2-(2,5-Dioxopyrrolidin-1-yl)-1,1,3,3-tetramethylisouronium tetrafluoroborate → Theophylline

Participants

Reaction Steps

The dye I (1,1'-(4-sulfobutyl)-3,3,3',3'-tetramethyl-6-carboxymethylindotricarbocyanine) was synthesized according to P. L. Southwick et al., Cytometry, 11 (1990) 418, dye XVIII. This dye is a water-soluble and reactive derivative of the dye HITC used in the previous examples. The absorption maximum in water was at 746 nm. The dye I was activated with TSTU (O-(N-succinimidyl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, Fluka, Switzerland) and dissolved in borate buffer (pH 8.5, 0.1M borate) containing aminotheophylline (8-(3-aminopropyl)theophylline). The reaction yielded a clear solution. Thin layer chromatography confirmed that the aminotheophylline was completely used up. The absorption spectrum of the reaction mixture was similar to that of pure dye I. In subsequent experiments, the reaction mixture was used without further purification.

Provenance & Evidence