Heterocyclizations of Functionalized Heterocumulenes with C,N- and C,O-Dinucleophiles: II.* Reaction of 1-Chloro- and 1,1-Dichloroalkyl Isocyanates and 1-Chloroalkylidenecarbamates with 2-Bensothiazolylacetonitrile, 2-Benzothiazolylacetates, and Bis(2-benzothiazolyl)methane

1-Chloroalkyl isocyanates react with 2-R-methylbenzothiazoles [R = CN, C(O)OAlk, 2-benzothiazolyl] in the presence of triethylamine to give 4-R-2,3-dihydro-1H-pyrimido[6,1-b][1,3]benzothiazol-1-ones. The same reaction at elevated temperature in the absence of a base yields isomeric 4-R-2,3-dihydro-1H-pyrimido[6,1-b][1,3]benzothiazol-3-ones. 4-R-1H-Pyrimido[6,1-b][1,3]benzothiazol-1-ones are formed in the reaction of 1,1-dichloroalkyl isocyanates or methyl 1-chloroalkylidenecarbamates with 2-benzothiazolylacetonitrile or bis(2-benzothiazolyl)methane.