Formic secondary formation

Refluxing a mixture of (lS, 4S, 7RS, 8R, 9R )-7-hydroxy-8-isobutyl-9-methyl-6-azatricy-clo[6.1.1.04-9]decane-6-carbaldehyde (5) and 95% formic acid for 12 hours gave a 1 1 mixture of (E)- and (Z)-(l/ , 4S,, 7S, 8/ )-9-isobutylidene-8-methyl-2-azatricyclo[5.2.1.04-8]decaiie-2-carbaldehyde (6) and the secondary formate (lR, 4S, 77 , 8R, 10S )-10-isobutyl-8-formy-loxy-7-methyl-2-azatricyclo[5.2.1.04,1°]decane-2-carbaldehyde (7) in 24% and 55% yield, respectively.87 The rearrangement is believed to involve the cyclobutyliminium ion, as shown.87... 

Formic acid forms esters with primary, secondary, and tertiary alcohols. The high acidity of formic acid makes use of the usual mineral acid catalysts unnecessary in simple esterifications (17). Formic acid reacts with most amines to form formylamino compounds. With certain diamines imida2ole formation occurs, a reaction that has synthetic utiHty (18) ... 

The methylation of secondary amines works better than for primary amines because there is no competition between the formation of mono- or dimethylated products. The best results for the microwave-enhanced conditions were obtained when the molar ratios of substrate/formaldehyde/formic acid were 1 1 1, so that the amount of radioactive waste produced is minimal. The reaction can be carried out in neat form if the substrate is reasonably miscible with formic acid/aldehyde or in DM SO solution if not. Again the reaction is rapid - it is complete within 2 min at 120 W microwave irradiation compared to longer than 4 h under reflux. The reaction mechanism and source of label is ascertained by alternatively labeling the formaldehyde and formic acid with deuterium. The results indicate that formaldehyde contri-... 

Inversion of configuration.1 The configuration of a secondary alcohol (2) can be inverted by reaction with dicyclohexylcarbodiimide (1) to form an isourea ether (3), which is allowed to react, without isolation, with formic acid with formation of the ester 4 with inverted configuration. 

Reductive alkylation can also be accomplished by heating carbonyl compounds at 150-250° with 4-5 mol of ammonium formate, formamide, or formates or formamides prepared by heating primary on secondary amines with formic acid at 180-190° (Leuckart reaction) [322]. An excess of85-90% formic acid is frequently used. Formyl derivatives of primary or secondary amines are sometimes obtained as products and have to be hydrolyzed to the corres-... 

Removal of the chloroacetyl protection in this molecule is accomphshed in the following manner. Subsequent reaction of the product (32.1.2.71) with thiourea in the presence of sodium bicarbonate results in the formation of a new thiazole derivative. Subsequent cleaving of the resulting secondary heteroaromatic amine with formic acid gives ceftriaxone... 

Vanadyl phosphate (VOPO4 2H2O), a layered material containing Lewis and Brpnsted acid sites, was also tested as an acid catalyst in the dehydration of fructose to HMF (Scheme 7) [76]. These catalysts afforded HMF with a selectivity of 80% at 46% conversion of fructose. Other catalytic systems, obtained by partial substitution of groups with trivalent metals (Fe ", Cr, Ga, Mn, Al, were also investigated. It has been shown that when Fe-substituted vanadyl phosphate was employed a selectivity of 90% to HMF was obtained at 38% conversion without the formation of secondary products such as levuUnic and formic acid. This catalyst was also proved to be efficient for the conversion of inuUn into HMF with the same selectivity as with fructose. 

Osmotic laxatives (e.g., lactulose, sorbitol) are poorly absorbed or nonabsorbable compounds that draw additional fluid into the GI tract. Lumen osmolality increases, and fluid movement occurs secondary to osmotic pressure. Lactulose is a synthetic disaccharide that is poorly absorbed from the GI tract, since no mammalian enzyme is capable of hydrolyzing it to its monosaccharide components. It therefore reaches the colon unchanged and is metabolized by colonic bacteria to lactic acid and to small quantities of formic and acetic acids. Since lactulose does contain galactose, it is contraindicated in patients who require a galactose-free diet. Metabolism of lactulose by intestinal bacteria may result in increased formation of intraluminal gas and abdominal distention. Lactulose is also used in the treatment of hepatic encephalopathy. 

Formic acid, methyl formate, and CO were detected when photoreduction was performed in Ti silicalite molecular sieve using methanol as electron donor.173 Mechanistic studies with labeled compounds indicated, however, that CO originates from secondary photolysis of formic acid, whereas methyl formate emerges mainly from the Tishchenko reaction of formaldehyde, the initial oxidation product of methanol. 

Volatile buffers were reconsidered for the modified method. Triethylamine was ruled out primarily because it could not be obtained in high purity and because the secondary and primary amines contaminating it could potentially react with solutes present in the water sample. Preliminary evidence of reaction between ethidium bromide and triethylammonium bicarbonate was obtained, but the reaction product was not characterized. The components of volatile buffers that appeared acceptable on the basis of chemical purity were ammonia, acetic acid, and formic acid. A few exploratory experiments were conducted involving the elution by ammonium formate and ammonium acetate of EB or quinaldic acid exchanged onto AG MP-50 or IRA 900. These experiments showed that 1 M ammonium formate in water was a very poor eluent, but that EB could be eluted from AG MP-50 with 1 M ammonium formate in methanol. Elution was essentially complete with 6 bed volumes of the methanolic eluent, whereas neither methanol alone nor aqueous 1 M ammonium formate was able to elute this solute. This situation pointed out the necessity for a counterion to displace exchanged solutes and, additionally, indicated that the displaced solute be highly soluble in the eluting solvent. 

Reduction ofimines using formates Ammonium formates and formic acid have been employed as reducing agents in the synthesis of secondary amines from imines. By simple mixing of the reagents and microwave irradiation without solvent, the amines were produced in good yields within 2.5-10 min (Scheme 4.28)51. 

This reaction allows the preparation of tertiary methylamines from secondary amines via treatment with formaldehyde in the presence of formic acid. The formate anion acts as hydride donor to reduce the imine or iminium salt, so that the overall process is a reductive amination. The formation of quaternary amines is not possible. 

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