Potassium tert-butylate

On autoxidation by aeration in tertiary butyl alcohol containing potassium tert-butyl oxide, quininone yields quininic acid (98 per cent.) and meroquinenine terf-butyl ester, CgHi N. CO. O. C4H9, b.b. 127°/20 mm., dj 0-9832, [a]o° -(- 50-0° (EtOH), identified by hydrolysis to meroquinenine (meroquinene) and eonversion of this to the better-known ethyl ester (p. 438). (Doering and Chanley.)... 

Dimesitylimidazolium chloride in the presence of potassium tert-butylate reacts with [RuCl2(PCy3)2(=CHPh)] or [RuCl2(PCy3)2(=CHCH=CMe2)] to yield the mixed phosphine-carbene complexes [RuCL(L)(PCy3)(=CHPh)] or... 

O-isopropylidene derivative (57) must exist in pyridine solution in a conformation which favors anhydro-ring formation rather than elimination. Considerable degradation occurred when the 5-iodo derivative (63) was treated with silver fluoride in pyridine (36). The products, which were isolated in small yield, were identified as thymine and l-[2-(5-methylfuryl)]-thymine (65). This same compound (65) was formed in high yield when the 5 -mesylate 64 was treated with potassium tert-hx Xy -ate in dimethyl sulfoxide (16). The formation of 65 from 63 or 64 clearly involves the rearrangement of an intermediate 2, 4 -diene. In a different approach to the problem of introducing terminal unsaturation into pento-furanoid nucleosides, Robins and co-workers (32,37) have employed mild base catalyzed E2 elimination reactions. Thus, treatment of the 5 -tosylate (59) with potassium tert-butylate in tert-butyl alcohol afforded a high yield of the 4 -ene (60) (37). This reaction may proceed via the 2,5 ... 

A similar study of the oxidation of sulphoxides by potassium tert-butyl hydroperoxide found similar results70. 

C22H22C1N,0 114772-55-3) see Losartan potassium tert-butyl chloroformate (C5H9CIO2 24608-52-4) see Cefalexin 2-butyl-4-chloro-5-hydroxymethyiimidazole (CSII13CIN2O 79047-41-9) see Losartan potassium 2-butyl-4-cbloro-lif-imidazole-5-carboxaldehyde (CnHiiClNjO 83857-96-9) see Eprosartan Losartan potassium... 

C4 H35C1N 0 120568-18-5) see Losartan potassium tert-butyl (4R,6S)-2-(6-cyanomethyl-2,2-dimcthyl-13-di-oxan-4-yl)acetale... 

When potassium tert-butylate in the solid state comes into contact with a few drops of methanol, ethanol, or 1- or 2-propanol it causes the alcohols to combust after a latency period of two, seven, and one minute(s) respectively. If the alcohol is in the vapour state, ignition can also take place. However, if there is a large quantity of alcohol, there is no incident since alcohol in excess absorbs the heat produced. 

Potassium tert-butylate leads to ignition of halogen derivatives, which is more or less immediate, depending on their nature and physical state two minutes with liquid dichloromethane and gaseous chloroform one minute with liquid carbon tetrachloride and epichlorhydrin immediate ignition with gaseous chloroform. 

When acetone comes into contact with potassium tert-butylate, which is an extremely strong base, acetone combusts immediately. The same goes for butanone and methylisobutylketone. 

In the presence of potassium tert-butylate and as with most organic compounds, esters combust spontaneousiy after a period of induction that is generally very short. Such accidents have been reported with propyl formate, ethyl acetate and dimethyl carbonate. 

Salts with the same structure have been put forward to explain the detonations or ignitions that were observed during several accidents involving DMSO and sodium hydride, sodium isopropylate and potassium tert-butylate. However, it is known that the last-named base causes the ignition of nearly all organic compounds. 

The ultraviolet spectrum of the monosodium salt of luminol shows the absorptions of both the mono- and the dianion of luminol on addition of potassium tert. butylate the equilibrium is shifted to the dianion109). On the other hand, even small quantities of water shift the equilibrium back to the monoanion. The luminol dianion Lum2< ) was found to have a higher fluorescence efficiency than the monoanion. Absorption and fluorescence data for luminol, Lum< > and Lum2< > are listed in Table 4. 

