Synlett 2007(8): 1305-1307  
DOI: 10.1055/s-2007-977443
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of 7,8-Benzo-4-hydroxy-1,9-diazabicyclo[3.3.1]non-3-enes by Cyclization of 1,3-Bis(silyl enol ethers) with Quinazoline

Andreas Schmidta, Jörg-Peter Gütleina, Satenik Mkrtchyana, Helmar Görlsb, Peter Langer*a,c
a Institut für Chemie, Universität Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
Fax: +49(381)4986412; e-Mail: peter.langer@uni-rostock.de;
b Institut für Anorganische und Analytische Chemie, Universität Jena, August-Bebel-Str. 2, 07740 Jena, Germany
c Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein-Str. 29a, 18059 Rostock, Germany
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Publikationsverlauf

Received 7 December 2006
Publikationsdatum:
18. April 2007 (online)

Abstract

Functionalized 7,8-benzo-4-hydroxy-1,9-diazabicyclo[3.3.1]non-3-enes were prepared by one-pot cyclization of 1,3-bis(silyl enol ethers) with quinazolines.

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General Procedure for the Cyclization of Quinazolines with 1,3-Bis(silyl enol ethers) To a CH2Cl2 soln (40 mL) of quinazoline (0.521 g, 4.0 mmol) was added the 1,3-bis(silyl enol ether) (5.6 mmol) and methyl chloroformate (1.512 g, 16.0 mmol) at 0 °C. The solution was stirred for 2 h at 0 °C and for 12 h at 20 °C. The solvent was removed in vacuo. The residue was purified by chromatography (silica gel, heptane → heptane-EtOAc = 2:1).
Synthesis of 3a
Starting from quinazoline (0.521 g, 4.0 mmol), 2a (1.460 g, 5.6 mmol) and methyl chloroformate (1.512 g, 16.0 mmol), 3a was obtained as a colorless solid (0.750 g, 52%). 1H NMR (250 MHz, CDCl3): δ = 2.41 (dd, 2 J = 17.5 Hz, 3 J = 1.5 Hz, 1 H, CH2), 2.99 (br dd, 1 H, CH2), 3.76 (s, 3 H, OCH3), 3.80 (s, 3 H, OCH3), 3.87 (s, 3 H, OCH3), 5.40 (br, 1 H, NCHCH2), 7.03-7.13 (m, 2 H, CH, Ar), 7.20-7.26 (m, 1 H, CH, Ar), 7.38 (br, 1 H, NCH), 7.75 (br, 1 H, CH, Ar), 12.26 (s, 1 H, OH). 13C NMR (75.5 MHz, CDCl3): δ = 38.0 (CH2), 48.7 (br, NCHCH2), 52.0, 53.2, 53.3 (OCH3), 58.9 (NCH), 98.0 (CCO2CH3), 124.2, 124.4, 126.8, 127.6 (CH, Ar), 126.3, 134.4 (br, C, Ar), 153.4, 154.0 (NCO), 170.6 (COO), 173.2 (br, COH). IR (mull): 3080 (w), 1707 (s), 1652 (m), 1613 (m), 1494 (m), 1335 (m), 1287 (s), 1263 (m), 1230 (s), 1196 (m), 1142 (m), 1111 (m), 1064 (m), 1039 (m), 1008 (m), 954 (w), 873 (w), 824 (w), 778 (m), 737 (w) cm-1. MS (EI, 70 eV): m/z (%) = 362 (10) [M+], 303 (100), 271 (36), 212 (23), 180 (21), 239 (13). Anal. Calcd for C17H18N2O7 (362.33): C, 56.35; H, 5.01; N, 7.73. Found: C, 56.35; H, 5.13; N, 7.46.

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CCDC-617334 contains all crystallographic details of this publication and is available free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html or can be ordered from the following address: Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB21EZ, UK; fax: +44(1223)336033; or deposit@ccdc.cam.ac.uk.