Di-t-butyl dicarbonate

The direct high-pressure animation of ethylene with ammonia to give ethylamine occurs in the presence of acidic zeolite catalysts such as H-elinoptilolite, H-erionite or H-offretite38. Primary amines R1NH2(R1 = Bu, cyclohexyl, PhCH2, Ph or Ar) have been monoalkylated by reaction with di-t-butyl dicarbonate, followed by successive treatment of... 

The potassium compound 19 is readily transformed into 20 (R = alkyl) by the action of alkyl halides. The products are converted into salts of alkylamines RNH2 by acidic hydrolysis50. Uses of di-t-butyl imidodicarboxylate (21) have been reviewed46. Treatment of formamide with di-t-butyl dicarbonate 22 gives the unstable formyl compound 23, which yields 21 by the action of 2-diethylaminoethylamine (equation 18)51. 

Very high yields of IV-t-butyloxycarbonylamines are obtained when solutions of hydrochlorides of primary or secondary aliphatic amines in methanol or ethanol are treated with di-t-butyl dicarbonate and ultrasound is applied until carbon dioxide is no longer evolved, e.g. equation 109. PhCH(OH)CHMeNHMe is acylated only at the nitrogen atom under these conditions349. 

In 1996, the tetraphenyl syn-bimane 1 (R = Ph) was obtained in 19% yield when the sodium salt of the 1,3,4-oxadiazinone 2 was treated with di-t-butyl dicarbonate in THF in an attempt to form the 3-Boc derivative. A mechanism was suggested for the conversion of 2 into syn-1 (R = Ph) which involved - ultimately - an intermediate of similar type to that which had been suggested previously for the transformation of 4-chloropyrazolin-5-ones into 1. 

Note. (1) Commercially available, designated as di-t-butyl-dicarbonate. It melts at 20-22 °C and should be stored in a refrigerator. 

One example of such a protecting group is the t-butoxycarbonyl group, also known as the BOC group. The BOC group can be attached to the nitrogen of the amine by reaction with di-t-butyl dicarbonate, which shown in the following equation ... 

The Step 3 product (450 mg) dissolved in 8 ml dioxane and 6 ml water was treated with 2.2 ml 1M NaOH followed by di-t-butyl dicarbonate (1.6 g) of and K2C03 (350 mg), then stirred 7 hours at 40°C. The dioxane was stripped off in vacuo at ambient temperature, the aqueous phase pH lowered to 3 1 with 10% citric acid, and the mixture extracted with 10 ml EtOAc. The organic phase was dried, concentrated, and 490 mg product isolated. The product was used without further purification. 

Bromo-p-phenylenediamine hydrochloride (0.07 mol) and di-t-butyl-dicarbonate (0.15 mol) were dissolved in 250 ml apiece of 2 M NaOH and trifluoromethyltoluene, heated to 45 °C, and stirred 3 days. Thereafter, additional di-t-butyl dicarbonate (0.14 mol) was added, the layers separated, and the aqueous phase extracted with CH2CI2. The combined extracts were evaporated to dryness and the residue mixed with 200 ml hexane. The precipitate was filtered, washed, and the product isolated in 82% yield, mp = 130°C. 

To 4-amino-1-benzylpiperidine (25 g) dissolved in 150 ml chloroform was added di-t-butyl dicarbonate (31.4 g) with ice cooling followed by stirring 2 hours at ambient temperature. The reaction mixture was diluted with chloroform, washed with water, dried, and concentrated. After recrystallizing from hexane/diisopropyl ether, 35.65 g of product was isolated. 

The product from Step 5 (0.096 mmol), di-t-butyl dicarbonate (0.55 mmol) and 4-dimethylaminopyridine (0.016 mmol) were dissolved in 3 ml acetonitrile and stirred 2 hours at ambient temperature. The mixture was concentrated, the residue purified by chromatography on silica gel using hexanes/EtOAc, 2 1 then 1 1, and 0.035 g product isolated. MS data supplied. 

Preparative Methods the commercial glycine Wmethylamide hydrochloride is converted to the racemic imidazolidinone (2) by imine formation with Pivalaldehyde and cyclization under acidic conditions (eq 1). The mandelate salt of like configuration is less soluble and is used for highly efficient resolution subsequent treatment with Boc anhydride (Di-t-butyl Dicarbonate) gives the enantiomeric Boc-BMI (1) (eq 2). 

