2-Furfurylidene

Furfural reacts with ketones to form strong, crosslinked resins of technical interest in the former Soviet Union the U.S. Air Force has also shown some interest (42,43). The so-called furfurylidene acetone monomer, a mixture of 2-furfurylidene methyl ketone [623-15-4] (1 )> bis-(2-furfurylidene) ketone [886-77-1] (14), mesityl oxide, and other oligomers, is obtained by condensation of furfural and acetone under basic conditions (44,45). Treatment of the "monomer" with an acidic catalyst leads initially to polymer of low molecular weight and ultimately to cross-linked, black, insoluble, heat-resistant resin (46). 

In 212 cc of water are mixed 21.2 grams (0.112 mol) of N-(benzylidene)-3-amino-2-oxa-zolidone, 8.93 grams of concentrated sulfuric acid, and 30.1 grams (0.124 mol) of 5-ni-tro-2-furaldehyde diacetate. This mixture is heated to effect the hydrolysis of N-(benzy-lidene)-3-amino-2-oxazolidone, steam distillation of the benzaldehyde and hydrolysis of 5-nitro-2-furaldehyde diacetate. Approximately IV2 hours are required for this reaction to take place. When the bulk of the benzaldehyde has been removed, 50 cc of 99% isopropanol are added, the reaction mixture is refluxed a short time, and the crystals of N-(5-nitro-2-furfurylidene)-3-amino-2-oxazolidone are filtered from the hot suspension. The product is washed with water and isopropanol and dried a yield of 23.3 grams, 92.8% based on N-(benzylidene)-3-amino-2-oxazolidone of MP 254° to 256°C is obtained, according to U.S. Patent 2,759,931. 

A yellow crystalline precipitate was immediately formed, which, after crystallization from acetic acid, melted at 182°C and consisted of N-(5-nitro-2-furfurylidene)-3-amino-5-methyl-mercaptomethyl-2-oxazolidinone. 

Chemical Name 1-[[(5-nitro-2-furanyl)methylene]amino]-2,4-imidazolidinedione Common Name N-(5-nitro-2-furfurylidene)-1-aminohydantoin Structural Formula CB—H... 

In contrast with the above situation, the polymerization of 2-furfurylidene methyl ketone, di-2-fiirfurylidene ketone and their homologues has been the subject of a large volume of (mainly technical) publications because of the useful applications of the final cross-linked products. As pointed out in the introduction, this review does not deal with the technological aspects of furan resins and in this section only the mechanistic aspects of the first phase of these polymerizations will be discussed. 

The well-known condensation between 2-furaldehyde and acetone in a basic medium yields what is usually called furfurylidene acetone monomer composed of a mixture of 2-furfurylidene methyl ketone, di-2-furfurylidene ketone, mesityl oxide and other oligomers derived from further condensation reactions135. This mixture is then polymerized by the action of an acidic catalyst in the first phase of the reaction a polymer of low molecular weight is produced which on further treatment cross-links to a black insoluble and heat-resistant material136. ... 

An effort has also been made to determine the structure of products providing coloration in the Maillard reaction prior to melanoidin formation. The reaction between D-xylose and isopropylamine in dilute acetic acid produced 2-(2-furfurylidene)-4-hydroxy-5-methyl-3(2/f)-furanone (116). This highly chromophoric product can be produced by the combination of 2-furaldehyde and 4-hydroxy-5-methyl-3(2//)-furanone (111) in an aqueous solution containing isopropylammonium acetate. The reaction between o-xylose and glycine at pH 6, under reflux conditions, also pro-duces " 116. Other chromophoric analogs may be present, including 117,... 

Radicals derived from furan are named similarly to analogous radicals in the benzene series. Typical radicals are 2 (or a)-furyl (5), 2-furfuryl (6), 2-furoyl (7), and 2-furfurylidene (8) ... 

The Ar-(5-nitro-2-furfurylidene)aminotetrahydro-2-( 17/)-pyrimidone developed in China has exhibited both macro- and microfilaricidal activity in humans against lymphatic filariasis [56, 57]. Besides these compounds, various other drugs such as amodiaquine, primaquine, furazolidone and metrifonate, also have been tested as filaricidal in humans and were found to be ineffective [58] however, levamisole [38, 59] has demonstrated some micro- and macrofilaricidal effects in humans at 100 mg/kg, but it is less effective than DEC and produces more severe side-effects. The mode of action of several antifilarial drugs has also been investigated and reviewed by Rew and Fetterer [60] and Subrahmanyam [38]. 

