N,N,N-trimethyloctadecan-1-aminium chloride was used to prepare 6-dodecylnaphthen-2-ol. And three novel 3H-naphtho［2,1-b］pyrans with long chain substituents were synthesized by the condensation of 6-n-dodecylnaphthen-2-ol with prop-2-yn-1-ols, which are 8-dodecyl-3,3′-diphenyl-3H-naphtho［2,1-b］pyran(NP1), 8-dodecyl-3,3′-bis (p-methoxyphenyl) -3H-naphtho［2,1-b］pyran(NP2) and 8-dodecyl-3,3′-bis(p-n-butoxyphenyl) -3H- naphtho［2,1-b］ pyran (NP3), respectively. The incorporation of long alkyl groups into the rigid naphthopyran results in the liquid crystalline property. The liquid crystal phases of the three compounds were studied by means of differential scanning calorimetry (DSC) and Polarizing optical microscope (POM) with a heating stage. And the photochromis properties, doped in PMMA and dissolved in toluene, were investigated, too.
