Tetrahydro-4H-pyran-4-ones

The reaction flask is allowed to cool and is then immersed in an ice-water bath. A solution of 160-180 g. (4-4.5 moles) of sodium hydroxide pellets in 500 ml. of water is added slowly with stirring until the pH rises to 5. After the addition of400 ml. of ether, the products are transferred to a 5-1. separatory funnel and then shaken. The darkly colored organic upper layer is separated and the aqueous layer extracted with two 500-ml. portions of ether. The combined ether extracts are dried over anhydrous magnesium sulfate and concentrated to about 800 ml. under reduced pressure in a rotary evaporator. The concentrated extract is transferred to a 1-1. round-bottomed flask and fractionated through a 25-cm. Vigreux column under reduced pressure. A forerun of dioxane is collected and then tetrahydro-4H-pyrane-4-one distils as a colorless liquid, b.p. 59-60°/13 mm. The yield is 102-112 g. (50-55 %) for the two steps, based on 3-chloropropionyl chloride. 

THP-one = Tetrahydro-4H-pyran-4-one M = Number average molecular weight M . = Weight average molecular weight MW = Molecular weight PDI = Polydispersity Index Z = Benzyloxycarbonyl... 

C7H1202 tetrahydro-2,6-dimethyl-4H-pyran-4-one 1073-79-6 447.69 38.882 2 11590 C7H13CI 2-ch loro-1-heptene 65786-11-0 412.15 33.867 1.2... 

EINECS 267-305-0 4H-l ran-4-one, tetrahydro-3,5-bis(hydroxymethyl)- Tetrahydro-3,5-bis(hydroxymethyl)-4H-pyran-4-one Tetrahydro-3,5-dimethylol-4-pyrone. 

Pyran, 2-(2-methyl-1-propenyl)-4-methyltetrahydro-. See Tetrahydro-4-methyl-2-(2-methyl -1 -propenyl )-2H -pyran 2H-Pyran-2-one, 5-butyl-5-ethyltetrahydro-. See Ethyl butyl valerolactone 4H-Pyran-4-one, 2-methyl-3-(1-oxopropoxy)- 4H-Pyran-4-one, 2-methyl-3-( 1 -oxypropoxy)-. See Maltyl propionate... 

BF3 OEt2 promotes the condensation of hydroxyl silyl enol ethers with various aldehydes to give as-2,6-disubstituted 3,3-dimethyltetrahydro-4H-pyran-4-ones. The tetrahydro-4f/-pyran-4-one moiety of the natural compound cyanolide A is enantioselectively prepared using this method... 

C2 Ha aBrNOa 9 2-p-Bromophenyl-4a,5,5a,6,7,8,9,9a,10,10a-decahydro-5a-methyl-10a-morpholino-4H-naphtho[2,3-b]pyran, 40B, 336 C211H3fiNeO, N,N -Bis-(2-cyanoethyl)-l, 10-diaza-4,7,13,16-tetraoxa-cyclo-octadecane malononitrile complex, 45B, 417 C25H20CINO13, 6,7-Bis(methoxycarbonyloxy)-l,2,3,4-tetrahydro-iso-quinoline-[1,2-c]-oxazol-2-one-[3,4-b]-1-chloro-3-methoxycarbonyl-oxy-6,7-methylenedioxyindane, 45B, 418 C2 5H21 Cl2NO, 3-(3,5-Dichloro-2,4,6-trimethylphenyl)-4-diphenylmeth-ylene-2-isoxazoline, 42B, 283... 

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