Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
2001-02-09
2004-05-04
Raymond, Richard L. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C544S216000, C544S217000
Reexamination Certificate
active
06730785
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a novel, highly efficient and general process for making 2-(2-oxyaryl)-4,6-bisaryl-1,3,5-triazines class of trisaryl-1,3,5-triazine UV absorbers and their precursors, 2-halo-4,6-bisaryl-1,3,5-triazines, from cyanuric halide. More specifically, the invention relates to a novel process for the synthesis of triazine compounds in the presence of a reaction facilitator comprising at least one Lewis acid and at least one reaction promoter. The process includes the reaction of a cyanuric halide with substituted or unsubstituted aromatic compounds to produce 2-halo-4,6-bisaryl-1,3,5-triazine compounds. This process produces halo-bisaryl-1,3,5-triazine compounds in higher yields than are possible using present methods. The triazine compounds that are produced are precursors of triazine UV absorbers which are used to stabilize organic materials against damage by light, heat, oxygen, or other environmental forces. The process of producing such UV absorbers can be carried out step-wise or continuously in an one-pot reaction process.
BACKGROUND OF THE INVENTION
Triazine UV absorbers are an important class of organic compounds which have a wide variety of applications. One of the most important areas of applications is to protect and stabilize organic materials such as plastics, polymers, coating materials, and photographic recording material against damage by light, heat, oxygen, or environmental forces. Other areas of applications include cosmetics, fibers, dyes, etc.
Triazine derived UV absorbers are a class of compounds that typically include at least one 2-oxyaryl substituent on the 1,3,5-triazine ring. Triazine based UV absorber compounds having aromatic substituents at the 2-, 4-, and 6-positions of the 1,3,5-triazine ring and having at least one of the aromatic rings substituted at the ortho position with a hydroxyl group or blocked hydroxyl group are generally preferred compounds.
In general this class of triazine UV absorber compounds is well known in the art. Disclosures of a number of such trisaryl-1,3,5-triazines can be found in the following U.S. patents, all of which are incorporated by reference as fully set forth herein: U.S. Pat. Nos. 3,118,887; 3,242,175; 3,244,708; 3,249,608; 3,268,474; 3,423,360; 3,444,164; 3,843,371; 4,619,956; 4,740,542; 4,775,707; 4,826,978; 4,831,068; 4,962,142; 5,030,731; 5,059,647; 5,071,981; 5,084,570; 5,106,891; 5,185,445; 5,189,084; 5,198,498; 5,288,778; 5,298,067; 5,300,414; 5,323,868; 5,354,794; 5,364,749; 5,369,140; 5,410,048; 5,412,008; 5,420,008; 5,420,204; 5,461,151; 5,476,937; 5,478,935; 5,489,503; 5,543,518; 5,538,840; 5,545,836; 5,563,224; 5,575,958; 5,591,850; 5,597,854; 5,612,084; 5,637,706; 5,648,488; 5,672,704; 5,675,004; 5,681,955; 5,686,233; 5,705,643; 5,726,309; 5,726,310; 5,741,905; and 5,760,111.
A preferred class of trisaryltriazine UV absorbers (UVAs) are based on 2-(2,4-dihydroxyaryl)-4,6-bisaryl-1,3,5-triazines, i.e., compounds with two non-phenolic aromatic groups and one phenolic aromatic group advantageously derived from resorcinol. The 4-hydroxyl group of the parent compounds, 2-(2,4-dihydroxyaryl)-4,6-bisaryl-1,3,5-triazines, are generally functionalized to make 2-(2-hydroxy-4-alkoxyaryl)-4,6-bisaryl-1,3,5-triazine compounds for end use.
A number of commercial products exist in which the para-hydroxyl group of the phenolic ring is functionalized and the non-phenolic aromatic rings are either unsubstituted phenyl (e.g., Tinuvin® 1577) or m-xylyl (e.g. Cyasorb® UV-1164, Cyasorb® UV-1164L, Tinuvin® 400, and CGL-1545). These UV absorbers are preferred because they exhibit high inherent light stability and permanence compared to other classes of UV absorbers such as benzotriazole and benzophenone compounds.
There are several processes known in the literature for the preparation of triazine based UV absorbers. (See, H. Brunetti and C. E. Luethi,
Helvetica Chimica Acta
, 1972, 55, 1566-1595, S. Tanimoto et al.,
Senryo to Yakahin
, 1995, 40(120), 325-339).
