Menthol chloroformate

It is significant that under these conditions, with unactivated alcohols, chloro-formates are isolated readily without a trace of the corresponding chloride (—)-menthol chloroformate and sec-butyl chloroformate were prepared in yields of 98% and 78%, respectively. 

There are four basic sensations salty, bitter, sweet, and sour. A combination of efforts is required to mask these tastes. For example, menthol and chloroform act as desensitizing agents a large number of natural and artificial flavors and their combinations are available to mask the bitterness most often found in organic compounds. Most formulators refer the selection of compatible flavors to companies manufacturing these flavors, as they may allow use of their drug master file... 

Enantiomers of carboxylic acids may sometimes be separated by GC as methyl esters, but special derivatives are mostly prepared for this purpose. Ackman et al. [188] resolved enantiomers of isoprenoid fatty acids after their conversion into L-menthyl esters. The acids under analysis were chlorinated by refluxing with distilled freshly prepared thionyl chloride and the chlorides produced were treated with L-menthol in the presence of pyridine under strictly anhydrous conditions. GC separation was carried out in a capillary column coated with butanediol succinate polyester. Annett and Stumpf [189] made use of L-menthyloxycarbonyl derivatives for the separation of enantiomers of methyl esters of hydroxy acids. The derivatization reagent, L-menthyl chloroformate, was prepared by the reaction of L-menthol with phosgene, with cooling with ice. Diastereoisomers of different hydroxy acids were thus separated on 1.5% OV-210. 

The theoretical amount of water is 5.9 mL. TLC analysis was conducted by the checkers on silica gel plates using 50 1 chloroform methanol as eluent and iodine and KMn04 for visualization. Under these conditions, the RfS of the product (KMn04) and menthol (I2) are 0.59 and 0.46, respectively. 

CjHjCljOj Noncombustible solid. Reacts with strong bases, amines, amides, inorganic hydroxides alkalis, alkaline earth metals alkali carbonates ammoniacal silver nitrate strong oxidizers soluble barbiturates producing chloroform and formate. Incompatible with camphor, menthol, or thymol. Contact with hydroxylamine produces poisonous hydrogen cyanide gas. Attacks metals in the presence of moisture. In heat of decomposition or fire, releases hydrogen chloride and other toxic fumes. 

Liquid. Slight odor resembling menthol. Pure Decalin does not smell of naphthalene. Volatile with steam. The commercial product may be practically all tram-Decalin, or a mixture contg up to 60% cis-Decalin. The commercial mixture has a flash pt (closed cup) of about 136 F (58 0. Autoignition temp 504 F. lnsol in water very sol in alcohol, methanol, ether, chloroform. Miscible with propyl and isopropyl alcohol miscible with most ketones and esters. LDM orally in rats 4.2 g/kg. Lethal conen for rats in air 500 ppm, Smyth er al.. Arch. Ind. Hyg Occup. Med. 4, 119 (1951). 

Liquid menthol and valerian odor cooling, faintly bitter taste, d 0 906-0.908. Insol in water freely sol in alcohol, chloroform, ether, oils dec by alkalies ... 

White, odorless Crystals, mp 131-133. Becomes grayish on exposure to air and light. Poisonous d 1.45 bp 309. Sublimes when slowly heated. One gram dissolves in 1.7 ml water, 1.3 ml ale, 1.6 ml ether slightly sol in benzene, chloroform, carbon disulfide. The aq soln darkens on exposure to air, quite rapidly when alkaline. Keep well closed and protected from tight. Incompat. Alkalies, ammonium hydroxide. antipyrine. camphor, phenol, menthol. LDH orally in rabbits 1.6 g/kg (Dollahite). 

White, needle-like crystals sweetish taste. Becomes pink on exposure to tight and air, or by contact with iron, d 1.272. mp 109-111. bp 280°, but volatilizes at lower temp and is slightly volatile with steam. One gram dissolves in 0.9 ml water, 0.2 ml water at 80°, 0.9 ml alcohol freely sol in ether, glycerol slightly sol in chloroform. pH 5.2. Protect from light. Incompat. Acetanilide, albumin, alkalies, antipy -line, camphor, ferric salts, menthol, spirit nitrous ether, nrethan. 

It has been shown by Griesinger and co-workers that it is possible to measure long-range H-C dipolar couplings for the water insoluble compounds in orienting media. The measurements have been performed for menthol dissolved in solution of poly-y-benzyl-glutamate in chloroform. The results have been used to check the usefulness of the method for elucidation of the stereochemistry of the studied compound. 

