Ethanol yields

The diethyl ester which is precipitated rapidly solidifies on stirring. Filter it at the pump, wash with water (2 portions each of about 20 ml.), and recrystallise from methylated spirit or from 95% ethanol. Yield of pale yellow crystals, 8-9 g. m.p. 135-I37 ... 

A simplified procedure is possible by using polyphosphoric acid as the condensing agent. Add 160 g. of polyphosphoric acid to a solution of 11 g. of resorcinol in 13 g. of ethyl acetoacetate. Stir the mixture and heat at 75-80° for 20 minutes, and then pour into ice-water. Collect the pale yellow solid by suction filtration, wash with a little cold water, and dry at 60°. The yield of crude 4-methyl-7-hydroxycoumarin, m.p. 178-181°, is 17 g. Recrystalbsation from dilute ethanol yields the pure, colourless compound, m.p. 185°. 

Other catalysts that can be used are boron trifluoride (5), copper—chromium oxides (6), phosphoric acid (7), and siUca-alurnina (8). Under similar conditions, ethanol yields /V-ethylaniline [103-69-5] and /V,/V-diethylaniline [91-66-7] (9,10). 

After 30 hours, the maximum and critical fermentation is underway and the pH must remain above 4.0 for optimal fermentation. However, accompanying bacterial contamination from various sources such as yeast contamination, improper cleaning procedures, slow yeast growth, or excessive temperatures can result in a pH below 4.0. The remaining amylase enzymes, referred to as secondary conversion agents, are inactivated and can no longer convert the dextrins to maltose. Under these circumstances, the fermentor pH continues to drop because of acid production of the bacteria, and the pH can drop to as low as 3.0. The obvious result is a low ethanol yield and quaUty deterioration. 

Quinoxaline mono-N-oxides are also available by a direct synthesis from n-nitroaniline derivatives. Condensation of acetyl chloride derivatives with o-nitroaniline followed by treatment with sodium ethoxide in ethanol yields the mono-N-oxides in good yields (Scheme 20) (64JCS2666). 

Evaporation of the mother liquor gives a solid enriched in the 2,4 -isomer. Recrystallization of this solid from ethanol yields crystals containing 45% of the 2,4 -isomer. 

Ciemlk and Mistr (66CCC4669) demonstrated that heating diethyl 3,8-dioxode-canedioate 35 and phenylhydrazine under reflux in aqueous ethanol yielded the expected bispyrazol-3-one 36 in 55% yield (Scheme 10). 

Quaternization of harman (235) with ethyl bromoacetate, followed by cyclization of the pyridinium salt 236 with 1,2-cyclohexane-dione in refluxing ethanol yielded an ester which on hydrolysis gave the pseudo-cross-conjugated mesomeric betaine 237. Decarboxylation resulted in the formation of the alkaloid Sempervirine (238). The PCCMB 237 is isoconjugate with the 11/7-benzo[u]fluorene anion—an odd nonalternant hydrocarbon anion—and belongs to class 14 of heterocyclic mesomeric betaines (Scheme 78). 

An interesting variation of this theme starts with the a-chlorination of dicyclohexylketone (58). Treatment of the halo-genated intermediate with base leads to the acid, 60, by the Favorski rearrangement. Esterification of the acid with 2(1-pyrolidino)ethanol yields dihexyrevine (61). Both this agent and its earlier congener are recommended for use in GI spasms. 

Alkylation of that amine with p-(2-chloroethyl)aniline affords anileridine (82), an analgesic similar to the parent compound but somewhat more potent. In similar fashion alkylation by means of w-(2-chloroethyl)morpholine gives morpheridine (83), while the use of 2-(chloroethyl)-ethanol yields carbethl-... 

The resulting solution was stirred overnight at ambient room temperature. The p-acetyl-benzenesulfonamide thus prepared was collected by filtration. Recrystallization of the filter cake from aqueous ethanol yielded purified p-acetylbenzenesulfonamide melting at about 176° to 179°C. 

The acetone was removed by evaporation in vacuo, and about 750 ml of water were added to dissolve the resulting residue. The solution was filtered. The potassium salt of N-p-ace-tylphenylsuifonyl-N -cyclohexylurea formed in the above reaction, being water-soluble, passed into the filtrate. Acidification of the filtrate with 6 N aqueous hydrochloric acid caused the precipitation of N-p-acetylphenylsulfonyl-N -cyclohexylurea which was collected by filtration. Recrystallization of the filter cake from 90% aqueous ethanol yielded purified N-p-acetylphenylsulfonyl-N -cyclohexylurea melting at about 188°-190°C. 

In about 5-10 minutes a clear solution resulted, whereupon slow crystallization occurred and the temperature rose to about 6°-7°C. The crystallization was permitted to continue overnight at 5°C, and the very fine precipitate was then isolated by centrifugation and in the centrifuge washed with water, ethanol, and ether, yielding the dihydrate of DL-seryl-(2,3,4-trihydroxy-benzylidene) hydrazide hydrochloride, which melted at 134°-136°C and was poorly soluble in cold water, but very readily dissolved in hot water. The condensation was also effected in absolute ethanol yielding the anhydrous form of the hydrazone, which melted at 225°-228°C. 

C Preparation of p,p -Diacetoxybemhydrylidenecyclohexane 56 g of p,p -dihydroxy-benzhydrylidenecyclohexane (0.2 mol) was mixed with 250 ml of acetic anhydride and 500 ml of pyridine. The mixture was refluxed for 2 hours and was then poured into water, the substance crystallizing out. The crystals were filtered off and washed with water. Finally the substance was recrystallized from ethanol. Yield 62 g. MP 135° to 136°C. 

