Dehydrozingerone

Yellow solid Vanillylidene acetone has a very sweet, warm and tenacious odor.

General procedure: To a solution of substituted benzaldehydes (6a1–d1, 6e, 6f) and acetone (10–25 equivalents, excess) in ethanol was added 20percent (w/v) aqueous NaOH at 0–5°C. The reaction mixture was stirred at ambient temperature and the progress of the reaction was monitored by TLC. When the substituted benzaldehyde was consumed, the excess acetone was removed in vacuo; cold water was then added and the resulting solution was acidified with 3M HCl. The product which appeared as a solid was collected by vacuum filtration, washed with water and dried in vacuo. The residue was purified by column chromatography or recrystallized from appropriate solvent system to yield the substituted 4-phenylbut-3-en-2-ones 7a1–d1, 7e and 7f.4-(4-Hydroxy-3-methoxy-phenyl)but-3-ene-2-one: To a solution of acetone (15.30 g, 263.76 mmol) in a mixture of ethanol (35 niL) and water (15 mL) were added sodium hydroxide (2.90 g, 72.54 mmol) and 4-hydroxy-3-methoxybenzaldehyde (5.01 g, 32.97 mmol). The reaction mixture was stirred at room temperature for 15 h. The reaction was cooled to 0° C and quenched with 2.0 N hydrochloric acid until the solution became slightly acidic. The solution was extracted with ethyl acetate (4x 100 mL). The combined organic layers were washed with water (50 mL) and saturated aqueous sodium chloride (50 mL). EPO General procedure: A mixture of aromatic aldehyde (2 mmol) and ketone (2 mmol) was added in one portion to 11 mol percent of dry catalyst A-2XMP at RT and was stirred for 1 h. Progress of the reaction was monitored by TLC (hexane:ethylacetate :: 88:12, v/v). After completion of the reaction, excess of ethyl alcohol was added. The reaction mixture was filtered and the filtrate was concentrated under reduced pressure. Crystallization was observed at RT. Pure products (15a-18a) were purified by recrystallization from ethyl alcohol giving 87-94percent yields.4.1.2. General procedure for the preparation of compounds (1f, g). Toa stirred solution of p-hydroxybenzaldehydes (10 mmol) in anhydrousacetone (15 mL) was added 10percent NaOH solution (25 mL), andthe mixture was stirred for 3 h at room temperature. Acidification using 10percent HCl until the color change of Congo red paper from red toblue. The resulting mixture was extracted with dichloromethane(30 mL3). The organic layers werewashed with brine (20 mL) and dried over MgSO4 were filtered, evaporated, and the residue waspurified by column chromatography (ethyl acetate/n-hexane1:10)to give pure 1f-g.Vanillin (20 g) was dissolved in acetone (50 mL) in a round bottomflask and 40percent KOH (5 mL) was added to this reaction mixture.It was kept on stirring at room temperature. After the completionof reaction (monitored by TLC), reaction mixture was acidified withdilute hydrochloric acid until pH 7 was achieved. It was thenpoured in ice-cold water, filtered and dried to get the desired product, that is, vinyldenacetone (VDA). The physical data of vinyldenacetoneis given below:4.2.1. (E)-4-(4-Hydroxy-3-methoxyphenyl)but-en-2-one (VDA)Yield 72percent; mp 71–73 C. 1H NMR (CDCl3, 500 MHz, d, TMS = 0):2.36 (s, 3H), 3.91 (s, 3H), 6.58 (d, J = 16.5 Hz, 1H), 6.92 (d, J = 7.5 Hz, 1H), 7.04–7.08 (m, 2H), 7.45 (d, J = 16.5 Hz, 1H). 13C NMR (CDCl3, 125 MHz, d, TMS = 0): 27.22, 55.84, 109.56, 114.99, 123.52, 124.82, 126.79, 144.03, 147.08, 148.51, 198.72.Vanillin (20g) was dissolved in acetone (50ml) in a round bottom flask and 40percent KOH (5ml) was added to this reaction mixture. It was kept on stirring at room temperature. After the completion of reaction (monitored by TLC), reaction mixture was acidified with dilute hydrochloric acid until pH 7 was achieved. It was then poured in ice-cold water, filtered and dried to get the desired product i.e. vinyldenacetone (VDA). The physical data of vinyldenacetone is given below. Yield 72percent; mp 71–73°C. General procedure: A suspension of an appropriate aromatic aldehyde (1 eq.), and ylide I or II (1.3–1.5 eq.) inwater (4–10 mL) was stirred at 90 °C for 0.5–24 h. Next, the heterogeneous reaction mixturewas cooled to room temperature, and the aqueous phase was extracted with DCM (3 10 mL).The solvent was evaporated under diminished pressure. Column chromatography (hexane–ethylacetate, or chloroform–methanol) of the residue gave the E-alkene as the major product.

Molecular Weight:192.21
XLogP3:1.7
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:3
Exact Mass:192.078644241
Monoisotopic Mass:192.078644241
Topological Polar Surface Area:46.5
Heavy Atom Count:14
Complexity:223
Undefined Bond Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes