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Isocyanates 1.3.5- triazin-2 -ones

The Wittig-type reactions of iminophosphoranes with isocyanates and related compounds have also been extensively used in heterocyclic synthesis. Examples include the preparations of the mesoionic [l,3,4]thiadiazolo[2,3-c][l,2,4]triazines (210) from (209), 0 bicyclic guanidines, e.g. (212), from (211), naphthypyridines (215), (216), and (217) from (213) and (214), 2 pyrido[l,2-f]pyrimido-[4,5-d)pyrimidines (218), 7H-pyrido-[4,3-c]- (219) and 10H-pyrido[3,4-b]- (220) carbazoles, tricyclic fused 2,4-diimino-l,3-diazetidines (222) from the bisiminophosphorane (221), benzotriazepines (225) from (223) and (224), 6 and mesoionic thiazolo-[2,3-b]-1,3,4-thiadiazoles (227) and N,N-bisheteroarylamines from the iminophosphorane (226), derived from 3-amino-4-phenylthiazole-2(3H)-thione. The carbodiimides (229), prepared from the iminophosphorane (228), can be converted into quinolines or a-carboline derivatives depending on the nature of the isocyanate used in the reaction with (228) and the reactions of iminophosphoranes (230) and (231) with aryl and styryl isocyanates provide one-pot syntheses of quinoline, a-carboline, and quinindoline derivatives. 9... [Pg.345]

The condensation of isocyanate esters with diguanides proceeds in an entirely comparable manner, providing a corresponding series of s-triazin-2-ones (i.e. substituted ammelines) 378). However, since loss of water from carbamoyl-intermediates [e.g. RNHCONH C( NH)NH C( NH) -NH2] occurs much less readily than loss of hydrogen sulphide from their thiocarbamoyl-analogues, melamines are not formed in this reaction 378). The production of adducts from phenyl isocyanate and tetra-. [Pg.67]

However, when pyridyliminophosphorane (306a) is treated with phenyl isocyanate or isothiocyanate (Scheme 110), mixed carbodiimides are obtained, which are capable of an intermolecular Diels-Alder reaction resulting in triazine 308. The cycloaddition occurs specifically with one C = N double bond of the carbodiimide serving as the dienophile (77ZC371). [Pg.222]

Reactions involving the [4 + 1 + 1] principle, an example of which is shown in equation (136), are rather uncommon and of strictly limited utility [3 + 2 + 1] and [2 + 2 + 2] processes, on th,e other hand, are well known. Representative [3 + 2+1] three-bond formation processes are given in equations (137)—(141), from which it can be seen that the common situation is where ammonia, a substituted amine or formamide constitutes the one-atom fragment. Many [2 + 2 + 2] atom fragment syntheses are known and some are familiar reactions. Thus, the cobalt(I)-catalyzed condensation of nitriles and isocyanates with alkynes gives pyridines and 2-pyridones, often in excellent yield (e.g. equation 142), while the cyclotrimerizations of nitriles, imidates, isocyanates, etc., are well established procedures for the synthesis of 1,3,5-triazine derivatives (e.g. equation 143). Further representative examples are given in equations (144)-(147), and the reader is referred to the monograph chapters for full discussion of these and other [2 + 2 + 2] processes. Examination of the... [Pg.86]

The same methods used for 1,2,4-benzotriazines have,also been applied to the synthesis of naphtho-l,2,4-triazines. l-Amino-2-arylazonaphthalenes (663) with phosgene yield naphtho[l,2-e][l,2,4]-triazin-2-ones (664) (05MI21900), and the isomeric 2-amino-l-arylazonaphthalenes (665) with phosgene or isocyanates similarly gave naphtho[2,l-c]-[l,2,4]triazin-3-ones (666) <78HC(33)189, p.732). 3-Iminonaphtho[2,1 -e][ 1,2,4]triazines (667, 668) were obtained when (665) reacted with cyanogen bromide (08MI21900) or with isothiocyanates and mercury(II) oxide (Scheme 24). [Pg.445]

