3- Ethoxycarbonyl-5-nitro

Coumarines as dienophiles were chosen on the basis of earlier study in which the 9kbar pressure and moderate heating (30-70 °C) were used for Diels-Alder reactions of dienes with coumarins substitute at C-3 position with phenylsulfonyl, carboxy, ethoxycarbonyl, nitro, thiophenyl, and pyridyl groups [73]. The corresponding tetrahydro-6H-benzo[c]chromen-6-ones were prepared in excellent yields. When carried out at atmospheric pressure, the reaction yields and selectivities were greatly reduced. 

When large groups, such as phenyl, bromo, ethoxycarbonyl or nitro are attached at position 3, the principal products are l-alkylcinnolin-4(l/f)-ones. Cyanoethylation and acetylation of cinnolin-4(l/f)-one takes place exclusively at N-1. Phthalazin-l(2/f)-ones give 2-substituted derivatives on alkylation and acylation. Alkylation of 4-hydroxyphthala2in-l(2/f)-one with an equimolar amount of primary halide in the presence of a base leads to 2-alkyl-4-hydroxyphthalazin-l(2/f)-one and further alkylation results in the formation of 4-alkoxy-2-alkylphthalazinone. Methylation of 4-hydroxy-2-methyl-phthalazinone with dimethyl sulfate in aqueous alkali gives a mixture of 4-methoxy-2-methylphthalazin-l(2/f)-one and 2,3-dimethylphthalazine-l,4(2//,3//)-dione, whereas methylation of 4-methoxyphthalazin-l(2/f)-one under similar conditions affords only 4-methoxy-2-methylphthalazinone. 

Mercury(II) acetate tends to mercurate all the free nuclear positions in pyrrole, furan and thiophene to give derivatives of type (74). The acetoxymercuration of thiophene has been estimated to proceed ca. 10 times faster than that of benzene. Mercuration of rings with deactivating substituents such as ethoxycarbonyl and nitro is still possible with this reagent, as shown by the formation of compounds (75) and (76). Mercury(II) chloride is a milder mercurating agent, as illustrated by the chloromercuration of thiophene to give either the 2- or 2,5-disubstituted product (Scheme 25). 

Nitrones or aci-nitro esters react with alkenes to give in some cases A/-substituted isoxazolidines and in others 2-isoxazolines. When the intermediate isoxazolidines were observed, a number of procedures transformed them into the 2-isoxazolines. Acrylonitrile and phenyl rzcf-nitrone esters produced an A/-methoxyisoxazolidine. Treatment with acid generated a 2-isoxazole while treatment with base generated an oxazine (Scheme 118) (68ZOR236). When an ethoxycarbonyl nitrone ester was reacted with alkenes, no intermediate isoxazolidine was observed, only A -isoxazolines. Other aci-mtro methyl esters used are shown in Scheme 118 and these generate IV-methoxyisoxazolidines or A -isoxazolines which can be further transformed (72MI41605). 

Thiazole, 5-amino-4-ethoxycarbonyl-2-methyl-synthesis, 6, 306 Thiazole, 2-amino-4-(2 -furyl)-bromination, 6, 256 Thiazole, 2-amino-4-hydroxy-synthesis, 6, 296 Thiazole, 5-amino-2-hydroxy-synthesis, 6, 301 Thiazole, 5-amino-2-mercapto-synthesis, 6, 301 Thiazole, 2-amino-4-methyl-alkylation, 6, 256 synthesis, 6, 300 Thiazole, 2-amino-5-nitro-antiparasitic activity, 1, 180... 

Thiophene, 2-amino-3-cyano-5-phenyl-synthesis, 4, 888-889 Thiophene, 3-amino-4,5-dihydro-cycloaddition reactions, 4, 848 Thiophene, 2-amino-3-ethoxycarbonyl-ring opening, 4, 73 Thiophene, 2-amino-5-methyl-synthesis, 4, 73 Thiophene, 2-anilino-synthesis, 4, 923-924 Thiophene, aryl-synthesis, 4, 836, 914-916 Thiophene, 2-(arylamino)-3-nitro-synthesis, 4, 892 Thiophene, azido-nitrenes, 4, 818-820 reactions, 4, 818-820 thermal fragmentation, 4, 819-820 Thiophene, 3-azido-4-formyl-reactions... 

Some examples for the introduction of amino protecting groups such as 2-(4-nitro-phenyl)ethoxycarbonyl (npeoc) or benzyloxycarbonyl (Z) were already given in the compilation of carbamates produced with imidazolium caiboxylates in Section 4.6.1. 

