1 -Hydroxybenzotriazol

Hydroxybenzotriazole hydrate (HOBt) [2592-95-2] M 135.1, m 159-160 . Crystd from aqueous EtOH or water. [Dryland and Sheppard J Chem Soc Perkin Trans 1 125 1986.]... 

There was never any doubt that the major tautomer in the case of in-dazole 27 is the IH-one 27a (Scheme 16), and C chemical shifts compared with those of the two V-methyl derivatives confirmed that this is the case in DMSO-dg (770MR716). NMR has been used to determine the equilibrium isomeric composition of N-CHROH, N-C(CH3)20H, N-COCH3 and N-Si(CH3)3 derivatives for azoles and benzazoles, the conclu-sipn being that this composition parallels the annular tautomeric composition [78JCS(P2)99]. The tautomerism of 1-hydroxybenzotriazole was also studied... 

A side chain carboxyl group in perhydropyrido[l,2-a]pyrazines was obtained from an ester group by acidic or alkalic hydrolysis. A side chain carboxyl group was converted into a carboxamide group by the treatment with an amine in the presence of 1-hydroxybenzotriazole (OOJAP(K)OO/ 86659). 

Saponification next frees the carboxy group for condensation with -butyl 7-aminocephalosporinate mediated by dicyclohexyl-carbodiimide and 1-hydroxybenzotriazole. The synthesis is... 

Dimethoxy-6-quinoxalinamine (125, R = H) gave 6-lauramido-2,3-dimethoxy-quinoxaline [6-dodecanoylamino-2,3-dimethoxyquinoxalme 125, R = Me-(CH2)ioCO] [Me(CH2)ioC02H, (C6HnN=)2C, 1-hydroxybenzotriazole hydrate, no further details 87%]. ... 

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

Hydroxybenzotriazole is also useful in conjunction with DCCI.138 For example, Boc-protected leucine and the methyl ester of phenylalanine can be coupled in 88% yield with these reagents. 

At the present time, the coupling is usually done via an activated ester (see Section 3.4). The coupling reagent and one of several A-hydroxy heterocycles are first allowed to react to form the activated ester, followed by coupling with the depro-tected amino group. The most frequently used compounds are A-hydroxysuccinimide, 1-hydroxybenzotriazole (HOBt), and l-hydroxy-7-azabenzotriazole (HOAt).47... 

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

For the coupling of a supported peptide fragment with an N-protected amino acid (or a peptide), CDI and 1-hydroxybenzotriazole (HOBt) were used.[35]... 

Another solid phase fragment condensation with CDI and 1-hydroxybenzotriazole in the synthesis of the human insulin B-chain afforded the oligopeptide in 75% yield. The reaction time with the coupling pair CDI/HOBt was shorter than in the case of the DCC/ HOBt system.136 The CDI/HOBt activation method was also applied to the synthesis of a... 

Reported redox potentials of laccases are lower than those of non-phenolic compounds, and therefore these enzymes cannot oxidize such substances [7]. However, it has been shown that in the presence of small molecules capable to act as electron transfer mediators, laccases are also able to oxidize non-phenolic structures [68, 69]. As part of their metabolism, WRF can produce several metabolites that play this role of laccase mediators. They include compounds such as /V-hvdi oxvacetan i I ide (NHA), /V-(4-cyanophenyl)acetohydroxamic acid (NCPA), 3-hydroxyanthranilate, syringaldehyde, 2,2 -azino-bis(3-ethylben-zothiazoline-6-sulfonic acid) (ABTS), 2,6-dimethoxyphenol (DMP), violuric acid, 1-hydroxybenzotriazole (HBT), 2,2,6,6-tetramethylpipperidin-iV-oxide radical and acetovanillone, and by expanding the range of compounds that can be oxidized, their presence enhances the degradation of pollutants [3]. 

Half maximal effective concentration 17a-Ethinyl estradiol Fluidized bed reactor 1 -Hydroxybenzotriazole High performance liquid chromatography Hydraulic retention time... 

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