Cationic polymerization behavior of seven-membered cyclic sulfite

Cationic ring-opening polymerization behavior of a seven-membered cyclic sulfite ( 1 ) was examined. 1 was prepared by the reaction of 1,4-butanediol with SOCl₂ in 58% yield. The cationic polymerization of 1 was carried out at 0, 25, 60, or 100°C with trifluoromethanesulfonic acid (TfOH), methyl trifluoromethanesulfonate (TfOMe), BF₃ · OEt₂, SnCl₄, methyl p-toluenesulfonate (TsOMe), or MeI as an initiator in bulk under a nitrogen atmosphere to afford the polymer with M̄_n 1000–10,400. The order of activities of the initiators for 1 was as follows, TfOH ≅ TfOMe > SnCl₄ > BF₃ · OEt₂ > TsOMe ≅ MeI. The polymerization of 1 with TfOMe afforded a poly(sulfite) below 25°C, but afforded a polymer containing an ether unit at 60°C, which was formed by a desulfoxylation. The higher the activity of the initiator was, the more easily the desulfoxylation occurred. We expected volume expansion on polymerization because cyclic sulfites have large dipole moment values, but it turned out that 1 showed 4.34% shrinkage on polymerization. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3673–3682, 1997     

Cyclic carbonates,novel expandable monomers on polymerization

A variety of cyclic carbonates was shown to undergo volume expansion on polymerization. The degree of volume expansion, which was measured by the density gradient tube method, was ranging from 1.1% to 7.7%. The volume expansion was examined by assuming a change in molecular interaction such as dipole moment between monomer and polymer states.     

Polymerization of optically active disubstituted acetylene monomers by Pd catalyst bearing bulky phosphine ligand

Chloro- and aryl-substituted acetylene monomers having an optically active group were polymerized by a Pd catalyst [(^tBu₃P)PdMeCl] bearing a bulky phosphine ligand, and by MoCl₅ for comparison. The corresponding disubstituted acetylene polymers with M_n's = 2000–19,500 and 6900–10,800 were obtained in 29–83% and 11–62% yields when the Pd and Mo catalysts were used, respectively. The formation of polyacetylenes, poly[(R)- 1p ], poly[(R)- 1m ], and poly[(S)- 2p ] were confirmed by SEC and the presence of a Raman scattering peak based on the alternating double bonds of the main chain. Pd-based poly[(R)- 1m ] exhibited CD signals around 350 nm assignable to a certain secondary structure, while Mo-based poly[(R)- 1m ] did not. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3011–3016     

Computational Analysis Reveals a Critical Point Mutation in the N-Terminal Region of the Signaling Lymphocytic Activation Molecule Responsible for the Cross-Species Infection with Canine Distemper Virus

Infection of hosts by morbilliviruses is facilitated by the interaction between viral hemagglutinin (H-protein) and the signaling lymphocytic activation molecule (SLAM). Recently, the functional importance of the n-terminal region of human SLAM as a measles virus receptor was demonstrated. However, the functional roles of this region in the infection process by other morbilliviruses and host range determination remain unknown, partly because this region is highly flexible, which has hampered accurate structure determination of this region by X-ray crystallography. In this study, we analyzed the interaction between the H-protein from canine distemper virus (CDV-H) and SLAMs by a computational chemistry approach. Molecular dynamics simulations and fragment molecular orbital analysis demonstrated that the unique His28 in the N-terminal region of SLAM from Macaca is a key determinant that enables the formation of a stable interaction with CDV-H, providing a basis for CDV infection in Macaca. The computational chemistry approach presented should enable the determination of molecular interactions involving regions of proteins that are difficult to predict from crystal structures because of their high flexibility.     

Isolation of o-xylylene (o-quinodimethane) dirivatives. A strong through-bond interaction in 2,3-benzobicyclo[2.2.0]hexane system

Some o-xylylene (o-quinodimethane) derivatives were isolated as stable cyrstalline materials. A strong through-bond interaction in tetracyanoethylene addition product of tetraphenylbenzodicyclobutadiene ($\text{21}$ is suggested.     

A novel synthesis of theophylline derivatives

Treatment of 6-amino-5-arylazo-1,3-dimethyluracils with ethyl propiolate gave the corresponding Michael-type adducts, 5-arylazo-1,3-dimethyl-6-ethoxycarbonylvinylaminouracils, which on treatment with a mixture of hydrochloric acid and acetic acid caused the acid-catalyzed rearrangement accompanied with rearrangement to give rise to the corresponding 8-anilinomethyltheophylline derivatives. In the case that the arylazo group possesses an electron-releasing substituent such as methoxy, the reaction proceeded in a different way to afford 1,2-bis(theophyllin-8-yl)ethane. The presumable reaction mechanisms for the above purine syntheses were proposed.     

A synthesis of lumazine derivatives

Treatment of 6-amino-1,3-dimethyl-5-nitrosouracil (Ia) with dimethyl acetylenedicarboxylate (DMAD) in dimethylformamide (DMF) afforded 6,7-bis(dimethoxycarbonyl)-1,3-dimethyllumazine (II). Similarly, the reaction of 6-amino-1,3-dimethyl-5-phenylazouracil with DMAD gave also II. Hydrolysis of II with hydrochloric acid gave 1,3-dimethyllumazine-6-carboxylic acid (III). III was chlorinated with thionyl chloride and then aminated with ethanolic ammonia to give rise to 6-carbamoyl-1,3-dimethyllumazine (V). V was alternatively synthesized by the treatment of Ia with propiolamide in DMF.     

Functional integral representations of the Pauli-Fierz model with spin 1/2

A Feynman-Kac-type formula for a Lévy and an infinite-dimensional Gaussian random process associated with a quantized radiation field is derived. In particular, a functional integral representation of e−tHPF generated by the Pauli-Fierz Hamiltonian with spin 1/2 in non-relativistic quantum electrodynamics is constructed. When no external potential is applied HPF turns translation-invariant and it is decomposed as a direct integral . The functional integral representation of e−tHPF(P) is also given. Although all these Hamiltonians include spin, nevertheless the kernels obtained for the path measures are scalar rather than matrix expressions. As an application of the functional integral representations energy comparison inequalities are derived.     

Interpolation error estimates of a modified 8-node serendipity finite element

Summary. Interpolation error estimates for a modified 8-node serendipity finite element are derived in both regular and degenerate cases, the latter of which includes the case when the element is of triangular shape. For defined over a quadrilateral K, the error for the interpolant is estimated as , where in the regular case and in the degenerate case, respectively. Thus, the obtained error estimate in the degenerate case is of the same quality as in the regular case at least for . Results for some related elements are also given. Received June 2, 1997 / Published online March 16, 2000