Synthesis of santonin related compounds

(±)-1-Nordesmotroposantonin ( 2 ), a thermolysis product of santonin, and its isomer, α-(1,2,3,4-tetrahydro-1,7-dihydroxy-α,6-dimethyl-2-naphthalene)acetic acid γ-lactone ( 3 ) were synthesized from 4-(4-methoxy-3-ethylphenyl)butanoic acid.     

In-plane vibrational modes of cytosine from an ab initio MO calculation

Harmonic force constants, in-plane vibrational frequencies, and in-plane vibrational modes of cytosine were calculated by an ab initio Hartree—Fock SCF MO method. The force contants were calculated by the use of an energy gardient method with the STO-3G basis set, and then they were corrected into “4-31G force constants” by the scaling factors given by us previously for the case of uracil. The corrected set of force constants can produce a calculated vibrational spectra of cytosine and cytosine-1,amino-d₃, that can be well corrected with the observed Raman and infrared spectra of these compounds, with little ambiguity. Thus, the assignments of all the in-plane vibrations are now practically established. The calculated vibrational modes, in addition, can account for the recently published resonance Raman effects of cytosine residue.     

Pyrolysis of amines: Infrared spectrum of vinylamine

The gas-phase infrared absorption bands of vinylamine were observed in the pyrolysis products of amines. These were characterized by doublets reflecting the ground state inversion splitting. Its half-life in the absorption cell was more than 20 min. The general valence force constants were calculated by an ab initio MO method. Some molecular characteristics were compared with those of isoelectronic formamide and investigated by the MO theory.     

Substituted benzaldehydes in the darzens condensation with alkyl dihaloacetates

The Darzens reaction of dihaloacetic acid esters with aromatic aldehydes produces either arylhaloglycidic or arylhalopyruvic esters depending on the nature of the substituent in the aromatic ring. Alkyl p-methoxyphenylchloropyruvates undergo spontaneous intermolecular cyclocondensation to form pyranone or furanone derivatives depending on the character of the alkyl fragment. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1402–1410, August, 2006.     

Infrared spectrum of trans-acrolein

The gas-phase infrared absorption spectrum of acrolein is observed from 4000 to 400 cm⁻¹ with a resolution of 0.06 or 0.03 cm⁻¹. The previously unlocated vinyl CH stretching band is observed at 3069 cm⁻¹ and its CH out-of-plane modes whose assignments have been in confusion are investigated in detail. The mode assignments of some other bands are revised on the basis of the calculated frequencies and relative intensities by an ab initio MO method.     

RGB‐Color Intensiometric Indicators to Visualize Spatiotemporal Dynamics of ATP in Single Cells

Adenosine triphosphate (ATP) provides energy for the regulation of multiple cellular processes in living organisms. Capturing the spatiotemporal dynamics of ATP in single cells is fundamental to our understanding of the mechanisms underlying cellular energy metabolism. However, it has remained challenging to visualize the dynamics of ATP in and between distinct intracellular organelles and its interplay with other signaling molecules. Using single fluorescent proteins, multicolor ATP indicators were developed, enabling the simultaneous visualization of subcellular ATP dynamics in the cytoplasm and mitochondria of cells derived from mammals, plants, and worms. Furthermore, in combination with additional fluorescent indicators, the dynamic interplay of ATP, cAMP, and Ca²⁺ could be visualized in activated brown adipocyte. This set of indicator tools will facilitate future research into energy metabolism.     

Determination of low-pressure crystalline--liquid phase boundary of SnI(4)

The location of the liquidus in the low-pressure crystalline phase of SnI(4) was determined utilizing in situ x-ray diffraction measurements under pressures up to approximately 3.5 GPa. The liquidus is not well fitted to a monotonically increasing curve such as Simon's equation, but breaks near 1.5 GPa and then becomes almost flat. The results are compared to those from molecular dynamics simulations. Ways to improve the model potential adopted in the simulations are discussed.