218432-75-8

Upstream product

• 90-15-3 α-naphthol 
• 101597-25-5 1,1-bis(4-methoxyphenyl)-2-propyn-1-ol 
• 218432-78-1 2,3-dihydro-2,2-bis(4-methoxyphenyl)naphtho<1,2-b>pyran-4-one 
• 90-96-0 bis(p-methoxyphenyl)methanone 
• 218432-79-2 3,4-dihydro-2,2-bis(4-methoxyphenyl)-2H-naphtho<1,2-b>pyran-4-ol acetate 
• 711-79-5 1-hydroxy-2-acetonaphthone 

Downstream Products

• 218432-77-0 3,4-dihydro-2,2-diphenyl-4-<2,2-bis(4-methoxyphenyl)vinyl>-2H-naphtho<1,2-b>pyran 
• 858-60-6 3,4-dihydro-2,2-diphenyl-2H-naphtho<1,2-b>pyran-4-one 

Relevant academic research and scientific papers

Observations on the synthesis of photochromic naphthopyrans

1-Naphthol reacts with 1,1-diarylprop-2-yn-1-ols 5a,b, under alumina catalysis, by two pathways to give the photochromic naphtho[1,2-b]pyrans 6a,b, together with the propenylidenenaphthalenones 7a,b, representatives of a new class of merocyanine dyes. With 2-methyl-1-naphthol, formation of the photochrome is suppressed; the only products are merocyanines 7c,d. The cyclocondensation of 2-naphthol with 5a,b proceeds much more efficiently, to give the naphtho[2,1-b]pyrans 14a,b. Pyran formation is not suppressed from either 1-bromo- or 1-(4 -methoxyphenyl)-2-naphthol; reaction with 5a,b merely results in expulsion of the C-1 substituent. An alternative pathway supervenes in the reaction of 1-methyl-2-naphthol with 5a to give the benz[e]indanone 17, the constitution of which was determined by X-ray crystallography. Reaction of the 1,3,3-triarylpropynols 19a,b with 1-naphthol affords the naphthopyrans 20 together with merocyanines 21, whilst the isomeric pyrans 23 are efficiently produced from 2-naphthol. The configuration of merocyanines 7a and 21a was unequivocally established by X-ray crystallography. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Reactions between some 6-Halogeno-2,2-dimethyl-, 2,2,6-Trimethyl- and 2,2-Diaryl-2H-naphthopyrans and 1,1-Diphenylethene

6-Halogeno-2,2-dimethyl- and 2,2,6-trimethyl-2H-naphthopyrans reacted with 1,1-diphenylethene in acidic solution to give 6-halogeno-3,4-dihydro-2,2-dimethyl- and 3,4-dihydro-2,2,6-trimethyl-4-(2,2-diphenylvinyl)-2H-naphthopyrans, respectively, along with their corresponding dimers. However, the reaction between 2,2-diaryl-2H-naphthopyrans and 1,1-diphenylethene, under identical conditions, yielded 4-(2,2-diarylvinyl)-3,4-dihydro-2,2-diphenyl-2H-napthopyrans, by a different mechanism involving ring opening of the pyran ring.