Condensation with sodium

Its chief importance is as a source of cinnamic acid by condensation with sodium ethan-oate and ethanoic anhydride and as a source of triphenylmethane dyestuffs by condensation with pyrogallol, dimethylaniline, etc. It is also used in the manufacture of perfumes. 

It has been thought that when an oxygen atom is inserted between the phenyl group and the furanone moiety, the activity may be enhanced. A series of alkoxy-lactones 101 were synthesized according to the procedure described by Scheme 30 (99BMC2207). Alcohols are condensed with sodium chloracetate to provide the... 

The esters LXXVIII and LXXIX also fail to undergo the Claisen condensation with sodium ethoxide as the catalyst, but do give the reaction if mesitylmagnesium bromide is used.480... 

Other methods of preparing flavone include the action of ethanolic alkali on 2 -acetoxy-a,/3-dibromochalcone 7 Claisen condensation of ethyl o-ethoxybenzoate and acetophenone, and cyclization of the resulting 1,3-diketone with hydriodic acid 8 and treatment of 3-bromoflavanone with potassium hydroxide in ethanol.9 Flavone has also been prepared from ethyl phenyl-propiolate by condensation with sodium phenoxide and subsequent cyclization with phosphorus pentachloride in benzene 10 by fusing o-hydroxyacetophenone with benzoic anhydride and sodium benzoate 11 by the dehydrogenation of 2 -hydroxychal-cone with selenium dioxide 12 and by the action of alkali on flavylium chloride.13... 

Condensation, with sodium cy imdichloracetic acid with sodium ethoxide, 35, 59... 

These compounds are obtained by treating Grignard s reagents with finely powdered selenium, when an addition compound results, which is decomposed by ice and hydrochloric acid and the arylselenomercaptan formed extracted as alkali salt from its ether solution, this salt then being condensed with sodium chloracetate in aqueous alcohol solution, the process being summarised as follows ... 

A Hylic sulfones (cf., 9, 132). In the presence of this Pd(0) complex, allylic acetates condense with sodium p-tolylsulfinate to form allylic sulfones (predominately E). The more substituted isomer is formed initially, but rearranges after extended reaction time to the more stable allylic sulfone.22... 

It can also be obtained when benzyl chloride and trichloroarsane are condensed with sodium (133). 

Diorgano tellurium dihalides condense with sodium or potassium O-alkyl dithiocarbonates in chloroform1 in a mixture of an alcohol, carbon disulfide and tetrahydrofuran1 in methanol, ethanol, or isopropanol2, or in toluene to give diorgano tellurium bis [O-alkyl dithiocarbonates]. 

Cinnamic Acid by Perkin s Reaction.—Cinnamic acid has the constitution assigned to it above as is proven by the following synthesis from benzaldehyde by condensation with sodium acetate in the presence of acetic anhydride. 

Benzaldehyde, ortho-Nitro Cinnamic Acid, ortho-Nitro Phenyl Propiolic Acid.—Later he started with benzaldehyde and obtained first benzal chloride which by condensation with sodium acetate yielded cinnamic acid salt. 

Method of manufacture phenylhydrazine p-sulfonic acid is condensed with sodium ethyl oxalacetate the product obtained from this reaction is then coupled with diazotized sulfanilic acid. 

Condensation catalyst. In the synthesis of trans-stilbene by the phosphonate modification of the Wittig reaction formulated, Seus and Wilson" eifected the terminal condensation with sodium methoxide in dimethylformamide. The reaction... 

