The C-formylation of 1,3-dimethyl-2(3H)-benzimidazolone and 4-methyl-2H-1,4-benzoxazin-3(4H)-one was performed using 1,1-dichloromethyl methyl ether at the Friedel-Crafts reaction conditions. The formylation of 3-methyl-2(3H)-benzoxa- and -thiazolone at the 6-position was carried out by modified Duff's method with hexamethylenetetramine in trifluoroacetic acid.

Some N-Mannich Bases of 2(3H)-Benzothiazolones and Their Analgesic Activity. -A series of Mannich bases (VI) is synthesized by reaction of benzothiazoles (III) with formaldehyde (V) and the secondary amines ( IV). All compounds are tested for their analgesic activity. -(PETROV, O. I.; ANTONOVA, A. TS.; KALCHEVA, V. B.; DALEVA, L. D.; Med. Chem. Res. 5 (1995) 6, 442-448; Dep. Chem., Sofia Univ., BG-1126 Sofia, Bulg.; EN)

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Synthesis of Benzo[b]imidazo[1,5-d][1,5]thiazepines. Derivatives of a Novel RingSystem. -A variety of derivatives of a novel tricyclic system having a benzothiazepine skeleton (VII) (11 examples) are synthesized via intramolecular cyclization of 1-(hydroxycarbonylmethylthiophenyl)imidazolones (VI) in PPA. -(PETROVA*, K.; PETROV, O.; ANTONOVA, A.; KALCHEVA, V.; Synth. Commun. 33 (2003) 24, 4355-4366; Fac. Chem., Univ. Sofia, BG-1126 Sofia, Bulg.; Eng.) -Staver 17-169

Derivatives of a new type tricyclic system having a 1,4-benzothiazine skeleton are described. The reaction of l-(2-mercaptophenyl)-2//-imidazol-2-ones 2 with excess formaldehyde in acid medium resulted in the formation of 2,4-dihydro-lH-imidazo[5,l-c][l,4]benzothiazin-l-one 3. The starting compounds 2 were prepared by a modification of a previously described method of ring transformation of 3-(2-oxopropyI)-2(3//)-benzothiazoIones in reactions with primary amines.

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