{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,13]],"date-time":"2025-11-13T06:33:11Z","timestamp":1763015591026},"reference-count":24,"publisher":"CLOCKSS Archive","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["HETEROCYCLES"],"published-print":{"date-parts":[[2006]]},"DOI":"10.3987\/com-06-s(w)26","type":"journal-article","created":{"date-parts":[[2009,3,3]],"date-time":"2009-03-03T04:29:18Z","timestamp":1236054558000},"page":"93","source":"Crossref","is-referenced-by-count":29,"title":["Diastereoselective Synthesis of Atropisomeric 3-(2-Substituted Aryl)quinazolin-4-ones and Their Stereochemical Properties"],"prefix":"10.13030","volume":"70","author":[{"given":"Hideaki","family":"Natsugari","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takashi","family":"Tokitoh","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Toshitake","family":"Kobayashi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eisuke","family":"Nakada","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tohru","family":"Inoue","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Satoshi","family":"Yokoshima","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hideyo","family":"Takahashi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"5187","reference":[{"key":"10.3987\/COM-06-S(W)26-1","unstructured":"1. Current address: Pharmaceutical Research Division, Takeda Pharmaceutical Company Ltd., 10 Wadai, Tsukuba, Ibaraki 300-4293, Japan."},{"key":"10.3987\/COM-06-S(W)26-2","doi-asserted-by":"crossref","unstructured":"2. J. Jungh\u00e4nel, V. Buss, T. Beyrich, and T. Jira, Chirality, 1998, 10, 253.","DOI":"10.1002\/(SICI)1520-636X(1998)10:3<253::AID-CHIR8>3.0.CO;2-A"},{"key":"10.3987\/COM-06-S(W)26-3","doi-asserted-by":"publisher","DOI":"10.1016\/S0960-894X(00)00622-3"},{"key":"10.3987\/COM-06-S(W)26-4","doi-asserted-by":"publisher","DOI":"10.1021\/np50124a015"},{"key":"10.3987\/COM-06-S(W)26-5","doi-asserted-by":"publisher","DOI":"10.1039\/b514561a"},{"key":"10.3987\/COM-06-S(W)26-6","doi-asserted-by":"publisher","DOI":"10.1021\/ja042216x"},{"key":"10.3987\/COM-06-S(W)26-7","doi-asserted-by":"publisher","DOI":"10.1021\/jm030197g"},{"key":"10.3987\/COM-06-S(W)26-8","doi-asserted-by":"publisher","DOI":"10.1021\/ja026436r"},{"key":"10.3987\/COM-06-S(W)26-9","doi-asserted-by":"publisher","DOI":"10.1021\/ja0171198"},{"key":"10.3987\/COM-06-S(W)26-10","doi-asserted-by":"publisher","DOI":"10.1021\/ol010076f"},{"key":"10.3987\/COM-06-S(W)26-11","doi-asserted-by":"publisher","DOI":"10.1021\/jm990220r"},{"key":"10.3987\/COM-06-S(W)26-12","doi-asserted-by":"publisher","DOI":"10.1016\/j.tet.2004.01.097"},{"key":"10.3987\/COM-06-S(W)26-13","unstructured":"7. Since partial racemization at the amino acid moiety during the reaction, presumably at the step of 7&rarr; 8, was observed in the preliminary experiments, racemic amino acids (5) (DL-alanine and DL-phenylalanine) were used in this study to avoid the complexity of the chemistry, and thus the compounds (5-9) are racemic, but only one enantiomer is depicted for convenience."