Evaluation of alizarin and purpurin dyes for their ability to visualize latent fingermark on porous surfaces.

Anthraquinones are a group of dye with many members and a wide range of industrial uses ranging from food, textiles to printing. Even though the reactions of anthraquinone dyes with amino acids are known, they have not yet been subjected to an examination regarding their ability in fingermark detection. In the presented study, the potential of alizarine and purpurin, natural anthraquinone dyes, as a fingermark reagent was examined in comparison with ninhydrin and lawsone. Alizarin and purpurin react with latent fingermark residue on copier paper and thermal paper to yield yellow-orange coloured impressions. The products formed also display photoluminescence properties when illuminated at 440 nm viewed through red filter. Both natural anthraquinone dyes exhibited some superior properties at the development of latent fingermarks on these surfaces compared to ninhydrin and lawsone.

Novel O-propyl, S-propyl, and N-propyl substituted 1,4-naphthoquinones and 1,4-anthraquinones as potential fingermark development reagents for porous surfaces.

Lawsone is a 2-substituted-1,4-naphthoquinone derivative, which has been proposed as an alternative to the reagents currently used for fingermark detection on porous surfaces. 2-substituted-anthraquinones, which contain an additional conjugated benzene ring, have a similar chemical structure to that of lawsone. In this study, a new series of 2-substituted-1,4-naphthoquinones and 2-substituted-1,4-anthraquinones were synthesized and completely characterized by1 H NMR,13 C NMR, IR, and HPLC-TOF/MS analyses. All newly synthesized 2-substituted-1,4-quinones were investigated for their ability to develop latent fingermarks on porous surfaces, and this ability was compared with that of lawsone. Each fingermark developed was graded using an established method; thus, quantitative data were attributed to each fingermark. It has been demonstrated that the 1,4-quinones react with amino acids present in latent fingermarks on selected paper surfaces to produce faint yellow-orange impressions, which exhibit strong photoluminescence when illuminated with a forensic light source at 440 nm and observed through a red filter. None of the compounds caused background darkening. The results obtained were generally similar to those of lawsone, however, 8-dibromo-2-(propylamino)naphthalene-1,4-dione and 5,8-dibromo-2-(propylthio)naphthalene-1,4-dione yielded better results for copier paper and colored (blue) copier paper used in this analysis. To the best of our knowledge, this is the first study to examine the role of 1,4-anthraquinone derivatives as potential fingermark development reagents. The results indicate that 1,4-quinones have a potential to be used as reagents for enhancement of latent fingermarks.

Functionalization of anthracene: A selective route to brominated 1,4-anthraquinones.

Efficient and stereoselective syntheses are described for the preparation of 2,3,9,10-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydroanthracenes 7, 8 and the corresponding 1,4-diol 17 by silver ion-assisted solvolysis of hexabromotetrahydroanthracene 6. Base-promoted aromatization of 7 and 8 afforded synthetically valuable tribromo-1-methoxyanthracenes 10 and 11. The reaction of 17 with sodium methoxide generated tribromodihydroanthracene-1,4-diol 27, whose oxidation with PCC gave 2,9,10-tribromoanthracene-1,4-dione (28). Therefore a selective and efficient method was developed for the preparation of compound 28 starting from 9,10-dibromoanthracene (1), in a simple four-step process. Compounds 10 and 11, and diol 27 constitute key precursors for the preparation of functionalized substituted anthracene derivatives that are difficult to prepare by other routes. The studies also reveal the broad range of reactivity and selectivity of the stereoisomeric anthracene derivatives.