Isocyanates (one equivalent) react smoothly with azomethines (two equivalents) in the presence of Lewis acids to form l,3,5-triazin-2-ones in moderate to excellent yields (40— 100%) (equation 96). Isothiocyanates can be used in an analogous way (61JOC767). [Pg.515]

When two equivalents of an isocyanate are treated with one equivalent of an enamine, a l,3,5-triazine-2,4-dione is formed. The novel spiro compound (171) may be prepared by this route. The spiro derivative is isomerized on heating (69CB931). [Pg.515]

Amino-5-methyltriazole and carbethoxy isothiocyanate, stirred in acetonitrile, gave 3-methyl-5-thioxo-l,2,3-triazolo[l,5-a][l,3,5]triazin-7-pne (104) (25°C, 30 min, 65%) (76JHC589). 5-Phenyltriazole-4-diazonium chloride and phenyl isocyanate, stirred in dichloromethane, provided 3,6-diphenyl-l,2,3-triazolo[5,l-d][l,2,3,5]tetrazine-4-one (105) (25°C, 41%) (79TL4253). Finally, diazotized 4-aminotriazole was coupled to 2-naphthol. The product, refluxed in methanol, was cyclized to naphtho[2,l-e][l,2,3]-triazolo[l,5-h] triazine (106) (2 days, 80%) (74JHC867). [Pg.190]

New 2-aryl-l,2,4-triazin-3-ones and 2-aryl-l,2,4-tri-azepin-3-ones were prepared in a three step reaction sequence from readily available aryl isocyanates and aminoacetals or ketals. The key step in the reaction scheme was the formation of 2-arylsemicarbazides by the treatment of arylureas with the aminating reagent 0-(4-nitrophenyl)hydroxylamine. 2-Aryl-1,2,4-triazin-3-ones... [Pg.122]

Aryl-l,2,4-triazepin-3-ones (2) were also prepared from the appropriate aryl isocyanate and 3-(methylamino)propionaldehyde diethyl acetal (Scheme 4). The yields in each reaction step were comparable to those for the synthesis of the triazin-3-ones. [Pg.123]

An amino group can also be acylated <84JHC697, 86JHC935) it reacts with sulfonyl chlorides and aryl isocyanates <86JHC935>, and also with nitrous acid to give, via the diazonium salt (281), either the triazinone by reaction with water or the chloro-triazine by reaction with chloride ions (Scheme 50). Nitrosation of 3-amino-1,2,4-triazine 2-oxides (282) and subsequent thermolysis of the diazonium tetrafluoroborate salts (283) afforded 3-fluoro-1,2,4-triazine 2-oxides (284) (Scheme 51). In one instance the diazonium tetrafluoroborate was isolated <85H(23)1969>. [Pg.549]

Reaction of 4-amino-6-methyl-3-thioxo-3,4-dihydro-l,2,4-triazin-5-one (339) with isocyanates in DMF yields 4Ff-l,3,4-thiadiazolo[2,3-c]l,2,4-triazin-4-one derivatives (340) (Equation (43))... [Pg.554]

Amino-6-methyl-3-methylthio-l,2,4-triazin-5(2/f)-one (343) reacts with diarylcarbodiimides to form 8-aryl-7-arylamino-3-methyl[l,2,4]triazolo[5,l-c][l,2,4]triazin-4(8//)-ones (344), and the same products are formed from the iminophosphoranes (345) with isocyanates (Scheme 62) <86H(24)3363>. The iminophosphoranes are prepared from the corresponding amines with triphenylphosphine dibromide. [Pg.554]

Guo et al. have developed a convenient one-pot synthetic route for the preparation of asymmetric l,3-dialkyl-l,3,5-triazine-2,4,6-triones 237 from readily available alkyl or aryl isocyanates 235, primary amines 236, and A -chlorocar-bonyl isocyanate in excellent yields (Scheme 36). Subsequent alkylation with N-protected amino alcohols afforded the desired l,3,5-triazine-2,4,6-triones 238 in good yields <2005BML693>. [Pg.243]

