Triethyl orthoformate, condensation

Triethyl orthoformate, condensation with N,N -diphenylethylene-diamine, 47, 14... 

Otherwise, the main reactions at the methylene group are the dialkylation with alkyl haUdes (77), the acetylation with acetyl chloride which yields acetylma1 ononitrile [1187-11-7] (78), the Knoevenagel condensation, as well as the condensation with triethyl orthoformate, gives... 

In order to expand the utility of the reaction, modification of the route to anilidomethylene malonic ester equivalents was developed. Simple condensation of triethyl orthoformate with cyanoacetic ester, acetoacetic ester, or malonic ester in the... 

In a 250-ml. round-bottomed flask equipped with a gas-inlet tube and reflux condenser 20 g. (0.094 mole) of N.N -diphenyl-ethylenediamine (1,2-dianilinoethane) (Note 1) and 100 ml. of purified triethyl orthoformate (Note 2) are heated by an oil bath under nitrogen (Note 3) for 5 hours. The oil bath is maintained between 190° and 200°, and water is allowed to stand in the condenser. The water in the condenser begins to boil slowly, and the alcohol which is produced is allowed to escape (Note 4). The reaction product which crystallizes during the reaction is filtered after cooling and washed with ether. There is obtained 19-20 g. (91 95%) of product, m.p. 285° (dec.) (Note 5). 

Diphenylcyclopropenone, 47, 62 Dii henyldiacetylene, 45, 39 Diphenyl disulfide, oxidation to methyl benzenesulfinate, 46, 62 1,1-Diphenylethylene, reaction with N,or diphenylmtrone, 46,129 N,N -Diphi iiyli tiiyleni diamine, condensation with triethyl orthoformate, 47, 14... 

Chiral imidazoline nitrone (88) was synthesized by condensation of hydrochloride a-amino oxime (87) with triethyl orthoformate according to Scheme 2.33... 

N,a-diphenylnitrone, 46,129 N,N -Diphenylethylenediamine, condensation with triethyl orthoformate, 47,14... 

The unsubstituted 1,2,4-oxadiazole has been prepared from formamidoxime and the mixed anhydride of acetic and formic acid, or formamide <67BSB92>. 5-Unsubstituted 1,2,4-oxadiazoles are formed by heating the condensation products of amide oximes with formic acid <63CI(M)1238>. Alternatively, amidoximes are treated with triethyl orthoformate in the presence or absence of... 

All the syntheses of this type give piperid-4-ones or pyrid-4-ones. Errera reported that diethyl acetonedicarboxylate condensed with triethyl orthoformate in hot acetic anhydride, and that treatment of the product with ammonia gave a poor yield of the pyrid-4-one (644) (1898CB1682). It is certain that the intermediate is the di(ethoxyvinyl) ketone (643), so that this is perhaps better classified as a [5 + 1] synthesis, but most developments from this beginning do not involve isolation of intermediates. An arylamine has been used to obtain an A-arylpyrid-4-one (645) (46JA1253). 

Hydroxymethylpyrazolo[3,4-b]pyridines have provided a number of derivatives via conversion to the alkyl halide and subsequent reaction with nucleophiles.95,249,250 The 7-position in dione 143 (R1 = Ph R2 = NH2, Ph R3 = H) was sufficiently reactive for condensation with araldehydes, giving benzals (278).139,140 Further, the amino analog afforded the dialkyl-ated product 279139 however, with triethyl orthoformate, reaction also occurred at the amino function. The compound obtained (280) reacted with amines yielding mixtures of products 281 and 282.139 Similarly, diones 283 were converted to 5,5 -dimers.251... 

Condensation of 4-amino-5-ethoxycarbonyl-2-hydrazinopyrimidine (351) with triethyl orthoformate gave 5-amino-6-ethoxycarbonyl-l,2,4-triazolo[4,3-a]pyrimidine (354) and not the isomeric 6,7-disubstituted derivative 353. Similarly, 352 and triethyl orthoacetate gave 5-amino-6-(2-ethoxy)ethylidenecarbazoyl-3-methyl-l, 2,4-triazolo [4,3-a]pyrimidine (355) (86H1899) (Scheme 68). 

In a 500-ml. three-necked flask equipped with a reflux condenser, a gas-inlet tube (Note 1) reaching to the bottom of the flask, a thermometer, and a magnetic stirrer is placed a mixture of 90.0 g. of triethyl orthoformate (Note 2) and 49.2 g. of glacial acetic acid The flask is immersed in an oil bath maintained at 125-130° (Note 3). When the internal temperature of the mixture reaches 115°, a moderate stream of ammonia is introduced. 

The title compound, 1,3-dideuteriated malondialdehyde, MDA-46, formed in a lipid peroxidation process involved in the pathogenesis of many human diseases45,46, has been needed for quantitative determination of MDA in human blood or urine by isotope dilution mass spectrometry. It has been synthesized47 by condensation of deuteriated butyl vinyl ether with deuteriated triethyl orthoformate in the presence of montmorillonite clay K-10 (equation 18). 

The condensation of 2-aminopyridine derivatives 64 with ethyl cya-noacetate gave amides 65, which were cyclized to 2//-pyrido[l,2-a] pyrimidin-2-ones 66 by the treatment of triethyl orthoformate and acetic anhydride (90IZV229). 

Azapurines were also synthesized by the condensation of 5-amino-l,2,3-triazole carboxamides 118 or 119 with formamide or with formamidinium acetate. When the triazole carried neutral substituents at N-l such as in 118, the expected 8-azapurin-6-ones 121 were formed, but when an acidic substituent was present in the same positions as in 4-carboxyphenyltri-azolamide 119, the condensation reaction gave a mixture of 6-amino-8-azapurine 120 together with 121 in addition to a small amount of Dimroth isomer 122. However, reaction of 119 with triethyl orthoformate gave a mixture of azapurine 121 and an excess of the isomeric triazole 122 (80FES308 90CZ246) (Scheme 24). 

The TV-amino functions in the derivatives (286) condense with triethyl orthoformate to yield the intermediate condensation products (287) which are readily cyclized by the action of p-toluene-sulfonic acid to yield the tricyclic systems (288) (Scheme 22) <92EJM73>. The isothiazolopyrimidines (290) are formed by condensation of compound (289) with aldehydes (Equation (37)) <83MI 712-02). 

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