5- Hydroxymethyl furan

In many cases, substituents linked to a pyrrole, furan or thiophene ring show similar reactivity to those linked to a benzenoid nucleus. This generalization is not true for amino or hydroxyl groups. Hydroxy compounds exist largely, or entirely, in an alternative nonaromatic tautomeric form. Derivatives of this type show little resemblance in their reactions to anilines or phenols. Thienyl- and especially pyrryl- and furyl-methyl halides show enhanced reactivity compared with benzyl halides because the halogen is made more labile by electron release of the type shown below. Hydroxymethyl and aminomethyl groups on heteroaromatic nuclei are activated to nucleophilic attack by a similar effect. 

Furan-2-carbaldehyde, 5-hydroxymethyl- C NMR. 4, 565 <76AJC107) Furan-2-carbaldehyde, 3-methoxy-... 

Benzo[b]furan, 2,3-dihydro-2-hydroxymethyl-4//-chromene synthesis from, 3, 764 Benzo[b]furan, 2,3-dihydro-2-isopropenyl-synthesis, 4, 678, 680... 

Furan, 3-acetyl-5-(hydroxymethyl)-2-methyl-synthesis, 4, 663 Furan, 2-acyl-synthesis, 4, 148, 690 Furan, 3-acyl-synthesis, 4, 662, 670 Furan, 4-acyl-2-alkyl-synthesis, 4, 688 Furan, 3-acylamino-tautomerism, 4, 38... 

Timko and Cram were the first to prepare true crown ethers containing the furanyl subcyclic unit ° . Destructive distillation of sucrose yielded 2-hydroxymethyl-5-formyl-furan 7 in 41% yield. This could be reduced to the corresponding diol in 91% yield by treatment with sodium borohydride. Reaction of the diol with tetraethylene glycol dito-sylate, and potassium t-butoxide in THE solution afforded the crown in 36% yield. The approach is illustrated below as Eq. (3.26). 

Hydroxymethylation and alkylation of furans, thiophenes, and pyrroles in the presence of H" " cations 98KGS3. 

Some of the typical conditions of polycondensations used for aliphatic and aromatic monomers are not suitable for furan derivatives, e.g., the melt polycondensation of 2,5-furan dicarboxylic acid chloride with 2,5-b/s(hydroxymethyl) furan at about 80 °C only yields a black insoluble product5. The hydrochloric acid liberated in the reaction is clearly responsible for the charring of the furanic diol which like its simpler homologue furfuryl alcohol, resinifies rapidly in acidic media (see below). 

Before 1983, branched-chain sugars had not been found in bacterial polysaccharides, but there are now five examples belonging to this class. The LPS from Coxiella burned phase I contains both 6-deoxy-3-C-methyl-L-gulose (L-virenose) as pyranoside (12) and 3-C-(hydroxymethyl)-L-lyxose as furan-oside (13). Another 6-deoxy-3-C-methylhexose, having the manno configuration, is a component of the Nitrobacter hamburgiensis 0-antigen. ... 

Sulfur tetrafluoride, Triethylamine See Sulfur tetrafluoride 2-(Hydroxymethyl)furan, Triethylamine... 

Hydroxymethyl)furan, Triethylamine Jenzen, A. F. et al., J. Fluorine Chem., 1988, 38, 205-208 Reaction of sulfur tetrafluoride with 2-hydroxymethylfuran in presence of triethylamine at —50°C is explosive in absence of a solvent. 

The development of synthetic methods for the selective introduction of short-chain perfluoroalkyl groups into organic molecules is of interest in drug development [464]. Fluoromodifications often confer unique properties on a molecule, for example in terms of increased metabolic stability and lipophilicity and, as a consequence, the pharmacokinetic profiles are often improved [465]. Burger and coworkers developed a domino process consisting of a SN reaction combined with a Claisen and a Cope rearrangement which allows the transformation of simple fluorinated compounds into more complex molecules with fluoro atoms [466]. Treatment of furan 2-917 with 2-hydroxymethyl thiophene (2-918) in the presence... 

An unusual rearrangement of a 3-hydroxymethyl-4-hydroxybutenolide into a furan-3-carboxylic acid occurs in the natural product, photogedunin, when it is treated with alkali the reaction is really related to some of those in sub-sections B, C, and E.llla... 

Hydroxymethyl-4,8-dimethylfuro[2,3-/z]chromen-2-one was realized in an efficient manner via a Claisen rearrangement of 4-(hydroxybut-2-ynyloxy)-4-methylchromen-2-one as depicted in the following scheme. Other examples with substitution of hydroxyl and with other substituents, such as chloro, amino, acetoxy were also reported <06JHC763>. A new approach for the synthesis of oxygenated benzo[fe]furans was developed via epoxidation and cyclization of 2 -hydroxystilbene <06T4214>. 

The hydrogenation of HMF in the presence of metal catalysts (Raney nickel, supported platinum metals, copper chromite) leads to quantitative amounts of 2,5-bis(hydroxymethyl)furan used in the manufacture of polyurethanes, or 2,5-bis(hydroxymethyl)tetrahydrofuran that can be used in the preparation of polyesters [30]. The oxidation of HMF is used to prepare 5-formylfuran-2-carboxylic acid, and furan-2,5-dicarboxylic acid (a potential substitute of terephthalic acid). Oxidation by air on platinum catalysts leads quantitatively to the diacid. [32], The oxidation of HMF to dialdehyde was achieved at 90 °C with air as oxidizing in the presence of V205/Ti02 catalysts with a selectivity up to 95% at 90% conversion [33]. 

