Synthesis 2002(16): 2399-2403
DOI: 10.1055/s-2002-35219
PAPER
© Georg Thieme Verlag Stuttgart · New York

Novel Synthesis of 3,4,4-Trisubstituted Thiadiazolines from 3,4-Diphenyl-1,2,5-Thiadiazole 1,1-Dioxide. Competition with the Intra-Molecular Aryl-Aryl Cyclization of 3,4-Diphenyl-1,2,5-Thiadiazole 1,1-Dioxide

María F. Rozasa, Oscar E. Pirob, Eduardo. E. Castellanoc, María V. Miríficoa,d, Enrique J. Vasini*a
a Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Departamento de Química, Universidad Nacional de La Plata, C.C. 16, Suc. 4, (1900) La Plata, Argentina
Fax: +54(221)4254642; e-Mail: vasini@inifta.unlp.edu.ar;
b Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata and IFLP (CONICET), C. C. 67, 1900 La Plata, Argentina
c Instituto Física de São Carlos, Universidade de São Paulo, C.P. 369, 13560 São Carlos (SP), Brazil
d Departamento de Ingeniería Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata , La Plata, Argentina
Further Information

Publication History

Received 19 March 2002
Publication Date:
04 November 2002 (online)

Abstract

3,4-Diphenyl-1,2,5-thiadiazole 1,1-dioxide (1) reacted, in the presence of anhydrous aluminum trichloride, with aromatic nucleophiles possessing electron donor substituent groups to give novel (2a-e, Figure [1] ) 3,4,4-trisubstituted 1,2,5-thiadiazoline 1,1-dioxides in good yield. In the presence of aluminum trichloride, but without the addition of nucleophiles, a slower, but practically quantitative intramolecular cyclization reaction (Scholl reaction [1] ) of 1 to phenanthro[9,10-c]-1,2,5-thiadiazole 1,1-dioxide (3), took place. Both reactions occur through the intermediation of a strong electrophile formed by 1 and aluminum trichloride. Spectral data and structure (through single-crystal X-ray diffraction, with the exception of 2c) were measured for all new compounds.