CS261665B1 - Photochromic l-Sub-4,4-diphenyl-2, B-bis (subst. Phenyl) -1,4-dihydropyridines and their production methods - Google Patents

Abstract

Photochromic 1-Sub-4,4-diphenyl-2,6-bis- (Substituent phenyl, 1,4-dihydropyridines of Formula I wherein X is hydrogen, alkyl having 1 to 2 or halogen and R is Methyl, phenyl or benzyl, having photochromic properties, are prepared by substituting ammonium for the 1,3,3,5-tetraaryl-1,5-pentanedione (II) wherein X is as defined above. the tartrate of formula (III) wherein R is as defined above in an organic solvent.

Description

The present invention relates to ¹¹ -substituted-4,4-diphenyl-21-. -bis {subst. phenyl) -1,4-dihydropyridides of formula (I), wherein X is. wadífc, aáliíyl · with carbon number of 1-2 or a halogen and R is methyl, phenyl or 4? · sn ^{of the} yl '

To date, a derivative in which X and R are hydrogen atoms has been prepared by the cyclocondensation reaction of 1,3,3,5-tetrafenyl-1,5-pentanedione with ammonium acetate in acetic acid.

The newly prepared 1,4-dihydropyridines of formula (I) in crystalline state exhibit a crystalline state. Significant photochromy after exposure to sunlight. Said 1,4-dihydropyridines are potential components of light-sensitive layers useful in microelectronics, photomaterials and the like.

The process for the preparation of 1,4-dihydropyridines of the formula I according to the invention is characterized in that the 1,3,3,5-tetraaryl-1,5-pentanediones of the formula II in which X is as defined above are treated with substituted ammonium acetates of formula III, wherein R is as defined above, in acetic acid.

Their photochromic properties are shown in the following examples.

EXAMPLE

Process for producing 1,4-dihydropyridine I (X = H, R — CH ₃ )

A solution of 2.0 g (5 mmol) of 1,3,3,5-tetrafenyl-1,5-pentanedione and 2.7 g (30 mmol of methylammonium acetate) in 25 ml of glacial acetic acid was heated under reflux for two hours. 1.4 g of a crystalline product was obtained, which was a 74% yield, and recrystallized from acetone to give a melting point of 182-184 ° C.

Example 2

Process for preparing 1,4-dihydropyridine I (X = H, R-phenyl)

A solution of 2.0 g (5 mmol) of 1,3,3,5-tetrafenyl-1,5-pentanedione and 4.6 g (30 mmol) of phenylammonium acetate in 25 ml of acetic acid was refluxed for 13 hours. Since upon cooling the solid did not crystallize, 20 ml of water was added to the reaction mixture and the mixture was extracted with 3 x 20 ml of benzene. The combined organics were dried over calcium chloride and the solvent was evaporated to give a mixture separated by silica gel column chromatography (eluent tetrachloromethane and 10% chloroform in carbon tetrachloride). The product fraction, 0.76 g (33% yield) was obtained first and had a melting point of 168-170 ° C after recrystallization from acetone. From the other factions! the starting materials obtained.

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Process for the preparation of 1,4-dihydropyridine I (X-H, R = benzyl)

A solution of 2.0 g (5 mmol) of 1,3,3,5-tetrafenyl-1,5-pentanedione and 5.0 g (30 mmol) of benzylammonium acetate in 25 ml of acetic acid] was refluxed for 13 hours. Further work-up of the reaction mixture is analogous to Example 2. Chromatography on silica gel eluting with carbon tetrachloride gave 1.6 g of product (66% yield) which, after recrystallization from acetone, had a melting point of 176-178 ° C.

Example 4

Process for producing 1,4-dihydropyridine I (X = CH; ,, R = CH ₃ )

A solution of 1,5-bis (p-tolyl) -3,3-diphenyl-1,5-pentanedione (2.16 g, 5 mmol) and methylammonium acetate (4.55 g, 50 mmol) in glacial acetic acid (25 ml) was refluxed. hours. Further work-up of the reaction mixture is analogous to Example 2. Chromatography on silica gel eluting with carbon tetrachloride gave 1.0 g of product (37% yield) which, after recrystallization from acetone, melted at 212-214 ° C.

Example 5

Process for preparing 1,4-dihydropyridine I (X-Br, R = CH ₃ )

A solution of 2.81 g (5 mmol) of 1,5-bis (p-bromophenyl) -3,3-diphenyl-1,5-pentanedione and 4.55 g (50 mmol) of methylammonium acetate in 25 ml of glacial acetic acid] was refluxed. 17 hours. Further work-up of the reaction mixture is similar to that of Example 2. Chromatography on silica gel eluting with carbon tetrachloride gave 1.41 g (66% yield) which, after recrystallization from acetone, had a melting point of 218-219 ° C.

Analogously, 2,6-bis (p-fluorophenyl) -4,4-diphenyl-1,4-dlhydropyridine (X-F, R = H) was prepared in 70% yield, mp 192-196 ° C.

Photochromic properties of substances

The light-induced color change for compounds I was observed in the solid state. When irradiating crystalline samples of substances I with sunlight, the required exposure time varies from a few minutes to several hours. By keeping the colored crystals in the dark, color is lost in a few hours. A similar effect can also be achieved with dissolution or heating. For substance I (X = R = H), photochromizus in solvent solutions such as e.g. tetra251665

In the absence of the general formula (I), liydrofuran, dioxane and acetone give the following oxygen content. Examples of photochromism in la- table:

Pr. Substance I color of the substance before irradiation color of the substance after irradiation

Χ — Ή R — phenyl

X = H R = benzyl

X = CH ₃ HR

X = CH ₃ R = CH ₃

X = Br R = CH ₃ colorless colorless colorless colorless violet violet violet blue-green violet

Claims (4)

1. Photochromic 1-substituted-4,4-diphenyl-2,6-bls (substr. Phenyl) -1,4-dihydropyridines of the general formula I, in which X is hydrogen, alkyl having 1 to 2 carbons or halogen and R is is methyl, phenyl or benzyl. 2. A process for the preparation of 1-Substituted-4,4-diphenyl-2,6-bisphosphate. phenyl) -1,4-dihydropyridines of formula (I) according to claim 1, characterized in that the 1,3,3,5-tetraaryl-1,5-pentanedione of formula (II), wherein X is as defined above, is treated with a substituted ammonium monovalent acetate of formula III, wherein R is as defined above, in an organic solvent. 3. A process according to claim 2, wherein the solvent is an organic acid and the reaction is carried out at a reflux temperature of the solvent for 2 to 20 hours. 4. A process as claimed in claim 2, wherein the ammonium salts are used in a 4- to 15-fold molar excess to the pentenedione of formula II.