The hydrochloride of 3-amino-4-hydrazinopyridine 65 was prepared by reaction of the 4-chloro-3-nitropyridine derivative with ethoxycarbonyl-hydrazine in phenol to give the hydrochloride of ethyl 3-(3-nitro-4-pyridyl)carbazate 64 (R2 = OEt), which on successive heating in concentrated hydrochloric acid and hydrogenation over Pd/C gave 65. Its reaction with phenylacetic acid or with phenoxyacetic acid gave the hydrochloride... 

In an example given in Scheme 51, tricyclic system 331 is generated by cyclocondensation between the ethoxycarbonyl group at C-5 of the triazole ring and the amino group of the substituent at N-l. The process that starts from catalytic reduction of the nitro group in derivative 329 does not stop at amine 330, but the subsequent spontaneous cyclocondensation leads directly to product 331 that is isolated in 60% yield <2002EJM565>. 

Arylazo-4-(3-ethoxycarbonylureido)furoxans 62, which were synthesized by the reactions of 4-amino-3-arylazo-furoxans with ethoxycarbonyl isocyanate, were subjected to cascade rearrangements under the action of potassium r/-butoxidc in dimethylformamide or by heating in dimethyl sulfoxide to form 4-amino-2-aryl-5-nitro-2//-l,2,3-triazoles 63 (Scheme 13) <2001MC230, 2003RCB1829>. 

In only a few cases are ring transformation reactions found in which a in-termolecular CCC transfragment reaction occurs. An example of this rearrangement has been observed in the reaction of 3,5-dinitropyridin-4(l//)-one (99) with diethyl sodio-3-oxopentanedioate. It provided in good yield 3,5-di(ethoxycarbonyl)pyridin-4-(lH)-one (102) and 1,3-dinitroacetone as second product (78H108). Its structure was proven by the formation of l-phenyl-3-nitro-4-hydroxy-5-phenylazopyrazole (103), obtained on heating of the diphenylhydrazone of 1,3-dinitroacetone (Scheme III.53). 

Similarly, o-phthalaldehyde is cyclized by ethyl nitroacetate to give 2-nitro-2-ethoxycarbonyl-indane-l,3-diol (86) in 71% yield, which can be hydrogenated to the corresponding amino acid (87)... 

Aus Benzoesaure-chlorid-(4-nitro-benzylimid) und Oxalsaure-ethylester-nitril entsteht ein Gemisch aus 5(4)-Ethoxycarbonyl-4(5)-(4-nitro-phenyl)-2-phenyl- (21%) und 5(4)-Ethoxy-carbonyl-2-(4-nitro-phenyl)-4(5)-phenyl-imidazol (6%)301 ... 

Aus den Synthesekomponenten C —N-C—N + C ist nur die Herstellung von 5-(2,6-Dimethyl-anilino)- -(2,6-dimethyl-phenyl)-4-(1-ethoxycarbonyl-ethenyl)-2-(4-nitro-phenyl)-imidazol in 89% Ausbeute aus 2,6-Dimethyl-phenylisocyanid mit 4-Nitro-benzoesaure-(2,6-dimethyl-phe-nylimid)-(2-ethoxycarbonyl-l-propenylidenamid) beschrieben306. 

HiCiOOC —CH2—Cl KOC2H, ]-( Ethoxycarbonyl-methyl) -2-methyl-4-nitro-... 86 112 855... 

Die analoge Umsetzungmit l,2-Dimethyl-5-nitro-imidazol fiihrt zu l-Methyl-5-nitro-2-(2-oxo-2-phenyl-ethyl)-imidazol iV>17,. Mit Oxalsaure-chlorid-ethylester als Acylierungsreagens wird 2-(2-Ethoxycarbonyl-2-oxo-ethyl)-l-methyl-5-nitro-imidazol erhalten1073. 

Die katalytische Hydrierung von N-Ethoxycarbonyl-2-nitro-anilinen liefert o-Diamino-arene ( 100%), die sich thermisch zu l-Alkyl-2-hydroxy-benzimidazolencyclisieren lassen590. 

CX n n°2 CI-CH2-COOC2H, K2C03 HjC-CN 2,5 h Ruckfl, 1-(Ethoxycarbonyl-melh-yl)-2-nitro-benzimidazol 84 137-139 210... 

Wahrend Diazo-diphenyl-methan mit Benzofurazan-l-oxid am heterocyclischen Ringreagiert (s.S.803), bildet 5-Nitro-benzofurazan-l-oxid mit Diazo-essigsaure-methylester bzw. -ethyl-ester 8-Ethoxycarbonyl- bzw. 8-Melhoxy-carbonyl-6H-[Pg.805]

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