EDUCATION & EVALUATION DE SOI DANS LA PARATIQUE ET LA SPIRITUALITE DE L'ISLAM

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G. Höfle, W. Steglich and H. Vorbrüggen, Angew. Chem., 1978, 90, 602–615 ( Angew. Chem., Int. Ed. Engl., 1978, 17, 569–583) CrossRef and references therein. b) U. Mäeorg, L. Grehn and U. Ragnarsson, Angew. Chem., 1996, 108, 2802–2803 ( Angew. Chem., Int. Ed. Engl., 1996, 35, 2626–2627) CrossRef; This article first appeared in Maritime Risk International, December 2022. Free pratique is permission given by a port for a vessel to enter once it has been certified free of infectious disease by the competent health authorities. It is required for the vessel to be determined legally ready to load or discharge the cargo, thereby allowing the tender of the vessel’s Notice of Readiness (NOR) and is thus important for the calculation of laytime and demurrage. B. Nyasse, L. Grehn, U. Ragnarsson, H. L. S. Maia, L. S. Monteiro, I. Koppel and J. Koppel, J. Chem. Soc., Perkin Trans. 1, 1995, 2025–2031 RSC. En 1547, dans la préface de La Geometrie practique, Bovelles remercie Oronce Fine pour l'aide qu'il lui a apportée dans la confection des gravures de son livre.

b) H.-J. Knölker, T. Braxmeier and G. Schlechtingen, Angew. Chem., 1995, 107, 2746–2749 ( Angew. Chem., Int. Ed. Engl., 1995, 34, 2497–2500) CrossRef. In parallel with the work of Grieco et al. the present authors performed structure–activity studies on compounds containing pyrrole 2-carboxylic acid and, to avoid the formation of cyclic dimers, attempted to protect pyrrole nitrogens by Boc. 7 As the methods of Boc-protection of that time did not furnish the desired products we started searching for conditions that would allow substitution also of such non-basic NH-groups. This work resulted in a procedure also involving Boc 2O/ DMAP, but with catalytic amounts (10%) of DMAP, only a small excess of Boc 2O and without additional base. This procedure later proved useful in a wider context. An early attempt to react acetanilide with dimethyl dicarbonate in the presence of DMAP was unsuccessful 13 but with 4-thiazolidinone as substrate a methyloxycarbonyl derivative was obtained, although in lower yield than with Boc 2O. 23 The latter substrate with Cbz 2O/ DMAP also afforded the corresponding Cbz-protected product. 23 Of other analogous reagents investigated only di-1-adamantyl dicarbonate with DMAP was preparatively useful. 47 C. Hulme, J. Peng, G. Morton, J. M. Salvino, T. Herpin and R. Labaudiniere, Tetrahedron Lett., 1998, 39, 7227–7230 CrossRef CAS. b) U. Ragnarsson, L. Grehn, L. S. Monteiro and H. L. S. Maia, Synlett, 2003, 2386–2388 CrossRef CAS.

pra•tique

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. P. M. T. Ferreira, H. L. S. Maia, L. S. Monteiro and J. Sacramento, J. Chem. Soc., Perkin Trans. 1, 1999, 3697–3703 RSC. With the aim to develop practically useful, reductively more labile alternatives to tosyl for protection of amino functions, a number of N-arenesulfonyl-protected derivatives were prepared and studied by cyclic voltammetry. 26b Among them were various 1- and 2-naphthalenesulfonamides, 1-Ns- and 2-Ns-amides, that all cleaved at significantly less negative potential than tosyl compounds. Actually both groups could be cleaved by Mg/ MeOH without prior conversion to sulfonylcarbamate. It was also concluded that N-arenesulfonyl-protected derivatives that give CV peaks above −2.30 V can be cleaved by Mg/ MeOH. Later the 2-Ns-analogue of the previously mentioned Gabriel reagent TsNHBoc was also made. 26c

J. R. Henry, L. R. Marcin, M. C. McIntosh, P. M. Scola, G. D. Harris Jr and S. M. Weinreb, Tetrahedron Lett., 1989, 30, 5709–5712 CrossRef CAS. Whilst the world has experienced various and serious epidemics in parts of the world since those cases in the 1970s, they were particular to those areas such that free pratique in those areas then might not be a ‘mere formality’ but could continue to be elsewhere in the world. COVID-19 was something different however, affecting the entire planet such that, at its height, there could be no ‘mere formality’ for any vessel entering any port worldwide. By analogy with what is said in section 4.1 above, in Boc 2N-derivatives one Boc-group is highly acid-labile and can be cleaved under very mild acidic conditions as exemplified by 1.5 equiv. trifluoroacetic acid 32a or with catalytic amounts of a Lewis acid like Mg(ClO 4) 2. 32b This reagent is believed to form a six-membered imidodicarbonate chelate that eliminates one molecule of isobutylene and then collapses. More recently CeCl 3·7H 2O, 32c indium and zinc powder, 32d montmorillonite K10 32e and BiBr 3 32f have also been used in this context. As Boc-derivatives of primary amines have previously been selectively alkylated, two different alkyl substituents can in principle be introduced stepwise into Boc 2NH when used instead of phthalimide. 33 b) J. W. Barton, Protection of N–H bonds and NR 3. In Protective Groups in Organic Chemistry, J. F. W. McOmie, Ed., Plenum Press, London, 1973, Chapter 2 Search PubMed. L. Grehn and U. Ragnarsson, Angew. Chem., 1984, 96, 291–292 ( Angew. Chem., Int. Ed. Engl., 1984, 23, 296–301) CrossRef CAS.M. M. Hansen, A. R. Harkness, D. S. Coffey, F. G. Bordwell and Y. Zhao, Tetrahedron Lett., 1995, 36, 8949–8952 CrossRef CAS. L. Grehn, K. Gunnarsson and U. Ragnarsson, Acta Chem. Scand., Ser. B, 1987, B41, 18–23 CrossRef CAS and reference therein. W. Steglich and G. Höfle, Angew. Chem., 1969, 81, 1001 ( Angew. Chem., Int. Ed. Engl., 1969, 8, 981) CrossRef.

convenient; handy Antonym: incommode Cette télécommande est vraiment pratique. ― This remote control is really convenient. It has always been the case that a vessel needs to be legally ready to load or discharge the cargo on board, the health of the crew being one of the requirements to meet that legal readiness. It became recognised that, if the crew were healthy, confirming this would be a ‘mere formality’ and as such should not prevent the running of laytime. La perspective practique is the second edition of the treatise on perspective and brings together the three volumes which were published in 1642, 1647 and 1649.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. 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. b) L. A. Carpino, E. M. E. Mansour and A. El-Faham, J. Org. Chem., 1993, 58, 4162–4164 CrossRef CAS. experience C’est un homme qui a la pratique des affaires. ― This is a man with business experience.