A quite similar method is employed in the one-carbon chain extension of a 5 -phosphonate isostere of pyridoxal 5 -phosphate (Scheme 5.50) The a , 3-O-isopropylideneisopyridoxal is converted into an oc,P-unsaturated phosphonate in yields up to 65% by condensation with sodium tetraethyl methylenediphosphonate. Selective hydrolysis with 10% HCOjH at reflux gives the key diethyl 2-(3-hydroxy-4-hydroxymethyl-2-methyl-5-pyridyl)vinylphosphonate intermediate in 98% yield. After catalytic hydrogenation of the double bond using 5% Pd/C in EtOH, a comparison of methods for the oxidation of the alcohol has been made, including use of MnOi in water, CrO, Py, and DMSO-DCC. Finally, oxidation with activated MnO2 in CHCl, was found to proceed smoothly to give the diethyl 2-(4-formyl-3-hydroxy-2-methyl-5-pyridyl)cthylphosphonate. ... 

The nitrosyl chloride adduct of cyclohexene (as the a-chlorooxime) condenses with sodium or potassium cyanide in dimethyl sulfoxide (or ethanol) to yield 3-amino-4,5,6,7-tetrahydroanthranil (185 R = NH2).265-266 Cycli-zation of the oximinothioamide 187 with alkoxide proceeds via loss of SH to give the 3-anilinotetrahydroanthranil (185 R = PhNH). In methanolic hydrogen chloride, however, aniline is eliminated and the unstable 4,5,6,7-tetrahydroanthranil-3-thiol (185 R = SH) is produced in 30% yield.267... 

The racemic laudanosine (7g) syntheses were referred to earlier in The Alkaloids (Vol. XII, p. 348). From the racemic mixture it is difficult to obtain (S)-(+)-laudanosine which is widely distributed in nature. The synthesis of its unnatural (R )-form (in poor yields) has been reported (asymmetric reduction of 3,4-dihydropapaverine with lithium butyl-(hydro)dipinan-3a-y borate) (363). Recently, a description of the biogenetic synthesis of these two forms from methyl-L-(+)-3,4-dihy-droxyphenylalaninate hydrochloride by condensation with sodium 3-(3,4-dimethoxyphenyl)glycinate at pH 4 and 35° was given. Thus, a dia-stereoisomeric mixture of the Pictet-Spengler products 11a and lib (ratio... 

Aniline was diazotized and condensed with sodium arsenite. The benzenearsonic acid, C6H6AsO(OH)2, so prepared was reduced by sulphur dioxide to a derivative of arsenious acid, C6H5.As(OH)2, and the sodium salt of the latter was again condensed by Bart s reaction with benzenediazonium chloride —... 

Ring fission of pyridinium ions with acceptor substituents, e.g. 7V-2,4-dinitrophenylpyridinium salts 221 (see p 280) leads, on treatment with secondary amines, to pentamethine cyanines 222 (Konig s salts). They condense with sodium cyclopentadienide to yield vinylogous aminofulvenes 223, which on cyclization produce azulene (azulene synthesis according to Ziegler and Hafner, see p 229 [73]) ... 

Table IV. Mixed Ester Condensations with Sodium Hydride ...

Modern workers have often chosen sodium hydride and a small amount of alcohol as the catalyst system. It is probable that the effective catalyst is actually the sodium alkoxide formed by reaction of the alcohol released in the condensation with sodium hydride. The sodium alkoxide is also no doubt the active catalyst in reactions... 

In many cases, the carboxyl portion of the amino acid starting material is converted to an aldehyde, allowing several reactions that are not available to carboxylic acids. An example of this approach is the conversion of N-Boc alanine (5.4) to N-Boc alinal (5.5X via conversion to the ester and reduction with lithium borohydride. The next step will be a common feature of this and succeeding chapters. Oxidation of the alcohol moiety in 5.5 to an aldehyde, in this case using S03 pyridine in DMSO, allowed condensation with sodium cyanide to give a cyanohydrin. Hydrol-... 

Perfluoroalkanesulfonyl fluorides, prepared by the electrochemical fluori-nation process, yield fluorinated carboxylic acids via the sulfonamide as the intermediate. The N-substituted perfluorohexanesulfonamide is condensed with sodium monochloroacetate in aqueous isopropyl alcohol [106] ... 

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