Synthesen mit 1, 3-Dithietanen. XIII. Synthesen von kondensierten Heterocyclen aus substituierten 5-Thioxo-Δ3-pyrazolin-4-carbonsäureestern

✍ Scribed by Doz. Dr. K. Peseke; Dr. C. Vogel; Dipl.-Chem. J. Blaesche; Dipl.-Chem. K.-H. Kollhof

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 592 KB
• Volume: 324
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/prac.19823240420

✦ Synopsis

Syntheses with 1, 3‐Dithietanes. XIII. Syntheses of Condensed Heterocycles from 5‐Thioxo‐3‐pyrazoline‐4‐carboxylates

3‐Amino‐2‐aroyl‐5‐thioxo‐3‐pyrazoline‐4‐carboxylates 1d–f react with bromoacetal‐dehydediethylacetale, phenacyl bromides, ethyl bromopyruvate, ethyl α‐chloro‐acetate or chloro‐acetylacetone to give ethyl dihydropyrazolo[5,1‐b]thiazolecarboxylates 2, 4, 5 or 7. The derivatives of ethyl tetrahydropyrazolo [5,1‐b]thiazolecarboxylates 8 or 9 are obtained by reaction of 1d–f with ethyl β‐anilino‐α‐chloro‐crotonate and oxalylchloride, respectively. The ethyl methylthiopyrazoline‐carboxylate 10d and an excess of hydrazine hydrate afford pyrazolo[3,4‐c]pyrazole 11. Compounds 10 react with phenyl isocyanate to give pyrazolo[3,4‐d][1,3]oxazin‐6‐ones 13. The dithietanes 12 and cinnamohydrazide yield pyrazolo[1,2‐a]pyrazolecarboxylates 15.