2-pyrazinecarboxylate

CjjHjjOj 35363-65-6) see Dimethisterone methyl pyrazine-2-carboxylate (QH N202 6164-79-0) see Pyrazinamide 5-methyl-2-pyrazinecarboxylic acid (QHfiN202 5521-55-1) see Adpimox Glipizide 5-methylpyrazine-2-carboxylic acid see under 5-methyl-2-pyrazinecarboxylic acid... [Pg.2422]

Azirines are dimerized under various conditions to dihydropyrazines or their dehydrogenated products, namely pyrazines (Section 8.03.9.5). Quinoxalines are oxidized with potassium permanganate to afford 2,3-pyrazinedicarboxylic acids, and pteridines are hydrolyzed to give 3-amino-2-pyrazinecarboxylic acid derivatives. Condensation of 3,4-diamino-l,2,5-thiadiazole 176 with a-diketones produces l,2,5-thiadiazolo[3,4- Jpyrazines 177, which are reduced to provide 2,3-diaminopyrazines 178 (Scheme 51) <1997JCM250>. [Pg.313]

The most convenient synthesis of halogenopyrazines and -quinoxalines is by halogenation of pyrazinones and quinoxalinones with phosphoryl or other acid halides for example, 5-hydroxy-2-pyrazinecarboxylic acid, rather than 5(477)-pyrazinone-2-carboxylic acid, is chlorinated with phosphorus pentachloride/phosphoryl chloride to afford a 63% yield of 5-chloro-2-pyrazinecarbonyl chloride <1994SL814>. Sato and Narita provided an improved synthesis of various halogenopyrazines in which 2(l//)-pyrazinones were activated with chlorotrimethylsilane to give silyl ethers (Section 8.03.7.3). This procedure is most effective for synthesis of bromopyrazines whose overall yields are 62-81% <1999JHC783>. Bromopyrazine is directly prepared by treatment of 2-(l//)-pyrazinone with phosphoryl... [Pg.317]

Carboxylic acids, acyl chlorides, and sulfonyl chlorides used for deri-vatization of 4-aminophenylalanine and >-4-am i n op h e ny I a I a n i n e are as follows 5-hydantoinacetic acid, / ran, v - 4 - co t i n i n ec a r b o xy I i c acid, isonicotinic acid, 3-pyridinepropionic acid, 4-hydroxyphenylacetic acid, 2-butynoic acid, 2-pyrazinecarboxylic acid, cyclopropanecarboxylic acid, 3-hydroxy-2-qui-noxaline carboxylic acid, 5-bromovaleric acid, propargyl chloroformate, 3,4-dimethoxybenzoyl chloride, 2-thiophenesulfonyl chloride, 3-thiophene-carboxylic acid, 2-thiophenecarboxylic acid, 2-methylbutyric acid, 2-thio-pheneacetyl chloride, benzoic acid, furylacrylic acid, 4-nitrophenyl acetic acid, 2,5-dimethoxyphenylacetic acid, p-toluenesulfonyl chloride, 4-(di-methylamino)phenylacetic acid, 3-indolepropionic acid, phenoxyacetic acid, 3-(dimethylamino)benzoic acid, cyclohexanecarboxylic acid, naphtha-lenesulfonyl chloride, 4-bromophenylacetic acid, 4-bromobenzoic acid, 2-phenoxybutyric acid, 3,4-dichlorophenylacetic acid, (l-naphthoxy)acetic acid. [Pg.284]

Valuable organic acids of industrial interest can be recovered from aqueous waste solutions, for example, from an enzymatic resolution process. Mass-transfer data for MBSE and MBSS in HF contactors for dimethylcydopropanecarboxylic acid (DMCCA) [97] and 5-methyl-2-pyrazinecarboxylic add (MPCA) [95, 96] have been estimated. Processes for recovery of DMCCA from a highly addic waste solution with pH below 2 containing about 19kgm 3 of DMCCA by MBSE and MBSS have been suggested [98], A solvent with 0.4 kmol m 3 of TOA in n-alkanes (dodecane fraction) was used. A recovery of more than 90% of DMCCA and a concentrate with about 200 kg m-3 of DMCCA can be achieved. [Pg.522]

Kubisova, L ., Sabolova, E., Schlosser, ., Martak, J. and Kertesz, R. (2004) Mass-transfer in membrane-based solvent extraction and stripping of 5-methyl-2-pyrazinecarboxylic acid and co-transport of sulphuric add in HF contactors. Desalination, 163, 27. [Pg.536]

