Hoffmann

Tissue culture studies have shown an additive effect from combined interferon and amantadine HCl treatment of chick embryo cells infected with influenza A/ SN Amantadine HCl has also been shown to be effective in tissue culture against strains of influenza A2 isolated in Japan in 1957, 1964 and 1965 and influenza A1 Isolated in 1953 but not on a 1964 influenza B strain. Classical fcwl cholera was sensitive to amantadine HCl in tissue culture O while preliminary studies indicate that oral doses of amantadine HCl reduce mortality from fowl plague in turkeys and influenza infections in quail.  

Cyclooctylamlne HCl demonstrated antiviral activity against a variety of myxovlruses as well as IBR, herpes zoster and vaccinia in tissue culture and against influenza kl/kk/z/bO and A/Swine/sl5 but not a/fR8 in mlce. Other amine and ammonium compounds were found to be effective against influenza A viruses in mammalian cells as measured by a quantitative immunofluorescent technic with a mechanism similar to that of amantadine HCl. 

IsOQuinolines - l-( -Methoxyphenoxymethyl)-3,4-dihydroisoquinoline HCl (UK 2371), l-( -chlorophenoxymethyl)-3,4-dihydroisoquinoline HCl (UK 2054) and l-phenoxymethyl-l,2,3,4-tetrahydroisoquinoline (UK 2792) were found to have antiviral activity against a number of different viruses in tissue culture and the chick embryo. Against some of the sensitive strains the compounds acted as virus inactivators against others there was an antiviral effect without inactivation. In a series of challenge studies 

Extensive laboratory studies indicated that 3,4-dihydro-1-isoquinoline acetamide (DIQA) possessed antiviral activity against both DNA and RNA viruses, a spectrum not usually found with nontoxic compounds. Infections of mice with herpes simplex, Columbia SK, ECHO 9 and influenza A and B strains responded to intraperitoneal (IP) or subcutaneous (SC) treatment of nontoxic concentrations of DIQA.  

Nucleosides - Laboratory data on 9-p-D-arabinofuranosyladenine (Ara-A) was extensively discussed in a series of reports30,31,32,33,34,35. Ara-A was effective against herpes simplex infections of mice by IP, SC, oral and topical treatment started either prior to or after infection. Topical treatment with Ara-A of scarified hamsters eyes infected with herpes simplex prevented death and healed the eyes. Although high doses of compound were necessary, the material had a low order of animal toxicity with no mortality in mice at 7,950 mg/kg orally and an IP LD q of 4,677 mg/kg. In tissue culture antiviral activity was reported against strains of adeno, cytomegalo, vaccinia, varicella and human and simian strains of herpes viruses. The topical activity and low toxicity of Ara-A Indicate it is a promising candidate for treatment of herpes infections. 

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R. Hoffmann, Solids and Surfaces. A Chemist s View ofBoruIing in Exteruled Structures,... 

R. Hoffmann, Solid and Surfaces A Chemist s View of Bonding in Extended Structures, VCH Publishers, New York, 1988. 

Zaera F, Hoffmann H and Griffiths P R 1990 Determination of moieouiar ohemisorption geometries using... 

Hoffmann H, Mayer U and Krisohanitz A 1995 Struoture of aikyisiioxane monoiayers on siiioon surfaoes investigated by externai refieotion infrared speotrosoopy Langmuir 1304-12... 

Lenk T J, Haiimark V M, Hoffmann C L, Raboit J F, Castner D G, Erdeien C and Ringsdorf H 1994 Structurai investigation of moiecuiar organization in seif-assembied monoiayers of a semifiuorinated amidethioi Langmuir 10 4610-7... 

The Woodward-Hoffmann method [52], which assumes conservation of orbital symmetry, is another variant of the same idea. In it, the emphasis is put on the symmetries of molecular orbitals. Longuet-Higgins and Abramson [53] noted the necessity of state-to-state correlation, rather than the orbital correlation, which is not rigorously justified (see also, [30,44]). However, the orbital symmetry conservation rules appear to be very useful for most themial reactions. 