Synonyms Isovaleric acid p-menth-3-yl ester p-Menthan-3-yl isovalerate Menthol valerate p-Menth-3-yl isovalerate Menthyl isovalerianate Menthyl valerate (1a,2p,5a)-3-Methylbutanoic acid 5-methyl-2-(1-methylethyl) cyclohexyl ester 5-Methyl-2-(1-methylethyl) cyclohexyl 3-methylbutanoate Validol Empirical C15H28O2 Formula (CH3)2CHCH2COOCioHig Properties Colorless llq. mild odor cooling, faintly bitter taste sol. in alcohol, chloroform, ether, and oils insol. in water m.w. 240.39 dens. 0.907 (15.4 C)... 

Gas chromatography Acesulfame-K, aspartame, cyclamate, saccharin, and stevioside are determined by gas chromatography, but the main drawback of this technique is that a derivatization is required. Acesulfame-K is methylated with ethereal diazomethane, aspartame is converted into its N- 2-methylpropoxycarbonyl) methyl ester derivative, menthol and isobutyl chloroformate are used to convert aspartame to 3-[(isobutoxycarbonyl)amino]-4-[[a-(methoxycarbonyl)phenethyl]amino]-4-oxobutyric acid, cyclamate is determined as cyclohexene resulting from the reaction with nitrite, saccharin is converted to N-methylsaccharin, and stevioside is hydrolyzed. Detection is carried out utilizing flame-ionization, flame-photometric electron-capture detectors or nitrogen-phosphorus detection. 

Sec. chlorides. Startg. xanthate (prepared by treating menthol with NaH, CS2, and Mel) in chloroform treated with 1 eq. SO2CI2 in chloroform at 0° for 3 h then at room temp, for 7 h - product. Y 82%. The method is especially useful for preparing hindered chlorides where SOCb is ineffective. F.e.s. A.P. Kozikowski, J. Lee, Tetrahedron Letters 29, 3053-6 (1988). 

Menthyl chloroformate (3.5 g, 0.0016 mol) in EtOAc (10 mL) and NaHCOs (1.35 g, 0.016 mol) in water (15 mL) were simultaneously added from two separate funnels over 20 min into a solution of the ester 27 (1.008 g, 6 mmol) in EtOAc (50 mL) while being cooled in an ice bath and stirred. Stirring was continued for 1 h with cooling and for 12 h at room temperature, keeping the pH above 8. The organic layer was separated, washed with water, dried (Na2S04), and concentrated. The residue was applied to a silica column prepared in hexane. Menthol and dimenthyl carbonate were eluted with 5% EtOAc/hexanes. Elution with 10% EtOAc/hexane yielded 28 and 29 as an oil (2.4 g, 73%). 

Chloroformates 34 of some levorotatory 8-substituted menthols 33 have been prepared with triphosgene in the presence of pyridine [28]. 

Silica gel or cellulose TLC is often used for the determination of pantothenic acid in multivitamin preparations and mixed feeds. Ganshirt and Malzacher (1960) separated pantothenic acid on silica gel G plates with the mobile phase acetic acid-acetone-menthol-benzene (5 5 20 70). Thielemann (1974) used activated commercial silica gel sheets to separate pantothenic acid in multivitamin preparations. Puech et al. (1978) used silica gel GF254 layers to separate calcium pantothenates, pantolactone, and other degradation products of pantothenic acids from pharmaceutical preparations the mobile phase used was chloroform-ethanol-acetic acid (10 7 3). Baczyk and Szczesniak (1975) separated the B-complex vitamins, including pantothenic acid, on cellulose MN300HR layers with -butanol-acetic acid-water (8 1 11) as the mobile phase. 

Unlike the solutions of 1-3, the chloroform solution of 4 emits a green light at 523 nm with a Opp of 2.8%. Because its monomer is a weak emitter when molecu-larly dissolved, the green light observed here thus should be associated witii the backbone emission. We also checked the AIE property of 4 by adding menthol into its chloroform solution. The PL intensity can, however, barely be enhanced even when 90 vol % menthol is added. The reason 4 is AIE inactive may be similar to that... 

In 1962, Inoue et al [140, 141], first succeeded in carrying out an asymmetric selective polymerization of /-propylene oxide (J,/-PO) using dialkylzinc-optically active (+)-borneol or (-)-menthol catalysts with a conversion of 30% (Scheme LVIII) the polymer was found to be optically active, levorotatory in benzene solution and dextrorotatory in chloroform, like the polymer obtained by Price [92] from the purified /-enantiomer monomer. There were no absorption bands corresponding to the original alcohol detected in the IR spectrum and the optical activity of the polymer must, therefore, be attributed to the prevalence of one of the two enantiomeric units. 

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