'-binaphthyl-7-yl moiety were effectively synthesized and their base-induced chemiluminescent decomposition was investigated by the use of alkaline metal (Na(+) and K(+) ) or Mg(2+) alkoxide in MeOH. When 2a-c were treated with tetrabutylammonium fluoride (TBAF) in dimethyl sulfoxide (DMSO) as a reference system, they showed chemiluminescence as a flash of orange light (maximum wavelength λmax (CL)  = 573-577 nm) with efficiency Φ(CL)  = 6-8 × 10(-2) . On the other hand, for an alkaline metal (Na(+) or K(+) ) alkoxide/MeOH system, 2a-c decomposed slowly to emit a glow of chemiluminescence, the spectra of which were shifted slightly toward red from the TBAF/DMSO system, and Φ(CL) (= 1.