56022-26-5

Upstream product

• 333-20-0 potassium thioacyanate 
• 147-93-3 Thiosalicylic acid 
• 89430-08-0 C₂₀H₁₅N₂PS₂ 

Downstream Products

• 23588-63-8 2-(N-methyl-anilino)-benzo[e][1,3]thiazin-4-one 

Relevant academic research and scientific papers

Alkylation of 1,3-benzothiazin-4-one 2-oxo-, 2-arylimino-, and 2-thioxo derivatives

[Figure not available: see fulltext.] Sodium salt of 3H -benzo[e][1,3]thiazine-2,4-dione is easily alkylated at position 3. In the case of 2-(arylimino)-2,3-dihydrobenzo[e][1,3]-thiazin-4-ones, the alkylation reaction at this position occurs regioselectively. Alkylation of 2-thioxo-2,3-dihydrobenzo[e][1,3]thiazin-4-one under the same conditions produced regioisomers, but S-alkylation at the exocyclic sulfur atom occurred in the presence of triethylamine. The reaction of 1-(4-oxo-3,4-dihydrobenzo[e][1,3]thiazin-2-ylidene)guanidine with methyl anthranilate led to the formation of tetracyclic quinazolino[2,1-b]quinazolinedione.

Generalized method for the production of 1,3-benzoxazine, 1,3-benzothiazine, and quinazoline derivatives from 2-(hydroxy, thio, or amino) aromatic acids using triphenylphosphine thiocyanogen

A modified one-pot method was developed for the synthesis of 1,3-benzoxazines, in which the preparation of unstable thiocyanogen was omitted. The method was found to be general for substituted (methyl, methoxy, halo, and hydroxy) 2-hydroxy benzoic acids and 2-hydroxy naphthoic acids. The method was extended to 2-thio, 2-amino, and N-methyl aminobenzoic acid with which the synthesis of 1,3-benzothiazine and quinazoline derivatives has been achieved, respectively. It was also found that 3-hydroxypyridine-2-carboxylic acid and 2-hydroxynicotinic acid using a modified method gave 2-thioxo-2,3-dihydro-4H- pyrido[2,3-e][1,3]oxazin-4-one and 2-thioxo-2,3-dihydro-4H-pyrido[3,2-e][1,3] oxazin-4-one, respectively. The structures of the new compounds were confirmed by the analysis of their IR, 1H, and 13C NMR spectra. Copyright Taylor & Francis, Inc.