6-(4-Fluorophenyl)-8-phenyl-2,3-dihydro-4H-imidazo[5,1-b][1,3]thiazin-4-one: an unusual [6-5] fused-ring system.

The title compound, C(18)H(13)FN(2)OS, is the first structural example of a [6-5] fused ring incorporating the 2,3-dihydro-4H-imidazo[5,1-b][1,3]thiazin-4-one molecular scaffold. The six-membered 2,3-dihydro-1,3-thiazin-4-one ring adopts an envelope conformation, with the S-CH(2) C atom displaced by 0.761 (2) A from the five-atom plane (all within 0.05 A of the mean plane). The imidazole ring is planar. The phenyl ring is twisted from coplanarity with the imidazole ring by 23.84 (5) degrees and the 4-fluorophenyl ring is twisted by 53.36 (6) degrees , due to a close C(aryl)-H...O=C contact with the thiazin-4-one carbonyl O atom. The primary intermolecular interaction involves a CH(2) group with the F atom [C...F = 3.256 (2) A and C-H...F = 137 degrees ].

Parallel microwave-assisted library of imidazothiazol-3-ones and imidazothiazin-4-ones.

A methodology for the generation of a microwave-assisted parallel library and its conversion into a second library is described. A 24-membered library of substituted 4(5)-sulfanyl-1H-imidazoles was generated and subsequently converted into a second library of bicyclic imidazo[5,1-b]thiazol-3-ones and imidazo[5,1-b]thiazin-4-ones. The first library was generated using a three-component reaction and transformed into a daughter library with a polymer-supported coupling agent. The procedure involved the use of an array of expandable reaction vessels, which can accommodate pressure buildup due to microwave heating without loss of volatile solvents or reagents. Library generation time for each library was 16 min.