. By the same procedure as described above, the hydrochloride of 3 was prepared in 92% yield: mp 197-200 °C; [a]20D +148.1°(c 0.1, methanol); IR 1725, 1620, 1580 cm"1; MS, m/e 527 (M+ + 1).(+)-9-Amino-4-demethoxy-9-deoxy-l-methoxydaunomycin (37). By the same procedure as described for the preparation of 36, the hydrochloride 37 was prepared in 76% yield: mp [198][199][200][201][202] °C; [a]20D +78.9°(c 0.1, methanol); IR 1730, 1620,1585 cm™1; MS, m/e 527 (M+ + 1).Acknowledgment. We are grateful to Mr. H. Sato for skillful technical assistance.

2220 (m), 1595 (m), 1440 (s), 1150 (s); MS, m/e 285 (El); exact mass caled for 016 01 02 285.0556, found 285.0553. 2-Chloro-4-cyano-3-ethoxy-l-hydroxydibenzofuran (37).A solution of 0.25 g (0.70 mmol) of 33d and 0.10 mL (0.77 mmol) of trimethylsilyl chloride in 75 mL of dry CCI4 was added dropwise to 300 mL of refluxing CC14. The solution was heated at reflux for 1.5 h and then concentrated. The residue was absorbed on to silica gel and subjected to flash chromatography (1:1 hex-anes/ethyl acetate) to give 0.15 g (76%) of off-white crystals (37): mp 214-215 °C;

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Die Thiolyse der 3,3-Dichloracrylonitrile 1 fuhrt zu Dithiolaten 3, die sich zu Keten-dithioacetalen 5 alkylieren oder mit Phosgen zu den Titelverbindungen 8 acylieren lassen. Das uber die 1-Cyanoalkylidene-substituted 1 ,IDithietanones as Cyanothioketene Equivalents. Conversion into 1,3,5-Dithiazin-4-ones and 2-Azetidinethiones Thiolation of 3,3-dichloroacrylonitriles 1 leads to dithiolates 3, which can be alkylated to give ketene dithioacetals 5 or acylated with phosgene to yield the title compounds 8. rert-Butyl(cyan0)-thioketene (912) formed via 12 + 21 cycloreversion of 8c was found to be highly unstable. However, dithietanone 8c can be used directly as thioketene equivalent in the reaction with dimethylamine or aminoazirines 28 to give thioamides 12b, 33,34, and the 3-thiazoline 30. On addition of azomethines 17 or 2-thiazolines 24 to 8c, 1,3,5-dithiazin-4-one derivatives 19 or 25 are formed via nucleophilic attack at C-2 of the four-membered ring. The constitution of 19e was proven by an X-ray structural investigation. In the presence of an electron-rich 6-aryl residue, heterocycles 19 easily eliminate carbon oxide sulfide to give the azetidinethiones 21d -f , h, which can be considered as [2 + 21 cycloadducts of thioketene 9 c with azomethines. On heating, 8c and the 2-thiazoline 24b react to give bicyclic 27, whose constitution could be derived from an X-ray study.Seit Cyanketene durch Thermolyse von 2,S-Diazido-I ,4-benzochinonen bequem zuganglich sind, zahlt vor allem tert-Butylcyanketen zu den am haufigsten benutzten Ketenen'). Versuche, das zum Vergleich interessierende tert-Butyl(cyan)thio keten (9c) durch Blitzthermolyse von 4-terr-Butyl-l,2,3-thiadiazol-5-carbonitri12) oder durch 0 Verlag