La perspective practique publiée en 1651 est la deuxième édition du traité de perspective et réunit les trois volumes publiés en 1642, 1647 et 1649. b) U. Mäeorg, L. Grehn and U. Ragnarsson, Angew. Chem., 1996, 108, 2802–2803 ( Angew. Chem., Int. Ed. Engl., 1996, 35, 2626–2627) CrossRef;

L. Grehn, K. Gunnarsson and U. Ragnarsson, Acta Chem. Scand., Ser. B, 1986, B40, 745–750 CrossRef CAS. Paclitaxel is a drug of immense medicinal and commercial interest, originally isolated from the bark of the Pacific yew tree. It inhibits cell division and is therefore used in the treatment of various types of cancer. Structurally it is composed of a highly functionalized tetracyclic skeleton with one carbonyl and two free hydroxyls and another four esterified such, one of which in the A-ring notably in this context with a N-benzoylated β-amino acid sidechain. Several elegant total syntheses of the drug have been reported. A related drug of comparable importance is docetaxel in which one of the previously mentioned paclitaxel skeleton ester groups in the B-ring is replaced by a free hydroxyl and the sidechain N-benzoyl group is missing and instead substituted with a Boc-group. The obvious case for a delay in obtaining free pratique is that the crew are unwell which could be some contagious disease. For that reason, the standard Declaration of Health must be completed, answering questions about the health of the crew before the vessel can enter the port. Any positive answers are likely to cause delay and so the Master cannot say then that obtaining free pratique will be a formality. convenient; handy Antonym: incommode Cette télécommande est vraiment pratique. ― This remote control is really convenient.A Reaxys search (June 2013) for R-CO- N-R′(Boc), both R and R′ any group except hydrogen, corrected for R-N(Boc) 2 below that are obviously included, gave 7800 − 5600 = 2200 hits. C. Hulme, J. Peng, G. Morton, J. M. Salvino, T. Herpin and R. Labaudiniere, Tetrahedron Lett., 1998, 39, 7227–7230 CrossRef CAS. Boc 2N-compounds were originally prepared from urethanes with Boc 2O/ DMAP. 13 For amine synthesis from halides alkylation of Boc 2NH is rather convenient. Similarly, alkylation of Cbz(Boc)NH provided a product of type Cbz(Boc)N-R. 34 Reacting an easily obtained Cbz-protected spermidine substrate with Boc 2O/ DMAP ultimately provided N 8-Boc- N 1-Cbz-spermidine via a derivate of this kind, i.e. full discrimination between two primary and one secondary amino functions was accomplished. 35a In the same way Cbz-hydrazine served as a reagent for stepwise alkylation/ acylation of hydrazine. 35b,c Also chiral products of these and related types have been obtained in the presence of a proper ligand. 36

A Reaxys search (June 2013) for R-N(Boc) 2, R any group except hydrogen, gave 5630 hits and for R-NCbz(Boc) 230 hits.Many standard form voyage charterparties do just that. In this respect, there a number of different approaches. Some forms use the expression “whether in free pratique or not” or similar – e.g., Gencon 1994, HeavyliftVoy, meaning that the vessel can give the NOR in those circumstances. Of course, by giving the NOR, the Master is affirming that his vessel is ready – if it is not and there will be a delay (i.e., it will be more than a formality), this clause does not allow the tender of the NOR. To that end, this clause replicates what the common law says. L. Grehn and U. Ragnarsson, Angew. Chem., 1984, 96, 291–292 ( Angew. Chem., Int. Ed. Engl., 1984, 23, 296–301) CrossRef CAS. The articles of the SO Series have a practicle pressure lid, realized in polyethylene, with tamper evident seal to the first use. Make your living room or bedroom your new gym area. At Pratique em Casa you can do different exercises without the need for any professional device, using only your body or common objects in your home. The reactions of Boc 2O with amines and alcohols in the presence and absence of DMAP have been investigated by Basel and Hassner with respect to products and mechanisms under widely varying conditions. 45 Different products were obtained depending on the ratio of reagents, polarity of the solvent and type of amine used. Without DMAP aliphatic amines gave Boc-derivatives in quantitative yields. In the presence of DMAP isocyanate formation was favoured at low temperatures, whereas otherwise in addition to Boc- and Boc 2-amine also urea and carbamic-carbonic anhydrides and related substances could be isolated. It was suggested that carbamic acids could occasionally play a role as reaction intermediates. Aliphatic alcohols gave O-Boc derivatives and symmetrical carbonates in the presence of DMAP. From cysteine methyl ester in the presence of DMAP, the N-Boc-, N, S-Boc 2- and N, N, S-Boc 3-derivatives could all be isolated.