Naphthyl isocyanate deriv

Recrystallized from dioxan-petroleum ether (b.p. 65-110°). t The 1-naphthyl isocyanate derivative. 

C12-C18 alkyl 10-mole ethoxylates 1 -naphthyl isocyanate derivatives optimization studv and separation by alkyl... 

The reaction of a-naphthyl isocyanate with alcohols has been reported to be a convenient analytical method for the preparation of solid derivatives [16-18]. In addition, the by-product dinaphthylurea is very insoluble in hot ligroin (b.p. 100°-120°C). The urethanes are readily soluble in hot ligroin, and on cooling the solution they recrystallize to sharp-melting solids. It is recommended that two recrystallizations be performed to obtain substances for analysis. Primary alcohols react well without the need for heating the reaction mixture. Secondary alcohols require additional heat, and the yields of urethane oft are smaller than when primary alcohols are used. Tertiary alcohols other than /-butyl [17] or /-amyl [17] were not able to react under the conditions used. Table V lists some representative alcohols and their a-naphthylurethane derivatives. 

Phenols but not polyhydroxybenzenes also react with a-naphthyl isocyanate to give a-naphthylurethanes. In some cases in which solid derivatives were difficult to obtain, the addition of 1 or 2 drops of triethylamine solution in ether... 

Using 9.2 mmoles each of o-cresol and a-naphthyl isocyanate in 3.00 ml of purified ligroin, the effect of catalysts was tested. The sealed tubes were heated in a 65°C bath and after a definite time the solid urethane derivative was isolated, washed, dried, and weighed. The results (see Fig. 1) show that tri-ethylamine is the most effective amine, boron trifluoride etherate being the most effective acid tested at that time [7]. 

Resolution of alcohols (cf., l-(naphthyl)cthyl isocyanate, 8, 356 357). A practical synthesis of the methyl ester of (S)-5-HF,TF. (1) from arachidonic acid involves chromatographic separation of the diastereomeric urethanes preparecT from the Isocyanate derived from dehydroabietylamine (hydrogen chloride and phosgene).1 Urethanes from other chiral amines are less useful. The urethanes are cleaved with triethylamine and trichlorosilanc to give the corresponding pure enantiomeric esters, which can be hydrolyzed by base. 

The 1,3-diazetidine derivatives are most commonly synthesized by the dimerization of heterocumulenes. At elevated temperature they undergo dissociation and are in equilibrium with their monomers. For example, 1,3-diazetidine 108, formed by the reaction of a-naphthyl isocyanate 106 with dicyclohexylcarbodiimide 107, upon thermal dissociation furnished products of its [2+2] cycloreversion reaction, that is, cyclohexyl isocyanate 110 and a-naphthylcyclohexylcarbodiimide 109 (Scheme 10) <1962AGE621>. 

Anilides, toluides, and a-naphthalides ate prepared from phenyl, p-tolyl, and a.-naphthyl isocyanates, respectively, by reaction with a Grignard reagent. The reaction is valuable for the identification of halogen compounds of the type that form organometallic derivatives. The reaction occurs in ether solution at room temperature. In general, the yields of N-arylamides are excellent. This method has been used in the preparation of N-(a.-furyl)-propionamide (89%). ... 

Form Supplied in racemic, (R), and (S) forms all as colorless, neat liquids. Solid derivatives phenyl isocyanate, mp 60 °C a-naphthyl isocyanate, mp 102 °C. 

Dehydration of keto diol ( )-A derived from geraniol furnished furanone ( )-B. Its reduction with sodium borohydride yielded alcohol ( )-C as the major product. Treatment of ( )-C with the isocyanate derived from (/ )-l-(l-naphthyl)ethylamine gave a mixture of carbamates E and F. These were separable by medium-pressure liquid chromatography (MPLC), and E gave (+)-C, while F afforded (—)-C. 