R,5S)-4-HYDR0XYMETHYL-(5-0-tert-BUTYLDIMETHYLSIL0XYMETHYL)FURAN-2(5H)-ONE D-erythro-PENTONIC ACID, 2.3-DIDE0XY-5-0-[(1,1-DIMETHYLETHYL)DIMETHYLSILYL]-3-HYDROXYMETHYL)-, y-LACTONE (164848-06-0), 75, 139... 

PHOTOINDUCED-ADDITION OF METHANOL TO (5S)-(5-0-tert-BUTYLDIMETHYLSILOXYMETHYL)FURAN-2(5H)-ONE (4R,5S)-4-HYDROXYMETHYL-(5-0-tert-BUTYLDIMETHYLSILOXYMETHYL)FURAN-2(5H)-ONE (2(5H)-Furanone, 5-[[[(1,1-dimethylethyl)dimethylsilyl]oxy]methyl]-, (S)-and D-erythro-Pentonic acid, 2,3-dideoxy-5-0-[(1,1-dimethylethyl)dimethylsilyl]-3-(hydroxymethyl)-, y-lactone)... 

The photoinduced-addition of alcohols to cycloalkenones has been investigated by Fraser-Reid and co-workers,4 by Paquette,5 and was used as the key step in the synthesis of the prostaglandin endoperoxide analogue (15S)-hydroxy-9a,11a-epoxymethanoprosta-(52,13E)-dienoic acid,6 and for the recent synthesis of 2, 3 -dideoxy-3 -hydroxymethyl-5 -carbanucleosides.7 No work (other than our own) has been reported on the photoinduced-addition of alcohols to 5-substituted furan-2(5H)-ones. 

Chlorine, Antimony trichloride, Tetramethylsilane, 4047 Chlorine, 2-Chloroalkyl aryl sulfides, Lithium perchlorate, 4047 Sulfur tetrafluoride, 2-(Hydroxymethyl)furan, Triethylamine, 4350 Titanium, Halogens, 4919... 

El Haji, T. Masroua, A. Martin, J.-C. Descotes, G. Synthesis of 5-(hydroxymethyl)-furan-2-carboxaldehyde and its derivatives by acid treatment of sugars on ion-exchange resins, Bull Soc. Chim. Fr., 1987, 855-860. 

Elming, N. Clauson-Kaas, N. 6-Methyl-3-pyridinol from 2-hydroxymethyl-5-aminomethyl-furan, Acta Chem. Scand., 1956, 10, 1603-1605. 

D-Erythrose has also been exposed to a boiling solution in pH 4.5 buffer. Low yields (<0.2%) of a number of products were obtained, as shown in Scheme 3. These included 5-(hydroxymethyl)-2-furaldehyde (11), 2-acetyl-5-(hydroxymethyl)furan (12), 3,4-dihydroxyacetophenone (13), 3,4-dihydroxy be nzaldehyde (14), 3,4-dihydroxybenzoic acid (15), 2,3-dihydroxytoluene (16), and 1,2-benzenediol (pyrocatechol) (17). Also detected were formic, hydroxyacetic, and 3-hydroxypropanoic acids. Pyrocatechol seems to be a product formed from all carbohydrates boiled in aqueous solutions at pH 4-10 it may constitute a statistical product arising from retro-aldol and re-aldol reactions. It has been shown that the aldol reaction may operate at a pH as low as 4. An aldol reaction... 

Thermolysis of D-fructose in acid solution provides 11 and 2-(2-hydrox-yacetyl)furan (44) as major products. Earlier work had established the presence of 44 in the product mixtures obtained after acid-catalyzed dehydrations of D-glucose and sucrose. Eleven other products were identified in the D-fructose reaction-mixture, including formic acid, acetic acid, 2-furaldehyde, levulinic acid, 2-acetyl-3-hydroxyfuran (isomaltol), and 4-hydroxy-2-(hydroxymethyl)-5-methyl-3(2//)-furanone (59). Acetic acid and formic acid can be formed by an acid-catalyzed decomposition of 2-acetyl-3-hydroxyfuran, whereas levulinic acid is a degradation prod-uct of 11. 2,3-Dihydro-3,5-dihydroxy-6-methyl-4//-pyran-4-one has also been isolated after acid treatment of D-fructose.The pyranone is a dehydration product of the pyranose form of l-deoxy-D-eo f o-2,3-hexodiulose. In aqueous acid seems to be the major reaction product of the pyranone. 

Hydroxymethylfurfural may be oxidized to 5>hydroxymethyl-furan-2-carboxylic acid (LV), the ethyl ester of which is easily hydrogenated to ethyl 5-hydroxymethyltetrahydrofuran-2-carboxylate (LVI). This ester is a potential source of adipic acid by the following series of... 

Hydroxymethyl furfural. 2,5-diformylfuran (DFF) is a furan derivative that has many uses, including use as a polymer building block. By utilizing a platinum catalyst supported on carbon, and running the reaction in water at high temperatures, DFF is produced as the major product in neutral solution. If low temperatures and high pH are employed, 2,5-furandicarboxylic acid results. 

Hydroxymethylfurfural. 2,5-Di(hydroxymethyl)furan can be synthesized from 5-HMF via hydrogenation (Scheme 16). Under a hydrogen pressure of 7 MPa at 140 °C in the presence of platinum or copper catalysts, practically quantitative yields of 2,5-di(hydroxymethyl)furan can be obtained.However, under similar conditions but with palladium or nickel as catalyst, hydrogenation of the ring system occurs so that 2,5-di(hydroxymethyl)-tetrahydrofuran is obtained as the predominant product. 

---