Ferf-butoxycarbonyl

BOC (f-BOC) ferf-butoxycarbonyl LHMDS lithium bis(trimethylsilyl)amide... 

This category is exemplified, albeit poorly, in the reaction of 3-methyl-1,2-benzenediamine (405) with tri-ferf-butyl 2-hydroxy-3-oxo-l,2,5-pyrrolidinetricar-boxylate (406) in aqueous ethanolic sodium hydrogen carbonate under reflux for 3 h. This gave, as minor products, an inseparable mixture (in 9% yield) of tert-butyl 3-[2-(ferf-butoxycarbonyl)-2-(ferf-butoxycarbonylamino)ethyl]-5-methyl-2-quinoxalmecarboxylate (407, Q = Me, R = H) and its 8-methyl isomer (407, Q = H, R = Me). ... 

In SPPS, there are two main protecting groups commonly used for Ai -protection [3] ferf-butoxycarbonyl (Boc) [7] and 9-fluorenylmethoxycarbonyl (Fmoc) [8] (Fig. 2). 

FIGURE 3.17 Reagents for protection of amino groups as the ferf-butoxycarbonyl derivatives. terf-Butyl chloroformate is rarely used because of its low boiling point. The oxime is 2-ferf-butoxycarbonyloximino-2-phenylacetonitrile,45 Boc20 = di-ferf-butyl dicarbonate, or di-terf-butyl pyrocarbonate.46 (Tarbell et al., 1972 Pozdvev, 1974). Acylations are carried out at pH 9 to avoid dimerization. 

N Itoh, D Hagiwara, T Kamiya. A new ferf-butoxycarbonylating reagent, 2-ferf-butyl oxycarbonyloxyimino-2-phenylacetonitrile. Tetrahedron Lett 4393, 1975. 

R Schwyzer, B Rittel. Synthesis of intermediates for a corticotropic nonadecapeptide. I. A, -ferf-Butoxycarbonyl-L-lysine, A a(M-/c rt-biitoxycarbonyl-i,-lysyl)-/Vr-/< rt-butoxycarbonyl-L-lysine, M-tert-butoxycarbonyl-L-lysyl-i.-prolyl-i.-valylglycine and derivatives. Helv Chim Acta 44, 159, 1961. 

AR Mitchell, SBH Kent, IC Chu, RB Merrifield. Quantitative determination of d-and L-amino acids by reaction with ferf-butoxycarbonyl-L-leucine A-hydroxysuccin-imide ester and chomatographic separation as d,l and l,l dipeptides. Anal Chern 50, 637, 1978. 

When the ferf-butoxycarbonyl (Boc) carbamate-derived sulfone 5 was subjected to the Bi(OTf)34H20-catalyzed allylation conditions (Scheme 2), the cyclic carbamate 6 was obtained as the major product (36%, diastereoisomeric ratio (dr) = 82 18), along with the corresponding allylation product 7, although in low yield (16%). Such cyclic carbamate resulting from the internal capture of an intermediate (3-silyl cation with the Boc group and concomitant loss of isobutylene has already been reported in the literature [59]. 

Treatment of 4-methoxy-2-oxazolidinone 86 with indolylmagnesium bromide 87, followed by A-protection with a ferf-butoxycarbonyl (Boc) group affords NJd -di-Boc-4-(3-indolyl)-2-oxazolidinone 88. Subsequent treatment with A-bromosuc-cinimide (NBS) in the presence of azobisisobutyronitrile (AIBN) followed by electrochemical reduction yields the protected 4-(3-indolyl)-2(3//)-oxazolone 90 (Fig. 5.23). The Boc groups are easily removed by pyrolysis."" "" ... 

The ene-reaction, which is mechanistically related to the Diels-Alder reaction, has also been reported. The thermal addition of 3-ferf-butoxycarbonyl-2(3//)-oxazolone 236 to 2,2 -biindole 235 affords 4-(2,2 -biindol-3-yl)-2-oxazolidinone 237, probably via the indoline derivative. The product is further converted to the fused aromatic compound 238 by bromination with NBS and AIBN, followed by dehydrobromination (Fig. 5.58). ... 

V"-(Fluoren-9-ylniethoxycarbonyl)-V7 -(ferf-butoxycarbonyl)-5-0-[6-0-(ferf-butyldiphenylsilyl)-3,4-0-... 

The identical chemistry can be applied to the preparation of enantiopure co-hydroxy amino acids by reaction of the (25)-2-[bis(ferf-butoxycarbonyl)amino]-5-oxopentanoate with co-trityloxyalkylidene triphenylphosphoranes. After hydrogenation of the double bond, the... 

Diethyl (i S)-2-[(4i )-3-(ferf-Butoxycarbonyl)-2,2-dimethyloxazolidin-4-yl]-l,l-difluoro-2-hydroxy-ethvlphosphonatef109 ... 

Other reagents which have been found useful for the synthesis of t-BOC derivatives include the hazardous ferf-butoxycarbonyl azide... 

Allyl (i )-jV-(ferf-Butoxycarbonyl)(3,5-diisopropoxy-4-methoxyphenyl)glycinate (45) [81)... 

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