The separation of the positional isomers of acetic and butyric acid-substituted diacylglycerols (palmitoyl and stearoyl) from butteroil was accomplished as their dinitrophenyl isocyanate derivatives on a YMC-Pack 3,5-(/ )-(-l-)-l-(l-naphthyl)-ethylamine column (2 = 226 nm) at 25 C using a 40/10/1 hexane/1,2-dichloro-ethane/ethanol mobile phase [661]. Injections were IO-20ng and elution was complete in <30 min. 

Place 1 g of the anhydrous alcohol or phenol in a round-bottom flask, and add 0.5 mb of phenyl isocyanate or a-naphthyl isocyanate be sure to recap the bottle of isocyanate tightly to minimize exposure of the reagent to atmospheric moisture. If you are preparing the derivative of a phenol, also add 2 or 3 drops of dry pyridine as a catalyst. Affix a drying tube to the flask and warm the reaction mixture... 

In studying the action of phenyl isocyanate on insulin, Hopkins and Wormall (226) observed that the amino nitrogen of the original insulin was several times greater than could be attributed to the lysine. Before they could isolate the unknown amino acid, Jensen and Evans (23) obtained the phenyl carbamido and a-naphthyl carbamido derivatives of phenylalanine from crystalline insulin treated with phenyl and a-naphthyl isocyanates. Jensen and Evans showed that, whereas there were 25 free amino groups per mole insulin before treatment with phenyl isocyanate, there were only 6 afterwards. The most recent amino acid analyses of insulin (20, 382) indicate that there are about 20 phenylalanine and only 6-8 lysine residues. 

Shake 1 g of the dry alcohol with 0 5 g of 1-naphthyl isocyanate in a dry test-tube. Primary alcohols usually react exothermically and the derivative soon separates. Secondary alcohols require gentle heating on an oil-bath (100°) for a few minutes. When heat has to be applied, it is essential that the alcohol and containing vessel be dry, for any water present converts the reagent into di-l-naphthy-lurea, (m.p. 297°). Tertiary alcohols react very slowly and give poor yields due to dehydration of the alcohol. 

Naphthyl)ethyl isocyanate 2 for chromatographic resolution of alcohols, hydroxy esters thiols via diastereomenc derivatives. 

A series of reactions was developed to transfer amines to ureido- and thioureido-derivatives for separation. The reaction of ureido-derivatives is widely used by the reaction with 1-phenylethyl isocyanate (PEIC) [8] or the naphthyl-analogue 1-(1-naphthyl)ethyl isocyanate (NEIC) [9]. Both reactions can be used not only for chiral amines but also for alcohols and thiols. 

Recently, poly(vinyl alcohol)-isocyanate reactions have been run successfully in dimethylsulfoxide solutions by several lab- oratories, including ours. While there are reports of solvent derived products from the reactions of isocyanates in DMSO (60), these reactions do not seem to pose a problem in the reaction with poly(vinyl alcohol). This solvent has been used to react PVA with methoxymethyl isocyanate (61.62) and a series of isocyanates including methyl, ethyl, isopropyl, phenyl and 1-naphthyl (63). This reaction is illustrated in Equation 17 where R is... 

The r-donor phases (typically naphthyl-amino-acid derivatives covalently bonded to silica) require the analyte to contain a r-acceptor group such as the dinitrobenzoyl group. The dinitrobenzoyl group can easily be added to a wide range of compounds such as alcohols, amines and carboxylic acids using dinitrobenzoyl chloride, isocyanate or dinitroanaline, as already mentioned above. 

Polymerisation of w-butyl isocyanate was carried out with the Pruitt-Baggett adduct Re(OR)2Cl [267] at ambient temperature, yielding polyamide, a polymer of the nylon-1 type (Table 9.3) [268]. For more detailed mechanistic studies, -butyl isocyanate was also subjected to polymerisation with a catalyst derived from the reaction of the Pruitt-Baggett adduct with /i-naphthyl-/V-( -butyl) urethane (for the sake of clarity, the catalyst association and internal complexation of the Fe atom by etheral O atoms of the OR substituent are omitted in formulae) ... 

