Notiz zur Struktur des Umsetzungsproduktes von 4-Isothiocyanato-4-methyl-2-pentanon mit Hydrazin ?�ber das 2,4,5,6-Tetrahydro-5,5,7-trimethyl-3H-1,2,4-triazepin-3-thion

Novel 14-Membered Hexaaza Macrocycles

“…The DFT calculations at the B3LYP/6-31+G(d,p) level also showed that the (E)-isomer of 14a was more stable (1.91 kcal/mol in DMSO) than the (Z)-isomer. Since the 1 H and 13 C NMR spectra of the major isomers of 14a and 14b were similar, we concluded that the major isomer of 14b also had the (E)-configuration. Since macrocycle 19a has two distant chiral centers, we expected it to form as a mixture of two diastereomers in approximately equal amounts.…”

A General Stereoselective Approach to 1,2,4-Triazepane-3-thiones/ones via Reduction or Reductive Alkylation of 2,4,5,6-Tetrahydro-3H-1,2,4-triazepine-3-thiones/ones

“…The reported syntheses of 1,2,4-triazepin-3-ones/thiones include the reaction of β-isocyanato and β-isothiocyanato ketones with hydrazines [16][17][18][19][20][21][22][23][24], condensation of semicarbazides and thiosemicarbazides with various 1,3-dicarbonyl compounds or their derivatives [10,[25][26][27][28][29][30][31][32][33], reaction of arylidene ketones with N2H4•2HNCS [34], addition of semicarbazides and thiosemicarbazides to α,β-unsaturated carbonyl compounds or their synthetic equivalents [35][36][37][38][39], reaction of γ-hydrazinosubstituted amines with phosgene equivalents [8,[13][14][15]40], and intramolecular cyclization of 4-(γ-oxoalkyl)semicarbazides and 4-(γ-oxoalkyl)thiosemicarbazides or their derivatives [17,22,41,42]. Generally, these methods give access to 1,2,4-triazepin-2-ones/thiones with one or two double bonds in the 7-membered ring.…”

A novel selective synthesis of β-isothiocyanato ketones

“…Since the first representatives of 1 have been described in 1946 [1], their chemistry was extensively studied [2,3]. They were used in preparation of various pyrimidines [4][5][6], 1,3-thiazines [7,8], 1,3-oxazines [9], pyridines [10], nucleosides [11,12], pyrroles [13], 1,2,4-triazepines [14], condensed heterocycles [15][16][17], etc.…”