299. Cyclisation of some thiobenzamido-compounds

Abstract

Lawsout autd Searle: 299. Cyclisation of Some T h i o b e n z a r n i d o -c u d . By ALEXANDER LAWSON and C. E. SEARLE. N-Thiobenzoylsarcosie and N-ethyl-N-thiobenzoylglycine undergo ring closure in hot acid anhydrides, to give meso-ionic compounds (IV). Thiobenzamidoacetaldehyde diethyl acetal has been cyclised to the ethoxythiazoline (VI) and the thiazole (VII). Thiobenzoyl-semicarbazide and -thiosemicarbazide are cyclised to the hydroxy-(IX) or mercapto-thiadiazole (XII) or the aminothiadiazole (X) , depending on the conditions.

PEPPSI‐Type Palladium Complexes Containing Basic 1,2,3‐Triazolylidene Ligands and Their Role in Suzuki–Miyaura Catalysis

“…Recent work has shown that the electron-donor properties of N-heterocyclic carbene ligands [9] substantially increase when the heteroatoms of the ring are positioned at remote positions. [10] For example, mesoionic [11] 1,2,3-triazol-5-ylidenes (B, Figure 1) bear only one nitrogen adjacent to Abstract: A series of PEPPSI-type palladium(II) complexes was synthesized that contain 3-chloropyridine as an easily removable ligand and a triazolylidene as a strongly donating mesoionic spectator ligand. Catalytic tests in Suzuki-Miyaura cross-coupling re-A C H T U N G T R E N N U N G actions revealed the activity of these complexes towards aryl bromides and aryl chlorides at moderate temperatures (50 8C).…”

The oxidation of 1-thioaroylsemicarbazides

“…167-169 "C; 1.25-1.40 g, 65-72%). Crystallisation by dissolution in a large volume of acetone (4 x 50 ml per g) and vacuum evaporation of the filtered liquid (to half-volume or less) gave opaque deep-yellow microcrystalline (16a), m.p. 166-168 "C (decomp.)…”

“…PhCONH2,21' PhCONMe2,21b tico, 170. 4 . The fully heteroaromatic nature and consequent enhanced resonance stabilisation of the latter is a factor likely to contribute to this difference.…”

Proceedings of the Biochemical Society

“…This reaction has been successfully applied to other DNP-amino acids including DNIP-sarcosine and DNP-proline. The fact that these derivatives decarboxylate readily indicates that a cyclic intermediate, either of the type proposed by Cornforth & Elliott (1950) or by Lawson & Searle (1957), may not be essential for this decarboxylation as these amino acid derivatives contain tertiary aminogroups.…”