Synthesis 2009(15): 2539-2546  
DOI: 10.1055/s-0029-1216879
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

1,2,3-Thiadiazoles with Unsaturated Side Chains; Synthesis, Polymerization, and Photocrosslinking

Mousa Al-Smadi*a,b, Norbert Hanoldb, Helga Kalbitzb, Herbert Meier*b
a Department of Applied Chemical Sciences, Jordan University of Science and Technology, Irbid, Jordan
e-Mail: mariam10@just.edu.jo;
b Institute of Organic Chemistry, University of Mainz, Duesbergweg 10-14, 55099 Mainz, Germany
Fax: +49(6131)3925396; e-Mail: hmeier@mail.uni-mainz.de;
Further Information

Publication History

Received 23 February 2009
Publication Date:
26 June 2009 (online)

Abstract

1,2,3-Thiadiazoles with polymerizable functionalities in the 4-position were synthesized as potential negative photoresists. The polymerization to soluble, film-forming materials must leave the heterocyclic rings intact, because they are needed for photocrosslinking reactions to give insoluble materials. 1,2,3-Thiadiazoles 1 cycloeliminate N2 on irradiation. The resulting 1,3-diradicals 2 have various options for stabilization processes leading to alkynes 3 or to higher heterocycles 5-12. The generation of atomic sulfur and its involvement in these subsequent reactions must be avoided. Therefore, systems like model compound 1a, in which the 1,3-diradicals form 2-methylene-1,3-dithioles (dithiafulvenes) 9 were selected here. Optimization gave ultimately two materials for application as photoresists. Monomer 1c could be polymerized in the presence of boron trifluoride to soluble 1c′, which on irradiation formed 1c′′ as a cross-linked insoluble polymer. Furthermore, thiadiazole 1f was attached to polystyrene 26. The resulting soluble polymer 1i′ yielded the insoluble material 1i′′ on irradiation.

28

For the polymerization of related phenylglycidyl ethers see refs. 29 and 30.

31

The ¹³C NMR signals of 9a published in ref. 32 cannot be correct, because they contain too many CH and too few Cq signals.