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1.2.4- Triazines, condensed

Preparation of the anticonvulsant agent lamotigrine (91-3) illustrates an alternate approach to 1,2,4-triazines. Condensation of acyl cyanide (91-1) with dicyanamide gives imine (91-2) as the initial product. Treatment of that intermediate with a base leads to the addition of the guanidino anion to the nitrile and thus the formation of the triazine ring [92]. [Pg.378]

In contrast to the 1,2,3-triazines, the monocyclic 1,2,4-triazines are well known, but there is less information on 1,2,4-benzotriazines (2). Besides 1,2,4-benzotriazines a large number of 1,2,4-triazines condensed with carbocycles are known, such as cyclobuta-, cyclopenta-, cyclohepta-, cycloocta-, naphtho[l,2-e]- (3), naphtho[2,l-e]- (4) and naphtho[2,3-e]- 1,2,4-triazines (5). [Pg.386]

In addition to 1,2,4-triazines condensed with carbocycles, 1,2,4-triazines condensed with heterocycles can also be used as dienes with inverse electron demand in Diels-Alder reactions. Thus, it has been shown that pyrimido[4,5-e]-1,2,4-triazines react with enamines to yield pyrido[2,3-tflpyrimidines 29 (5-deazapteridines).415... [Pg.654]

In addition to monocyclic 1,2,4-triazines, condensed 1,2,4-triazines, such as pyrimido-[4,5-cJ-l,2,4-triazines,418 benzofuro[3,2-e]-l,2,4-triazines,203 and benzothieno[3,2-e]-l,2,4-tri-azines203 can be used in intramolecular Diels-Alder reactions. [Pg.655]

The second chapter is by E. S. H. E) Ashry, N. Rashed, M. Taha, and E. Ramadan of Alexandria, Egypt. They contribute the first of a two-part essay on fused 1,2,4-triazines. The present chapter deals with triazines fused to heterocycles with three-, four-, and five-membered rings. In a subsequent volume of the series we will cover triazines condensed with six-membered and larger rings. [Pg.380]

Uformite [Rohm Haas]. TM for synthetic resins based on urea-formaldehyde, melamine-formaldehyde, and triazine condensates. Supplied as colorless or light-colored aqueous solutions or solutions in volatile solvents. Solvent type produces hard, alkali-resistant, colorless coatings on curing with adhesion to a variety of surfaces. [Pg.1298]

Of the three possible triazine systems the 1,2,3-triazines is by far the least studied class of compounds. Besides the name 1,2,3-triazine, v-triazine and /i-triazine were used in the older literature. The number of known monocyclic 1,2,3-triazines is still limited. The parent compound 1 was first prepared in 1981.1 In contrast, condensed 1,2,3-triazines, condensed with carbocycles or heterocycles, and especially 1,2,3-benzotriazines, are well-known compounds. The first 1,2,3-benzotriazine was prepared in 1887,2 while the first synthesis of the unsubstituted 1,2,3-benzotriazine (2) was published in 1971.3 More than 50% of almost 3000 publications up to 1992, dealing with different aspects of 1,2.3-triazines and condensed 1,2,3-triazines, discuss chemical, biological and analytical aspects of compound 3 (azinphos methyl, Guthion, Bayer 17147), a widely used plant protection agent.344... [Pg.530]

The usual nucleophilic substitution of substituents directly bound to the heterocyclic ring was observed for monocyclic and condensed 1,2,3-triazines. These reactions may be accompanied by a ring opening of the 1.2,3-triazine ring after the nucleophilic attack at the 4-position. 1,2,3-Benzotriazines and monocyclic 1,2,3-triazines seem to be less stable than 1,2,3-triazines condensed with heterocycles. [Pg.559]

Amino-oxy-triazines condense with aldehydes and ketones, isocyanates, chloroformates, and sulfonyl halides in the normal way <87AKZ749>. [Pg.605]

Melamine - formaldehyde polymers. Melamine (2 4 6-triamino-1 3 5-triazine), obtained by heating dicyandiamide under pressure, condenses with formalin to give melamine - formaldehyde polymers (Beetle - Melamine), which have similar uses, but better stability to heat... [Pg.1017]

Formamidinoyl isothiocyanates (157) combine with 2-aminothiazoles the ring nitrogen attacks the spC part of the electrophilic reagent (312) further reaction then yields aza-condensed thiazolo-s-triazines (158) (Scheme 99) (313). Mesoionic S-alkvlthiazolo[3.2-fl]-i-tria2ine-5,7-diones (159) are obtained when 2-alkylaminothiazoles react with phenoxycar-bonyl isocyanate (304). [Pg.65]

