2624 J. zyxwv Org. Chem. zyxwvuts 1988,53, 2624-2629 0 zyxwvutsrq = 105.8 (lO)O, zyxwvutsrqponmlkjih Z = 2, Dcalcd = 1.113 g cm-,. Intensities of 1280 (F zyxwvutsrqponm 2 3489) independent reflections with 28 values up to 95' were collected on a Rigaku AFC-5 diffractometer with graphite- monochromated Cu Ka radiation, using the zyxwvutsr w-28 scanning technique. The final R value was 0.147. The structure was resolved by direct methods by using the MULTAN 84 program.8 Reaction of 2 with p-Toluenesulfonic Acid. A solution of 2 (60 mg) and calcium chloride (60 mg) in dry benzene (10 mL) was refluxed with p-toluenesulfonic acid (5 drops) for 3 h. After the reaction ceased, water was added to the solution, and the product was extracted with benzene. The organic layer was washed with water. Then the extracts were dried over Na2S04, and the solvent was removed in vacuo. The residue was chro- matographed on silica gel, using benzene as eluent, to give 3p- acetoxy-9,10-seco-5a-cycloarta-l(lO),8(9)-dien-7-one (4, 40 mg, 69%): mp 129-130 "c; ["ID -28O (c 0.28, CHC1,); IR (KBr) zyxwvut u 1735 (OAc), 1664 (C=O), 1625 cm-' (C=C); UV (CHCl,) 244 nm (17610); 'H NMR (CDC13) 6 5.44 (1 H, m, w/2 = 8.64 Hz, CH=C), 4.73 (1 H, br, w/2 = 20 Hz, CH-OAc), 2.07 (3 H, s, OCOCH,); MS m/z 482.3711, C32H&, calcd 482.3747. Elution with benzene-ethyl acetate (20:l) afforded 3~-acetoxy-9,10-seco- cycloarta-5(10),8(9)-dien-7-one (5,14 mg, 24%): amorphous; [a]D +16O (c 0.50, CHCI,); IR (KBr) u 1735 (OAc), 1665 cm-' (C=O); UV (CHCl,) 242 nm (33452); 'H NMR (7CDC13) 6 4.68 (1 H, br, w/2 = 20 Hz, CH-OAc), 3.09 (1 H, br, w/2 = 4.2 Hz, allylic H), 2.05 (3 H, s, OCOCH,); MS miz 482.3710, C32H&, calcd 482.3747. We thank Dr. Ken-ich Kawai, Faculty of Pharmaceutical Sciences, Hoshi University, for the X-ray crystallographic analysis of 2 and Drs. Toshio Takido and Mitsuro Aimi, Nihon University, for mea- surement of lH NMR and mass spectra. Registry No. 1, 4575-74-0; 2, 113948-10-0; 3, 24564-12-3; 4, Acknowledgment. 68326-42-1; 5, 113975-06-7. (8) Main, P.; Germain, G.; Woolfson, M. M. "MULTAN 84. A Com- puter Program for the Automatic Solution of Crystal Structures from X-ray Diffraction Data", University of York, York, England, 1984. Photocycloadducts of Dimethylmaleic Anhydride with Unsaturated Acids and Esters M. L. Winzenburg, E. K. Fields,* and D. P. Sinclair Research and Development Department, Amoco Chemicals Corporation, Naperuille, Illinois 60566 G. J. Ray Research Department, Amoco Corporation, Naperuille, Illinois 60566 M. E. Wright and H. K. Hall, Jr. Department of Chemistry, University of Arizona, Tucson, Arizona 85721 Received October 26, 1987 UV irradiation of dimethylmaleic anhydride (1) alone or with other unsaturated compounds yields [2 + 21 pho- tocycloadducts as shown in eq 1 and 2. [2 + 21 photo- 0 cycloadducts of 1 with olefins, alkynes, and some unsatu- rated heterocycles such as furan, indene, and ketene have been reported.' Fields and co-workers have recently re- ported the photocycloadducts of 1 with unsaturated anhydrides such as that shown in eq 3. Adducts of this type are monomers for polyimide engineering resins.2 1t d G - hv Workers at Ciba-Geigy and elsewhere have used the ability of 1 to form [2 + 21 photocycloadducts to prepare herbicides, fungicides, and polymers useful for adhesives, coatings, photoresists, and photoimaging formulation^.^ We now report the preparation and characterization of some novel photocycloadducts with unsaturated acids, esters, and allyl derivatives and our evaluation of some of these adducts as monomers for condensation polymers. Experimental Section O * O 131 0 0 0 Dimethylmaleic anhydride (1) was prepared from maleic an- h~dride.~ All other reagents and materials were purchased from commercial sources and used without further purification. Most spectroscopic and physical analyses were performed by Amoco Corp. Analytical Services. Survey 'H and 13CNMR spectra were obtained with a Nicolet NT-200 wide-bore, superconducting spectrometer at 200 and 50 MHz, respectively. Some 'H NMR spectra were run on a Perkin-Elmer R32B (90 MHz) and will be so designated. Chloroform-d solutions were employed except for compounds 8 and 10 (acetone-d,) and 9 (DMSO-d,). We recorded the infrared spectra with a Perkin-Elmer 237B with the samples prepared as Nujol mulls between NaCl plates. Melting points were taken on a Mel-Temp heated block and are uncorrected. Gas chromatograms were obtained with a Hewlett-Packard 5710A using a 10 ft X in. stainless steel column of 3% OV-17 on SO/lOO Supelcoport. Inherent viscosities of polymers were determined at a con- centration of 0.4 g/dL in 40/60 trichloroethylene/phenol at 30 "C. Thermal evaluations were performed by the Polymer Physics Division of Amoco Chemicals Corp. All 'H NMR spectra for the difference nuclear Overhauser effect (DNOE) experiments were acquired at 300 MHz on a Nicolet NT-300 spectrometer. Spectra were obtained with a 90' pulse (12 ps). The spectral width and number of data points were adjusted to give a digital resolution of 0.2 Hz. Spin-lattice re- laxation times were obtained by using an inversion-recovery sequence and standard Nicolet software on a Nicolet 1280 com- puter. DNOE spectra were obtained by using a steady-state presa- turation m e t h ~ d . ~ The decoupler was turned on at a given resonance frequency for 12 s with the power set to give 80-90% saturation of the resonance. Then the decoupler was gated off and data were acquired. 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