Ring-chain-transfer reactions. Part VII. Application of the ring-chain-transfer concept to the synthesis of 4-(.omega.-aminoalkyl)imidazole analogs of histamine

Thioamides as Useful Synthons in the Synthesis of Heterocycles

“…The ring−chain reactions of thioacylamidines with binucleophilic compounds result in the formation of ω-aminoalkyl derivatives of heterocyclic compounds, including analogues of histamine. The S -alkylated thioacylamidines 380 react with 1,2-binucleophiles as the C−N−C synthons to afford the ω-aminoalkyl derivatives of 1,2,4-triazole 383 (Y = NR), 1,2,4-oxadiazole 383 (Y = O), and imidazole 384 (Scheme ). − According to the postulated mechanism, the reactions proceed via the spiroheterocyclic intermediate 382 . This ring−chain transformation sequence is known as the ANSARO ring transformation (addition of nucleophile, spiro annulation, ring opening).…”

Synthesis of 5-Amino-4-(2-azacycloalkylidene)-2-phenyl-2,4-dihydro-3H-pyrazol-3-ones

“…1 One of the synthetic routes to 1 involves the reaction between lactim ethers 2 or lactam acetals 3 and 1,3-dinucleophiles, with the latter mostly exemplified by 1,3-SCN (thioamides) and 1,3-NCN (a-aminoazaheterocycles) compounds. The resultant substituted amidines 1 (X = N, Y = S, NR) have been widely used to prepare w-aminoalkyl-functionalized thiazoles, 2 imidazoles, 3 isoxazoles, 4 1,2,4-triazoles, 5 1,2,4-thiadiazoles, 6 and bicyclic heterocycles. 7…”

Bicyclic AminoalkylN-Heterocycles by Ring-Chain-Transformationof Bridged­ 1,3-Dicarbonyl Heteroanalogues with Aminopyrazolesand Aminotriazole­

“…by reactions where the ring motif in the starting material becomes a side chain in the product and vice versa. Aminoalkyl heterocycles, such as histamine, antitussive aminoalkyloxadiazoles or aminoalkylimidazoles and blood pressure reducing aminoalkylindoles, [2][3][4][5] have attracted interest as biologically active compounds. Recently, bicyclic aminoalkyl heteroaromatics have gained interest as promising compounds in the treatment of cancer by stabilizing the active conformation of the protein P 53 6 and as potent inhibitors of Lck, a src family of tyrosine kinase, which are interesting for treatment of autoimmune and inflammatory diseases.…”