Inline forming

Relatively little data are available on sulfonamido derivatives of heterocyclic systems with five-membered rings.26111 The tautomeric equilibrium between structures 222 and 223 has been shown to favor the inline form by about 10 1 by comparison of the ultraviolet spectrum of the parent compound with those of both methylated forms.262... 

A useful variant of the inline-forming reaction just discussed involves the treatment of a ketone or aldehyde with hydrazine, H2NNH2, in the presence of KOH. This reaction, discovered independently in 1911 by Ludwig Wolff in Germany and N. M. Kishner in Russia, is a valuable method for converting a ketone or aldehyde into an alkane, RjOO — RjCHj. The Wolff-Kislmer reaction was originally carried out at temperatures as high as 240°C, but a modification in which dimethyl sulfoxide is used as solvent allows the process to take place near room temperature. 

A Schiff base is an inline formed by condensation of a primary amine and a carbonyl compound. 

Fig. 16. Two-hquid flotation flow sheet (39). The original ROM is kaolin (white clay) that contains 11% impurity in the form of mica, anatase, and siUca. Treatment produces high purity kaolin and a Ti02-rich fraction. A, Kaolin stockpile D, dispersant (sodium siUcate plus alkah) W, water K, kerosene C, collector (sodium oleate) RK, recycled kerosene S, screen M, inline mixer SPR, separator CFG, centrifuge P, product and T, to waste.

High Shear High shear impellers take a variety of proprietary forms and are used primarily for producing emulsions. Their design maximizes the portion of the mixing energy dissipation which is classified as shear. High shear impellers are available for both tank and inline applications. 

Bis(semicarbazones) with N202 donor set form six-coordinate complexes with distorted octahedral geometry. The well-studied (potentially pentadentate) 2,6-diacetylpyridine bis(semicarbazone) (H2daps, 448) forms two type of crystals containing the same complex [Ni(Hdaps)2].1267 The ligands are coordinated through their pyridine and the inline N atoms and the O atom of one arm. 

Domino transformations combining two consecutive anionic steps exist in several variants, but the majority of these reactions is initiated by a Michael addition [1]. Due to the attack of a nucleophile at the 4-position of usually an enone, a reactive enolate is formed which can easily be trapped in a second anionic reaction by, for example, another n,(5-urisalurated carbonyl compound, an aldehyde, a ketone, an inline, an ester, or an alkyl halide (Scheme 2.1). Accordingly, numerous examples of Michael/Michael, Michael/aldol, Michael/Dieckmann, as well as Michael/SN-type sequences have been found in the literature. These reactions can be considered as very reliable domino processes, and are undoubtedly of great value to today s synthetic chemist... 

Jacobsen and co-workers (87) investigated the carbenoid-transfer reaction to inline acceptors. These workers found that bis(oxazoline)Cu(I) complexes are most effective among the catalysts screened, providing moderate yields and selec-tivities in this process. The reaction is complicated by the formation of pyrrolidines in racemic form as side products (Eq. 75). 

The sulfonylimine 72 reacts with cyclopentadiene in benzene at 0°C to afford solely the exo-adduct 73 in 84% yield (equation 48)42. The unstable inline 75, formed from the phosphorus compound 74 and ethyl glyoxylate by an aza-Witig reaction, adds to dienes... 

Through this modification, they hoped to capture a later conformational intermediate poised to form an inline transition state. The technique used was that of time-resolved crystallography, one that has successfully captured protein intermediates (see Section 3.7.2.3). The data determining the crystal structure has been deposited in the Protein Databank as PDB 379D. 

When enamines are treated with alkyl halides, an alkylation occurs that is analogous to the first step of 2-15. Hydrolysis of the inline salt gives a ketone. Since the enamine is normally formed from a ketone (6-14), the net result is alkylation of the ketone at the a position. The method, known as the Stork enamine reaction is an alternative to the ketone alkylation considered at 0-95. The Stork method has the advantage that it generally leads almost exclusively to monoalkylation of the ketone, while 0-95, when applied to ketones, is difficult to stop with the introduction of just one alkyl group. Alkylation usually takes place on the less substituted side of the original ketone. The most commonly used amines are the cyclic amines piperidine, morpholine, and pyrrolidine. 

The inline bond of 5,6-dihydro-4//-l,3-oxazines reacts with oxiranes to form bicyclic adducts (Scheme 31) <66AG(E)875) and with ketenes to yield cepham analogues (Scheme 32) (75AP481). 

One of the most spectacular and useful template reactions is the Curtis reaction , in which a new chelate ring is formed as the result of an aldol condensation between a methylene ketone or inline and an imine salt. The initial example of this reaction was the formation of a macrocyclic nickel(II) complex from tris(l,2-diaminoethane)nickel(II) perchlorate and acetone (equation 53).182 The reaction has been developed by Curtis and numerous other workers and has been reviewed.183 In mechanistic terms there is some circumstantial evidence to suggest that the nucleophile is an uncoordinated aoetonyl carbanion which adds to a coordinated imine to yield a coordinated amino ketone (equation 54). If such a mechanism operates then the template effect is largely, if not wholly, thermodynamic in nature, as described for imine formation. Such a view is supported by the fact that the free macrocycle salts can be produced by acid catalysis alone. However, this fact does not... 

In the reaction of /h/f-difluoro ketones with amines, a,/I-unsaturated / -amino ketones are formed, either by inline formation and imine enaminc tautomerization or via elimination of hydrogen fluoride and subsequent substitution of the other fluorine.22 Geminal sp2-bonded difluoridcs arc converted into ketenimines.12-49,89,90... 

A great variety of aza macrocycle complexes have been formed by condensation reactions in the presence of a metal ion, often termed template reactions . The majority of such reactions have inline formation as the ring-closing step. Fourteen- and, to a lesser extent, sixteen-membered tetraaza macrocycles predominate, and nickel(II) and copper(II) are the most widely active metal ions. Only a selection of the more general types of reaction can be described here, and some closely related, but non metal-ion-promoted, reactions will be included for convenience. The reactions are classified according to the nature of the carbonyl and amine reactants. 

Anilide 8 is transformed under Vihineitr conditions into the quinoline derivative19 9. In the process, phosphoryl chloride attacks the carbonyl group of anilide 8 and initially forms inline 24, which is in equilibrium with the corresponding enamine 25. 

When unknown compounds are identified without the aid of spectroscopy classification tests are used. Reacting the carbonyl in a ketone or aldehyde with an amine (2,4 dinitro-phenylhydrazine) to form an inline is the easiest way to detect a ketone or aldehyde (Reaction l). The iinine that forms is a highly colored solid. The color of the solid also helps to indicate structural characteristics. Ketones and aldehydes with no conjugation tend to form itnines with yellow to orange colors, while highly conjugated ketones or aldehydes form imines with red color. 

Allylation of carbonyl or inline functions is an important carbon-carbon bond forming methodology that also adds functionality for further elaboration and offers... 

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