},{"key":"#cr-split#-10.3987\/COM-06-S(W)26-14.1","doi-asserted-by":"crossref","unstructured":"(a) H. Fuwa, T. Kobayashi, T. Tokitoh, Y. Torii, and H. Natsugari, Synlett, 2004, 2497.","DOI":"10.1055\/s-2004-834805"},{"key":"#cr-split#-10.3987\/COM-06-S(W)26-14.2","doi-asserted-by":"crossref","unstructured":"(b) H. Fuwa, T. Kobayashi, T. Tokitoh, Y. Torii, and H. Natsugari, Tetrahedron, 2005, 61, 4297.","DOI":"10.1016\/j.tet.2005.02.038"},{"key":"10.3987\/COM-06-S(W)26-15","doi-asserted-by":"publisher","DOI":"10.1016\/j.tet.2005.02.038"},{"key":"10.3987\/COM-06-S(W)26-16","doi-asserted-by":"publisher","DOI":"10.1007\/BF00808768"},{"key":"10.3987\/COM-06-S(W)26-17","doi-asserted-by":"publisher","DOI":"10.1016\/j.tet.2005.02.038"},{"key":"10.3987\/COM-06-S(W)26-18","doi-asserted-by":"publisher","DOI":"10.1021\/jo982149n"},{"key":"10.3987\/COM-06-S(W)26-19","doi-asserted-by":"publisher","DOI":"10.1021\/jo9914364"},{"key":"10.3987\/COM-06-S(W)26-20","doi-asserted-by":"publisher","DOI":"10.3987\/COM-03-S12"},{"key":"10.3987\/COM-06-S(W)26-21","unstructured":"10. Representative procedures forthe dehydrative cyclization of 8 to 9 (method B): (a) A mixture of the amidine (8a), which was prepared from the iminobenzoxazine (7a) (1.70 g) and piperidine (4.20 mL) in EtOAc (150 mL), 1,4-dioxane (80 mL), and 0.2 M aq. KHSO4 (80 mL) was stirred at rt overnight. The organic layer was diluted with EtOAc, and the mixture was washed with H2O, dried over Na2SO4, and concentrated. Purification of the residue on flash chromatography (Fuji Silysia silica gel BW300, 30&rarr;50% EtOAc\/hexane) gave 9R*-a (0.99 g, 58 %) and 9S*-a (0.24 g, 14 %). Selected data for 9R*-a: colorless crystals; mp 199-200 \u00b0C; 1H NMR (CDCl3) \u03b4 8.58 (m, 1H), 8.30 (d, J = 7.6 Hz, 1H), 7.94 (d, J = 7.2 Hz, 1H), 7.82 (m, 1H), 7.75 (d, J = 7.2 Hz, 1H), 7.56-7.47 (m, 2H), 5.45 (m, 1H), 4.38 (m, 1H), 1.50-1.30 (m, 12H); 1H NMR (DMSO-d6) \u03b4 8.59 (d, J = 4.8 Hz, 1H), 8.15 (d, J = 8.4 Hz, 1H), 8.06 (d, J = 13.6 Hz, 1H), 7.92 (d, J = 7.8 Hz, 1H), 7.79 (d, J = 14.0 Hz, 1H), 7.70 (dd, J = 7.2, 4.4 Hz, 1H), 7.61 (d, J = 7.8 Hz, 1H), 7.42 (d, J = 7.2 Hz, 1H), 4.13 (m, 1H), 1.39-1.05 (m, 12H); Selected data for 9S*-a: colorless crystals; mp 131-132 \u00b0C; 1H NMR (CDCl3) \u03b4 8.58 (d, J = 4.0 Hz, 1H), 8.29 (d, J = 7.2 Hz, 1H), 7.84 (m, 1H), 7.79-7.72 (m, 2H), 7.57-7.45 (m, 2H), 5.58 (m, 1H), 4.43 (m, 1H), 1.49-1.31 (m, 12H); 1H NMR (DMSO-d6) \u03b4 8.50 (d, J = 4.8 Hz, 1H), 8.25 (d, J = 8.0 Hz, 1H), 8.14 (d, J = 8.4 Hz, 1H), 7.91 (d, J = 7.4 Hz, 1H), 7.76 (d, J = 8.4 Hz, 1H), 7.64 (dd, J = 8.4, 5.6 Hz, 1H), 7.59 (d, J = 7.8 Hz, 1H), 7.18 (d, J = 9.2 Hz, 1H), 4.38 (m, 1H), 1.39-1.19 (m, 12H). (b) A mixture of the amidine (8b) (0.56 g), silica gel 60 (Merck) (12 g), and CHCl3 (56 mL) was