Study of ππ → KK and Kπ reactions

We provide the partial-wave solution of the $\text{ππ →}\text{K}\text{K}$ reaction in the f-meson region. By the use of the unitarity constraint given by our $\text{ππ →}\text{K}\text{K}$ solution and the smoothness condition of the amplitude zeros in various charge configurations, we show that the (???) type solution seems the correct one among the four types of ππ partial-wave solutions. Other possibilities, especially the (+??) type, are also discussed briefly. The study of the behaviour of poles and zeros of the $\text{ππ →}\text{K}\text{K}$ and Kπ amplitudes gives corroborative evidence of the dual resonance model satisfying the gauge condition.     

The synthesis of benzofuroquinolines. V. Some benzofuro[3,2-B]quinoline derivatives

Some benzofuro[3,2-b]quinoline derivatives 1a-d and 3a were synthesized by condensation of 2-amino-benzaldehyde, 2-aminoacetophenone, 2-aminobenzophenone, isatin, or 2-aminobenzoic acid with 3(2H)-benzofuranone. The benzofuroquinolinone 3a was also obtained from 2-aminobenzoic acid and phenoxy-acetyl chloride in two steps and converted to 10-chloro derivative 1e . Similarly, some 8-halobenzofuro[3,2-b]-quinoline derivatives 1d,e and 3a (X = F, Cl, Br, I) were synthesized from 5-haloisatin or 2-amino-5-halo-benzoic acid. And benzofuro[3,2-b]quinolines 1a-e thus obtained were converted to corresponding N-oxides 2 .     

The Dakin-West reaction of N-alkoxycarbonyl-N-alkyl-alpha-amino acids employing trifluoroacetic anhydride

The Dakin-West reaction of N-alkoxycarbonyl-N-alkyl-alpha-amino acids (1a-j) with trifluoroacetic anhydride in the presence of pyridine gave alpha-amido trifluoromethyl ketones (2a-j), in which probable intermediates were mesoionic 1,3-oxazolium-5-olates (munchnones). The diastereoselective reduction of 2a-f with NaBH4 gave the threo-aminoalcohols (5a-f), which may be explained by the Felkin-Anh model. This was confirmed by converting 5a-f into trans-5-trifluoromethyl-2-oxazolidinones (6a-f) in good yields.     

Synthesis, properties and molecular structure of a new isomer of [2.4]-paracyclophanetetraene:(E,Z,E,Z)-[2.4]-paracyclophanetetraene

(E,Z,E,Z)-[2_.4]-Paracyclophanc is first obtained together with other isomers by the McMurry coupling of 4,4′-diformyl-(Z)-stilbene; an X-ray analysis of the new cyclophane shows an ellipsoidal structure with more strained (E)-stilbene skeleton than its tetrahydro compound.     

Equilibrium cyclotrimerization of ether oxygen-substituted aliphatic aldehydes

This article describes the equilibrium cyclotrimerization of β-methoxypropionaldehyde (MPA), 4,7-dioxaoctanal (DOA), and n-octanal (OA) initiated by boron trifluoride etherate in toluene at a temperature range of ?10 to 25°C. The enthalpy and entropy changes corresponding to the conversion of 1 mole of the monomers to 1/3 mole of their cyclic trimers in toluene solution, at the initial monomer concentration of 1 mole/liter, were evaluated as follows: ΔH_ss = ?5.9 ± 0.3 kcal/mole and ΔS_ss = ?19.1 ± 1.3 cal/mole deg for the MPA system; ΔH_ss = ?7.4 ± 0.4 kcal/mole and ΔS_ss = ?24.1 ± 1.7 cal/mole deg for the DOA system; ΔH_ss = ?6.1 ± 0.4 kcal/mole and ΔS_ss = ?21.2 ± 1.5 cal/mole deg for the OA system. The comparison of these values with those in their polymerization indicates that the cyclotrimerization of aldehydes is thermodynamically of greater advantage than their polymerization. The effects of long and polar substituents are discussed from the view-point of the intermolecular interactions by the polar groups in monomers and their cyclic trimers.     

γ- and ultraviolet-radiation-induced solid-state polymerization of maleimide in a few binary systems

The solid-state polymerization of maleimide by γ- and ultraviolet irradiation was carried out in binary systems with succinimide, maleic anhydride, and acenaphthylene. Polymaleimide obtained from the solid-state polymerization of maleimide by γ-rays was amorphous, while that obtained from the solid-state polymerization by ultraviolet rays was highly crystalline. In the maleimide–succinimide system the rate of polymerization reached a maximum nearly at the eutectic composition when the polymerization was carried out by γ-irradiation. With ultraviolet irradiation the rate of polymerization became higher with increasing content of succinimide in the feed. In the maleimide–maleic anhydride system a copolymer of both constituents was formed by γ-irradiation, but almost no homopolymer was produced. On the other hand, two kinds of polymers, a crystalline copolymer and an amorphous one, were produced by ultraviolet irradiation. The results were compared with those obtained from the copolymerization in solution. In the maleimide-acenaphthylene system the main products with ultraviolet irradiation was the dimer of acenaphthylene.