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Butane-2,3-dione, synthesis

Butanediol dehydration, 41 155 Butane-2,3-dione synthesis, 41 302-303 Butanethiol, dissociation, 37 292 -Butanol, see 1-Butanol 2-Butanol... [Pg.58]

King Jr reported a facile synthesis of chlorinated dioxo-lanones by a simple, one-pot, direct addition of phosgene to 1,2-diones (Ref. 225). Thus, the reaction of 2,3-butane dione with phosgene in the presence of pyridine affords trans-4,5-dichloro-4,5-dimethyl-1,3-dioxolane-2-one in 82% yield as shown in scheme 172. [Pg.173]

Attempted synthesis of the bis(2//-azirine) system from the 2,3-dimethyl-1,4-diphenyl-1,4-butane-dione bis(hydrazonium) salt under basic conditions gives 3,4-dimethyl-2,5-diphenylpyrrole in 89% yield (equation 66). ° ... [Pg.789]

The reaction between amino group (-NH2) and a carbonyl group (C=0) elsewhere in the same molecule has been used in the synthesis of many heterocyclic compounds. For example as shown in Equation 9.53, substituted quinolines can be produced by acid-catalyzed cyclization of the appropriate aminoketones (formed during the Friedlander synthesis, in this instance between propanone and ortho-aminobenzaldehyde, in an aldol-type reaction with loss of water this chapter, vide infra), and even more than one reaction can be induced to occur. Thus, in Equation 9.54,1,2-benzenediamine (ort/io-aminoaniline) undergoes acid-catalyzed addition to 2,3-butane-dione to produce 2,3-dimethyl-13-benzopyrazine (23-dime thy Iquinoxaline). ... [Pg.808]

Mosslemin MH, Yavaii I, Anary-Abbasinejad M, Nateghi MR (2004) Reaction between tert-butyl isocyanide and l,l,l-trifluoro-4-aryl-butane-2,4-diones. Synthesis of new trifluoro-methylated furan derivatives. J Fluor Chem 125 1497-1500... [Pg.227]

Synthesis The condensation of 4-methylacetophenone with ethyl acetate by means of NaOMe in refluxing methanol gives 4,4,4-trifluoro-1-(4-methylphenyl)butane-1,3-dione, which cyclized with 4-hydrazinophenyl-sulfonamide in refluxing ethanol (Graul et al., 1977 Talley et al. (Searle Co.), 1995. [Pg.46]

An interesting approach for the synthesis of some fused pyrimidines has been reported by Shaaban [102] via reaction of 4,4,4-trifluoro-l-(thien-2-yl)butane-1,3-dione in the presence of triethylorthoformate with 5-aminopyrazole or 1,2,4-aminotriazole or 2-aminobenzimidazole under microwave irradiation. The resulting trifluoromethyl derivatives of pyrazolo[l,5-a]pyrimidine 56, l,2,4-triazolo[l,5-a] pyrimidine 57 and pyrimido[l,2-a]benzimidazoles 58 were obtained in excellent yields and purity (Scheme 42). [Pg.190]

Synthesis of Enantiomerically Pure C2-symmetric Vicinal Diamines via Chirality Transfer from DPEN. Several C2-sym-metric vicinal diamines and their derivatives are prepared in optically pure form by chirality transfer from DPEN. For example, condensation of (5, 5)-DPEN with butane-2,3-dione in benzene at the reflux temperature is followed by stereoselective reduction with NaBHsCN and PPTS at -20 °C to afford the (25,35,5R,6R)-piperazine 4 and its diastereomer in a 15 1 ratio (eq 12). The crude product is purified by silica gel column chromatography. Formation of the biscarbamate followed by reductive cleavage of benzylic C-N bonds with lithium in liquid ammonia, and then removal of isobutyloxycarbonyl with HBr in acetic acid results in (/ ,/ )-2,3-diaminobutane dihydrobromide 5 in 99% ee. [Pg.306]

Another situation in which the chemically robust nature of the 4-methyI-l, 2,4-triazole-3,5-dione adducts has been exploited is in the synthesis of bicyclobutane derivatives.Addition of 4-methyl-l,2,4-triazole-3,5-dione to bicyclo[1.1.0]butane gave the urazole 20, which was converted to 2,3-diazabicyclo[2.1.1]hex-2-ene and by thermolysis or photolysis back to bi-cyclo[1.1.0]butane. While this is not in itself a useful synthetic sequence, the urazole intermediates in such a sequence can be chemically modified in ways that would be impossible for the bicyclobutanes themselves. Hence for the adduct 21 of dimethyl bicyclo[1.1.0]butane-l,3-dicarboxylate, the ester groups can be modified into ethyl, vinyl, substituted vinyl, hydroxymethyl, bromo and other substituents and this was used to prepare, for example, 1,3-divinylbicyclo[1.1.0]butane (22) and l-ethyl-3-vinylbicyclo[1.1.0]butane. ... [Pg.1098]

Chromones.- Enamines have previously been converted into chromones and in another approach, the enamine (104) reacted with thionyl chloride to give the chromone (105 n=2) in moderate yield. The sulphinic acid was readily oxidized to the sulphonic acid (105 n=3) by 3-chloroperoxybenzoic acid.110 A convenient synthesis has been described of 2-methylchromene-4-thione in 57% yield from 4-(2-hydroxyphenyl)butane-1,3-dione.111 The t-amino-methylchromones (106) have been synthesized and shown to be central nervous system depressants. A new synthesis of 2-substituted chromones (including flavones) uses 2-acetoxyphenacyl bromide (107) which is converted into its phosphorane (108). Heating this with an alkanoyl or aroyl chloride or anhydride in pyridine gave good yields of the chromone (109).113... [Pg.396]

This sequence has been used for the synthesis of 6-methoxymurrayanine (232) (Scheme 55) [214]. Reaction of butane-2,3-dione (226) with 4-methoxyphenyl isocyanate (227) to 4,5-dimethylene-3-(4-methoxyphenyl)-l,3-oxazolidin-2-one (228) followed by regioselective boron trifluoride-catalyzed Diels-Alder reaction with acrolein afforded the oxazolone 229. Only minor amounts of the undesired regioisomer were formed. Aromatization using 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) afforded the benzoxazol-2-one 230. Saponification of the cyclic carbamate and subsequent O-methylation led to the diarylamine 231. Finally, oxidative cyclization using stoichiometric amounts of palladium(ll) acetate provided 6-methoxymurrayanine (232). [Pg.246]

Synthesis of HDBNTFA (8) Dithiobenzoic acid l-(4-(4,4,4-trifluoro-butane-l,3-dione)-naphthalen-l-yl)-ethyl ester (HDBNTFA)... [Pg.22]


See other pages where Butane-2,3-dione, synthesis is mentioned: [Pg.137]    [Pg.731]    [Pg.361]    [Pg.213]    [Pg.623]    [Pg.652]    [Pg.173]    [Pg.361]    [Pg.496]    [Pg.252]    [Pg.553]    [Pg.422]    [Pg.107]    [Pg.396]   
See also in sourсe #XX -- [ Pg.302 ]




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1,3-Diones synthesis

Butanal synthesis

Butane Synthesis

Butane-1,4-diones

Butane-2,3-dione

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