A majority of the approaches consist of three stages. The first stage, the synthesis of the key intermediate, 2-chloro-4,6-bisaryl-1,3,5-triazine, from commercially available materials can involve single or multi-step processes. Thereafter in the second stage, 2-chloro-4,6-bisaryl-1,3,5-triazine is subsequently arylated with 1,3-dihydroxybenzene (resorcinol) or a substituted 1,3-dihydroxybenzene in the presence of a Lewis acid to form the parent compound 2-(2,4-dihydroxyaryl)-4,6-bisaryl-1,3,5-triazine. The parent compound 2-(2,4-dihydroxyaryl)-4,6-bisaryl-1,3,5-triazine, as mentioned above, may be further functionalized, e.g., alkylated, to make a final product 2-(2-hydroxy-4-alkoxyaryl)-4,6-bisaryl-1,3,5-triazine.
There have been several approaches reported in the literature on the synthesis of the key intermediate 2-chloro-4,6-bisaryl-1,3,5-triazine. Many of these approaches utilize cyanuric chloride, a readily available and inexpensive starting material. For example, cyanuric chloride is allowed to react with aromatics (ArH, such as m-xylene) in the presence of aluminum chloride (Friedel-Crafts reaction) to form 2-chloro-4,6-bisaryl-1,3,5-triazine, which is allowed to react in a subsequent step with resorcinol to form 2-(2,4-dihydroxyphenyl)-4,6-bisaryl-1,3,5-triazine (See, U.S. Pat. No. 3,244,708). There are several limitations to this process, viz., the reaction of cyanuric chloride with aromatics is not selective and leads to a mixture of mono-, bis-, and tris-arylated products including unreacted cyanuric chloride (See, Scheme 1). The desired product, 2-chloro-4,6-bisaryl-1,3,5-triazine, must be isolated by crystallization or other purification methods before further reaction.
Another major drawback of the above mentioned process is that the reaction of cyanuric chloride with aromatics is not generally applicable to all aromatics. It is well known in the literature that the process provides a useful yield of the desired intermediate, 2-chloro-4,6-bisaryl-1,3,5-triazine, only when m-xylene is the aromatic reagent (GB 884802). With other aromatics, an inseparable mixture of mono-, bis-, and trisaryl products are formed with no selectivity for the desired 2-chloro-4,6-bisaryl-1,3,5-triazine (See, H. Brunetti and C. E. Luethi,
Helvetica Chimica Acta
, 1972, 55, 1575; and S. Tanimoto and M. Yamagata,
Senryo to Takahin
, 1995, 40(12), 325-339). U.S. Pat. No. 5,726,310 describes the synthesis of m-xylene based products. 2-chloro-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine is first synthesized and without isolation allowed to react with resorcinol in a one-pot, two-step process to produce 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, which is subsequently purified by crystallization. A one pot process for preparing asymmetric tris-aryl-1,3,5-triazines from cyanuric chloride as well as from mono-aryl-dichloro triazines was earlier described in U.S. Pat. No. 3,268,474.
Several approaches were developed in an attempt to solve the above mentioned problems related to the formation of the key intermediate 2-chloro-4,6-bisaryl-1,3,5-triazine from cyanuric chloride. For example, cyanuric chloride is allowed to react with an aryl magnesium halide (Grignard reagent), to prepare 2-chloro-4,6-bisaryl-1,3,5-triazine (See, Ostrogovich, Chemiker-Zeitung, 1912, 78, 738; Von R. Hirt, H. Nidecker and R. Berchtold,
Helvetica Chimica Acta
, 1950, 33, 365; U.S. Pat. No. 4,092,466). This intermediate after isolation can be subsequently reacted in the second step with resorcinol to make a 2-(2,4-dihydroxyphenyl)-4,6-bisaryl-1,3,5-triazine (See, Scheme 2). This approach does not selectively synthesize 2-chloro-4,6-bisaryl-1,3,5-triazine; the mono- and tris-arylated products are formed in significant amounts (See, H. Brunetti and C. E. Luethi,
Helvetica Chimica Acta
, 1972, 55, 1575). Modifications with better results have been reported (See, U.S. Pat. No. 5,438,138). Additionally, the modified process is not suitable for industrial scale production and is not economically attractive.
Alternate approaches were developed
Cappadona Russell C.
Gupta Ram B.
Jakiela Dennis J.
Pai Venkatrao K.
Venimadhavan Sampath
Balasubramanian Venkataraman
Cytec Technology Corp.
Jubinsky James A.
Raymond Richard L.
Schultz Claire M.
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