Hydroxybenzotriazole hydrate

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.]... 

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%]. ... 

The following procedure describes the preparation and analysis of the (R)-a-methylbenzylamide of (R)-a-methylbenzenepropanoic add. A flame-dried, 10-mL, round-bottomed flask equipped with a Teflon-coated magnetic stirring bar and a rubber septum is charged with 25 mg (0.15 mmol) of (R)-a-methylbenzenepropanoic acid, 31 mg (0.23 mmol) of 1-hydroxybenzotriazole hydrate, 44 mg (0.23 mmol) of 1-(3-dimethylamino)propyl-3-ethylcarbodiimide hydrochloride, and 0.50 mL of anhydrous N,N-dimethylformamide. This mixture is stirred at 23°C for 10 min, then cooled to 0°C in an ice-water bath. To the cooled solution, 24 pL (0.19 mmol) of R-(+)-a-methylbenzylamine and 86 pL (0.62 mmol) of triethylamine are added. Within 1 min, a fine white precipitate appears. The mixture is stirred for 1 hr at 0°C, then warmed to 23°C. After stirring for 20 hr at 23°C, the mixture is transferred to a 30-mL separatory funnel with 10 mL of dichloromethane. The product solution is extracted, sequentially, with four 10-mL portions of 1 N aqueous hydrochloric acid solution, 10 mL of saturated... 

Phenylbutyl phosphinic acid 2-Ethylhexanoic acid, sodium salt 1-Chloroisobutyl propionate Ammonium n-butyl sulfate Hydroxybenzotriazole hydrate N,N -Dicyclohexylcarbodiimide... 

A slurry of methyl-l-(l-oxopropoxy)propoxy](4-phenylbutyl)phosphinyl]acetic acid (B-isomer), dried in vacuo at room temperature for 72 hours, (230.4 g, 0.6 moles) and hydroxybenzotriazole hydrate, dried, in vacuo at 80°C for 24 hours, (101.1 g, 0.66 mole) dichloromethane (sieved dried) (6 L) was chilled in an ice/acetone bath and treated with N,N-dicyclohexylcarbodiimide (136 g, 0.66 mole). The mixture was warmed to room temperature and stirred for 3 hours. The mixture was then chilled in ice/acetone and treated with (trans)-4-cyclohexyl-L-proline, hydrochloride (154.2 g, 0.66 mole) followed by diisopropylethylamine (170.7 g, 1.32 mole). The reaction mixture was stirred at room temperature for 18 hours. The mixture was then chilled, treated with water (1 L) and concentrated in vacuo to remove dichloromethane. The residue was diluted with ether (3600 ml) and water (3600 ml) and filtered. 

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

A mixture of the Step 5 product (1.15 mmol) and Fmoc-Val-OH (1.28 mmol) dissolved in 30 ml CH2C12 was treated with 1-hydroxybenzotriazole hydrate (1.76mmol) followed by 4-methyl-morpholine (1.7mmol) and l-(3-dimethylaminopropyl)-3-ethylcarbodiimide HC1 (1.41 mmol), then stirred 16 hours at ambient temperature. The mixture was diluted with EtOAc and washed once with saturated NH4C1 solution, saturated NaHC03, and once with brine, then dried, and concentrated. The residue was purified by flash chromatography using 35% EtOAc/hexanes and the product isolated in 91% yield as a white solid. 

A solution of the Step 7 product (0.16 mmol) and 1-hydroxybenzotriazole hydrate (0.16 mmol) in CH2C12 was cooled to 0°C, then stirred 30 minutes, and treated sequentially with pyrrolidine (0.16 mmol), 3-ethyl-3 -(dimethylamino)propyl-carbodiimide hydrochloride (0.16 mmol), and 60 pi triethylamine. Stirring was continued for additional 30 minutes at 0°C and 2 days at ambient temperature. The mixture was then partitioned between 1.5 ml water and 20 ml EtOAc and combined organic extracts washed with 1.5 ml brine, dried with Na2S04, and concentrated. 

The resin was washed with NMP (5x1 mL), and then coupled with the active ester of A-Fmoc-L-Glu( Bu)-OH, which was freshly prepared in a separate vessel by mixing 65 mg (0.15 mmol) A-Fmoc-L-Glu( Bu)-OH, 21 mg (0.15 mmol) 1-hydroxybenzotriazole hydrate (HOBt), 24 pL (0.15 mmol) A,A-diisoproplcarbo-diimide (DIPCDI) in 1 mL NMP at room temperature for 20 min, and then adding to the resin. Agitation (by gentle rocking motion) was continued for 2 h, then the reaction solution was removed by filtration and the resin was washed with NMP (5 X 1 mL). 

Beilstein Handbook Reference) Benzazimidol hydrate IH-Benzotriazole, 1-hydroxy- IH-Benzotriazole, 1-hydroxy-, hydrate BRN 0004515 CCRIS 2605 EINECS 219-989-7 HOBt 1-Hydroxybenzotriazole l-Hydroxybenzotriazole hydrate 1-Hydroxy-IH-benzotriazole hydrate N-Hydroxy-benzotriazole hydrate. Widely used additive to decrease racemization during dicyclohexylcarbodiimide-catalyzed peptide coupling. Crystals mp = 157-158°, Janssen Chimica Lancaster Syrrthesis Co. Sigma-Aldrich Fine Chem. 

Hydroxybenzopyridine. See 8-Hydroxyquinoline 1 -Hydroxybenzotri azole CAS 2592-95-2 EINECS/ELINCS 219-989-7 Synonyms Benzazimidol hydrate 1H-Benzotriazole, 1-hydroxy-, hydrate 1-Hydroxy-1H-benzotriazole hydrate N-Hydroxybenzotriazole hydrate Classification Aromatic heterocyclic Empirical CeHsNsO H2O Properties M.w. 135.14 m.p. 156-158 C Toxicology LDLo (oral, rat) 5 g/kg low toxicity by ing. primary eye irritant TSCA listed Precaution Potentially explosive (heated above 160 C)... 

Hydroxy-1 H-benzotriazole hydrate N-Hydroxybenzotriazole hydrate. See 1-Hydroxybenzotriazole... 

Abbreviations CDMT = 2-chloro-4,6-dimethoxy-l,3,5-triazine EDCI = l-ethyl-3-(3-dimethyla-minopropyl)carbodiimide BOP = benzotriazol-l-yloxy-tris-(dimethylamino)phosphonium hexa-fluorophosphate DIPEA = diisopropylethylamine DEPC = diethylphosphoryl cyanide CBM IT = l,l-carbonylbis(3-methylimidazolium triflate HOBt = 1-hydroxybenzotriazole hydrate HBPyU = 0-(benzotriazole-l-yl)-iV,Af,A,Af-bis(tetramethylene)uronium hexafluorophosphate. 

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