Formamides aldehydes

BOROHIDRURO SODICO (Spanish) (16940-66-2) Combustible solid. Dust or powder forms explosive mixture with air autoignition above 550°F/288°C. Reacts with water, steam, moist air, alcohols, glycols, phenols, cresols, palladium dust, producing flammable hydrogen gas. Violent reaction with acids, forming diborane gas, with the possibility of explosion. Violent reaction with oxidizers, dimethyl formamide, aldehydes, ketones, metal powders, metal salts, sodium hydroxide. Polymerization may be caused by contact with bases, acrylonitrile, sodium borohydride. Forms explosive material that is ultra-sensitive to friction or shock, and moisture-sensitive with salts of ruthenium. Attacks metals. Corrodes glass slowly. 

Concentrated acids Dimethyl formamide Aldehydes and ketones... 

The conversion of an aldehyde or ketone into the corresponding amine by heating with ammonium formate or with formamide and formic acid at about... 

Aromatic and heterocycHc compounds are formylated by reaction with dialkyl- or alkylarylformamides in the presence of phosphoms oxychloride or phosgene (Vilsmeier aldehyde synthesis) (125). The Vilsmeier reaction is a Friedel-Crafts type formylation (126), since the intermediate cation formed by the interaction of phosphoms oxychloride with formamide is a typical electrophilic reagent. Ionic addition compounds of formamide with phosgene or phosphoms oxychloride are also known (127). 

The condensation of a vinylogous formamide with an enamine has been applied to an aza azulene synthesis (351). The point of attachment of the aldehyde to the enamine in condensations with indolenin derived poly-enamines was found to favor the second double bond (352,353). 

Furfuryl dimethyl amine is first produced. This may conveniently be accomplished by employing the Leuckart synthesis known to those skilled in the art, which involves the use of an aldehyde or a ketone, and formate of ammonia or an amine, or corresponding formamide derived by dehydration of formate of ammonia or an amine. 

Although a number of reagents can be used to reduce an isoxazole ring, molybdenum hexacarbonyl31 was selected for use in this synthesis. The action of this reagent on 24 reduces the weak N-0 bond of the isoxazole ring and produces a //-amino-a,//-unsaturated aldehyde (i.e. a vinylogous formamide) (see Scheme 19). Intermediate 87 forms smoothly upon deprotection of the terminal acetylene carbon with basic methanol-THF. 

Formylation of alkenes can be accomplished with N-disubstituted formamides and POCl3. ° This is an aliphatic Vilsmeier reaction (see 11-15). Vilsmeier formylation can also be performed on the ot position of acetals and ketals, so that hydrolysis of the products gives keto aldehydes or dialdehydes ... 

Aldehydes, formates, primary, and secondary alcohols, amines, ethers, alkyl halides, compounds of the type Z—CH2—Z, and a few other compounds add to double bonds in the presence of free-radical initiators/ This is formally the addition of RH to a double bond, but the R is not just any carbon but one connected to an oxygen or a nitrogen, a halogen, or to two Z groups (defined as on p. 548). The addition of aldehydes is illustrated above. Formates and formamides " add similarly ... 

Pr)4, " borohydride-exchange resin,and formic acid. When the last is used, the process is called the Wallach reaction. Conjugated aldehydes are converted to alkenyl-amines with the amine/silica gel followed by reduction with zinc borohydride.In the particular case where primary or secondary amines are reductively methylated with formaldehyde and formic acid, the method is called the Esch-weiler-Clarke procedure. It is possible to use ammonium (or amine) salts of formic acid, " or formamides, as a substitute for the Wallach conditions. This method is called the Leuckart reaction,and in this case the products obtained are often the N-formyl derivatives of the amines instead of the free amines. Primary and secondary amines can be iV-ethylated (e.g., ArNHR ArNREt) by treatment with NaBH4 in acetic acid. Aldehydes react with aniline in the presence of Mont-morillonite KIO clay and microwaves to give the amine. Formaldehyde with formic acid converts secondary amines to the N-methyl derivative with microwave irradiation. 

Disubstituted formamides can give addition of 2 mol of Grignard reagent. The products of this reaction (called Bouveault reaction) are an aldehyde and a tertiary amine.The use of an amide other than a formamide can give a ketone instead... 

Alkylation of enamines Addition of amines to triple-bond compounds Addition of amines to aldehydes or ketones Reaction between Grignard reagents and formamides Reaction of phosphonates with aldehydes or ketones... 

Reaction of aldehydes with the conjugate base of formamide ... 

Benzaldehyde reacts with formamide and MesSiCl 14 on heating to give, via 435, the N,N-acetal 469, which reacts in situ with p-toluenesulfinic acid, in high yields, to give 470 [58]. The analogous reaction of excess a,)9-unsaturated ahphatic primary amide with aliphatic aldehydes in the presence of TMSOTf 20 in 1,2-di-chloroethane at 25 °C affords the unsaturated N,N-acetals in high yield [58 a]. Benzaldehyde also condenses with excess HMDS 2, in the presence of catalytic amounts of ZnCl2, via 471, to 472 and HMDSO 7 [59] (Scheme 5.21). 

Aldehydes can also be obtained from Grignard reagents by reaction with formamides, such as A-formylpiperidine. In this case, the initial adducts are stable and the aldehyde is not formed until hydrolysis during workup. 

Luche and coworkers extended their studies on the applications of ultrasound to synthesis to include a variety of systems. Among these applications are the syntheses of lithioorganocuprates(ll), of aldehydes from formamides(12), of organozinc intermediates(13),... 

In 2001, Sarko and coworkers disclosed the synthesis of an 800-membered solution-phase library of substituted prolines based on multicomponent chemistry (Scheme 6.187) [349]. The process involved microwave irradiation of an a-amino ester with 1.1 equivalents of an aldehyde in 1,2-dichloroethane or N,N-dimethyl-formamide at 180 °C for 2 min. After cooling, 0.8 equivalents of a maleimide dipo-larophile was added to the solution of the imine, and the mixture was subjected to microwave irradiation at 180 °C for a further 5 min. This produced the desired products in good yields and purities, as determined by HPLC, after scavenging excess aldehyde with polymer-supported sulfonylhydrazide resin. Analysis of each compound by LC-MS verified its purity and identity, thus indicating that a high quality library had been produced. 

The conversion of a Grignard or an organolithium reagent to an aldehyde has been accomplished by a variety of reagents. The methods include such reagents as N-ethoxymethyleneaniline 2 ethyl ortho-formate 2" p-dimethylaminobenzaldehyde 25 dimethyl formamide 3 a... 

Anthrapyrimidine and its substituted derivatives are obtained by condensation of 1-aminoanthraquinone (or its derivatives) with formamide or aqueous form-aldehyde/ammonia in the presence of an oxidant, such as ammonium vanadate or m-nitrobenzosulfonic acid. A newly developed, more simple route proceeds via formamidinium chloride, which is prepared from 1-aminoanthraquinone with di-methylformamide and thionyl chloride or phosphorus oxychloride. Cyclization in a solvent in the presence of ammonium acetate affords the desired product ... 

Fused cyclic system 340 can be obtained by type (i) reaction through the reduction of the nitro aldehyde intermediate 339 and its sequential cyclization in acetic acid. Alternate type (iii) process starts from the corresponding formamide 341 that can be cyclized with phosphorus oxychloride by a Bischler-Napieralski reaction (Scheme 72 (1994JHC1033)). 

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