2- ethoxycarbonyl-5,6,7,8-tetrahydro

Cyclohexen 4,5-Dicarboxy-l-methoxy- VII/2b, 1794 Furan 3,5-Dimethyl-2,4-dioxo-3-ethoxycarbonyl-tetrahydro- VI/2, 681... 

Oxepin, 4-ethoxycarbonyl-2,3,6,7-tetrahydro-synthesis, 7, 578 Oxepin, 2-methyl-enthalpy of isomerization, 7, 555 Oxepin, 2,3,4,5-tetrahydro-reduction, 7, 563 synthesis, 7, 578 Oxepin, 2,3,4,7-tetrahydro-synthesis, 7, 578 Oxepin, 2,3,6,7-tetrahydro-oxidation, 7, 563 reduction, 7, 563 Oxepin-2,6-dicarboxylic acid stability, 7, 565 Oxepinium ions synthesis, 7, 559 Oxepins, 7, 547-592 antiaromaticity, 4, 535 applications, 7, 590-591 aromatization, 7, 566 bond lengths and angles, 7, 550, 551 cycloaddition reactions, 7, 27, 569 deoxygenation, 7, 570 dipole moment, 7, 553 disubstituted synthesis, 7, 584... 

Thieno[2,3-c]pyridine, 2-amino-6-benzyl-3-ethoxycarbonyl-4,5,6,7-tetrahydro-biological activity, 4, 1015 Thieno[2,3-c]pyridine, 4,5,6,7-tetrahydro-biological activity, 4, 1015 Thieno[3,2-6]pyridine, 3-hydroxy-synthesis, 4, 1010... 

Propenyl)-1,3-dithiane, after lithiation and addition of zinc chloride, reacts with ethyl 2-oxopropanoate to give preferentially the. vvn-adduct37, which is an intermediate in the synthesis of racemic /ra .s-tetrahydro-2,3-dimethyl-5-oxo-2-furancarboxylic acid. It is assumed, that the ethoxycarbonyl group is brought to a pseudoaxial position in the cyclic transition state by the chelating zinc cation. 

CN [2S-[2a,6p(/ )]]-6-[[l-(ethoxycarbonyl)-3-phenylpropyl]amino]tetrahydro-5-oxo-2-(2-thienyl)-l,4-thiazepine-4(57/)-acetic acid... 

The synthesis of imidazo[2,Tc][l,2,4]triazolo-3-thiones has been investigated. For instance, the reaction of 1,2,4-triazoline-3-thione 361 <1995JHC275> with methyl trifluoromethanesulfonate affords the stable 3-methylmercapto-1,2,4-triazolium trifluoromethanesulfonate 362 in quantitative yield, which after treatment with sodium bicarbonate and bromine provides 6-bromomethyl-2,6-dimethyl-7-ethoxycarbonyl-2,3,5,6-tetrahydro-7//-imidazo[2,T4-[l,2,4]triazolo-3-thione 10 in 47% yield, via intermediate 363 (Scheme 36) <1996T791>. 

Mit Oxo-bernsteinsaure-diethylester wird dagegen 6-(Ethoxycarbonyl-methylen)-5-oxo-4,5,6.7-tetrahydro-(pyrazino[2,3-c furazan) gebildet239 ... 

Singh and Lai [73IJC959 76IJC(B)685] prepared 8,9,10,11-tetrahydro-benzothiazolo[3,2-c]quinazolin-7-ium perchlorate (287) by dehydrative cyclization of 4-[(2-oxocyclohexyl)thio]quinazoline (286) with sulfuric acid and then perchloric acid. 2-(2-Azidophenyl)benzothiazole (288) reacted with triphenylphosphine to give the iminophosphorane, which cyclized to 289 on treatment with ethoxycarbonyl isocyanate (89T4263). 

Reactions of 6,7,8,9-tetrahydro-ll//-pyrido[2,l-b]quinazolin-l 1-one (7), its 2-ethoxycarbonyl derivative (120, R = 2-COOEt), and 1,2,3,4,6,7,8,9-octahydro-ll//-pyrido[2,l-b]quinazolin-ll-one with diethyl oxalate in ethanol in the presence of sodium ethoxide at ambient temperature for 12 h gave 6-ethoxalyl derivatives (23 and 24) [89JCS(P2)1613]. 

The presence or absence of the dioxolane protecting group in dienes dictates whether they participate in normal or inverse-electron-demand Diels-Alder reactions.257 The intramolecular inverse-electron-demand Diels-Alder cycloaddition of 1,2,4-triazines tethered with imidazoles produce tetrahydro-l,5-naphthyridines following the loss of N2 and CH3CN.258 The inverse-electron-demand Diels-Alder reaction of 4,6-dinitrobenzofuroxan (137) with ethyl vinyl ether yields two diastereoisomeric dihydrooxazine /V-oxide adducts (138) and (139) together with a bis(dihydrooxazine A -oxide) product (140) in die presence of excess ethyl vinyl ether (Scheme 52).259 The inverse-electron-demand Diels-Alder reaction of 2,4,6-tris(ethoxycarbonyl)-l,3,5-triazine with 5-aminopyrazoles provides a one-step synthesis of pyrazolo[3,4-djpyrimidines.260 The intermolecular inverse-electron-demand Diels-Alder reactions of trialkyl l,2,4-triazine-4,5,6-tricarboxylates with protected 2-aminoimidazole produced li/-imidazo[4,5-c]pyridines and die rearranged 3//-pyrido[3,2-[Pg.460]

The 9-benzoyl- and 9-[(ethoxycarbonyl)carbonyl]tetrahydro-4//-pyrido[l,2-a]pyrimidin-4-ones also exhibit predominantly the 1,6,7,8-tetrahydro tautomeric forms in solution [85JHC593 89JCS(P2)1613]. 

Reaction of 3-formyl-4//-pyrido[l,2-a]pyrimidin-4-ones 409 with [(ethoxycarbonyl)methylene]triphenylphosphorane in a Wittig reaction in dimethylformamide at ambient temperature for 10 hours gave 3-trans-acrylates 410 (92JHC559). The 3-formyl group of 3,9-diformyl-l,6,7,8,-tetrahydro and 3-formyl-9-phenylhydrazono-6,7,8,9-tetrahydro-4//-pyr-ido[l,2-a]pyrimidines was transformed to a trans-acrylate side chain in a Wittig reaction with [(ethoxycarbonyl)methylene]triphenylphosphorane in dimethyl sulfoxide at room temperature for 24 hours (84JMC1253). 

COOEt R1 = H, Me) were acylated with diethyl oxalate in diethyl ether in the presence of sodium ethylate at 0-20°C [89JCS(P2)1613]. After the acidification of the reaction mixture, 9-(ethoxycarbonyl)carbonyl derivatives 577 were obtained from the sodium salts. The 9-(ethoxycarbonyl)car-bonyl derivatives 577 exist as 1,6,7,8-tetrahydro tautomers. 

Chemical Name 3-(Ethoxycarbonyl)-6,7,8,9-tetrahydro-6-methyl-4-oxo-4H-pyrido[l,2-a]pyrimidine-9-acetic acid... 

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