Data for A114 and A192 are summarized in Tables II and III, alongside data for 4-hydroxy-5-methyl-3(2JH)-furanone and 2-furfurylidene-4-hydroxy-5-methyl-3(2H )-furanone, respectively. A178 is a new colored compound, the data for which are summarized in Table IV. Both HPLC and FIS data for the 10 other colored compounds isolated are summarized in Table V. 

A192, C10H8O4 The data for A192 match closely the data for 2-furfurylidene-4-hydroxy-5-methyl-3(2H )-furanone (see Table III). The two have identical HPLC retention and TLC RfS, and closely matching mass, PFIR, IR,and electronic absorption spectra. They have identical melting points, a 1 1 mixture melting sharply at the same temperature. There can be no doubt about their identity. 2-Furfurylidene-4-hydroxy-5-methyl-3(2Jd) furanone has previously been isolated from the products of... 

Common Name N-(5-Nitro-2-furfurylidene)-l-aminohydantoin Structural Formula ... 

A mixture of 2.5 grams (0.016 mol) of 5-nitro-2-furaldoxime, 3.9 grams (0.018 mol) of N-(n-heptylidene)-l-aminohydantoin and 5 cc of sulfuric acid (density 1.84) is placed in a 250 cc beaker. It is heated with stirring at steam bath temperature for about 1.5 hours. Upon cooling, a solid precipitates which is collected by filtration, washed with water, isopropanol and ether in turn and dried at 110°C for 4 hours. There is obtained N-(5-nitro-2-furfurylidene)-l-aminohydantoin in 96 to 98% yield, according to US Patent 2,927,110. 

The yields of the coloured 2-furfurylidene-4-hydroxy-5-methyl-3(2//)-furanone and 2-furfurylidene-5-methyl-3(2//)-pyrrolinone from xylose and alanine at pH 5 were strongly affected, depending on whether the reaction was carried out at atmospheric pressure or at 400 MPa.109 Formation of both colorants increased progressively... 

Furfural-ketone copolymers have found commercial use, particularly in the Soviet Union, in applications ranging from floor coverings, anti-corrosion coatings, wood adhesives, and binders for carbon/graphite. When an alkaline catalyst is used, furfural is known to react with acetone to form the so-called furfurylidene acetone monomer, a mixture of 2-furfurylidene methylketone (6), bis(2-furfurylidene) ketone (7), mesityl oxide, and other oligomers. 

Treatment of the monomer with an acidic catalyst leads initially to polymers of low molecular weight and ultimately to crosslinked, black, insoluble, heat-resistant resin (17). Despite their reportedly excellent properties, virtually no commercial use of such resins exists outside the Soviet Union. The structure and polymerization mechanism of these furfural-ketone polymers are described in a recent study (18). An excellent combustion-resistant resin has been reported (19) from the addition of dialkylphosphites to bis(2-furfurylidene) ketone (6). Furfural condensates with other aliphatic and aromatic ketones have been reported (20,21) to provide photo-crosslinkable resins and hypergol components. 

Ammonium Dimethyl-[(5-nitro-2-furfuryliden-hydrazino)-methy-len]- -4-methyl-benzolsulfonat E14b, 670 (R2N-CHO/ R-S02-C1/R-CH = N- NH2)... 

Hexanal 2-Furfuryliden- VH/1, 78 Indan 1,2-Dimethoxy- El9c, 83 (aus Inden/Methanol) Isochroman... 

SYNS NF 246 l-(((5-NITRO-2-FL RANYL)METHYL-ENE)AMINO)-2-IMIDAZOLIDINONE N-(5-NITRO-2-FURFURYLIDENE)-l-AMINO-2-IMIDAZOLIDONE N-(5-NTTRO-2-FURFURYLIDENEAMINO)-2-I flDAZO-LIDINONE l-((5-NITROFURFURYLIDENE)AMINO)-2-IMIDAZOLIDINONE NSC-6470 OXAFURADENE OXYFURADENE RENAFUR... 

FURADONIN FURANTOIN FUROBACTINA ITURAN MACRODANTIN NCI-C55196 N-(5-NITRO-2-FURFURYLIDENE)-l-AMINOHYDANTOIN N-(5-NITROFURFURYLIDENE)-l-AMINOHYDANTOIN... 

NITROFURFURYLIDENE)ANnNO)-2-OXAZOLIDONE see NGG500 N-(5-NITRO-2-FURFURYLIDENE)-3-AAnNO-2-OXAZOLIDONE see NGG500 (5-NITRO-2-FURFURYLIDENEAi nNO)UREAsee NGE500... 

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