Pyrrolo thiazoles, 2,3-dihydro

Pyrrolo[l,2-A]thiazoles are aromatic compounds but only one fully conjugated derivative has been described. A few dihydro and tetrahydro derivatives have been prepared, mainly in connection with search for biologically active drugs. Saturated compounds are also known. 

N- Phenacyl-2-methylthiazolylium salts (229) react under aprotic conditions with sodium acetate in acetic anhydride to form a pyrrolo[2,1 -b]thiazole (230). When the reaction is carried out in an aqueous solution of sodium hydrogen carbonate, extension of the ring occurs with formation of the dihydro- 1,4-thiazine derivative (231). 

Very simple and straightforward alkylation of NH-heterocycles (NaH, Cl(CH2) SMe, = 2 or 3, 68-86%) permits one-pot preparation of pyrrole and carbazole sulfide models for the reaction with triflic anhydride <2003S1191>. Cyclization of the (l/7-pyrrol-l-yl)alkyl sulfides 1470 obtained leads to 2,3-dihydropyrrolo[2,l- ][l,3]thiazole 1472 and 3,4-dihydro-2/7-pyrrolo[2,T ][l,3]thiazine 1473 via intermediate l-methyl-2,3-dihydropyrrolo[2,l-/ ][l,3]thiazol-1-ium or l-methyl-3,4-dihydro-27/-pyrrolo[2,T ][l,3]thiazin-Tium salts 1471 (n = Z or 3), respectively, that were isolated in high yields in most cases (Scheme 281) <2003S1191>. 

Die Reaktion von N-Thiobenzoyl-prolin mit einem UberschuB Thioessigsaure fuhrt zum bicyclischen, mesoionischen System Anhydro-l-Mercapto-3-phenyl-6,7-dihydro-5H-(pyrrolo[l, 2-c]thiazol 116 ... 

Methyl-1,3-dihydropyrrolo[ 1,2-c]thiazole-6,7-biscarbamates have been described as active compounds against murine P388 lymphocytic leukemia <87JMC2109>. Several 5-aryl-2,3-dihydro-pyrrolo[2,l-fe]thiazole-6,7-dimethanol-6,7-bis(isopropylcarbamate)s were tested for growth inhibitory activity with the HL-60 human promyelocytic leukemia cell line. The 5-phenyl, 5-(4-fluorophenyl), and 5-(3,4-dichlorophenyl) have antileukemic activity. These compounds were also cytotoxic to HT-29 human colon carcinoma cells <88JMC1427>. 

Thiazolo[3,2-a]pyrrolo[2,3-Hantzsch thiazole synthesis has made compounds of the above... 

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