Amylopectins. — The effects of acrylamide graft copolymerization on the solution properties of amylopectin have been discussed. Amylopectin has been dyed with DyAmyl-L and used in this form as a substrate for the assay of a-amylase. Amylopectin has been treated with isocyanate derivatives of 4-amino-( 1,1-dimethyl ethyl)-3-(methylthio)-l,2,4-triazin-5(4/f)-one ( metribuzin ) or acid chloride derivatives of 2,4-dichlorophenoxyacetic acid ( 2,4-D ) and 2,2-dichloropropionic acid ( dalapon ), to produce controlled-release polymeric pesticide systems. The solvent system utilized for these reactions, a lithium chloride or bromide salt in AW-dimethylacetamide, allows dissolution of the reactant salt and facilitates analysis of the polymer product by such techniques as i.r., U.V., and n.m.r. spectroscopies and gel permeation chromatography. Derivatives of other naturally occurring polysaccharides, including amylopectin, cellulose, chitin, and dextran, were also prepared. [Pg.629]

Masquelin et al. have also reported the production of pyrazolo[l,5-a][l,3,5]triazines and pyrozolo[l,5-(j][l,3 5]triazm-4-ones from polymer-bound 3//-pyrozolo[l,5-a][l,3,5] triazin-4-one intermediates 38 (Scheme 12.10). Resin 38 was prepared by condensing4,5-disubstituted 2//-pyrazol-3-ylamine with ethoxycarbonyl isocyanate in dry acetone followed by treatment with sodium ethanolate in ethanol at 65°C and finally attaching onto the Menifield resin. Using such a method, the solid-phase attachment was used to both purify the 3//-pyrazolo[l,5-a][l,3,5]triazin-4-ones via a scavenging process and also introduce a... [Pg.391]

Insertion reactions of isocyanates into the C-NR2 bond of R2NCH2NHCOOR and R2NCH20R and into the C-OR bond in R2NCH(OR)2 are also known. In the reaction of (RS)2CHNR2 with isocyanates, an insertion into the C-SR bond occurs The cyclic trimer obtained from formaldehyde and aniline 254 reacts with phenyl isocyanate at 130 °C to give the 1,3,5-triphenylhexahydro-5-triazine-2-one 255. The reaction most likely proceeds by dissociation of the trimer to a 1,4-dipolar intermediate which adds phenyl isocyanate. [Pg.120]

Cyclosilazane (R2SiNR) reacts with phenyl isocyanate at 60-90 °C to give the six-membered ring insertion products in high yield Silylated imines 289 react with one equivalent of isocyanate to give the insertion products 290, which on further reaction with a different isocyanate afford 5,6-dihydro-l,3,5-triazine-2,4(l//,3i/)-diones 291 with two different substituents . [Pg.125]

Tetrahydro-2H-thiazolo[3,2-a]-s-triazin-4-ones from 2,4-diaza-l,3-diene groups and isocyanates... [Pg.393]

Phenyl isocyanate added at room temp, to N,N-dimethyl-N -( 2 thiazolin-2-yl)-formamidine in benzene, and the product isolated after 10 min. -> 2-dimethyl-amino-3-phenyl-3,4,6,7-tetrahydro-2H-thiazolo[3,2-a]-s-triazin-4-one. Y 91%. F. e. and products s. R. Richter and H. Ulrich, B. 103, 3525 (1970). [Pg.393]


See other pages where Isocyanates 1.3.5- triazin-2 -ones is mentioned: [Pg.251]    [Pg.372]    [Pg.87]    [Pg.383]    [Pg.442]    [Pg.540]    [Pg.267]    [Pg.320]    [Pg.342]    [Pg.387]    [Pg.383]    [Pg.442]    [Pg.123]    [Pg.159]    [Pg.78]    [Pg.586]    [Pg.614]    [Pg.147]    [Pg.400]    [Pg.720]    [Pg.738]    [Pg.319]    [Pg.129]    [Pg.309]    [Pg.367]   


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1.2.4- Triazine-3 -ones

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