The biomechanics of ring avulsion injuries was studied in a cadaveric simulation model. Custom-fitted metal rings attached to a rigid frame were placed over the proximal phalanx of fresh or thawed fresh-frozen specimens. Ring avulsion injuries in 44 fingers were produced with a standardized force applied to the proximal ulna. The progress of injury was evaluated with simultaneous high-speed cinematography and continuous force measurements. The injured digits were x-rayed and categorized according to Urbaniak's classification. Continuous force measurements produced similar curves for all classes of injuries. The average maximum force resulting in class I injuries was 80 N. The average maximum force producing amputation in class III injuries was 154 N, a force much lower than expected. Force measurements for class II injuries were nearly identical to those of class III. This surprisingly minimal force resulting in digit amputation was explained by high-speed cinematography, which showed that the rings tilt on the digits concentrating disruption forces as a result of ring angulation on the finger. Incomplete amputations were due to loss of ring purchase by skin flap eversion. Finally, comparison of high-speed cinematography with force curves suggests that skin rupture rather than skeletal or tendon disruption accounted for the maximum force during ring avulsion injury.

Analogues of 4-Guanidino-Neu5Ac2en (Zanamivir) have been prepared containing carbamate substituents at the 7-hydroxy position. (4S,5R,6R)-5-Acetylamino-6-[1R-[(6-aminohexyl)carbamoyloxy]-2R,3-dihydroxypropyl]-4-guanidino-5,6-dihydro-4H-pyran-2carboxylic acid and (4S,5R,6R)-5-Acetylamino-6-[1R-[heptylcarbamoyloxy]-2R,3-dihydroxypropyl]-4-guanidino-5,6-dihydro4H-pyran2-carboxylic acid were the two analogues possessing activity comparable to Zanamivir, showing potent inhibition of influenza virus sialidases and good antiviral activity in vitro.

Young, Ronald M.D.; Stoltz, Randall M.D.*; Swanson, Stephen M.D.†; Watters, Harry D.O.‡; Barrett-Connor, Elizabeth M.D.§; Grimm, Richard M.D., Ph.D. Author Information

The factors that determine the selectivity of the acid-catalysed dealkoxylation of unsymmetrically substituted tricarbonyl(η4-alkoxycyclohexa-1,3-diene)iron(0) complexes have been investigated. Regioselective demethoxylation of complexes with a variety of substitution patterns has indicated that the selectivity arises from differences in the stabilization of the reaction intermediates and transition states by the diene substituents on the π-bound ligand. The observed regioisomers correspond to the product of the most stabilized intermediate pathway, rather than the product of minimum rearrangement. The reactions have been shown to proceed under kinetic control.

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Acid catalysed demethoxylation of tricarbonyl(η4-2-methoxy-6-phenyl-1,3- cyclohexadiene)iron(0) leads to the exclusive formation of a 3-phenyl salt, rather than the product of minimum rearrangement, a 1-phenyl salt. With an additional 2-methyl substituent present, the competing directing influence is overcome by the phenyl group. The importance of the phenyl substituent in promoting regioselectivity is demonstrated by the demethoxylation of a 2,5-dimethyl-3-methoxy substituted complex, which led to a mixture of products.

The regioselective formation and alkylation of tricarbonyl(η5-2-arylcyclohexadienyl)iron(1+) salts provides a new, controlled route to intermediates for the preparation of 5-substituted 2-arylcyclohexadienes. The best regiocontrol was obtained when an electron donating group was placed on the arene substituent.

AbstractThe η5‐(methoxycyclohexadienyl)iron complex (I) is arylated with the diarylzinc agents (II) and then demethoxylated to produce the η5‐(phenylcyclohexadienyl)iron tricarbonyl salts (V).

Experiments with intact callus cultures of Andrographispaniculata and a derived cell-free system have established that: (1) the biosynthesised γ-bisabolene has the Z-configuration 6; (2) the biosynthetic intermediate is a 6-trans-13 and not a 6-cis-15 farnesyl pyrophosphate; (3) in paniculide B 17, and probably also in γ-bisabolene 14, the ring carbon derived from C-2 of mevalonate is anti to the side chain; (4) mevalonolactone and trans,trans-famesyl pyrophosphate are incorporated into γ-bisabolene without hydrogen loss respectively from C-5 and C-1; cyclisation to the bisabolenyl cation therefore does not involve prior trans to cis isomerisation of the terminal double bond of farnesol by a redox mechanism; (5) taken together with our previous findings, it is established that Andrographis cultures contain two independently functioning enzymes: (i) a trans,trans- to cis,trans-farnesol isomerase, and (ii) a trans,trans-farnesyl pyrophosphate isomerase-cyclase. The absolute configuration of paniculide B has been established by an X-ray cristallographic analysis of its bis-p-bromobenzoate.

Tissue Cultures of Andrographis paniculate transform trans,trans-[1-3H2; 12,13-14C2]farnesy pyrophosphate, and (3R,5R)- and (3R,5S)-(5-3H)-mevalonolactones into Z-γ-bisabolene without tritium loss; the absolute configuration of paniculide B (7a) has been determined by an X-ray crystal structure determination of its bis-p-bropmobenzoate.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTrichodiene biosynthesis and the enzymic cyclization of farnesyl pyrophosphateDavid E. Cane, Stephen Swanson, and Pushpalatha P. N. MurthyCite this: J. Am. Chem. Soc. 1981, 103, 8, 2136–2138Publication Date (Print):April 1, 1981Publication History Published online1 May 2002Published inissue 1 April 1981https://pubs.acs.org/doi/10.1021/ja00398a063https://doi.org/10.1021/ja00398a063research-articleACS PublicationsRequest reuse permissionsArticle Views322Altmetric-Citations41LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

AbstractHexakis‐brommethyl‐benzol (Ia) wird zum Hexakis‐sulfid (Ib) und weiter zum entsprechenden Polysulfon (Ic) oxidiert.

AbstractDie Tendenz zur Bildung von Einschlußverbindungen (EB) wird für die Hexa‐(mercaptomethyl)‐benzol‐Derivate (Ia) (Darstellung früher beschrieben), (Ib) und (Ic) untersucht.

The synthesis of the first chiral hexa-host molecule (III) is described: an X-ray analysis of the acetic acid adduct of (III) allows the first direct observation of dimeric acetic acid.

AbstractZu Untersuchungen über Einschlußverbindungen mit Dioxan werden aus Hexakis‐(brommethyl)‐benzol (I) die Substitutionsprodukte (II) hergestellt und diese in die entsprechenden Clathrate übergeführt.

The synthesis of the first chiral hexa-host molecule (III) is described: an X-ray analysis of the acetic acid adduct of (III) allows the first direct observation of dimeric acetic acid.

AbstractAus dem Tribrom‐cyclododecatrien (I) erhält man mit entsprechenden Cu‐thiophenolaten die Substitutionsprodukte (IIa) und (IIb), die Einschlußverbindungen mit Cyclopentan, Cyclohexan, Fluorcyclohexan, 1,4‐Dioxan, Diäthyläther, tert.‐Butylacetylen, 2,2‐Dimethylbutan etc. bilden.