Formaldehyde acyclic derivatives

Utilitarian aspects of these heterocyclic phosphines are much less studied than those of their acyclic analogues. Thus, the fire resistivity of materials increases on treatment with aminomethylphosphines. With this aim, polymers generated by the interaction of phosphine with formaldehyde and amine can be used (62BRP919267). The same effect is observed for l,3,5-triaza-7-phosphaadamantane (74USP374584) and 3,7-dicyano-3,5,7-triaza-l-phosphabicyclo[3,3,l]-nonane and its derivatives (74-USP391189). 

More recently, a catalyst-free aqueous version of this strategy was proposed with simple acyclic 1,3-dicarbonyls, formaldehyde, and styrene or anilines derivatives (Scheme 40) [131], In the first case (Scheme 40), the very reactive 2-methylene-1,3-dicarbonyl intermediate reacts smoothly at 80°C with a variety of substituted styrenes to give the corresponding dihydropyrans in moderate to good yields. Remarkably, when styrenes were replaced by A-ethylaniline, a novel five-component reaction involving twofold excess of both formaldehyde and 1,3-dicarbonyl selectively occurred (Scheme 41). The result is the formation of complex fused pyranoquinolines following a Friedel-Craft alkylation - dehydration sequence to furnish the quinoline nucleus, which suffers the Hetero-Diels-Alder cyclization in synthetically useful yields. 

Similarly, both acyclic and cyclic allyl amine derivatives have been applied in 1,3-dipolar cycloadditions (134-138). Langlois et al. (139) used a,()-unsaturated-y-lactams derived from (5)-pyroglutaminol, such as 91 and 92, in the 1,3-dipolar cycloaddition with the A -benzylnitrone derived from formaldehyde (Scheme 12.30). For compound 91, one of the 1,3-dipolar cycloaddition product isomers obtained... 

Benzyl Acetals Acyclic acetals are used for the protection of OH groups. The most common ones are derived from formaldehyde. The benzyl acetal of formaldehyde is known as the benzyl-oxymethyl (BOM) protecting group. The hydrogenolysis of the benzylic C-O... 

Corey and Yamamoto 233) used the P-oxido synthesis 2341 of trisubstituted olefins for the preparation of the acyclic sesquiterpene famesol 433. In this preparation the isoheptenylphosphonium salt 430 is converted into the hydroxyfamesol derivative 432 by reaction with the tetrahydropyranyl ether — protected hydroxy aldehyde 431 and formaldehyde 205. 432 is converted into famesol 433 via several steps. Other reactions of432 likewise proceeding via several steps lead to 434 which is a positional isomer of a C17-juvenile hormone 233) (Scheme 75). 

The protection of formaldehyde or other aldehydes as acyclic dithioacetals, sulfanylethers, sulfonylethers, thiosulfoxides, diselenoacetals, aminothioacetals and aminals, as well as cyclic dithioacetals, dioxolanes, oxazolidines and imidazolidines, allows the preparation of different type of protected acyllithium derivatives IV-XI by deprotonation (see... 

The Mannich reaction of enaminones was examined intensively. Enamines derived from dimedone are aminoalkylated in the -position in good yield if the nitrogen is unsubstituted or monosubstituted31,34. Primary amines and formaldehyde react with enaminones to yield tetrahydropyrimidines34 (equation 21). A similar reaction is observed for acyclic enaminones. With primary amines and formaldehyde, tetrahydropyrimidines are formed35 (equation 22). 

Monosaccharides. - 1.1.1 Acyclic Compounds. A new route to 2-deoxypentose dialkyl dithioacetals 2 involved opening of the L-ascorbic add-derived epoxide 1 with lithiated formaldehyde dialkyl dithioacetals. Standard protecting group manipulations converted 2 (R = Bu ) to the 4-mesylate 3. ... 

The aldol reaction in the presence of an acyclic amino acid has been harnessed in total synthesis. Takabe reported the organocatalytic ot-hydro)ymethylation of a cyclic ketone in aqueous formaldehyde with L-threonine, as the key step for the formal synthesis of chiral jasmine lactone. In a similar way, the team of Chen and Chai prepared several cyclohexanone derivatives. Much more recently, a synthesis of phaitanthrin A by aldol reaction of tryptanthrin with acetone in the presence of the potassium salt of L-phenylalanine has been performed in gram-scale quantities. Numerous derivatives have been obtained with yields of up to 98% and ee of up to 99%. 

Jerome et al. reported the catalyst-free reaction of mostly acyclic 1,3-dicarbonyl compounds with formaldehyde 72 and styrene derivatives in water at elevated temperatures... 

The first example of an addition reaction of an C(sp -B based organoboronic add to an iminium ion was reported by Petasis and Akritopoulou in 1993 [24]. They demonstrated the addition of ( )-alkenylboronic acids to preformed iminium ions derived from secondary amines and formaldehyde, to generate allylic amines 1 (Scheme 7.1). Typically, a two-stage process was employed for the formation of 1. Initially, a secondary amine (including, dialkyl, acyclic and cydic examples) was heated with paraformaldehyde in dioxane or toluene solvent at 90 °C for 10 min. An ( )-alkenyl-boronic acid was then added, and the solution either stirred at 90 °C for 10 min, or at room temperature for 3 h. The allylic amine product 1 was then isolated through a standard aqueous work-up (sequential treatment with aqueous HCl and NaOH). The synthetic utility of this chemistry was demonstrated in this first report by a synthesis of the oral antifungal agent naftifine (2). 

Nuclear aminomethyl derivatives are obtained by the Mannich synthesis when phenols or napthols are reacted with secondary cyclic and acyclic a%l amines. p-HydroxydimethylbenzylamLne (m.p. 200°C) is obtained from dimethylamine, formaldehyde, and phenoP - . ... 

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