HOBt, 1 -hydroxybenzotriazole

Fig. 6 Commonly used additives and coupling reagents. DCC dicyclohexylcarbodiimide, HOSu A-hydroxysuccinimide, HOBt 1 -hydroxybenzotriazole, HOAt 1 -hydroxy-7-azabenzotriazole...

Scheme 3 Abbreviations EDC, 1-[3-(dimethylamino)propyl]-3-ethyl-carbodiimidejhydrochloride HOBt, 1-hydroxybenzotriazole DEAD, diethyl azodicarboxylate.

FIGURE 4.11 Data showing the effect of the /V -substituent of the activated residue on stereomutation.31 Percentable -d-l-isomer formed in couplings in dimethylformamide at+5°C. Ester.HCl salts neutralized with /V-methyl morpholi ne. MxAn = Mixed anhydride using ClC02iPr with 5-minute activation time at -5°C. DCC = dicyclohexylcarbodiimide, HOBt = 1-hydroxybenzotriazole. 

FIGURE 8.3 Synthesis of amides by aminolysis of unisolated activated esters obtained using carbodiimide by (A) ammonium hydroxide,12 (B) diaminomethane dihydrochloride neutralized with Et3N,15 and (C) the amine of crystalline salts of additives, R = H, Me, Et.13 DCC = dicyclohexylcarbodiimide HOBt = 1-hydroxybenzotriazole HONSu = A-hydroxysuccin-imide HONp = p-nitrophcnol HODhbt = 3-hydroxy-4-oxo-3,4-dihydrobenzotriazine. 

Abbreviations BOP, benzotriazol-l-yloxy-tris(dunethylamino)phosphonium hexafluoro-phosphate DCC, N.N -dicyclohexylcarbodiimide DIC, /V./V -diisopropylcarbodiimide DME, dimethoxyethane DMF, /V./V-dimethyl form amide DIEA, /V-cthyldiisopropyla-mine Et20, diethyl ether HOBt, 1-hydroxybenzotriazole HOSu, iV-hydroxysuccimmide t-BuOMe, tert-butylmethylether TFA, trifluoroacetic acid TIS, triisopropylsilane. 

EDC 1 -Ethyl-3-(3-dimethylaminopropyl)carbodiimide HMDS Hexamethyldisilazane HOBT 1-Hydroxybenzotriazole MS-4 A Molecular sieves 4 A... 

SCHEME 11.4 Convergent concept demonstrated by the Lansbury group. Bn, benzyl cHex, cyclohexyl DIPEA, diisopropylethylamine DMSO, dimethyl sulfoxide DNP, 2,4-dinitrophenyl HBTU, 2-(l//-benzotriazol-l-yl)-l,l,3,3-tetramethyluronium hexafluorophosphate HOBt, 1-hydroxybenzotriazole Ts, tosyl. 

SCHEME 12.20 Total synthesis of starfish ganglioside LLG-3. CAN, ceric ammonium nitrate, DTBMP, 2,6-di-tcrt-butyl-4-methylpyridine, HOBt, 1-hydroxybenzotriazole. 

SCHEME 14.6 Synthesis of muramyl pentapeptide 48 with DAP residue by Boons et al. All, allyl Boc, fert-butoxycarbonyl HOBt, 1-hydroxybenzotriazole. 

Reagents (i), EDCI [l-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide hydrochloride], HOBt (1-hydroxybenzotriazole hydrate), DIPEA (.V,A -diisopropylcthylamine), rt, 18 h. 

Abbreviations used Dde, N-[l-(4,4-dimethyl-2,6-dioxocyclohexadiene)]-ethyl DIEA, diisopropylethylamine DMF, N,N-dimethylformamide EDC, l-Ethyl-3-(3 -dimethylaminopropyl)carbodiimide hydrochloride HOBt, 1-hydroxybenzotriazole NHS, N-hydroxysuccinimide NMP, l-methyl-2-pyrroIidinone PAL, Peptide Amide Linker [5-(4-(9-fluorenylmethyloxycarbonyl) aminomethyl-3,5-dimethoxyphenoxy) valeric acid] PyBOP, Benzotriazole-l-yl-oxy-trispyrrolidino-phosphonium hexafluorophosphate TFA, trifluoroacetic acid. 

Scheme 12.1 Synthesis of ferrocenoyl amino acid esters (4) via the acid chloride and active ester methods (i) PCI5 or SOCI2 (ii) carbodiimide such as DCC (N Ji -dicy clohexy lcarbodiimide) or EDC (1 -ethyl-3-(3-dimethyl-aminopropyl)carbodiimide), HOBt (1-hydroxybenzotriazole) (iii) and (iv) peptide or amino acid and base.

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