Formamidine derivatives could be used as the building blocks for substituted heterocyclic compounds with various biological activities. N′-Aryl-N,N-dimethylformamidinium chlorides have been synthesized in high yields by reaction of aromatic primary amines with Vilsmeier–Haack reagent at room temperature. The structures of all the new compounds were identified by ESI-MS, IR and NMR spectra. The steric structures of some of these compounds were clarified by X-ray single crystal analysis.

Synthesis and photophysical properties of different generations of poly(ester−amine) dendrimers with focal 4-amino-N-benzylphthalimide (4-ANBP) as the core were studied. The λmax abs of dendronized 4-ANBP was nonsensitive to the solvents used and located at 334 nm, while that of bare 4-ANBP was very sensitive. The fluorescence behaviors of dendronized 4-ANBPs showed much dependence on the generation of the dendrimers used and the media. As compared with bare 4-ANBP, the fluorescence intensity of 3 (G1.0), 5 (G2.0), 7 (G3.0), and 9 (G4.0) in methanol was reduced to 6.2-, 26-, 50-, and 56.5-fold, respectively, and had a 83 nm blue shift. The corresponding fluorescence quantum yields were also measured (4-ANBP-0.12, 3-0.017, 5-0.0042, 7-0.0028, 9-0.0016). Addition of sulfuric acid to the methanol solution of 9 (3.27 × 10−5 M/L), resulted in a strong fluorescence, and the fluorescence intensity was amplified 181 times. Acid titration experiments showed that all of the tertiary amines in 3, 5, and 7 were protonated, but only 12 in 15 of the tertiary amines in G4.0δ9 were protonated. Repeated acid−base titrations caused the fluorescence to switch on and off. After many cycles of acid−base titration, slight changes in fluorescence intensity were observed.

The fragmentation patterns of a novel kind of dithiocarbamic acid esters with excellent anticancer activity were analyzed by positive ion electrospray ionization mass spectrometry in conjunction with tandem mass spectrometry (ESI/MSn). The fragmentation patterns of sodium adduct ions [M + Na]+ were characterized with elimination of hydrogen cyanide and most of their counterparts could be observed. The fragmentation patterns of protonated molecular ions [M + H]+ were characterized with single bond cleavage between thiocarbonyl group and nitrogen atom, and between thiocarbonyl group and sulfur atom. The piperazine moiety of the molecular of [M + H]+ favors a rearrangement to expel azirane, and the suggested rearrangement mechanism is consistent with experimental observations.