Sodium glycolate synthesis

Sodium carboxymethyl cellulose, RceiiO-GHjCOO Na " (CMC), is another common cellulose ether. The degree of substitution (D.S.) that can be obtained for this product usually ranges between D.S. = 0.1 to D.S. = 1.2. As a by-product, sodium glycolate can be formed in the synthesis. Pure CMC is commercially available. Carboxymethyl cellulose in itself is a weak acid that can be precipitated from CMC solutions with a mineral acid. The pH of precipitation varies between 6 for low substitution values to 1 for high substitution (D.S of about 0.9). 

The synthesis works with some excess of NaOH and chloroacetic acid or sodium chloroacetate. The ethoxylation grade of nonionics and the water content influence the conversion and reaction rate. Along with NaCl, a certain amount of sodium glycolate and sodium diglycolate Na00CCH20CH2C00Na is formed. 

The synthesis of the initial compound (277) can be effected in three ways (Scheme 106). The first of them consists in the reduction with alkali metals and alcohol of 2,6-dimethoxynaphthalene (280) [79, 950, 951]. The second method starts from 6-methoxytetralin (275) which, on treatment with lead tetraacetate, gives the acetate (276) which forms compound (274) when acetic acid is split out oxidation of the latter with perbenzoic acid and pyrolysis leads to the desired product (277) [952, 953]. The most suitable method for large amounts proved to be the third method, starting from 6-methoxy-1-tetralone (272), the synthesis of which has been described in Chapter II (Scheme 1). The tosylhydrazone (273) obtained from it, on being heated with sodium glycolate and subsequently distilled in vacuum over potassium bisulfate gives the tetraene (274), which, on oxidation with peracetic acid and treatment of the reaction product with hydrochloric acid forms the ketone (277) [954]. 

Stoddart and his coworkers have reported syntheses of the trans-syn-trans and the trans-anti-trans isomers of dicyclohexano-18-crown-6 The synthesis of these two compounds from trans-l,2-cyclohexanediol was accomplished in two stages. First, the diols were temporarily linked on one side by formation of the formal, and this was treated with diethylene glycol ditosylate and sodium hydride to form the hemi-crown formal. Removal of the formal protecting group, followed by a second cychzation completed the synthesis. The synthesis of the trans-anti-trans compound is illustrated below m Eq (3 12) and the structures of the five possible stereoisomers are shown as structures 1—5. 

Pyrimidines have also served as electrophiles in crown synthesis from this group. 4,6-Dichloropyrimidine reacts with diethylene glycol and sodium hydride in anhydrous xylene solution to form the 20-crown-6 derivative as well as the other products shown in Eq. (3.48). Note that a closely related displacement on sy/rr-trichlorotriazine has been reported by Montanari in the formation of polypode molecules (see Eq. 7.5). 

An example of this is found in the synthesis of a crown containing a mefa-xylylene unit (see also Sect. 3.5) and a convergent methoxyl group. 4-Methyl-2,6-bishydroxymethyl-anisole was treated with pentaethylene glycol and sodium hydride in THF solution to afford the crown (mp 71—73°) shown in Eq. (3.52) in 59% yield. 

For unsubstitUted or lower alkylated dioxotriazines, it is advantageous to cyclize semicarbazones by sodium ethylate in ethylene glycol as described by Chang and XJlbricht. In this reaction 6-aza-uracil is obtained in 66% yield. The procedure was used for the preparation of labeled 6-azauracil ° and later for the synthesis of a number of 6-alkyl derivatives including 6-azathymine. °... 

Of greater versatility is an extension of Albert and Royer s acridine synthesis. The first successful use of this in the quinazoline series was for the removal of the chlorine atom in 2-chloro-4-phenylquin-azoline, although it had been used previously to prepare 8-nitro-6-methoxyquinazoline in very poor yield. The 4-chloroquinazoline is converted to its 4-(A -toluene-p-sulfonylhydrazino) quinazoline hydrochloride derivative which is decomposed with alkali in aqueous ethylene glycol at lOO C (Scheme 13). The yields are high (60-70%) when R is Me, Cl, OMe but low when R is NO2, and in the latter case it is preferable to use dilute sodium carbonate as the base. This reaction is unsatisfactory if the unsubstituted pyrimidine ring is unstable towards alkali, as in 1,3,8-triazanaphthalene where the pyrimi-... 

A slightly more complex anti arrhythmic agent is pi rmentol (74). It is synthesized from 4-chloropropiophenone (72) by keto group protection as the dioxolane (with ethylene glycol and acid) followed by sodium iodide-mediated alkylation with cis 2,6-dimethyl pi peri dine to give 7. Deblocking with acid followed by addition of 2-1ithiopyridine completes the synthesis of pi rmentol (74). 