AMINO GROUP Boron trifluoride ether-ale. l-r-Bulyloxycarbonyltriazole-1,2,4, Di-t-butyl dicarbonate. 4-Dimethylamino-1-t-butyloxycarbonyl pyridinium chloride. CARBONYL GROUP Ceric ammonium nitrate. 1,2-Dihydroxy-3-bromopropane. Sodium N-chloro-p-toluenesulfonamide. Thallium(lll) nitrate. Trichloroethanol. Trimcthylsilyl cyanide. Chloromethyl methyl sulfide. N,N -Diisopropylhydra-zinc. Trichloroethanol. 

Protection of amino groups. Di-t.butyl dicarbonate called (Boc)20 (which is not made from the very unstable t.butyl chloroformate) is well known as the most popular reagent for the preparation of t.Boc protected amines, especially t.Boc-amino acids in peptide chemistry. 

Bis(tert-butoxycarbonyl)oxide CCRIS 2598 Di-t-butyl dicarbonate Di(tert-butyl) carbonate Dicarbonic xid, bis(1,1-dimethylethyl) ester EINECS 246-240-1. Plasticizer, mp = 23 bpo.s - 5557 . Fluka Lancaster Synthesis Co. Sigma-Aldrich Fine Chem. 

Preparation of indole-protected derivatives is usually straightforward, involving reaction of A "-Z or Boc protected carboxyl-tBu, Bzl, or phenacyl Trp ester with di-t-butyl dicarbonate or the appropriate chloroformate or in the presence of a tertiary base (Scheme 26). Subsequent removal of the carboxyl and/or amino groups followed by AT-terminal derivatization yields the Boc or Fmoc derivatives [141,142,147-149]. The formyl group is introduced with excess formic acid [150]. 

The ease with which BOC anhydride (di-t-butyl dicarbonate) can be used to introduce Na-B0C protecting groups has now led to the development of suitable methods for preparing the benzyl analogue, dibenzyl dicarbonate [Z20 ]. It is to be hoped that the compound is... 

F. Houlihan, F. Bouchard, J.M.J. Frechet, and C.G. WiUson, Phase transfer catalysis in the t butyloxycarbonylation of alcohols, phenols, enols and thiols with di t butyl dicarbon Can. 

Protection and Deprotection of Pendent Amino Groups. Scheme V illustrates a method used recently for the preparation of polyphosphazenes with i ndent all lamino groups (76). 2-Aminoethanol was first amino-protected by reaction with di-t-butyl dicarbonate to yield a"BOC"unit. The alcohol function was then converted to the alkoxide salt by treatment with sodium hydride, and this reagent was used for halogen replacement with poly(dichlorophosphazene). Subsequent deprotection of the amino unit then took place following exposure of the polymer to acid. 

PROTECTION OF AMINO GROUPS 2-BenzoyloxymethylbenzoyI chloride. Di-t-butyl-dicarbonate. Diphenylphosphinyl chloride. p-Phcnylbcnzoyl chloride. Phcnyl-[2-p-phenylazophenyDisopropyl]-carbonate. p-Toluenesulfonyl isocyanate. 

For the catalysis by DMAP of the t-butoxylcarbonylation of alcohols, amides, carbamates, NH-pyrroles, etc., see Di-t-butyl Dicarbonate. 

Diethylenetriamine pentaacetic acid (DTPA) 97% purity, ethylenediamine and carbonyldiimidazole were purchased from Aldrich and used as supplied. Acetic anhydride, pyridine, dimethylsulfoxide and dimethylformamide, also from Aldrich, were of Analar purity, and were dried over molecular sieves 3A before use. Dextran (MW 40000), di-t-butyl dicarbonate of 97% purity and Dowex 50Wx8x200 ion exchange resin, were supplied by Sigma. 

Finally, selective N-debenzoylation of taxol has been achieved by reaction with di-t-butyl dicarbonate with 2 -(benzyloxycarbonyl)-7-(triethylsilyl)taxol to give the carbamate 8.7.3, followed by treatment with base and deprotection. Using this chemistry, taxol can be converted to docetaxel in 39% yield, and various N-acyl analogs of taxol can also be prepared through intermediate 8.7.4 (340). 

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