Potassium hydroxide, effect

Heating of oxyprotoberberine 55, derived from dehydroprotoberberine (54), in methanol saturated with potassium hydroxide effected C-8—N bond cleavage to afford the zwitterionic salt 56, which was converted to amino ester 57 (Scheme 13) (50). The same reaction, however, could not be performed for oxyberberine (58), which lacks the additional double bond in ring B. 

Interaction of iV-pentafluorophenylcarbonimidoyl dichloride with benzonitrile and aluminium trichloride leads to l-pentafluorophenyl-4,6-diphenyl-13 -triazin-2-one along with urea derivatives . Reaction of perfluoro-5-azanon-4-ene with a range of bidentate nitrogen nucleophiles (urea, substituted amidine hydrochlorides and guanidine), in the presence of triethylamine or potassium hydroxide, effectively provides fluorinated 1,3,5-triazines 16-19 <00JFC(103)105>. 

Treatment of either the sc or the ap atropisomer of the diester (97) with potassium hydroxide effected the hydrolysis of only one of the ester groups for steric reasons, to afford monocarboxylic acid sc-98 and ap-98, respectively. The sc isomer was converted into a nienthyl ester (99) for resolution into optical isomers. Thus the three rotameric forms of the monocarboxylic acid ( + sc, -sc, ap) were isolated (142). 

The triketo ester (602) undergoes a Claisen condensation in aqueous potassium hydroxide yielding the chalcone (603). On heating, cyclization to the flavanone, pinocembrin (604), occurred (67JA6734). Methanolic potassium hydroxide effects an alternative cyclization to methyl 2,4-dihydroxy-6-styrylbenzoate. 

With this experience in hand, the amine hydrochloride IQ was transformed into the aminonitrile 2A as shown in Figure 4. This entire sequence was carried out on an approximate 0.5 mole scale via five separate reactions without isolation of intermediates to give a 67% overall yield of aminonitrile 1A based on amine IQ. Thus, the amine hydrochloride IQ was neutralized with concentrated potassium hydroxide, and the liberated free amine Q was taken up in ether. Treatment of this solution with N-chlorosuccinimide (NCS) gave a solution of the N-chloroamine 11. Further addition of ethanolic potassium hydroxide effected dehydrochlorination. The resultant bicyclic imine 12. in ethanolic ether was sequentially treated with aqueous sodium bisulfite and then solid sodium cyanide. The desired aminonitrile 1A was isolated as a distillable liquid. 

The problem of sodium and potassium hydroxides effect on the formation of efflorescence was explained by Dow and Glasser [356]. Solubility of CO in water is increasing with pH, that means with the concentration of sodium and potassium. CO2 in solution at pH slightly higher than 10 occurs mainly in the form of CO3 ion. In the carbonic acid solution, the main component of its dissociation is HCO3 ... 

It is frequently advisable in the routine examination of an ester, and before any derivatives are considered, to determine the saponification equivalent of the ester. In order to ensure that complete hydrolysis takes place in a comparatively short time, the quantitative saponi fication is conducted with a standardised alcoholic solution of caustic alkali—preferably potassium hydroxide since the potassium salts of organic acids are usuaUy more soluble than the sodium salts. A knowledge of the b.p. and the saponification equivalent of the unknown ester would provide the basis for a fairly accurate approximation of the size of the ester molecule. It must, however, be borne in mind that certain structures may effect the values of the equivalent thus aliphatic halo genated esters may consume alkali because of hydrolysis of part of the halogen during the determination, nitro esters may be reduced by the alkaline hydrolysis medium, etc. 

Ethynylation of ketones is not cataly2ed by copper acetyUde, but potassium hydroxide has been found to be effective (180). In general, alcohols are obtained at lower temperatures and glycols at higher temperatures. Most processes use stoichiometric amounts of alkaU, but tme catalytic processes for manufacture of the alcohols have been described the glycols appear to be products of stoichiometric ethynylation only. 

Titration of thioglycolate esters is also realized by iodine in alcohoHc solution. Titration of thioglycolic acid (acid number) in thioglycolate esters is effected by potentiometric titration with potassium hydroxide. 

Dilute solutions of ammonium hydroxide and sodium carbonate have Httle effect on tin, but strong alkaline solutions of sodium or potassium hydroxide, cold and dilute, dissolve tin to form stannates. 

The crown ethers and cryptates are able to complex the alkaU metals very strongly (38). AppHcations of these agents depend on the appreciable solubihty of the chelates in a wide range of solvents and the increase in activity of the co-anion in nonaqueous systems. For example, potassium hydroxide or permanganate can be solubiHzed in benzene [71 -43-2] hy dicyclohexano-[18]-crown-6 [16069-36-6]. In nonpolar solvents the anions are neither extensively solvated nor strongly paired with the complexed cation, and they behave as naked or bare anions with enhanced activity. Small amounts of the macrocycHc compounds can serve as phase-transfer agents, and they may be more effective than tetrabutylammonium ion for the purpose. The cost of these macrocycHc agents limits industrial use. 

