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tn; benzene, 25°) afforded the aminothiones10 4 and 5 (60-80%), which proved susceptible to ring closure by further condensation. Reaction of 4 with en (2 equiv), tn (2 equiv), and tn (6 equiv) in benzene (70°, 1 hr) yielded after separation from by-products the macrocycles 6 (40%, mp 286-289°), 711 (--'30 %, mp 220-222°), and 8 (30%, mp 147-148°), respectively, as white solids from chloroform-ethanol. Macrocycle 8 is better obtained from 5 and tn (2.5 equiv, benzene, 70°); yields of 90% have been achieved by this route.12 Molecular weights of 6-8 were confirmed by highresolution mass spectra (e.g., calcd for 12C241H2814N4

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The irradiation of 2-pyrone in benzene followed by pyrolysis gives a poor yield of cyclooctatetraene. The irradiation of 4-methoxy-6-methyl-2-pyrone in water gives cis-β-methyl glutaconic half ester and the corresponding diacid. Irradiation in benzene followed by the addition of water gives a mixture of the cis and trans glutaconic derivatives. It is believed that these substances derive from the β-lactone formed by irradiation, and support for this view is obtained from low temperature irradiations. An oligomeric intermediate (16) is suggested as a second intermediate in the irradiation in benzene, and a hemiketal (20) in the aqueous irradiation.