Synthesis of Different Classes of Five / Five Membered Heterocyclic Cyanine Dyes: A Review Paper

The paper reviews synthesis of different classes of biheterocyclic five/five membered heterocyclic cyanine dyes. In this review paper detailed synthesis steps for some of the biheterocyclic five/five membered cyanine dyes were represented by equations. The synthesis covers, monomethine cyanine dyes (simple cyanine dyes), aza-monomethine cyanine dyes, dimethine cyanine dyes, trimethine cyanine dyes (carbocyanine dyes), aza-trimethine cyanine dyes, tetramethine cyanine dyes, heptamethine cyanine dyes (tricarbocyanine dyes), styryl cyanine dyes (hemi cyanine dyes), aza-styryl cyanine dyes (aza-hemi cyanine dyes) and apocyanine dyes. In addition, in the introduction section we shed some light on the use and applications of cyanine dyes. Keywords: Cyanine dyes, synthesis, five/five membered cyanine dyes, application of cyanine dyes, uses of cyanine dyes, ESA, Pyridine, Cyanomethylene, Diphenylformamidine, triethoxymethane