Reactivities of 3-(1-Azolyl)-2-alken-1-ones and the related compounds with pyrrolidine

From the rate constants of the reaction with pyrrolidine, the reactivities of 3-(1-azolyl)-2-alken-1-ones with nucleophiles were evaluated to be rather high. Especially the reactivities of the quaternary salts of 3-(1-imidazolyl)-2-alken-1-ones were nearly equal to those of 3-chloro-2-alken-1-ones. In conclusion, 3-(1-imidazolyl)-2-alken-1-ones satisfied the practical requirements for the starting materials of the synthesis of 3-hetero-substituted 2-alken-1-ones.     

The nucleophilic substitution of methylthio group on the 1,4-dihydro-2-methylthiopyrimidine rings

N-Substituted 2-alkylthio-1,4-dihydro-4,4,6-trimethylpyrimidines easily reacted with methanol to give corresponding 2-methoxy-1,4-dihydropyrimidines, while the other nucleophiles did not react on the C-2 carbon of the pyrimidine rings. However, the substitution of alkylthio group easily proceeded intramolecularly even with weak nucleophilic groups, e.g., phenolic oxygen, thiophenolic sulfur, and anilino nitrogen atom, to yield bi- or tricyclic pyrimidine derivatives.     

The regioselective alkylation of 4,6-dimethyl-1-phenyl-2(1H)-pyrimidinone

4,6-Dimethyl-1-phenyl-2(1H)-pyrimidinone (I) was treated with alkyl halides in the presence of sodium hydride at low temperature to afford only C-6 alkylated products III and IV in good yields. Further, the mono-, IIIa-d, and di-alkylated 2(1H)-pyrimidinones IVa-d were selectively obtained by changing the amount of alkyl halides.     

Infrared-microwave double resonance of 12CH3OH with a CO2 laser

The Stark effect of the 2₂ ← 2₁(E₁), 2₁ ← 3₀(E₁) microwave transitions in the ground state and the 2₂ ← 2₁(E₁) microwave transition in the first excited CO stretching vibrational state are measured by means of infrared-microwave double resonance with the ^qQ₁(2)E₁ infrared transition as the pump transition in the range of 1000 to 2300 V/cm. The dipole moments μ_a and μ_b as well as the off-diagonal rotational constant D_ab are determined for both the ground and the excited states. The frequency of the ^qQ₁(2)E₁ infrared transition is found to be lower by 128 ± 2 MHz than that of the P(34) CO₂ laser.     

Difference frequency laser spectroscopy of OH and OD: Simultaneous fit of the infrared and microwave lines

The fundamental vibration rotation bands of OH and OD have been observed with an estimated accuracy of 0.001 cm^?1. Simultaneous fits of the infrared and microwave data are performed to improve the molecular constants in the v = 0 and v = 1 states. The correlated parameters γ_v and A_D are determined by combining the data for OH and OD. Some discussion is presented on the correlated molecular parameters.     

β-Lactams via photochemical reaction of monothioimides

Photolysis of acyclic monothioimides gave β-lactams and thioamides via Type II reaction involving γ-hydrogen abstraction by thiocarbonyl group.     

Alkylation of aminohydroxy anion,dissociated species of hydroxylamine

Aminohydroxy anion ($\text{3}$), dissociated species of hydroxylamine, was demonstrated to be nucleophilic on oxygen atom from INDO calculation, and to give directly O-alkylhydroxylamines.     

Biomethylation and biotransformation of arsenic in a freshwater food chain: Green alga (chlorella vulgaris)→shrimp (neocaridina denticulata)→killifish (oryzias iatipes)

Tolerance, bioaccumulation, biotransformation and excretion of arsenic compounds by the fresh–water shrimp (Neocaridina denticulata) and the killifish (Oryzias latipes) (collected from the natural environment) were investigated. Tolerances (LC₅₀) of the shrimp against disodium arsenate [abbreviated as As(V)], methylarsonic acid (MAA), dimethylarsinic acid (DMAA), and arsenobetaine (AB) were 1.5, 10, 40, and 150μg As ml^?1, respectively. N. denticulata accumulated arsenic from an aqueous phase containing 1 μg As ml^?1 of As(V), 10 μg As ml^?1 of MAA, 30 μg As ml^?1 of DMAA or 150 μg As ml^?1 of AB, and biotransformed and excreted part of these species. Both methylation and demethylation of the arsenicals were observed in vivo. When living N. denticulata accumulating arsenic was transferred into an arsenic–free medium, a part of the accumulated arsenic was excreted. The concentration of methylated arsenicals relative to total arsenic was higher in the excrement than in the organism. Total arsenic accumulation in each species via food in the food chain Green algae (Chlorella vulgaris) → shrimp (N. denticulata) → killifish (O. latipes) decreased by one order of magnitude or more, and the concentration of methylated arsenic relative to total arsenic accumulated increased successively with elevation in the trophic level. Only trace amounts of monomethylarsenic species were detected in the shrimp and fish tested. Dimethylarsenic species in alga and shrimp, and trimethylarsenic species in killifish, were the predominant methylated arsenic species, respectively.     

Sandwich-shaped silver(I) metallomacrocycles encapsulating a XF6(2-) (X = Si, Ge and Sn) anion

A series of sandwich-shaped complexes based on two square tetranuclear Ag(I) metallomacrocycles, [[Ag4(pprd)4]2(XF6)]-(BF4)6.8MeNO2 (pprd = 4-(2-pyridyl)pyrimidine; X = Si, Ge and Sn), in which a XF6(2-) anion is encapsulated, were prepared and their structures were characterized both in the solid state and solution.