Nonracemic NEA is equally useful in preparing diastereomeric carbamates. Typically, the carbamates are derived from alcohols and (R)-(+)-naphthylethyl isocyanate, which is conveniently prepared from (R)-(+)-NEA (see (R)-1-(1-Naphthyl)ethyl Isocyanate). However, the diastereomeric carbamates may also be... 

The isocyanates (9) were transformed into amino derivatives by standard reactions. Acid-sensitive aminocyclopropanes were obtained preferentially from benzyr ) -naphthyl or trifluorethyl-urethanes which were cleaved by hydrogen, EtSNa/DMF or alkaline hydrolysis. The hydrazinolysis of phthalimido compounds obtained from the urethane and phthalic anhydride also was useful Trimethylsilylethanol proved to be advantageous for the isocyanate-amine conversion the resulting urethanes gave amines upon addition of Bu4N p- 161 (e.g. synthesis of amine (21) from truns-crysanthemic acid via isocyanate (20) S equation 3). Contrarily to... 

End-group analysis of proteins. The reagent is used in the same way that phenyl-isocyanate is used (which see), and has the advantage for spectrophotometric analysis that the naphthyl derivatives have a maximum at 222 mp. of high intensity. ... 

Derivation Synthesized directly from 1-naphthol and methyl isocyanate or from naphthyl chlorofor-mate (1-naphthol and phosgene) plus methylamine. 

Combination of a nonracemic isocyanate and a l,3-disul)sliluted distannoxane has provided a new method for determination of the optical purity of chiral alcohols (Scheme 12.174) [316]. When a chiral alcohol was reacted with commercially available (l )-l-(l-naphthyl)efhyl isocyanate in the presence of 1,3-disubstituted distannoxane, formation of the desired carbamates occurred rapidly, with acid-labile functional groups such as ester, THP and /Miydroxyketone remaining intact. Subsequent HPLC analysis of the resulting carbamate revealed a pair of well-separated peaks of diastereomers derived from both enantiomeric alcohols. 

The dienophilic properties of vinylene carbonate (1,3-dioxol-2-one, 6) have been repeatedly exploited for the synthesis of cyclic polyols. Recently a number of ribofuranose derivatives have been synthesized starting from 6. The known adduct 7, obtained from 6 and furan, was c/r-hydroxylated, and after acetonation was hydrolyzed with base and cleaved with permanganate to give the dicarboxylic acid 8. The corresponding anhydride 9 gave, on treatment with trimethylsilyl azide, the isocyanate 10, which in turn was converted into the carbonate 11 on addition of methanol. The monoester 12, obtained in the reaction of anhydride 9 with isopropanol, was effectively resolved into enantiomers by the use of brucine or (/ )-l-(2-naphthyl)ethylamine. ... 

Simple chiral allenes have been prepared by the reaction of propargylic carbamates with lithium dialkylcuprates. The diastereomeric carbamates, derived from racemic propargylic alcohols and (/ )-1-(l-naphthyl)ethyl isocyanate, are readily separated by h.p.l.c. they are then treated with lithium dialkycuprates at -78 °C, producing the allenes with enantiomeric excess up to 80% in yields of around 70% (Scheme 2). The method is claimed to be an improvement on earlier methods in that it is much simpler and gives better optical yields. 

Isocyanates and thioisocycanates equally harbor cumulated double bonds. As they combine virtually quantitatively with all kinds of organic lithium, sodium, or potassium compounds, they were much appreciated as trapping reagents in the early history of polar organometallic chemistry. Moreover, the products derived from iV-phenyl, yV-naphthyl, or A/-rer/-butyl substituted (thio)isocyanates crystallize extremely well. 

Indirect chiral separation was performed derivatizing metoprolol, oxprenolol, and propranolol with 5-(- -)-benoxaprofen chloride, pindolol with 2,3,4,6-tetra-0-acetyl-/S-D-glucopyranosyl-isothiocyanate and propranolol, alprenolol, pindolol, oxprenolol, and bunitrolol with f -(—)-l-(l-naphthyl)ethyl isocyanate. The formed derivatives were further resolved to antipodes using achiral stationary phases. 

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