Ketones ketone hydrates

Monohydric alcohols, aldehydes (including chloral hydrate), ketones, cinnamic acid, amines (2-naphthylaminc is odourless), nitrophenols (resemble both phenol and nitro-compound),... 

Oxo Ion Salts. Salts of 0x0 ions, eg, nitrate, sulfate, perchlorate, hydroxide, iodate, phosphate, and oxalate, are readily obtained from aqueous solution. Thorium nitrate is readily formed by dissolution of thorium hydroxide in nitric acid from which, depending on the pH of solution, crystalline Th(N02)4 5H20 [33088-17 ] or Th(N02)4 4H20 [33088-16-3] can be obtained (23). Thorium nitrate is very soluble in water and in a host of oxygen-containing organic solvents, including alcohols, ethers, esters, and ketones. Hydrated thorium sulfate, Th(S0 2 H20, where n = 9, 8, 6, or 4, is... 

A solution of the 3-ketone hydrate (0.15 g) in acetone- -heptane is heated to boiling. After the acetone has been boiled off, a trace of concentrated hydrochloric acid is added to the -heptane solution and boiled for an additional 2 min. After cooling, the resulting crystals are collected by filtration, washed with dry -heptane and dried in vacuo overnight. Recrystallization from dry -heptane gives 17 -hydroxy-4,4-difluoroestr-5-en-3-one 0.98 g mp 123.5-124.5° [a] 134° (CHCI3). 

In contrast, the acid-catalyzed hydration of arylbenzoylacetylenes differs markedly from the hydration of a-unsaturated ketones. Hydration of unsaturated ketones has been shown to proceed via a 1,4-addition mechanism where protonation occurs on oxygen to give an oxonium salt, followed by attack of water at the 0-carbon to give a hydroxy enol. The rate-limiting step has been shown to be the protonation of the hydroxy enol (27) ... 

Ketones from Aoetylenes Alkylation of carbonyl compounds (p T 108) with propargyi halides gives 7,5-acetyienic ketones. Hydration then gives a 1,4-diketone of a type we shall use in Chapter T 25 as in the following example, ... 

Pt-catalyzed hydration of various aliphatic and aromatic alkynes under phase transfer conditions in (CH2C1)2/H20 in the presence of Aliquat 336 led to either a Markovnikov product, mixtures of two ketones, or ketones with the carbonyl group positioned away from the bulky side.72 In the absence of the phase transfer reagent, Aliquat 336, hardly any reaction took place. Recently, a hydrophobic, low-loading and alkylated polystyrene-supported sulfonic acid (LL-ALPS-SO3H) has also been developed for the hydration of terminal alkynes in pure water, leading to ketones as the product.73 Under microwave irradiation, the hydration of terminal arylalkynes was reported to proceed in superheated water (200°C) without any catalysts.74... 

The use of mesitoic acid esters has again been successfully employed by Burrows and Topping (1975) in the elucidation of intramolecular carbon acid participation. Under basic aqueous conditions, 2-acetylphenyl mesitoate [41] hydrolyses to yield mesitoic acid and 2-hydroxyacetophenone, reacting with intramolecular catalysis via the monoanion of the ketonic hydrate (see p. 192). However, in 47.5% aqueous ethanol containing potassium hydroxide, the reaction products from l-acetyl-2-naphthyl mesitoate [45] were found... 

Phosphinic acid Sulfonamide Sulfone Ketone hydrate... 

C-3 as determined by mass spectral analysis.(55) In a mechanism involving ketone hydration prior to bindTrTg, incorporation in recovered inhibitor should be at least 50%, a value corresponding to that expected for a single cycle of nonstereospecific addition/nonstereospecific elimination of water to the ketone carbonyl. The actual results then indicate that addition-elimination is a highly stereospecific process and thus enzyme-catalyzed. 

Title Polymer Compositions of Carbonyl-Hydrated Ketone-Aldehyde Resins and Polyisocyanates in Reactive Solvents... 

STATINE ANALOGUE DIFLUORO KETONE HYDRATE HYDROXYETHYLAMINE... 

Both acid and metal catalysis are usually required to accomplish hydration of alkynes to yield carbonyl compounds.34 The addition is usually regioselective, allowing for conversion of terminal alkynes to ketones. Hydration of acetylene to produce acetaldehyde used to be an industrially significant process but was replaced by the Wacker synthesis. 

In a similar way, perfluoro bieyelie ketone hydrate 15 rearranges under flash-vacuum pyrolysis to perfluorocyclohexa-2,4-dien-l-one (16).16... 

Peptidyl fluoromethyl ketones are widely used as fairly potent inhibitors for a variety of proteases, including serine, cysteine, and aspartyl proteases. Unlike other halomethyl ketones (Section 15.1.3), fluoromethyl ketones are reversible transition-state mimics. The electron-withdrawing fluorine(s) next to the carbonyl group enhances the electrophilicity of the a-fluoroalkyl ketone functionality, thereby making the carbonyl more susceptible to nucleophilic attack. a-Fluoroalkyl ketones are good mimics of peptide bonds due to the small size of the fluorine and the stability of C F bonds. There are three general classes of peptidyl fluoromethyl ketones fluoromethyl ketones (irreversible inhibitors of cysteine proteases), difluoromethyl ketones (reversible inhibitors of both serine and aspartyl proteases), and trifluoromethyl/perfluoroalkyl ketones, which typically exist in hydrated forms and are excellent inhibitors of both serine and cysteine proteasesJ1 ... 

A very reactive ketone, obtained by Swern oxidation, is condensed in one-pot with MeMgBr. Other oxidation methods lead to the isolation of the ketone hydrate, which fails to react efficiently with Grignard reagents. 

With regard to carboxylic derivatives, there is generally little difference in chemical shift among the various trifluoroacetic acid derivatives, as exemplified by the examples in Scheme 5.30. Also, the effect of moving the CF3 farther from the carboxylic acid function is similar to that seen with the aldehydes and ketones. Trifluoromethyl ketones will often be in equilibrium with their hydrated form, in which case signals from both the hydrate and water-free ketone will be observed, as is the case for the following pyruvate example. 

H20 or alcohols as nucleophiles give low molecular weight compounds when they add to the C=0 double bond of carbonyl compounds. These addition products are called aldehyde or ketone hydrates (Section 9.1.1) and hemiacetals or hemiketals (Section 9.1.2), respectively, depending on whether they result from the addition to an aldehyde or a ketone. Today, one no longer distinguishes systematically between hemiacetals and hemiketals, but the expression hemiacetal is frequently used to cover both. 

A further complication arises if the ketone hydrate is also present in solution. Measured rate coefficients for proton transfer involving ketones may also require correction for these effects [83]. 

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