2-Furaldehyde semicarbazone

Synonyms. Furacilinum Nitrofural. Proprietary Name. Furacin(e) 5-Nitro-2-furaldehyde semicarbazone C6H6N404= 198.1 CAS—59-87-0... 

NF NIFUZON 5-NITROFURALDEHYDE SEMICARBAZIDE 6-NITROFURALDEHYDE SEMICARBAZIDE 5-NITRO-2-FURALDEHYDE SEMICARBAZONE 5-KITROFURAN-2-ALDEHYDE SEMICARBAZONE 5-NITRO-2-FURANCARBOX-ALDEHYDE SEMICARBAZONE 2((5-NITRO-2-FURANYL)METHYLENE)HYDRAZINECARBOXAMIDE... 

Nitrofurflzone. 2-[(5 Nitro 2 /u ranyl imethylene)-hydrazinecarboxamide 5-nitro-2 furaldehyde semicarbazone Ami fur Furacin Chemofuran Fu resol Nifuzon Nitrofur l Nitrozone Furacinetten Furacoccid Furazol W Mammex Furaplast Coxistat Aldomycin Nefco Vabrocid. C6H6-mol wt 198,14. C 36.37%, H 3.05%, N 28.28%, O 32.30%. Prepd from 2-formyl -5 -nitrofuran and semicarba-zide hydrochloride Stillman, Scott, U-S, pat. 2,416,234... 

Repeat the preceding experiment, but use 0.3 g of 2-furaldehyde semicarbazone (prepared in Part B) and 0.3 mL of cyclohexanone in place of the cyclohexanone semicarbazone and 2-furaldehyde. 

Dihydroimidazole-2(3//)-thione (ETU) 5-Nitro-2-furaldehyde semicarbazone (Nitrofurazone) 7 45 4212... 

On interruption of the reaction at the minimum point, only a low yield of the final product, 5-(methoxymethyl)-2-furaldehyde, could be isolated as the semicarbazone, but a crystalline phenylosazone (m.p. 120.5-121.5°, [< ]d —9° in chloroform) was obtained. It was not isolable at the end of the reaction. No osazone was obtainable from the hydroxy-glycal without prior, acid treatment. Analyses of the osazone indicated that it was a mono-O-methyl derivative of the parent CgHgCh. This is the same formula that was found by Bergmann and Zervas (see above ) for the parent of the phenylosazone obtained by direct treatment of 2,3,4,6-tetra-0-acetyl-(2-hydroxy-D-glucal) with phenylhydrazine. Whereas Bergmann and Zervas were unable to acetylate the compound further, Wolfrom, Wallace and Metcalf introduced an O-acetyl group into their mono-O-... 

Nitro-2-furaldehyde (5-nitrofurfural), mp 36°C, is prepared by the nitration of 2-fliraldehyde. Some of its derivatives are bacteriostatic and bacteriocidal, e.g. the semicarbazone (Nitrofural), and are used to combat infectious diseases. 

Acetic anhydride added to a soln. of 5-nitro-2-furaldehyde 2-(2-hydroxypropyl)-semicarbazone in anhydrous dimethyl sulfoxide, and stirred 18 hrs. at 50° 4-... 

The principle of kinetic and thermodynamic control in organic chemistry may be illustrated by studying the competing reactions of semicarbazide (1) with two carbonyl compounds, cyclohexanone (2) and 2-furaldehyde (4), as shown in Equations 13.3 and 13.4, respectively. In this case, one compound, semicarbazide, reacts with two different compounds, cyclohexanone and 2-furaldehyde, to give two different semicarbazones, 3 and 5, respectively. Both products are crystalline solids that have distinctive melting points by which they may be easily identified. Thus, it is easy to determine experimentally which compound is the product of kinetic control and which is the product of thermodynamic control. 

For best results, the 2-furaldehyde should be freshly distilled immediately before use. Prepare the semicarbazone of 2-furaldehyde by following the procedure of Part A exactly, except use 0.4 mL of 2-furaldehyde instead of 0.5 mL of cyclohexanone. Recrystallization of the product is unnecessary. Obtain IR and NMR spectra of your starting material and product. Compare your spectra with those of authentic samples (Figs. 13.7-13.10). 

Place 0.3 g of cyclohexanone semicarbazone. prepared in Part A. 0.3 mL of 2-furaldehyde, 2 ml of 95% ethanol, and 10 mL of water in a 25-mL Erlen-meyer flask. Warm the mixture until a homogeneous solution is obtained (about 1 or 2 min should suffice), and continue warming for an additional 3 min. Cool the mixture to room temperature and then place it in an ice-water bath. Collect the crystals on a filter, and wash them with 2-3 mL of cold water. Thoroughly air-dry the crystals and determine their weight and melting point. 

On the basis of your results from experiments C. D. and E. deduce which semicarbazone is the product of kinetic control and which is the product of thermodynamic control. To do this, first use the observed melting points of the crystals produced in parts Cl, C2, and C3 to deduce whether the product in each part is the semicarbazone of cyclohexanone, of 2-furaldehyde. or of a mixture of the two. Note that in Cl the crystals of product separate almost immediately, in C2 after 1 or 2 min. and in C3 only after 10-15 min at a higher temperature thus the reaction time is shortest in Cl, intermediate in C2. and longest in C3. Then compare the product of D1 with that of C2 and the product of D2 with that of C3. 

Discuss the differences observed in the IR and NMR spectra of 2-furaldehyde and of its semicarbazone that are consistent with the replacement of the carbonyl function by a carbon-nitrogen double bond in this experiment. 

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