Chemical Name 2-Pyrazinecarboxylic acid, 5-methyl-, 4-oxide... [Pg.70]

Pteridine synthesis from pyrazine precursors are usually applied in such cases where the formation of special derivatives cannot be achieved easily by the pyrimidine approach. Methyl 3-amino-2-pyrazinecarboxylate (362) reacts with thiophosgene to give the corresponding 3-isothiocyanato derivative (363) which cyclizes with primary amines, arylalkylamines, aminoalcohols, amino acids,... [Pg.719]

Ethyl A-(2-azido-l-ethoxycarbonylethyl)-A-benzylglycinate (37) gave ethyl l-benzyl-5-ethoxy-l,2,3,6-tetrahydro-2-pyrazinecarboxylate (38) (Ph3P, PhMe, 100°C, 9 h 58%).1468... [Pg.8]

Methyl 2-cyano-A-(2-hydroxyimino-4-mcthylvalcryl)glycinatc (46, R = Me) gave methyl 3-amino-5-isobutyl-6-oxo-l, 6-dihdyro-2-pyrazinecarboxylate 4-oxide (47, R = Me) (AcOH, 70°C, 3 h >32%) 337 the ethyl ester (47, R = Et) (>62%) was made similarly.848... [Pg.9]

Methyl 2-(/8-aminostyrylimino)-2-cyanoacetate (48) gave methyl 3-amino-5-phenyl-2-pyrazinecarboxylate (49) (MeONa, MeOH—CH2C12, 20°C, 15 min 70%).941... [Pg.9]

Benzamidopropionic acid (95) underwent unsymmetrical self-condensation and aminolysis to give l-benzoyl-2,5-dimethyl-6-methylimino-3-phenyl-l,2,5,6-tetrahydro-2-pyrazinecarboxylic acid (97), possibly via intermediate (96) (MeNH2-POCl3, CHC13, reflux, 5 h 43%) several analogues were made similarly.1098... [Pg.16]

Diamino-2,3-dimethylbutane (200) and diethyl a-oxomalonate (201) gave ethyl 5,5,6,6-tetramethyl-3-oxo-3,4,5,6-tetrahydro-2-pyrazinecarboxylate (202) (EtOH, 20°C, 45 h then reflux, 7.5 h 83%).455 Also other examples.956,1269,1752... [Pg.28]

Ethyl 2-cyano-2-(tosyloxyimino)acetate (261) and diethyl 3-amino-4-cyanopent-2-enedioate (262) gave ethyl 6-cyano-3-(a-cyano-a-ethoxycarbonylmethyl)-5-oxo-4,5-dihydro-2-pyrazinecarboxylate (263) (Et3N, MeCN, 20°C, 2 days 70%) 1315 also analogues.301,1315... [Pg.36]

Hydroxyiminopropionaldehyde dimethyl acetal (264) and ethyl 2-formamido-2-formylacetate (265) gave ethyl 5-methyl-2-pyrazinecarboxylate 4-oxide (266) (HCl/AcMe, reflux %).1167... [Pg.36]

Ethyl 3,6-diethoxy-5-isopropyl-2,5-dihydro-2-pyrazinecarboxy]ate (85) gave ethyl 2-[a-(tert-butyldimethylsiloxy)benzyl]-3,6-diethoxy-5-isopropyl -2,5-dihydro-2-pyrazinecarboxylate (86) [Sn(0S02CF3)2, EtN(CH2)5, THF, —78°C or MgBr2, EtsN, MeCN, -20°C in both cases followed by BuTVle2Si0S02CF3, lutidine, CH2C12, -45°C —85% note lack of a lithiation step] 1634 also analogous examples.1739... [Pg.92]

In contrast, methyl 5-(pent-l-ynyl)-2-pyrazinecarboxylate (151, R = C CPr) gave methyl 5-pentyl-2-pyrazinecarboxylate (151, R = CH2Bu) (H2, Pd/C, MeOH, 20°C 94%).93 Also other examples.969,1588... [Pg.101]

Trimethylsilyl 2-pyrazinecarboxylate (174) gave 2-[a-(trimethylsiloxy)ben-zyljpyrazine (173) (neat PhCHO, N2, 200°C, 4 days 50%) or 2-[a-phenyl-a-(trimethylsiloxy)benzyl]pyrazine (175) (BzPh, 240°C, 13 days 23%) a rational mechanism was suggested.362... [Pg.105]

