3- 2-pyrazinecarbonitrile

The same substrate (91) and triethyl orthoacetate, however, gave a separable mixture of 5-ethoxy-3-methoxy-5-methyl-6-phenyl-4,5-dihydro-2-pyrazine-carbonitrile (93) and 3-methoxy-5-methyl-6-phenyl-2-pyrazinecarbonitrile (94) (likewise 35 and 43%, respectively) the dihydro product (93) gave its aromatic counterpart (94) quantitatively by loss of ethanol on treatment with pyridine or triethylamine.857... [Pg.16]

Diamino-3-phenylthioacrylonitrile (151) and glyoxal (152) gave 3-phenylthio-2-pyrazinecarbonitrile (153) (TsOH, H20—MeOH, reflux, 5 h 77%).1507... [Pg.23]

Like the foregoing isomeric substrates (Section 2.2.7), these isoxazolopyrazines were frequently made from pyrazines. Thus 3-(/V-hydroxyamidino)-2(l//)-pyrazi-none (102) was converted in two stages into isoxazolo[4,5-b]pyrazin-3-aminc (103), which on vigorous treatment with acetic anhydride afforded 2-acetoxy-3-(5-methyl-l,2,4-oxadiazol-3-yl)pyrazine (104) in 78% yield the same substrate (103) in hot formic acid for 5 min gave mainly 3-(l,2,4-oxadiazol-3-yl)-2(l/7)-pyrazi-none (105) (50%) but if heating was prolonged for 3 h only 3-oxo-3,4-dihydro-2-pyrazinecarbonitrile (106) was obtained, presumably via the oxadiazolopyrazine (105).1115... [Pg.63]

Diphenyl-2,3-pyrazinedicarbonitrile (145) gave 3-allyl-5,6-diphenyl-2-pyrazinecarbonitrile (144) (Me2SiCH2CH=CH2, MeCN, hv, A, 70 h 98% with a trace of phenanthrene as sensitizer, only 25 h was required) or 3-ben-zyl-5,6-diphenyl-2-pyrazinecarbonitrile (146) (Me3SiCH2Ph, trace phenanthrene, MeCN, hv, A, 25 h 98%).1087... [Pg.100]

This process was undoubtedly developed for the manufacture of pyrazinamide (Zinamide, etc.),1696 a second-line drug for Mycobacterium tuberculosis infections, resistant to more effective and less toxic agents. Thus a mixture of 2-methyl-pyrazine (323), ammonia, oxygen, and steam is passed (at 400°C) over an alumina- or pumice-supported catalyst comprising one to three oxides of Ce, Cr, Mo, Mn, P, Sb, Ti, or (most importantly) V the main product (in up to 90% yield) is 2-pyrazinecarbonitrile (324), easily converted into 2-pyrazinecarboxamide... [Pg.128]

Cyano-5-(3,4-dimethoxyphenyl)-l-methylpyrazinium iodide (356) gave 6-(3,4-dimethoxyphenyl)-4-methyl-4,5-dihydro-2-pyrazinecarbonitrile (357) [ Hantzsch ester (diethyl 2,6-dimethyl-l,4-dihydro-3,5-pyridinedicar-boxylate) (1 mol), MeCN, 20°C, 3 h 80% or NaBH4, MeCN, 20°C, 30 min 83%], and thence 6-(3,4-dimethoxyphenyl)-4-methyl-l,4,5,6-tetrahydro-2-pyrazinocarbonitrile (357a) (repeat procedures for 24 and 3 h, respectively, both affording 72%).1262... [Pg.133]

Amino-2-pyrazinecarbonitrile (29, R = H) gave regioselectively 3-amino-6-bromo-2-pyrazinecarbonitrile (29, R = Br) (substrate, AcOH, Br2/AcOH- slowly, 60°C, 4 h 85%).802... [Pg.142]

Chloro-2-pyrazinecarbonitrile (130) gave 3-(3-terl-butylamino-2-hydrox-ypropoxy)-2-pyrazinecarbonitrile (131) [NaOCH2CH(OH)CH2NHBu( (made in situ), Me2NCHO, 70°C, 18 h 83%]594 or analogous substituted-phenoxy derivatives.1010... [Pg.163]

Amino-5-chloro-2-pyrazinecarbonitrile (132, R = Cl) gave 3-amino-5-methoxy-2-pyrazinecarbonitrile (132, R = OMe) (MeONa, MeOH, reflux,... [Pg.163]

Chloro-3-dimethylamino-6-nitropyrazine (184) gave 3-dimethylamino-6-nitro-2-pyrazinecarbonitrile (185) (CuCN, Me2NCIIO, 155°C, 18 h 62%).1313... [Pg.173]

Bromo-5-methyl-2-pyrazinamine 4-oxide (187, R = Br) gave 3-amino-6-methyl-2-pyrazinecarbonitrile 1-oxide (187, R = CN) (CuCN, NaCN, Me2NCHO, 110°C, reflux, 4 h 59%).1508... [Pg.174]

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]

Amino-5-propionyl-2-pyrazinecarbonitrile gave 3-amino-5-(l-hydroxypropyl)-... [Pg.209]

Note Treatment of a pyrazinecarbonitrile with alkoxide ion may result in addition to afford the corresponding alkyl pyrazinecarboximidate (see Section 8.2.1) or in displacement to give an alkoxypyrazine (as here illustrated). [Pg.218]

Amino-6-dimethoxymethyl-2-pyrazinecarbonitrile from its 4-oxide (254) [neat (MeO)3P, reflux, N2, 4 h 68%].759,767... [Pg.232]

Phenylthio-2-pyrazinecarbonitrile gave 3 -phenylsulfonyl-2-pyrazinecarboni-trile (49) (ot-C1C6H4C03, CHC13, 10 - 20°C, 3 h 91%) 1507 and 5-bromo-3-methylthio- gave 5-bromo-3-methylsulfonyl-2-pyrazinamine (50) (likewise, 4 days 70%).1012 Also other examples.1551... [Pg.253]

This chapter covers pyrazines bearing nitrogenous substituents that are joined directly or indirectly to the nucleus through their nitrogen atom exceptionally, any isocyanato- or isothiocyanatopyrazines are relegated to Chapter 8 in order to be close to pyrazinecarbonitriles and the like. [Pg.259]

Dimethoxymethyl-3-dimethylaminomethyleneamino-2-pyrazinecarbonitrile 4-oxide (52) gave 3-amino-6-dimethoxymethyl-2-pyrazinecarbonitrile 4-oxide (53) [TsOH, (MeO)3CH, MeOH—H20, 20°C, 7 days 55%].759... [Pg.267]

Methyl-3 -methylamino-6-phenyliminomethyl-2-pyrazinecarbonitrile (54) gave 6-anilinomethyl-5-methyl-3-methylamino-2-pyrazinecarbonitrile (55) (Et3SiH, F3CC02H, CH2C12, 20°C, 4 h >95%).1599... [Pg.268]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...