Scheme 3b). It is instructive at this point to reiterate that the furan nucleus can be used in synthesis as a progenitor for a 1,4-dicarbonyl. Whereas the action of aqueous acid on a furan is known to provide direct access to a 1,4-dicarbonyl compound, exposure of a furan to an alcohol and an acid catalyst should result in the formation of a 1,4-diketal. Indeed, when a solution of intermediate 15 in benzene is treated with excess ethylene glycol, a catalytic amount of / ara-toluenesulfonic acid, and a trace of hydroquinone at reflux, bisethylene ketal 14 is formed in a yield of 71 %. The azeotropic removal of water provides a driving force for the ketalization reaction, and the presence of a trace of hydroquinone suppresses the formation of polymeric material. Through a Finkelstein reaction,14 the action of sodium iodide on primary bromide 14 results in the formation of primary iodide 23, a substance which is then treated, in crude form, with triphenylphosphine to give crystalline phosphonium iodide 24 in a yield of 93 % from 14.

A synthesis of 5-(aioylamino)-2-aryloxazoles 39 is outlined in Scheme 9. Heating the glycol 37 (Bt = benzotriazol-l-yl), prepared from glyoxal and benzotriazole, with an amide in the presence of an ion exchange resin yields the acylated diamine 38, which cyclises by the action of sodium hydiide in DMF <95JHC1651>. 

Any discussion of the prebiotic phosphorylation of nucleosides must take into account the probably neutral or alkaline conditions in a prebiotic environment. Some model phosphorylating systems have been studied, for example, the synthesis of /S-o-ribofuranose 1-phosphate from ribose and inorganic phosphate in the presence of cyanogen. Sodium trimetaphosphate will phosphorylate cw-glycols in good yield under alkaline... 

Synthesis. Bis(2-hydroxyethyl)phosphite was synthesized by adopting the procedures described by Borisov and Troev (6). Briefly, a molar ratio of 4 1 of ethylene glycol (73 mL 1.3 mole) to diethylphosphite (43 mL 0.33 mole) was placed in a round bottom flask equipped with a reflux condenser and a thermometer. A two mL fresh solution of sodium methoxide was added dropwise through a dropping... 

The reason why the acyloin synthesis is especially characteristic of aromatic aldehydes, depends on the circumstance that in the aromatic series the tertiary carbon atom in the ring does not allow of the aldol condensation, a reaction for which conditions are otherwise much more favourable. The simplest example of the acyloin condensation, moreover, was already encountered in the case of formaldehyde (p. 218) glycollic aldehyde is the simplest acyloin. Acyloin compounds are also produced, in the aliphatic series, by the action of sodium or potassium on esters, and hence are also formed as by-products in the acetoacetic ester synthesis (Bouveault, Scheibler). 

Marchand and co-workers ° synthesis of 5,5,9,9-tetranitropentacyclo[5.3.0.0 .0 °.0 ] decane (52) reqnired the dioxime of pentacyclo[5.3.0.0 .0 °.0 ]decane-5,9-dione (49) for the incorporation of the four nitro groups. Synthesis of the diketone precursor (48) was achieved in only five steps from cyclopentanone. Thus, acetal protection of cyclopentanone with ethylene glycol, followed by a-bromination, and dehydrobromination with sodium in methanol, yielded the reactive intermediate (45), which underwent a spontaneous Diels-Alder cycloaddition to give (46). Selective acetal deprotection of (46) was followed by a photo-initiated intramolecular cyclization and final acetal deprotection with aqueous mineral acid to give the diketone (48). Derivatization of the diketone (48) to the corresponding dioxime (49) was followed by conversion of the oxime groups to gem-dinitro functionality using standard literature procedures. 

Coburn also reported the synthesis of BPAF (41), the 3,4-bis-picrylamino derivative of furazan. Thus, reaction of two equivalents of aniline with 1,2-dichloroglyoxime (38) yields the bis-aniline (39), which on treatment with sodium hydroxide in ethylene glycol undergoes cyclization to the furazan (40), and nitration of the latter with concentrated nitric acid at room temperature yields BPAF (41). 

Adolph Wurtz, 1817—1884. Professor of chemistry at the ficole de Medecine in Pans. Discoverer of methyl and ethyl amines and the synthesis of hydrocarbons from alkyl iodides and sodium. He studied the oxidation products of the glycols and the homologs of lactic acid The proof of the elementary nature of gallium was demonstrated in his laboratory by Lecoq de Boisbaudran. 

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