The basic principles of the previous section (oxygen substituent) can be transferred to nitrogen as the substituent. Here most of the examples use either potassium tert-butylate or a stoichiometric deprotonation with n-butyllithium followed by protonation with methanol. 

When the reaction of enaminone (223) and dimethyl methoxymethy-lenemalonate was carried out in THF in the presence of butyllithium, pyrrolidinomethylenemalonate (224) was obtained in 4% yield. When this reaction conducted in DMF in the presence of potassium tert-butylate, pyrrolidinomethylenemalonate (224) and 2,3-dihydro- l//-indolizin-5-one (225) were prepared in 21 and 46% yields, respectively (88AP345). 

Triazoles (386, R1 = COOMe) were treated with potassium tert-butylate in a mixture of f r/-butanol and benzene for 15-60 min to give (substituted amino)methoxycarbonylmethylenemalonates (387, R1 = COOMe) in 28-54% yields. In the case of the acetyl derivative (386, R = Ph, R1 = COMe), the reaction was carried out in chloroform in the presence of triethylamine at ambient temperature for 8 hr, to give (pheny-lamino)acetylmethylenemalonate (387, R = Ph, R = COMe) in 38% yield. (Phenylamino)acylmethylenemalonates (387, R = Ph,R = COMe, COPh) were also prepared in 62-74% yields when diazo derivatives (388, R1 = COMe, COPh) were heated in benzene for 4-24 hr (80T1821) (Scheme 34). 

The second way is from 4-androsten-3,17-dione (21.5.6), which undergoes ethynylation by propargyl alcohol in the presence of potassium tert-butylate, forming 17 8-hydroxy-17a-(3-hydroxypropinyl)-4-androsten-3-one (21.5.9), the triple bond of which is completely reduced by hydrogen using as a catalyst a complex of triphenylphospine and... 

C4 H CIN60 12056)8-18-5) sec Losartan potassium tert-butyl (4ft,6/t)-2-(6-cyanonu thyl-2,2-diinethyl-l,3-di-oxan-4-yl)acetate... 

Naturally, it is possible to synthesise a similar ligand system without central chirality and in fact without the unnecessary methylene linker unit. A suitable synthesis starts with planar chiral ferrocenyl aldehyde acetal (see Figure 5.30). Hydrolysis and oxidation of the acetal yields the corresponding carboxylic acid that is transformed into the azide and subsequently turned into the respective primary amine functionalised planar chiral ferrocene. A rather complex reaction sequence involving 5-triazine, bromoacetal-dehyde diethylacetal and boron trifluoride etherate eventually yields the desired doubly ferrocenyl substituted imidazolium salt that can be deprotonated with the usual potassium tert-butylate to the free carbene. The ligand was used to form a variety of palladium(II) carbene complexes with pyridine or a phosphane as coligand. 

Reaction of nitriles 49 with nitrosobenzene and potassium tert-butylate under exclusion of oxygen gives vinylaminyloxides 51, the intermediate nitrones 50 being not isolable69. Apparently the nitrosobenzene operates as oxidizing agent to some extent. 

The PflN ligands 10a,b as well as the corresponding palladium complexes were synthesized as depicted in Fig. 2.14. Treatment of 2-(chloromethyl)pyridine with one equivalent of bis(2-methylphenyl)phosphane in the presence of potassium tert-butylate yielded ligand 10 a which was directly converted into the palladium diiodide complex 11b. Purification of 11b was achieved by column chromatography on sihca. 

In fact, the mediator, i.e. t-BuOH, is electrochemically reduced to the t-BuO anion that nucleophilically attacks PVDF, in much the same way as potassium tert-butylate, to yield elimination products. The authors also studied electrochemical dehydrochlorination of oriented poly(l,2-dichloro-ethylene) films under heterogeneous conditions [9]. The starting polymer was produced by chlorination of polyacetylene [10,20]. The elimination product, however, was found to be predominantly polychlorovinylene with a small proportion of carbynoid moieties. The authors came to that conclusion because of very low intensity of the IR absorption peak attributable to triple C=C-bonds. On the other hand, its low frequency at 2145 cm could... 

Strong bases, such as potassium tert-butylate or sodium methoxide, catalyse the reaction of carboxymethylation of aliphatic and aromatic amines at 90°C. 

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