{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T15:06:50Z","timestamp":1760368010071},"reference-count":8,"publisher":"Elsevier BV","issue":"17","license":[{"start":{"date-parts":[[2000,4,1]],"date-time":"2000-04-01T00:00:00Z","timestamp":954547200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Tetrahedron Letters"],"published-print":{"date-parts":[[2000,4]]},"DOI":"10.1016\/s0040-4039(00)00336-1","type":"journal-article","created":{"date-parts":[[2002,7,25]],"date-time":"2002-07-25T22:28:39Z","timestamp":1027636119000},"page":"3065-3068","source":"Crossref","is-referenced-by-count":41,"title":["Novel barrelene-fused chlorins by Diels\u2013Alder reactions"],"prefix":"10.1016","volume":"41","author":[{"given":"Ana M.G","family":"Silva","sequence":"first","affiliation":[]},{"given":"Augusto C","family":"Tom\u00e9","sequence":"additional","affiliation":[]},{"given":"Maria G.P.M.S","family":"Neves","sequence":"additional","affiliation":[]},{"given":"Jos\u00e9 A.S","family":"Cavaleiro","sequence":"additional","affiliation":[]}],"member":"78","reference":[{"key":"10.1016\/S0040-4039(00)00336-1_BIB1","doi-asserted-by":"crossref","unstructured":"Sternberg, E. D.; Dolphin, D. Tetrahedron 1998, 54, 4151\u20134202.","DOI":"10.1016\/S0040-4020(98)00015-5"},{"key":"10.1016\/S0040-4039(00)00336-1_BIB2","doi-asserted-by":"crossref","unstructured":"Tom\u00e9, A. C.; Lacerda, P. S. S.; Neves, M. G. P. M. S.; Cavaleiro, J. A. S. Chem. Commun. 1997, 1199\u20131200.","DOI":"10.1039\/a702504a"},{"key":"10.1016\/S0040-4039(00)00336-1_BIB3","doi-asserted-by":"crossref","unstructured":"Silva, A. M. G.; Tom\u00e9, A. C.; Neves, M. G. P. M. S.; Silva, A. M. S.; Cavaleiro, J. A. S. Chem. Commun. 1999, 1767\u20131768.","DOI":"10.1039\/a905016g"},{"key":"10.1016\/S0040-4039(00)00336-1_BIB4","unstructured":"Part of this work has already been presented: Silva, A. M. G.; Tom\u00e9, A. C.; Neves, M. G. P. M. S.; Cavaleiro, J. A. S. XVIIIth European Colloquium on Heterocyclic Chemistry, Abstract A-86, Rouen (France), 1998."},{"key":"10.1016\/S0040-4039(00)00336-1_BIB5","doi-asserted-by":"crossref","unstructured":"Porphyrin 1a was obtained as a by-product during the synthesis of 1c by the method of Bruce: Wang, Q. M.; Bruce, D. W. Synlett 1995, 1267\u20131268.","DOI":"10.1055\/s-1995-5244"},{"key":"10.1016\/S0040-4039(00)00336-1_BIB6","unstructured":"As an example, the spectroscopic data for chlorin 2d: 1H NMR (300 MHz, CDCl3, J Hz) \u03b4: \u22122.07 (s, 2H, NH), 4.64 (s, 2H, H-21,31), 5.72 (s, 2H, H-2,3), 6.76 (dd, J 6.3 and J 3.3, 2H, H-naphth.), 7.02 (dd, J 6.3 and J 3.3, 2H, H-naphth.), 7.07 (s, 2H, H-naphth.), 7.33 (s, 2H, H-naphth.), 7.40 (dd, J 6.3 and J 3.3, 2H, H-naphth.), 7.64\u20137.68 (m, 6H, H-Ph), 7.75 (dd, J 6.3 and J 3.3, 2H, H-naphth.), 7.81 (d, J 7.5, 2H, H-Ph), 7.94 (t, J 7.5, 2H, H-Ph), 8.01\u20138.13 (m, 8H, H-Ph), 8.32\u20138.36 (m, 4H, H-\u03b2), 8.54\u20138.56 (m, 4H, H-Ph, H-\u03b2); 13C NMR (75 MHz, CDCl3) \u03b4: 46.5 (C-21,31), 55.0 (C-2,3), 112.6, 121.9, 122.2, 122.6, 123.9, 124.5, 125.4, 126.61, 126.64, 126.8, 127.6, 127.8, 128.0, 128.7, 131.5, 131.95, 132.02, 132.5, 133.9, 134.1, 135.3, 135.7, 138.2, 140.8, 141.7, 142.0, 142.7, 152.4, 164.2; MS (LSIMS): 893 (M+H)+, 614 (TPP); UV\u2013vis (CHCl3), \u03bbmax\/nm (log \u03b5): 652 (4.35), 598 (3.71), 548 (3.99), 521 (4.08), 422 (5.27); C66H44N41\/2H2O: calcd C 87.87, N 6.21, H 5.03; found C 87.72, N 6.25, H 5.27."},{"key":"10.1016\/S0040-4039(00)00336-1_BIB7","unstructured":"There is a significant difference in the spectra of these compounds: the meso-H of 2a.1 resonate at \u03b4 9.20, 9.23 and 9.76 ppm while in 2a.2 they resonate at \u03b4 9.32, 9.72 and 9.82 ppm."},{"key":"10.1016\/S0040-4039(00)00336-1_BIB8","unstructured":"Porphyrin 3d: 1H NMR (300 MHz, CDCl3, J Hz) \u03b4: \u22123.06 (s, 2H, NH), 5.00 (s, 2H, H-21,31), 7.32 (dd, J 6.2 and J 3.3, 4H, H-naphth.), 7.60 (s, 4H, H-naphth.), 7.69 (dd, J 6.2 and J 3.3, 4H, H-naphth.), 7.72\u20137.76 (m, 6H, H-Ph), 8.08\u20138.20 (m, 10H, H-Ph), 8.33\u20138.35 (m, 4H, H-Ph), 8.76\u20138.84 (m, 6H, H-\u03b2); 13C NMR (75 MHz, CDCl3) \u03b4: 50.1, 119.1, 120.1, 122.1, 125.6, 126.6, 127.0, 127.5, 127.6, 128.8, 131.7, 134.3, 134.5, 142.1, 142.9, 143.2; MS (LSIMS): 891 (M+H)+; UV\u2013vis (CHCl3), \u03bbmax\/nm (log \u03b5): 647 (3.53), 591 (3.76), 551 (3.77), 516 (4.32), 420 (5.58)."}],"container-title":["Tetrahedron Letters"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0040403900003361?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0040403900003361?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2019,4,14]],"date-time":"2019-04-14T11:54:57Z","timestamp":1555242897000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0040403900003361"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,4]]},"references-count":8,"journal-issue":{"issue":"17","published-print":{"date-parts":[[2000,4]]}},"alternative-id":["S0040403900003361"],"URL":"https:\/\/doi.org\/10.1016\/s0040-4039(00)00336-1","relation":{},"ISSN":["0040-4039"],"issn-type":[{"value":"0040-4039","type":"print"}],"subject":[],"published":{"date-parts":[[2000,4]]}}}