Manufacture. A limited, amount of natural cinnamyl alcohol is produced by the alkaline hydrolysis of the cinnamyl cinnamate present in Styrax Oil. Thus treatment of the essential oil with alcohoHc potassium hydroxide Hberates cinnamyl alcohol of reasonable purity which is then subjected to distillation. This product is sometimes preferred in fine fragrance perfumery because it contains trace impurities that have a rounding effect in finished formulations. 

Similar alkylations may be effected on oxygen. l-(2-Chloroethyl)imidazolidin-2-one (312) when treated with potassium hydroxide or sodium hydride underwent ring closure to the tetrahydroimidazo[2,l-6]oxazole (313) (57JA5276). This approach can be used for the preparation of bicyclic hydantoins and the corresponding dihydro derivatives of (313) using the mesylate of (312) and NaH (77JHC5U, 79JMC1030). 

As with poly(vinyl alcohol), poly(vinyl cinnamate) is prepared by chemical modification of another polymer rather than from monomer . One process is to treat poly(vinyl alcohol) with cinnamoyl chloride and pyridine but this is rather slow. Use of the Schotten Baumann reaction will, however, allow esterification to proceed at a reasonable rate. In one example poly(vinyl alcohol) of degree of polymerisation 1400 and degree of saponification of 95% was dissolved in water. To this was added a concentrated potassium hydroxide solution and then cinnamoyl chloride in methyl ethyl ketone. The product was, in effect a vinyl alcohol-vinyl cinnamate copolymer Figure 14.8)... 

These formulae explain the scission products of the two alkaloids and the conversion of evodiamine into rutaecarpine, and were accepted by Asahina. A partial synthesis of rutaecarpine was effected by Asahina, Irie and Ohta, who prepared the o-nitrobenzoyl derivative of 3-)3-amino-ethylindole-2-carboxylic acid, and reduced this to the corresponding amine (partial formula I), which on warming with phosphorus oxychloride in carbon tetrachloride solution furnished rutaecarpine. This synthesis was completed in 1928 by the same authors by the preparation of 3-)S-amino-ethylindole-2-carboxylic acid by the action of alcoholic potassium hydroxide on 2-keto-2 3 4 5-tetrahydro-3-carboline. An equally simple synthesis was effected almost simultaneously by Asahina, Manske and Robinson, who condensed methyl anthranilate with 2-keto-2 3 4 5-tetrahydro-3-carboline (for notation, see p. 492) by the use of phosphorus trichloride (see partial formulae II). Ohta has also synthesised rutaecarpine by heating a mixture of 2-keto-2 3 4 5-tetrahydrocarboline with isatoic anhydride at 195° for 20 minutes. 

It has been claimed that the elimination of tosylates of 3a-alcohols in 5jS-series gives 3-oleflns with high selectivity. However, the homogeneity of these products is questionable, in view of recent findings concerning the ehmination of 3-chloro compounds (see below) and Fieser s results with the elimination of methyl lithocholate tosylate (ref. 232, cf. ref. 233). Neutral alumina may also be used to effect elimination of tosylates of 3j5-alcohols if the alumina is pretreated with potassium hydroxide the inverted alcohol is the predominant product. 

Alcoholic potassium hydroxide or sodium hydroxide are normally used to convert the halohydrins to oxiranes. Other bases have also been employed to effect ring closure in the presence of labile functional groups such as a-ketols, e.g., potassium acetate in ethanol, potassium acetate in acetone or potassium carbonate in methanol.However, weaker bases can lead to solvolytic side reactions. Ring closure under neutral conditions employing potassiunT fluoride in dimethyl sulfoxide, dimethylformamide or A-methyl-pyrrolidone has been reported in the patent literature. 

Under more forcing conditions than had been reported earlier [7], penta-fluorophenol, when heated in a strong solution of aqueous potassium hydroxide, gives a respectable yield of tetrafluororesorcinol [5] (equation 9) The process is much less effective with 2,3,5,6-tetrafluorophenol... 

The reduction of benzofuroxans can lead to a variety of products, depending upon the conditions. Deoxygenation to benzofurazans (40) can be effected either directly, using trialkyl phosphites, -tributyl or triphenyl - phosphine, or indirectly, via o-quinone dioximes (41), using methanol and potassium hydroxide, or hydroxyl-amine and alkali. - - The dioximes may be isolated, but... 

The opening of the isoxazole ring with a substituent at C-3 proceeds differently and the reaction can take various courses depending on the nature of the substituent. Besides sodium ethylate this reaction has been effected with sodium and potassium hydroxides in alcoholic or aqueous media (see, for instance, references 125 and 142). 

Potassium hydroxide with the use of the carrier is effective as an inhibitor of hexadecane destruction up to the temperature of 600°C. 

Cracking of w-alkanes is effectively inhibited by metallic sodium and potassium hydroxide with ABC carrier even under pressure and over a long period of time (Table 2). 

In case of polyethylene potassium hydroxide with an ABC carrier is effective as a thermostabilizer up to the temperature of 440°C. Regarding the thermostabiliz-... 

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