Heat a mixture of 6 grams of 2-sulfamyl-4-chloroaniline and 15 ml of ethyl orthoacetate at 100°-110°C for 1.5 hours. Cool and filter the solids. Recrystallize from aqueous ethanol yielding 3-methyl-7-chloro-1,2,4-ben2othiadiazine-1,1-dioxide. This substance is a white crystalline solid melting at 330°C. 

To a mixture of 3.0 grams of N,N -diacetyl-o-anilamide and 20 ml of acetic acid Is added a previously prepared solution of 1.5 grams of chlorine in 31 cc of acetic acid. The reaction mixture is allowed to stand at room temperature for 3 hours and is then evaporated to dryness on a steam bath under reduced pressure. The resulting solid residue is recrystallized from ethanol, yielding the intermediate N,N -diacetyl-2-sulfamyl-4-chloroaniline. The intermediate compound is fused in an oil bath at 250-260°C for 15 minutes, cooled and the product so obtained is crystallized from 80% ethanol yielding 3-methyl-7-chloro-1,2,4-benzo-thiadiazine-1,1-dioxide, MP 330°C. 

A) A mixture of 333 parts of 4-(1 -piperazinyDphenol dihydrobromide, 11.2 parts of acetic acid anhydride, 42 parts of potassium carbonate and 300 parts of 1,4-dioxane is stirred and refluxed for 3 days. The reaction mixture is filtered and the filtrate is evaporated. The solid residue is stirred in water and sodium hydrogen carbonate is added. The whole is stirred for 30 minutes. The precipitated product is filtered off and dissolved in a diluted hydrochloric acid solution. The solution is extracted with trichloromethane. The acid aqueous phase is separated and neutralized with ammonium hydroxide. The product is filtered off and crystallized from ethanol, yielding 5.7 parts of 1 acetyl-4-(4-hydroxyphenyl)piperazine MP 181.3°C. 

The nitrile may best be saponified with methyl alcoholic potash while heating to 190° to 200°C with application of pressure. After the methyl alcohol has evaporated the salt is introduced into water and by the addition of dilute mineral acid until the alkaline reaction to phenolphthalein has just disappeared, the amphoteric 1-methyl-4-phenyl-piperidine-4-carbOxylic acid is precipitated while hot in the form of a colorless, coarsely crystalline powder. When dried On the water bath the acid still contains 1 mol of crystal water which is lost only at a raised temperature. The acid melts at 299°C. Reaction with ethanol yields the ester melting at 30°C and subsequent reaction with HCI gives the hydrochloride melting at 187° to 188°C. 

One problem with elimination reactions is that mixtures of products are often formed. For example, treatment of 2-bromo-2-methylbutane with KOH in ethanol yields a mixture of two alkene products. What are their likely structures ... 

A problem often encountered in the oxidation of primary alcohols to acids is that esters are sometimes produced as by-products. For example, oxidation of ethanol yields acetic acid and ethyl acetate ... 

A. Dispiro[5.1.5.1]telradecane-7,14-dione. Cyclohexanecarbon-yl chloride (Note 1) (30.0 g., 0.205 mole) and 250 ml. of dry benzene are placed in a three-necked, round-bottomed flask equipped with a stirrer, condenser, and dropping funnel. A nitrogen atmosphere is maintained in the system. Dry triethylamine (35.0 g., 0.35 mole) is slowly added, and the mixture is heated under reflux overnight. The amine hydrochloride is then filtered, and the filtrate is washed with dilute hydrochloric acid and with water. Solvent is removed on a steam bath, and the residue is recrystallized from ligroin-ethanol yield 11-13 g. (49-58%), m.p. 161-162°. 

Method B (one-pot procedure)-. 5 g (33 mmol) of L-arabinose. 12 mL of ethanol and 4mL (36.7 mmol) of bcnzylaminc arc heated on a steam bath for 5 to 10 min to give a clear solution. After cooling, 2.5 mL of anliyd hydrogen cyanide are added. Spontaneous crystallization of the product begins within a few minutes. After cooling for 2 h with an ice-bath, the product is isolated by filtration and washed with ethanol yield 7.0-7.5g (79-85%) nip 129-131 C after recrystallization from ethanol mp 130-132 C. 

Reduction of hydrated RhCl3 with CO at 100°C (best results are with CO saturated with methanol or ethanol) yields volatile red crystals of the dimer... 

As discussed in Section 8.10, dediazoniation in methanol or ethanol yields mixtures of the corresponding aryl ethers and arenes, except with alcohols of very low nucleo-philicity such as trifluoroethanol, in which the aryl ether is the main product. Therefore aryl ethers are, in general, synthesized by alkylation of the respective phenol. Olah and Wu (1991) demonstrated, however, that phenylalkyl and aryl ethers can be obtained in 46-88% yield from benzenediazonium tetrafluoroborate using alkoxy- and phenoxytrimethylsilanes in solution in Freon 113 (l,l,2-trichloro-l,2,2-tri-fluoroethane) at 55-60 °C with ultrasonic irradiation. As seen from the stoichiometric... 

Treatment of Na2S4 with (Pli4P)2Cl in ethanol yields (Ph4P)2Ss [48] 2Na2S4 + 2Ph4PCl (Ph4P)2Ss + NaaSa + 2NaCl... 

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