Ring-chain transformations, IX[1] Synthesis and ring-chain tautomerism of 2-(-aminoalkyl)-1,3,4-thiadiazoles

✍ Scribed by Radics, Ute ;Liebscher, Jürgen ;Ziemer, Burkhard ;Rybakov, Viktor

• Publisher: Wiley (John Wiley & Sons)
• Year: 1992
• Tongue: English
• Weight: 691 KB
• Volume: 125
• Category: Article
• ISSN: 0009-2940
• DOI: 10.1002/cber.19921250614

✦ Synopsis

Thiohydrazide compounds 1 react with lactam acetals 2 or solution, however, most of them undergo a reversible ringlactim ethers 3 by condensation giving unusual zwitterionic chain transformation to novel 2-(o-aminoalkyl)-1,3,4-thiaditautomers 5 of lactam thioacylhydrazones 4. These compounds azole salts 9. Alkylation of zwitterionic thioacylamidrazones 5 5 form mixtures of tautomers in neutral solution. In acidic gives S-alkylation products 6.

Recently, we reported on the synthesis of (w-aminoalkyl)thiazolcs involving reaction of lactam acetals 2 or lactim ethers 3 with acidic S-methylisothioureas"'.

The latter reacted as 1,4-binucleophilic rc-s1 (R' = CH3CH2NH, R2 = CI-N2 114.0(5), Sl-Ci-C5 122.3(5), S l -C 4 -~3 113.8(5)