Synthesis of Novel 3‐Aryl‐5‐dichloromethyl‐Δ²‐1,2,4‐oxadiazolines

Abstract

The first synthetic approach to hitherto unknown 3‐aryl‐5‐dichloromethyl‐Δ2‐1,2,4‐oxadiazolines, of synthetic and biological interest, has been developed involving high‐yield reactions between N‐(2,2‐dichlorovinyl)benzimidoyl chlorides and hydroxylamine. The molecular structure of one member of this new family of compounds—5‐dichloromethyl‐3‐(4‐fluorophenyl)‐1,2,4‐oxadiazoline—has been determined by X‐ray crystallography. Density functional theory calculations supporting the proposed reaction pathway for the formation of these products have been carried out.

A novel synthetic approach to Pyrazolooxazines. One‐pot synthesis of Pyrazolo[5,1‐c][1,4]oxazine derivatives from 2,2‐dichlorovinylacetophenones

“…For some years we have been working in developing new synthetic approaches to six‐ and five‐membered heterocyclic compounds starting from chloral derivatives. For example, imidazo‐pyrazolones [22], oxadiazolines [23], triazoles [24], pyrimidines [25], isoxazolines [26], pyrazolines [27], thiazolines [28], oxazolines [29], etc. In connection with this line of research we report here a new, general and efficient method for preparing still almost unknown pyrazolooxazines based on 2,2‐dichlorovinylacetophenones, which are readily available chloral derivatives [30] capable to react efficiently with commercial 2‐hydroxyethylhydrazine.…”

“…4.10-4.14 (m, 2H), 4.23-4.26 (m, 2H), 4.86 (s, 2H), 6.11 (s, 1H), 7.01-7.05 (m, 2H), 7.40 (d, 1H, J = 3.9 2 ), 100.62 (CH), 126.44 (CH), 129.14 (CH), 130.16 (C), 131.39 (CH), 135.63 (C), 136.31 (C), 137.31 (C), 151.35 (C=N); MS (EI) m/z (%): 228 (M + , 100), 197(11), 171(19), 170(13), 145(23), 130(12), 115(8), 98 (4), 77 (6); Anal.…”