A series of compounded flame retardants, based on finely divided insoluble ammonium polyphosphate together with char-forming nitrogenous resins, has been developed for thermoplastics (52—58). These compounds are particularly useful as iatumescent flame-retardant additives for polyolefins, ethylene—vinyl acetate, and urethane elastomers (qv). The char-forming resin can be, for example, an ethyleneurea—formaldehyde condensation polymer, a hydroxyethylisocyanurate, or a piperazine—triazine resin. [Pg.476]

Many chemical compounds have been described in the Hterature as fluorescent, and since the 1950s intensive research has yielded many fluorescent compounds that provide a suitable whitening effect however, only a small number of these compounds have found practical uses. Collectively these materials are aromatic or heterocycHc compounds many of them contain condensed ring systems. An important feature of these compounds is the presence of an unintermpted chain of conjugated double bonds, the number of which is dependent on substituents as well as the planarity of the fluorescent part of the molecule. Almost all of these compounds ate derivatives of stilbene [588-59-0] or 4,4 -diaminostilbene biphenyl 5-membeted heterocycles such as triazoles, oxazoles, imidazoles, etc or 6-membeted heterocycles, eg, coumarins, naphthaUmide, t-triazine, etc. [Pg.114]

Melamine (I,3,5-triamino-2,4,6-triazine) was first prepared by Liebig in 1835. For a hundred years the material remained no more than a laboratory curiosity until Henkel patented the production of resins by condensation with formaldehyde. Today large quantities of melamine-formaldehyde resins are used in the manufacture of moulding compositions, laminates, adhesives, surface coatings and other applications. Although in many respects superior in properties to the urea-based resins they are also significantly more expensive. [Pg.680]

The reaction of 3-methyl-6-phenyl-l,2,4-tiiazine 4-oxides 117 with nitrobenz-aldehyde leads to the condensation product, 3-(nitrophenylvinyl)-1,2,4-triazine 4-oxides 118. [Pg.289]

The condensation of amidrazone with isonitrosoacetophenone occurs via formation of the hydrazone 136. The elimination of the ammonia molecule from intermediate 136 yields 3-methyl-6-phenyl-l,2,4-triazine 4-oxide 137 (71LA12). [Pg.293]

Reaction of 2,3-dichlorobenzoyl chloride with cyanide ion leads to the corresponding benzoyl cyanide (141). Condensation of that reactive intermediate with aminoguanidine 142 leads to the hydrazone-like product 143. Treatment with base results in addition of one of the guanidine amino groups to the nitrile function and formation of the 1,2,4-triazine ring. The product, lamo-trigine (144), is described as an anticonvulsant agent [31]. [Pg.120]

Triazines can be obtained either by condensation methods using the fluorinated anhydride (89IZV928) or by trimerization of nitriles, e.g., per-... [Pg.17]

Condensed 1,2,4-Triazines I. Fused to Heterocycles with Three-, Four-, and Five-Membered Rings... [Pg.39]

A large number of 1,2,4-triazines that are condensed with one or more heterocycles are well known and a wide variety of synthetic methods for their preparations are available. Compounds containing the 1,2,4-triazine moiety are in use as pharmaceuticals, dyes, pesticides, herbicides, etc., and a great number of reports have been directed to the synthesis of the title heterocycles having potentially useful biological properties. [Pg.41]

Various reviews dealing with the 1,2.4-triazines have been published. The most recent is that published by Neunhoeffer and Wiley (78HC749) covering the literature through 1974. Owing to the increase of the number of publications on the 1,2,4-triazines, a survey of the literature on their condensed ring systems with three- to five-membered heterocycles, from 1974 through 1992, constitutes the subject of this review. [Pg.41]

Furo[3,4-c][l,2,4]triazines 201 were prepared (75USP3962240 77USP-4013767) by condensing furandione 199 with the respective 2-aryl or pyri-dylcarboximidic acid hydrazide 200. Compound 201 (X = N) was oxidized to its N-oxide. Both 200 and 201 have sedative and tranquilizer properties (Scheme 42). [Pg.64]


See other pages where 1.2.4- Triazines, condensed is mentioned: [Pg.353]    [Pg.824]    [Pg.55]    [Pg.283]    [Pg.158]    [Pg.190]    [Pg.643]    [Pg.41]    [Pg.41]    [Pg.42]    [Pg.47]    [Pg.49]    [Pg.53]    [Pg.53]    [Pg.55]    [Pg.56]    [Pg.57]    [Pg.57]    [Pg.59]    [Pg.63]    [Pg.65]    [Pg.69]   
See also in sourсe #XX -- [ Pg.39 , Pg.59 ]




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Benzotriazines and Other Condensed 1,2,3-Triazines

Condensed 1,2,4-triazines, synthesis

Condensed 1,2,4-triazines: I. Fused

Condensed 1,2,4-triazines: I. Fused five-membered rings

Condensed 1,2,4-triazines: I. Fused heterocycles with three-, four-, and

Condensed 1,2,4-triazines: I. Fused heterocycles with three-, four-, and fivemembered rings

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