Electi ocyclic reactions are examples of cases where ic-electiDn bonds transform to sigma ones [32,49,55]. A prototype is the cyclization of butadiene to cyclobutene (Fig. 8, lower panel). In this four electron system, phase inversion occurs if no new nodes are fomred along the reaction coordinate. Therefore, when the ring closure is disrotatory, the system is Hiickel type, and the reaction a phase-inverting one. If, however, the motion is conrotatory, a new node is formed along the reaction coordinate just as in the HCl + H system. The reaction is now Mdbius type, and phase preserving. This result, which is in line with the Woodward-Hoffmann rules and with Zimmerman s Mdbius-Huckel model [20], was obtained without consideration of nuclear symmetry. This conclusion was previously reached by Goddard [22,39]. 

We have seen (Section I) that there are two types of loops that are phase inverting upon completing a round hip an i one and an ip one. A schematic representation of these loops is shown in Figure 10. The other two options, p and i p loops do not contain a conical intersection. Let us assume that A is the reactant, B the desired product, and C the third anchor. In an ip loop, any one of the three reaction may be the phase-inverting one, including the B C one. Thus, the A B reaction may be phase preserving, and still B may be attainable by a photochemical reaction. This is in apparent contradiction with predictions based on the Woodward-Hoffmann rules (see Section Vni). The different options are summarized in Figure 11. 

Fraaije, J.G.E.M., Van Vlimmeren, B.A.C., Maurits, N.M., Postma, M., Evers, O.A., Hoffmann, C., Altevogt, P., Goldbeck-Wood, G. The dynamic mean-field density functional method and its application to the mesoscopic dynamics of quenched block copolymer melts. J. Chem. Phys. 106 (1997) 4260-4269. 

I h c simplest approximation to tlic Scfi rod in gcr equation is an in clepen dcri l-eleelron appi oxim alion, sucli as Ui e H iiekel method for tr-clcetron systems, developed by H. Huckel. I-atcr, others, principally Roald Hoffmann of Cornell University, extended tlie Htiekel approximations to arbitrary systems having both nand a electrons the Hxtended Huckel Theory (KHT) approximation. ... 

Variation in energy for a tour (r-X-M-F) of the reciprocal lattice for a 2D square lattice of hydrogen 2S. (Figure adapted in part from Hoffmann R 1988. Solids and Surfaces A Chemist s View on Bonding in nded Structures. New York, VCH Publishers.)... 

Suprafacial attack of me ethene molecule on anotlier (left) is not permitted by the Woodward-Hoffmann id the alternative antarafacial mode of attack is sterically unfavourable. Suprafacial attack is however permitted Diels-Alder reaction between butadiene and ethene (right). 

Seetion treats the spatial, angular momentum, and spin symmetries of the many-eleetron wavefunetions that are formed as anti symmetrized produets of atomie or moleeular orbitals. Proper eoupling of angular momenta (orbital and spin) is eovered here, and atomie and moleeular term symbols are treated. The need to inelude Configuration Interaetion to aehieve qualitatively eorreet deseriptions of eertain speeies eleetronie struetures is treated here. The role of the resultant Configuration Correlation Diagrams in the Woodward-Hoffmann theory of ehemieal reaetivity is also developed. 

Along "Reaction Paths", Orbitals Can be Connected One-to-One According to Their Symmetries and Energies. This is the Origin of the Woodward-Hoffmann Rules I. Reduction in Symmetry... 

Hoffmann introdueed the so-ealled extended Hiiekel method. He found that a value for K= 1.75 gave optimal results when using Slater-type orbitals as a basis (and for ealeulating the Sg,v)- The diagonal h elements are given, as in the eonventional Hiiekel method, in terms of valenee-state IP s and EA s. Cusaehs later proposed a variant of this parameterization of the off-diagonal elements ... 

Along "reactionpaths", configurations can be connected one-to-one according to their symmetries and energies. This is another part of the Woodward-Hoffmann rules... 

Hoffmann introdueed the so-ealled extended Hiiekel method. He found that a value for K= 1.75 gave optimal results when using Slater-type orbitals as a basis (and for ealeulating the... 

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