stirred at rt for 5 days. Conventional work-up gave a mixture of 9R*-b and 9S*-b (0.48 g) (the ratio = 9.0:1 from 1H NMR) as a white solid, from which 9R*-b was isolated as colorless crystals (0.37 g, 77 %). Selected data for 9R*-b: mp 192-193 \u00b0C; 1H NMR (CDCl3) \u03b4 8.61 (d, J = 3.6 Hz, 1H), 8.31 (d, J = 8.0 Hz, 1H), 7.93-7.70 (m, 3H), 7.59-7.46 (m, 2H), 7.24-7.12 (m, 3H), 6.95 (d, J = 6.4 Hz, 2H), 5.21 (d, J = 9.2 Hz, 1H), 4.55-4.45 (m, 1H), 3.24 (dd, J = 13.6, 3.6 Hz, 1H), 2.87 (dd, J = 13.6, 9.2 Hz, 1H), 1.31 (s, 9H). Selected data for 9S*-b: diagnostic signals in the 1H NMR (CDCl3) are as follows: \u03b4 8.46 (d, J = 4.8 Hz, 1H), 8.24 (d, J = 6.6 Hz, 1H), 7.14 (dd, J = 4.8, 7.8 Hz, 1H), 6.22 (d, J = 7.8 Hz, 1H), 5.50 (d, J = 9.0 Hz, 1H), 4.54-4.45 (m, 1H), 3.31 (dd, J = 13.0, 9.6 Hz, 1H), 3.06 (dd, J = 13.0, 4.8 Hz, 1H), 1.41 (s, 9H). Similarly, the amidine (8c) gave 9R*-c and 9S*-c. Selected data for 9R*-c: mp 181-182 \u00b0C; 1H NMR (CDCl3) \u03b4 8.27 (d, J = 7.8 Hz, 1H), 7.81 (t, J = 7.3 Hz, 2H), 7.78 (m, 1H), 7.68 (t, J = 7.3 Hz, 1H), 7.58-7.50 (m, 2H), 7.14 (m, 3H), 6.85 (d, J = 6.6 Hz, 2H), 5.7-5.3 (broad, 1x0.8H), 5.11 (broad, 1x0.2H), 4.72 (ddd, 12.6, 4.8, 4.3 Hz, 1x0.8H), 4.56 (broad, 1x0.2H), 3.64 (s, 3H), 3.08 (dd, J = 13.8, 4.3 Hz, 1H), 2.83 (broad, 1H), 1.34 (s, 9x0.8H), 1.01 (s, 9x0.2H). Selected data for 9S*-c11: diagnostic signals in the 1H NMR (CDCl3) are as follows: 7.57 (t, J = 7.8 Hz, 1H), 6.90 (d, J = 7.2 Hz, 2H), 6.31 (d, J = 7.8 Hz, 1H), 4.51 (dd, J = 15.6, 8.4 Hz, 1H), 3.68 (s, 3H), 3.25 (dd, J = 19.2, 8.4 Hz, 1H), 2.95 (broad, 1H), 1.33 (s, 9x0.8H), 1.07 (s, 9x0.2H)."},{"key":"10.3987\/COM-06-S(W)26-22","unstructured":"11. The diastereomers (9R*-c and 9S*-c) showed the same Rf value on TLC and could not be separated by column chromatography. The single isomer (9R*-c) was isolated by crystallization and the structure was determined in X-Ray analysis (Figure 2). The structure of isomer (9S*-c) was confirmed with 1H- 1H COSY NMR using a mixture of 9R*-c and 9S*-c."},{"key":"10.3987\/COM-06-S(W)26-23","doi-asserted-by":"publisher","DOI":"10.1021\/ja055666d"}],"container-title":["HETEROCYCLES"],"original-title":[],"language":"en","deposited":{"date-parts":[[2024,6,24]],"date-time":"2024-06-24T20:45:17Z","timestamp":1719261917000},"score":1,"resource":{"primary":{"URL":"https:\/\/triggered.stanford.clockss.org\/ServeContent?doi=10.3987%2Fcom-06-s%28w%2926"},"secondary":[{"URL":"https:\/\/triggered.edinburgh.clockss.org\/ServeContent?doi=10.3987%2Fcom-06-s%28w%2926","label":"edinburgh"}]},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2006]]},"references-count":24,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2006]]}},"alternative-id":["COM-06-S(W)26"],"URL":"https:\/\/doi.org\/10.3987\/com-06-s(w)26","relation":{},"ISSN":["0385-5414"],"issn-type":[{"type":"print","value":"0385-5414"}],"subject":[],"published":{"date-parts":[[2006]]}}}