Cyclizations of the a,c-biladiene salts (3) and (4) t o give the porphyrins (5) and (6), respectively, have been studied in the presence of a variety of chelating agents and oxidants. As a standard, the established procedure [copper(ii) chloride-boiling dimethylformamide-6 min] gave compounds ( 5) and (6), in 37

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Zinc(II) porphyrins bearing unsubstituted ß positions can be mercurated at the ß position and at an adjacent meso position. Palladium/olefin reactions with the dimercurated porphyrins produce products possessing a five-membered isocyclic ring bridging the ß and meso positions and resembling that found in chlorophyll derivatives. With use of this methodology, novel syntheses of deoxophylloerythroetioporphyrin (2) and deoxophylloerythrin methyl ester (3), two degradation products of chlorophyll, are described.

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was not soluble). The ether washings were combined with the Freon and evaporated under reduced pressure to give a pale yellow thick oil (165 mg) which solidified on standing. It was recrystallized from benzene to give 2,6-dimethyl-/9-phenethylsulfonamide, identical with an authentic sample.The dark brown semisolid in the thermolysis tube was treated with hot ethyl acetate, filtered to remove black insoluble solid, and evaporated under reduced pressure to give a dark brwon resin (150 mg): IR (neat) 3240 (m), 1315 (s), 1145 (s), 1130 (s) cm"1. This mixture was chromatographed on neutral alumina (6 g) and eluted with methylene chloride and ethyl acetate to give 2,6dimethyl-d-phenethylsulfonamide (65.6 mg). Elution with 5% methanol in ethyl acetate gave a fraction (58.9 mg) which was recrystallized from benzene to give 5,8-dimethyl-3,4-dihydro-2,1-benzothiazine 2,2-dioxide ( 23): mp 180.5-182.0 °C (from benzene); IR (Nujol) 3190 (s), 1320 (s), 1145 (s), 1130 (s), 745 cm"1 (s); NMR (CDC13) 6.77, 6.64 (d, 2 ), 3.50 (t, 2 H, CH2S02, J = 7 Hz), 2.97 (t, 2 H, ArCH2CH2, <7=7 Hz), 3.37 (s, 1 , NH, D20 exchangeable), 2.19 (s, 3 ), 2.08 (s, 3 H, CH3); mass spectrum (70 eV), m/e (relative intensity) 211 ( +•, 12), 197 (s), 147 (33),