Ethyl acetate orthoformate

A solution containing 0.22 g (2 mmoles) of mimt in 5 mL of a solution containing ethyl acetate and triethyl orthoformate (95.5% v/v) is added to a solution containing 0.29 g (1 mmole) of hydrated cobalt(U) nitrate (Co(N03)2-6H20) in 10 mL of the same solvent. The resultant mixture is then refluxed in a 50-mL, single-necked, round-bottomed flask for 30 minutes. The subsequent treatment of the deep-blue crystalline product is the same as in (a). Yield, 90% as Co(C4H6N2S)2(N03)2. 

Condensation of the Grignard complex of 58 with triethyl orthoformate (59) gave a 75% yield of distilled hydroxyacetal 60. Partial hydrogenation of 60 to 61, followed by acidic hydrolysis, provided hydroxyaldehyde 62, which was isolated in the (all- -configuration. A Wittig reaction of 62 with the ylide of (a-ethoxycarbonylethyl)-tris(dimethylamino)-phosphonium bromide (63) furnished the hydroxyester 64. Treatment of 64 with ca. 0.5 mol equivalents of PBr3 in ether/hexane at -5°C in the presence of a small amount of pyridine gave an 84% yield of crystalline ester bromide 65, which could be transformed to the phosphonium bromide 55 (yield 93%) by reaction with triphenylphosphine in ethyl acetate. 

It is to be noted that excellent agreement is found between tt and results and the earlier tt values for the following 21 solvents n-hexane, cyclohexane, triethylamine, isopropanol, dioxane, -propanol, ethanol, tetrahydro-furan, ethyl acetate, methyl acetate, ethyl formate, ethanol, methyl orthoformate, 2-butanone, acetone, acetic anhydride, nitromethane, dimethylacetamide, dimethylformamide, sulfolane, and dimethyl sulfoxide. The aromatic and polychlorinated aliphatic solvents give lower rr i and ir 2 results than the uv-based tt values (as expected in the light of the fact that these are really (ir + d5) terms all nmr shifts so far studied have involved negative d values in Equation 95). 

Nitro compounds, ar. Nitrobenzene, m-Dinitrobenzene o Nitrophenol N-Nitramines Oxonium fluoroborate Trialkyloxonium salt T rialkyloxonium fluoroborate Pyrylium fluoroborate Carboxylic acid esters HCOOC2HS, p-Nitro-phenyl formate Isopropenyl acetate Ethyl cyanoacetate Chloroformic acid esters Ethyl chloroformate Methyl trichloroacetate Diethyl oxalate Ethyl malonate Orthoformic acid esters, Ethyl orthoformate (RC0)20 (CHsC0)20,... 

Some weak electrophilic reagents, which are usually inert toward azoles, also react with quaternized azoles. Diazonium salts yield phenylhydrazones (Scheme 48) in a reaction analogous to the Japp-Klingemann transformation of /S-keto esters into phenylhydrazones in the dithiolylium series illustrated the product has bicyclic character. Cyanine dye preparations fall under this heading (see also Section 4.02.1.6.5). Monomethine cyanines are formed by reaction with an iodo quaternary salt, e.g. Scheme 49. Tri- and penta-methinecar-bocyanines (384 n = 1 and 2, respectively) are obtained by the reaction of two molecules of a quaternary salt with one molecule of ethyl orthoformate (384 n = 1) or/S-ethoxyacrolein acetal (384 n =2), respectively. 

Bromobenzaldehyde has been prepared by the oxidation of -bromotoluene with chromyl chloride/ by saponification of the acetal from />-bromophenylmagnesium bromide and orthoformic ester/ by the oxidation of ethyl -bromobenzyl ether with nitric acid/ by the oxidation of /j-bromobenzyl bromide with lead nitrate/ and by the hydrolysis of i-bromobenzal bromide in the presence of calcium carbonate. ... 

Acrolein Acetal (ir, i) By treating acrolein with ethyl orthoformate in the presence of ammonium nitrate. Fischer and Baer, Helv. Chim. Acta i8, 514 (1935). 

Steroidal 17-cyanohydrins are relatively stable towards chromium trioxide in acetic acid (thus permitting oxidation of a 3-hydroxyl group ) and towards ethyl orthoformate in ethanolic hydrogen chloride (thus permitting enol ether formation of a 3-keto-A system ). Sodium and K-propanol reduction produces the 17j -hydroxy steroid, presumably by formation of the 17-ketone prior to reduction. ... 

Methylene, 287 Pivaldehyde Acetal, 289 Acetonide, 289 Cyclohexylidene. 289 Diphenylmethylene, 289 Ethyl Orthoformate, 290 Diisopropylsilylene Derivative, 290... 

In cases where decarboxylation is anticipated, the quinazolinone could be obtained by heating ammonium o-formamidobenzoate or o-forra ami do benz amide for several hours. This ring closure could be effected more conveniently by boiling the o-formamidobenzamide with 3% aqueous sodium hydroxide for a few minutes, o-Amino-benzamides have also been converted to quinazolinones by refluxing with ethyl orthoformate alone or preferably in the presence of acetic anhydride. ... 

Halogenation of the 7 position also proves compatible with good antiinflammatory activity. Construction of this compound, aclomethasone dipropionate (80), starts by introduction of the required unsaturation at the 6,7 position by dehydrogenation with DDQ (76). The highly hindered nature of the hydroxyl at position 17 requires that a roundabout scheme be used for formation of the corresponding ester. Thus treatment of 76 with ethyl orthoformate affords first the cyclic orthoformate This then rearranges to the 17 ester on exposure to acetic acid. Acylation of the 21 alcohol is accomplished in straightforward fashion with... 

Ethyloestradiol-3-ethyl ether Ethylestrenol Ethyl orthoacetate lazoxide Ethyl orthoformate Formocortal acetate Norethindrone Oxendolone Ethyl oxalate... 

Ammonium acetate, reaction with tn-ethyl orthoformate to give form-amidine acetate, 46, 39 Ammonium p chlorophenyldithiocarba mate, 46, 21... 

The fact that reaction can be made to go with (25), but not with the simple R OH, is due to the ASe (c/ p. 36) value for the former being more favourable than that for the latter, which involves a decrease in the number of molecules on going from starting material to product. Both aldehydes and ketones that are otherwise difficult to convert into acetals may often be transformed by use of orthoesters, e.g. HC(OEt)3, triethoxymethane ( ethyl orthoformate ), with NH Cl as catalyst. 

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