Styrylpyrazine 1-oxide (254, R = CH CHPh) gave 2-pyrazinecarboxylic acid 1-oxide (254, R = C02H) (KMn04, dicyclohexyl-18-crown-6, PhH, 20°C, 3 h 49%).1300... [Pg.117]

Dimethyl 2,3-pyrazinedicarboxylate gave l-ethyl-2,3-dimethoxycarbonylpyrazinium tetrafluoroborate (347) (Et3OBF4, C1CH2CH2C1, reflux, 2 h 80%) 415 methyl 2-pyrazinecarboxylate gave 3-methoxycarhonyl-l -methylpyrazininm iodide (348)... [Pg.131]

Ethyl 5-oxo-4,5-dihydro-2-pyrazinecarboxylate (1) gave ethyl 5-chloro-2-pyrazinecarboxylate (2) (POCl3, reflux, 90 min 88%).1681... [Pg.138]

Methyl 3-oxo-3,4-dihydro-2-pyrazinecarboxylate (22) gave methyl 3-chloro-2-pyrazinecarboxylate (23) (S02C1, trace Me2NCHO, PhMe, 80°C, N2, 3 h 80%) 54 the isomeric substrate, methyl 5-oxo-4,5-dihydro-2-pyrazinecarboxy-late, gave methyl 5-chloro-2-pyrazinecarboxylate (24, R = H) (neat POCl3, trace Me2NCHO, reflux, 2 h 68%) 85 and the homologous methyl 5-chloro-6-methyl-2-pyrazinecarboxylate (24, R = Me) (77%) was made similarly.85... [Pg.141]

Chloro-2-pyrazinecarboxylic acid gave 3-oxo-3,4-dihydro-2-pyrazinecar-boxylic acid (0.5 M NaOH, reflux, 1 h >95%).1271... [Pg.159]

Ethyl 5-chloro-2-pyrazinecarboxylate (133, R = Cl) gave ethyl 5-methoxy-2-pyrazinecarboxylate (133, R = OMe) (MeONa, MeOH, reflux, 20 min 40%).1681... [Pg.163]

Methyl 6-chloro-2-pyrazinecarboxylate 4-oxide gave methyl 6-thioxo-l,6-dihy-dro-2-pyrazinecarboxylate 4-oxide (138) (NaHS, EtOH, 20°C, 3 h 46%).89 2-Chloropyrazine gave 2( l//)-pyrazincthione [NaHS/MeOH (made in situ), reflux, 1 h 91%].1602... [Pg.165]

Methyl 3-chloro-2-pyrazinecarboxylate (173, R = Cl) gave methyl 3-azido-2-pyrazinecarboxylate (173, R = N3) (NaN3, Me2NCHO, 120°C, N2, 1 h ... [Pg.171]

Methyl 3-bromo-6-chloro-5-(4-methylpiperazin-l-yl)-2-pyrazinecarboxylate (177) gave methyl 6-chloro-5-(4-methylpiperazin-l-yl)-2-pyrazinecarboxy-late (178) (H2, Pd/C, THF, 20°C, 2 days 70% note selective debromination and intramolecular supply of the base).645... [Pg.172]

Chloromethyl-5-methylpyrazine (283) gave 5-methyl-2-pyrazinecarboxylic acid (284) [K2C03, H20—Bu OH, 60°C, electrolysis (freshly made nickel hydroxide anode Ni alloy cathode) 82% possibly via the hydroxymethyl intermediate but mechanism not elucidated].221... [Pg.190]

Pyrazinecarboxylic acid underwent microbiological hydroxylation to give 3-oxo-3,4-dihydro- (36, R = H) (Alcaligenes eutrophus 70%), 5-oxo-4, 5-dihydro- (37) (.Pseudomonas acidovorans 96%), or 6-oxo-l,6-dihydro-2-pyrazinecarboxylic acid (38) (Alcaligenes faecalis 85%) 1091 Similar procedures afforded 5-chloro-3-oxo-3,4-dihydro-2-pyrazinecarboxylic acid (Alcaligenes eutrophus 50%) and 5-oxo-4,5-dihydro-2-pyrazinecarbonitrile (Agrobacterium sp 78%).1091... [Pg.195]

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